Iran Platin is the premier source for ELECTRICAL CONTACTS...whether CONTACT RIVETS, WELDED CONTACTS OR FURNANCE BRAZING CONTACTS. Iran Platin's manufacturing capabilities include making CONTACT ASSEMBLIES .Iran Platin during the stamping operation for STAKED RIVET CONTACT ASSEMBLIES and WELDED WIRE CONTACT and TAPE ASSEMBLIES. Iran Platin uses over 500 PRECIOUS METAL MATERIALS including silver, gold, platinum, palladium alloys and many uncommon base metal alloys. SILVER TIN OXIDE has grown to a major alloy in recent years for automotive switches and electromechanical wires.
Iran Platin is a leader in producing rivet and welded contacts and assemblies using silver tin oxide and silver cadmium oxide contacts.

Contact Design

Developing the best contact solution for a specific application is complex because so many factors (and their interrelationships) must be considered. Therefore, it is necessary to study:
1. electrical design factors
2. mechanical design factors
3. environmental design factors
4. economic factors.

One must also consider the following factors as they may relate to the application:

1. welding or sticking of contacts
2. excessive resistance
3. contact transfer
4. contact erosion.

Iran Platin engineers are constantly designing contacts of every size, shape and description. Many types of highly specialized equipment and processes are utilized by Iran Platin to ensure that contacts of the specified quality are economically produced utilizing the optimal manufacturing method for the particular application. We will be glad to assist in designing and manufacturing the contact solution for a specific need. Sampling or prototyping is also available.
Simply put, the function of an electrical contact is to make and break an electrical circuit. In this broad spectrum, circuits may be handling currents ranging from microamps to hundreds of amperes. There is no universal contact construction or all-purpose contact material. Over the years, a great number of contact materials and alloys have been formulated to better meet the electrical and performance requirements of specific applications.
Before discussing the many possible combinations of precious and base metal alloys, consider the factors that influence contact performance and life.

Four Factors Which Affect Contact Life

1. Welding or sticking may be caused by:
 

2. Excessive resistance is the sum of the resistance of:
 

a. contact material resistance - this can be defined as the specific resistance of a  given material. b. constriction resistance - this is the resistance at the interface where the contacts touch. It is caused by crowding current through a very small area and is a significant amount of the total contact resistance. c. film resistance - this is the result of resistance caused by non-conducting or semi conducting particles between the contacts. These films or particles can be chemical and/or mechanical. Chemical films are caused by oxidation, corrosion or surface reaction to foreign materials. Mechanical films are the result of dust, oil and other foreign particles. Contact failure may be said to occur when the closed resistance is too high or the open resistance is too low.

3. Contact transfer
 

is the term employed when the contact material moves from one contact to another. In A.C. circuits this does not have a general direction unless there is an imbalance of contact temperatures. In this case, the material moves to the cooler contact. Contacts working in synchronism with line frequency will transfer, since they always break at the same point on the waveform. This, in effect, is the same as breaking a D.C. circuit. In a D.C. circuit, material may transfer in one of the following ways: to the negative contacts, commonly called bridge transfer. Bridge transfer is caused by operating below minimum arc voltage or current values for a given material. to the positive contact, usually termed arc transfer. Arc transfer is caused by operating above minimum arc voltage and current values.

4. Contact erosion                                                     
 

can be either electrical or mechanical. Mechanical wear in straight butt type operations is of little concern, but in wiping or rotary action it is a major problem. Mechanical design factors are covered more fully in Contacts Selection. The primary source of contact erosion is the arc. The energy in the arc heats the contact surface to the boiling point and causes material loss by vaporization. This loss of material directly relates to contact life and can have an effect on the dielectric strength of the surrounding mechanisms. The characteristics of arc erosion vary between different materials, but the rate of arc erosion for a given material is proportional to the circuit current and the frequency and number of operations.

Contact Selection

In addition to contact life, the following factors must be considered during contact selection.

Four Factors Governing Contact Selection

1. Electrical design factors - the electrical characteristics of the circuit in which the contact must perform are of prime importance in contact selection. Following are four important electrical considerations:
 

a. electrical current - as the major component of electrical energy, current affects all factors involved in contact performance. A high percentage of the energy dissipated at the contact is in the form of heat generated by constrictive resistance. Normally, contact temperature rises during operation until it reaches a point of equilibrium between radiation and conduction losses and heat input of resistance and the arc energy. Arc erosion, welding and sticking all occur in direct proportion to the contact current. b. voltage -circuit operating voltages are important in contact selection. All materials possess a characteristic arcing voltage in the 10-20 volt range. If the maximum voltage is below this range, arcing will not occur. Above this voltage, arcing and subsequent material loss must be expected. c. load - the type of load will have a direct bearing on contact performance. Here are the common types of electrical loads: resistance - a straight resistive load is very predictive and behaves consistently. inductive - An inductive load complicates the problem on contact break as it releases a considerable amount of energy. capacitive - A capacitive load creates a problem because of a high current inrush. motor - A motor load, while basically inductive, has a heavy staring current inrush. lamp - A lamp load, with a high current inrush, requires contacts of sufficient ability to handle the electrical load. d. contact protection - arc suppressers such as condensers, capacitors and blowout coils can reduce arcing at the contact points, thus offering longer life. Care must be exercised in selecting the type of suppresser. The best protective circuit is most often determined by actual test. d. contact protection - arc suppressers such as condensers, capacitors and blowout coils can reduce arcing at the contact points, thus offering longer life. Care must be exercised in selecting the type of suppresser. The best protective circuit is most often determined by actual test.

2. Mechanical design factors The following mechanical factors also affect contact selection:
 

a. force - The mechanical forces that close a pair of contacts play a vital role in the selection of contact material. The force employed on the make should be the maximum the material will withstand without excessive wear or deformation. To achieve stable conditions, the minimum contact force is:         METAL                                                    GRAM PRESSURE         Gold                                                        1-5         Platinum                                                 10-50         Gold Plate                                               5-50         High Percentage Silver Alloys                20-250         Tungsten                                                100         Base metals                                           1000 b. frequency of operation - the number of make and break operations in a given time will greatly affect the life of a contact. An accepted classification of frequency is as follows: low frequency - up to 1/min. intermediate frequency - 1/min. to 10/sec. high frequency - more than 10/sec. Problems encountered in low frequency operations are oxidation or film formation during idle time.In high frequency operations, the design must allow for high temperatures and heat dissipation. c. speed of operation - the speed of closing or opening a pair of contacts is important in both A.C. and D.C. operations. In D.C. operations, the snap action is most advantageous in both make and break. In A.C. applications, a fast make and a slow break result in the least arc damage. d. bounce or chatter - closing and opening contacts more than once per designed cycle will reduce contact life. In these cases, it normally requires some change in the spring material or contact mass to obtain a firm make and break. e. gap - the contact gap or space between the contacts in their open position must be sufficient to prevent continued arcing. This is particularly true in inductive loads with high counter EMF. f. wipe (over-travel) - depending on the application, a certain amount of wipe can be advantageous or undesirable. Wipe or sliding will break down some films and can increase the contact area. In D.C. circuits this can be a detriment due to material transfer and the resulting possibility of mechanical hang-up between the peak and crater.

3. Environmental design factors
- as stated in the factors which affect contact life, film resistance caused by the environment can have an adverse affect on the operation and life of a contact. These environmental factors include the following:
 

a. gases and fumes - sulfur fumes are primarily responsible for the tarnishing (silver sulfide) formation on contacts. This film will increase resistance and has been known to cause open circuits. Hydrocarbon fumes will have an adverse effect on the platinum alloys. Another source of fumes is the organic material used in the device (plastics), which on out gazing, can produce harmful films. To combat these problems, devices can employ gold flashing or plating. b. foreign materials - such contaminants as dirt, dust, lint, grit and loose metallic particles, as well as lubricant silicone (which breaks down to silicon dioxide and silica) can greatly increase arcing between contacts or cause excessive temperature rise through their inadvertent intrusion. Should enough particles lodge in the contact area, an open circuit will result. This can be alleviated somewhat by mounting the contacts vertically or designing a point or projection in the face. c. temperature and humidity - contact materials employed in high temperature application must be able to withstand abnormal oxidation and chemical reactions. High humidity will promote or increase corrosion and oxidation.

4. Economic factors
- Because contact materials are precious or rare metals, they are expensive.
Depending on the material used and the size of the contact, cost can vary from less than a cent to several dollars each. On all devices, the prime requisite is that the contacts operate dependably for their designed life. In some sophisticated devices, this cost may be immaterial In other applications, it may represent a major portion of the total cost.

Contact Materials

Gold and Gold Alloys
Platinum and Palladium Alloys
Silver and Silver Alloys
Fine Silver
Silver Copper Alloys
Silver Cadmium Alloys
Silver Platinum & Palladium Alloys Age-Hardenable Materials
Silver Semi-Refractory Materials Silver Tin Oxide Alloys
Silver Refractory Materials
Refractory Material-Tungsten
Contact Plating
Base Metals
Properties of Elements Used in Contact Applications
Contact Material Applications
 

Electrical contacts date back to the early 1800's when electrical researchers working in their laboratories noted that improper connections or poor contact caused irregularities in their experiments. At that time and throughout the latter part of the 19th century, copper and carbon were the most widely used contact materials. After the discovery of the electron in 1896, more and more research was undertaken to develop better contact materials for the ever-increasing demand and supply of electrical devices. The trite but true statement that there is no one universal contact material is substantiated by the sheer number of contact materials in use today. The requisites of an optimum contact material vary within the parameters of each particular application, but basically the contact material should exhibit high electrical and thermal conductivity and must be able to resist film formations. Depending on the application, additional attributes such as hardness, resistance to arching, reduced transfer and are of major importance. Contact materials fall into 5 distinct groups. Each of these groups has its own characteristics and associated advantages and disadvantages. Knowing the conditions that will be imposed on the contact and relating these to the characteristics of each group will simplify material selection.

Platinum and Gold Alloys

This group of materials is the most noble and resist film formations in most atmospheres. Because of this attribute, these materials find wide use in the low-current, high reliability applications. Because of their relatively low conductivity (compared to silver), they are limited to low current applications. The cost of these material is high, but the physical size is normally quite small.

Silver and Silver Alloys

This group of materials exhibits the highest conductivity, both electrical and thermal. There is an overlapping between this group and the Platinum Gold group in current range. Being better conductors, this group is capable of carrying higher currents. The main advantages here are relatively low cost materials capable of handling most light and medium current applications.
 

Contact Materials

Silver Semi-Refractories

The Silver semi-refractory materials are silver-rich dispersed phase materials that are capable of handling current loads higher than most silver alloys. They retain the high conductivity of silver and combine the attribute of less weldable or erodable materials. Their cost is generally less than the true silver refractory materials.

Silver Refractory Materials

While the silver semi-refractory materials are high in silver content, the silver refractory materials are high in refractory content. This group is unsurpassed in high-current, high-voltage applications. Since they are largely tungsten or tungsten carbide, they resist electrical erosion, yet retain good conductivity. Because these materials are made through powder metallurgy, their cost is somewhat higher than the semi-refractory materials.
 

Contact Materials

Tungsten

Tungsten is a true refractory materials. Its main advantages are a very high melting point and high hardness. This disadvantages are a limited current range and the requirement of high contact pressures. This chart below indicates the normal current range each group can handle.

Gold and Gold Alloys

IPC 200 (24 Karat Gold) is unsurpassed in resistance to oxidation and sulfidation. It will form a polymer but is much less likely to do so than the platinum materials. Gold is relatively soft and, because of a low melting point, is susceptible to erosion. For this reason, gold is limited to application less than one-half ampere. Typical applications for IPC 200 and the other gold alloys are the low level, high reliability situations in sensitive relays in sound circuits. Gold has worked well where contact forces are in the very low five to ten gram range.

To improve the hardness of gold, it is alloyed with silver, platinum and nickel. Increasing hardness generally leads to a corresponding decrease in conductivity. This is normally of little consequence in low level operations because contact problems in this area are surface related as opposed to bulk material relationships in the higher amperage range.

IPC-41 (69% gold, 25% silver, 6% platinum) is a well known gold alloy, and is used widely in telephone relay applications.

IPC-43 (72% gold, 26.2% silver, 1.8% nickel) retains enough gold to give good protection against sulfiding.

IPC-44 (75% gold, 25% silver) and IPC-47 (50% gold, 50% silver) are gold silver alloys which show improved strength.

IPC-337 (72.5% gold, 14% copper, 8.5% platinum, 4% silver, 1% zinc) is an alloy that can be age hardened to provide it with excellent spring properties, thus making it ideal for use in microstampings. This heat-treat process endows the alloy with high tensile strength, high hardeness and resistance to wear.

If low contact surface resistance is to be retained, gold content should not be lower than 65% to 70%. IPC-47, with 50% gold, will not be so noble as the other alloys listed, but does offer a lower cost gold material that will perform better than other basically silver alloys.
 

Contact Materials

Platinum & Palladium Alloys

The platinum family (platinum, palladium, ruthenium, iridium, osmium and rhodium) is one of the most important to the contact user. These materials and their alloys display exceptional qualities as they have high corrosion resistance, high resistance to arc erosion and a high melting point. The alloys of this family are very hard. Hence, they have good mechanical wear ability. When used in the proper applications, the platinum metals provide years of successful operation, but they have their limits. Due to fairly low conductivity, these materials are limited to light current applications, usually under five amperes. Another consideration is their cost which is relatively high in comparison with silver base materials. To secure a reasonable cost relationship, these materials are normally furnished as composite contacts with a nickel-plated backing. Some platinum materials, because of their lack of ductility, must be supplied as composites.

IPC-202 (99.9% minimum platinum) has excellent properties and is one of the most noble contact materials. It is used in high reliability, low force, low current level applications. It can be supplied in all conventional contact shapes.

Platinum is relatively soft. Dramatic gains in hardness can be achieved by the addition of iridium. IranPlatin materials IPC-213 (95% platinum, 5% iridium), IPC-205 (90% platinum, 10% iridium), IPC-214 (85% platinum, 15% iridium) and IPC-260 (80% platinum, 20% iridium) clearly demonstrate this gain. In addition to the gain in hardness, other benefits include higher melting temperature and greater resistance to transfer.

IPC-213 and IPC-205 are head able , but IPC-214 and IPC-260 must be used as composites. Again, these alloys are used in low current applications where the contact user desires greater mechanical wear ability .

Another platinum alloy group is arrived at by the addition of ruthenium. IPC-201 (95% platinum, 5% ruthenium) and IPC-227 (89% platinum, 11% ruthenium) are typical. Here, too there is a great increase in material hardness. Ruthenium achieves the same increase in hardness at twice the rate of iridium and, being a less expensive material, this group of materials will be somewhat more economical. The characteristics of the platinum ruthenium materials are the same as platinum iridium, and the end uses are also the same. IPC-201 is head able ; IPC-227 is not.

IPC-100 (99.9% minimum palladium) can, in certain applications, replace IPC-202 (99.9%) minimum platinum). Since at the present time palladium costs much less than platinum, it finds wide application in low current level operations. Typical of these are telephone relays and sensitive gages. IPC-100 is ductile, and is available in all the contact forms.

There are several palladium ruthenium alloys. IPC-208 (95% palladium, 5% ruthenium) and IPC-102 (90% palladium, 10% ruthenium) are typical of these. As with the platinum alloys, the addition of ruthenium increases the hardness of palladium. These alloys are resistant to tarnishing, and, of course, are much less costly than platinum ruthenium materials. Palladium ruthenium alloys are often used instead of IPC-100 when the application requires more resistance to wear.

IPC-262 (72% palladium, 26% silver, 2% nickel) exhibits excellent hardness, is more economical than most palladium alloys, and still retains the ability to resist sulphide tarnishing. This material is used in low current A.C. and D.C. applications. It is headable within a reasonable design range.*

IPC-30 (60% palladium, 40% silver) is an alloy containing the maximum amount of silver that will retain protection from silver sulphide tarnish. It is used in low current applications, and provides a cost saving over the higher percentage platinums and palladiums. As with IPC-262, it is headable within a limited range.

Properties Of Platinum, Palladium and Their Alloys 

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS	Melting Point F
IPC-202	99.9 min Pt	11.30	60 - 75	20 - 35	15	3215
IPC-213	95 Pt, 5 Ir	11.33	71 - 86	40 -70	9	3220
IPC-205	90 Pt, 10 Ir	11.34	87 - 92	5 - 90	7	3250
IPC-214	85 Pt, 15 Ir	11.36	90  - 95	75 - 120	6	3270
IPC-260	80 Pt, 20 Ir	11.40	93 - 97	100 - 145	5	3299
IPC-201	95 Pt, 5 Ru	11.90	84 - 89	60 - 115	5	3227
IPC-227	89 Pt, 11 Ru	11.45	91 - 96	85 - 150	4	3260
IPC-100	99.9 min Pd	6.31	62 - 78	28 - 47	16	2825
IPC-208	95 Pd, 5 Ru	6.32	79 - 89	54 - 75	8	2900
IPC-102	90 Pd, 10 Ru	6.34	84 - 92	70 - 100	6	3000
IPC-262	72 Pd, 26 Ag, 2 Ni	6.08	82 - 90	68 - 100	4	2520
IPC-30	60 Pd, 40 Ag	5.98	65 - 91	54 - 100	4	1440

 

Contact Materials

Fine Silver

Fine silver contacts work well in the light to medium ampere range and are ideal for contact applications requiring a light closing force where low contact resistance is to be maintained. As long as current and voltage are not excessive, silver is recommended for sensitive contacts under light and medium pressure, and will operate satisfactorily for long periods of time. Silver will carry high current loads without excessive heating when circuits are closed because of silver's high electrical conductivity.
The arc energy of the circuit is dissipated without excessive temperature increase or detrimental effect on the silver contact due to the high thermal conductivity of silver.

Silver is available in varying degrees of fineness. Fineness refers to the parts silver per thousand. Fine silver, which is the most commonly used material, is minimum 999.0 pure. Also available are AA fine silver minimum 999.5 and high fine minimum 999.9 pure.

The latter two are seldom required in contact applications. Silver is a ductile metal and is readily formed into contact rivets, weld buttons or in strip form used in contact stampings.

Some disadvantages of fine silver are...a relatively low melting point (1761 F), low hardness, and, under certain conditions, it will pit and transfer. Disadvantages may be overcome by combining silver with such metal as cadmium, copper, nickel, palladium, zinc, gold, platinum, iron, etc.

Addition of one or more of these alloying elements will, in some instances, raise the melting point, increase resistance to erosion due to arcing, increase hardness, increase corrosion resistance to undesirable chemical films and resistance to sticking or welding and reduce material loss and transfer.

Properties of Fine Silver : IPC-10  

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS	Melting Point F
IPC-10	99.90 min Ag	5.54	30 - 75	25 - 45	105	1761
Note: Hardness values are for comparative purposes only and should not be used in design specifications.

 

Contact Materials

Silver Cadmium Alloys

The development of the silver cadmium are alloys has produced a series of materials that provide good arc quenching characteristics, low contact resistance, and the ability to resist wear and arc erosion. These materials re used in both A.C. and D.C. applications in light to medium-heavy current ranges. The silver cadmium alloys are ductile and can be fabricated into all the contact forms. IPC-55 (85% silver, 15% cadmium) is one of the standard materials and has been used in high current inrush applications such as motor starters. IPC-54 (77% silver, 22.6% cadmium, .4% nickel) has been employed in D.C. Applications which require low surface resistance and the ability to reduce material transfer. The other alloys listed offer varying degrees of electrical and physical properties.

Properties of Silver Cadmium Alloys 

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS	Melting Point F
IPC-61	95 Ag,  5 Cd	5.48	40 - 76	31 - 56	60	1720
IPC-213	90 Ag, 10 Cd	5.42	45 - 80	36 - 58	47	1670
IPC-205	85 Ag, 15 Cd	5.37	51 - 83	38 - 68	35	1620
IPC-214	77 Ag, 22.6 Cd, .4 Ni	5.28	50 - 85	35 - 68	31	1560
Note: Hardness values are for comparative purposes only and should not be used in design specifications

 

Contact Materials

Silver Platinum & Silver Palladium Alloys

Alloying either platinum or palladium with silver produces a contact material which is harder than fine silver, has a higher melting point and exhibits a more noble surface.
Although these materials are slower to tarnish, they are not tarnish resistant until an alloy of 60% palladium or platinum has been reached. This group of materials is used in A.C. and D.C. applications, generally in low force requirements. Their main disadvantage is relatively high cost.
They are ductile and can be fabricated into the common contact forms.

Properties of Silver Platinum & Silver Palladium Alloys  

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS	Melting Point F
IPC-271	97 Ag, 3 Pd	5.62	45 - 77	25 - 47	48	1800
IPC-36	99 Ag, 1 Pd	5.51	44 - 76	26 - 47	79	1762
IPC-35	97 Ag, 3 Cd	5.56	45 - 77	27 - 48	58	1790
IPC-33	90 Ag, 10 Pd	5.61	63 - 80	34 - 53	30	1830
IPC-37	75 Ag, 25 Pd	5.74	72 - 86		14	2030
IPC-31	60 Ag, 40 Pd	5.82	77 - 87		21	2240
Note: Hardness values are for comparative purposes only should not be used in design specifications.

Age-Hardenable Materials

IranPlatn's family of heat-treatable noble contact materials provide excellent spring properties.
Hence, they are widely used as sliding or wiping contacts in potentiometers and in microbrush contacts.
All alloys listed on this page can be age hardened (a heat treat process that results in high tensile strength and resistance to wear, and yet does so without any attendant brittleness).
Since MDC-367 (0.5% gold, 1.5% platinum, 44% palladium 38% silver, 15% copper 1% nickel) contains little gold and has a lower specific gravity, it is more economical than IPC-40 (10% gold, 30% silver, 10% platinum, 35% palladium, 14% copper, 1% zinc). However, it too is highly resistant to corrosion and wear. IPC-372 (1% platinum, 44% palladium 39% silver, 14% copper, 1% zinc, 1% nickel) fills the need for a more economical contact alloy than IPC-40 for nickelchrome resistance wires but with the same properties that emerge after age hardening. Both IPC-40 and IPC-367 are widely used as Microbrush contact materials (see page 24). A more truly gold alloy that is also heat treatable to provide excellent spring properties is IPC-337 (72.5% gold, 14% copper, 8.5% platinum, 4% silver, 1% zinc).

Properties of Age Hardenable Materials

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS	Melting Point F
IPC-337	2.5 Au, 14 Cu, 8.5 Pt, 4 Ag, 1 Zn	8.38	200 - 370*	85 - 180*	11.15	1700
IPC-40	10 Au, 30 Ag, 10 Pt, 35Pd, 14 Cu, 1 Zn, 1 Ni	6.23	200 - 410*	110 - 205*	5.5	1860
IPC-372	1 Pt. 44 Pd, 39 Ag, 14 Cu, 1 Zn, 1 Ni	5.69	200 - 400*	100 - 215*	7.5	1780
IPC-367	1.5 Pt, 44 Pd, 38 Ag, 15 Cu, 0.5 Au, 1 Ni	5.69	170 - 380*	100 - 195*	6.7	1890
*Heat Treated Condition Note: Hardness values are for comparative purposes only should not be used in design specifications.

Silver Semi-Refractory Materials
 
Unlike the other contact materials that form true alloys, the silver semi-refractory materials are dispersed phase mixtures of silver and other metals or metallic oxides. These materials are produced by powder metallurgy or internal oxidation techniques. Since these materials are essentially a silver matrix with dispersed particles, they exhibit unusually good electrical conductivity. This family of materials is subdivided as follows:
a-Silver Cadmium Oxide
b- Silver Graphite
c-Silver Nickel
d-Other Semi-Refractory Materials

a. SILVER CADMIUM OXIDE
Prior to World War ll, there was little work done on this group of materials. The Germans were the first to discover the usefulness of cadmium oxide in contact applications and made great use of it during the war. Since then, many refinements have been made in the production of these materials. Today, silver cadmium oxide is employed in the majority of medium and high current applications.

The advantages of these materials are high conductivity, excellent ability to resist welding and a very low rate of electrical erosion.

One disadvantage is limited ductility in the higher percentages.
Typical applications include medium current range relays, electric lift truck contractors, A.C. motor controllers and automotive and aircraft relays.

Materials listed below are all made via both the internal oxidation or powder metallurgy processes and are all available as solid rivets, composite weld buttons and composite rivets. With the exception of IPC-91P and IPC-95P, these materials tend to fracture when doubleheaded.

Properties of Silver Cadmium Oxide Materials
 

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS
IPC-99	95 Ag, 5 CdO	5.45	32 - 76	20 - 35	84
IPC-91	90 Ag, 10 CdO	5.40	45 - 78	40 -70	75
IPC-91P	90 Ag, 10 CdO	5.40	55 - 78	5 - 90	74
IPC-95	86.5 Ag, 13.5 CdO	5.35	48 - 84	75 - 120	68
IPC-95P	86.5 Ag, 13.5 CdO	5.35	55 - 78	100 - 145	68
IPC-93	85 Ag, 15 CdO	5.34	50 - 85	60 - 115	65
IPC-90	83.2 Ag, 16.8 CdO	5.33	50 - 86	85 - 150	61
Hardness and tensile strengths of all materials are in the "as-annealed": condition, except for IPC-91P and IPC-95P. Note: Hardness values are for comparative purposes only and should not be used in design specifications.

b. SILVER GRAPHITE
The primary use of silver graphite is in sliding contact applications, such as brushes and slip rings, where the graphite provides good lubrication. These materials resist welding and sticking and are used in A.C. and D.C. applications. In the lower percentages, such as IPC-60 (99.75% Ag, .25 C) and IPC-69 (99.5 Ag, .5 C), silver graphite is headable within reasonable design range.* Above this range, the materials are brittle and are normally supplied in composite form.

Properties of Silver Graphite Materials
 

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS
IPC-60	99.75 Ag, .25 C	5.48	40 - 70	25 - 37	94
IPC-69	99.5 Ag, .5 C	5.43	40 - 69	36 - 42	90
IPC-301	93 Ag, 7 C	4.39	16 - 47	50
IPC-270	90 Ag, 10 C	3.51	10 - 30	40
*Refer to Engineering Data, Cold Heading Design Limits and Considerations.

c.SILVER NICKEL
Silver nickel semi-refractory materials exhibit good conductivity, good wearing qualities and good resistance to welding and erosion. These materials are used in A.C. and D.C applications where they replace fine silver or silver cadmium oxide in medium duty relays.
Silver nickel is ductile up to the 10% level, and can be headed into contact rivets. The 15% material is normally supplied as a composite as ductility is limited.

Properties of Silver Nickel
 

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS
IPC-286	95 Ag, 5 N	5.49	50 - 77	24	95
IPC-82	90 Ag, 10 N	5.44	50 - 78	25	87
IPC-301	85 Ag, 15 N	5.38	50 - 81	27	80
Note: Hardness values are for comparative purposes only and should not be used in design specifications.

d.OTHER SEMI-REFRACTORY MATERIALS
As with the silver alloys, there are dispersed phase materials that do not fall into a family series. One of these is IPC-65 (silver, magnesium oxide, nickel oxide). This is one of the more unusual silver alloys and is normally supplied in a heat treated condition. It is capable of withstanding elevated temperatures for extended periods without loss of temper. Because of this, IPC-65 will remain hard in high temperature brazing of composite contacts. This material is frequently used as a spring arm and contact tip. Applications are in the A.C. and D.C. areas. The magnesium oxide provides an antiweld characteristic which, when paired with IPC-51 in D.C. applications, minimizes material transfer. This material can be supplied in all forms, but it will not withstand doubleheading without cracking. IPC-81 (90% silver, 10% iron) is normally used in 120 volt applications replacing fine silver to reduce welding. Typical uses are household appliances and medium duty relays. The one disadvantage of IPC-81 is the probability of high surface resistance due to oxide formations. Due to this, it is not suitable for high temperature or high humidity applications. IPC-81 is available in solid rivet or composite form.

Properties of Miscellaneous Semi-Refractory Materials

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Tensile Strength x 1000 PSI	Electrical Conductivity % IACS
IPC-65	Ag, MgO, NiO*	5.52	80 - 85	65	70
IPC-81	90 Ag, 10 Fe	5.36	55 - 75	31	90
*Properties of IPC-65 are in the heat treated condition. Note: Hardness values are for comparative purposes only and should not be used in design specifications.

Contact Materials

Silver Tin Oxide Alloys

Silver tin oxide alloys were developed and used in Japan as an environmentally friendly substitute for silver cadmium oxide. Beginning in the 1980's, these alloys were found to give superior performance in U.S. automotive relay applications where high amperage anti-welding characteristics are necessary. These alloys offer the advantages of high conductivity, excellent resistance to welding and a very low rate of electric erosion. Alloys of silver tin oxide are now available world wide and are still used widely for automotive applications in the U.S. and abroad. While silver tin oxide is most frequently found in contacts used for DC applications, there are also a few AC devices that use silver tin oxide.

Due to the alloys tendency toward cracking during the manufacturing of rivets, design parameters must be carefully controlled. Common silver tin oxide alloys available in the U.S. include 88% silver 12% tin oxide (88/12), 90/10, and 92/8 with the higher percentages of silver offering better cold heading capabilities and less tendency toward cracking during rivet manufacturing or subsequent staking into blades or terminals. All of these alloys can be made into either solid or ECONOMET (machine composite) rivets. IranPlatin offers either rivets or in-die staked assemblies made from silver tin oxide.

Silver tin oxide alloys are also used widely in contact weld tape applications for the automotive industry. Welded tape contacts typically yield very large bond areas between the contact and substrate surfaces thus allowing high amperage passage through the device over many cycles. IranPlatin has lengthy experience and offers in-line automatic assemblies using state-of-the-art welding technology for silver tin oxide alloys.

Silver Refractory Materials

The silver refractory contact materials are made by powder metallurgy. This makes it possible to combine silver with such refractory materials as tungsten and tungsten carbide. These materials offer the contact user the high conductivity of silver and the high melting temperature of the refractory material. Use of these materials is in the high current ranges and heavy duty devices. Due to the high melting temperature of the refractory material, there is less chance of welding and greater resistance to arc erosion. Selection of the optimum material is a compromise between conductivity and non-welding properties. Higher silver content will produce less temperature rise whereas the higher refractory will give less erosion.

Contacts made of these materials are necessarily of composite construction where they are brazed to base metal backings such as screws or rivets.

IPC-280 (35% silver, 65% tungsten) is normally used in air circuit breaker in the fifty to hundred ampere range. It contains enough silver to be a good conductor yet resists erosion and welding.

IPC-87 (50% silver, 50% tungsten), with a higher silver content, is a better current carrying material and is used in relays where other silver alloys would not withstand arcing.
IPC-316 (40% silver, 60% tungsten carbide) is a material with very high hardness and provides maximum arc erosion characteristics. Since the tungsten carbide does not oxidize as readily as tungsten, this material will give less surface resistance than a silver tungsten of comparable composition. IPC-316 is used mainly in high current circuit breakers.
IPC-281 (50% silver, 50% tungsten carbide) and IPC-86 (65% silver, 35% tungsten carbide), both containing more silver than IPC-316 are capable of carrying high loads without undue temperature rise. These materials are widely used in industrial contactors.

Properties of Silver Refractory Materials
 

Refractory Materials TUNGSTEN

Tungsten is a refractory metal that has the highest melting point (6170 F) of any contact material. It is widely used in the light current range, up to 4-5 amperes, where the application calls for high resistance to electrical erosion, welding and mechanical wear. Typical of these applications are magnetos and horn relays.

Tungsten, unlike silver, will form stable oxides, which necessitates much higher forces than the other contact materials. Tungsten is so hard that is available only in composite form. The face configurations can be either flat or radius.

IPC-235 is a fine grain tungsten, end grain, cut from rod.

IPC-241 is an equiaxed grade employed to minimize stresses in applications where stress is detrimental.

Properties of Tungsten
 

 

Contact Materials

Contact Plating

The purpose of electroplating contacts is to upgrade the electrical characteristics or to provide protection to a lower cost material. Examples of this are nickel plating of steel to prevent corrosion, silver plating of copper to reduce oxidation, and gold plating of silver to retard sulphidation.

Nickel plating of steel components of composite contacts is universal and a standard thickness of .0001/.0002 gives good protection. If salt spray tests are to be employed, heavier deposits will be required. These test conditions should be specified and plating thickness adjusted accordingly.
Silver plating, normally over copper or brass, is seldom a replacement for a silver base contact, but can be employed in non-arcing, low mechanical force applications. Normally, silver plating is used on permanent connectors, semi-permanent connectors, or most commonly, to increase the nobility of copper and brass backings of composite contacts. In these instances, thicknesses of .000050 to .000100 will satisfy most applications.

Gold plating is a far more complex system that can be described more thoroughly by investigation of some of the problems encountered. The degree of protection obtained from gold is normally measured by its shelf life and operational life. To some degree, the plating thickness is a measure that can be used. But other factors (such as the purity of the gold, its porosity, subsequent handling and environment) play a large role.

Two problems, with gold over silver, are porosity and diffusion at elevated temperatures. The result is that silver sulfide forms at the pore sites and spreads over the gold surface ultimately covering the entire contact surface. Silver sulfide over gold has much higher resistance than silver sulfide over silver. In low current, low contact force applications, this could be disastrous.

In the higher amperage, higher force areas, gold is a benefit and the amount of protection is now more dependent on plating thickness. This can be subdivided into three levels: low, medium and high.

Gold Flash

Low or minimal protection can be achieved by employing a gold flash. The normal thickness of a gold flash is .000010/.000020.

Gold Treatment

Frequently there is a requirement for protection between that afforded by a gold flash and that obtained by the heavy, more expensive gold plates. To offer the contact user protection in this medium area, IranPlatin has developed a unique process termed Gold Treatment. This is a multistage application of gold that produces a protection level unattainable by regular electroplating of the same thickness. In today's contaminated atmospheres, this level of protection is frequently required.

Gold Plate

In the higher protection area, there are the gold plates which begin at thicknesses of .000050 and higher. At .000100 thickness, one can expect a virtually pore-free condition and less probability of diffusion dependent on temperature.

In gold plating of contacts, there are two types of gold normally employed. The 24 Kt. gold is the most pure and being more ductile, is normally employed. In audio circuits, it will produce less noise and, unless otherwise specified, this is the material supplied. The 23+ Kt. Gold is harder because it contains nickel or cobalt co-deposited with the gold. Being a harder material, it is employed on sliding contact applications and on semipermanent connections, to withstand the mechanical wear.
 

Contact Materials

Base Metals

Base metals are utilized in contact construction to provide a low cost composite contact and, in some cases, to gain a mechanical advantage in strength over a solid precious metal contact.

Depending on the particular process involved in manufacturing the base metal component, there is a selection of materials to be considered.

In considering steel, IPC-140 is a readily headable material, whereas IPC-287, a leaded steel, is not. If the component is to be made via a machining process, the IPC-287 would produce the best, least expensive part.

In copper, IPC-133 (OFHC) is the best heading grade and IPC-137 is the better machining material.

Brass is not as desirable a composite backing material as the coppers; however, it is required in many applications. If the part is to be headed, the selection would be IPC-120 as contrasted to the better machining IPC-122. In most instances, the leaded or sulphurized materials cannot be successfully headed without cracking.

In the manufacture of composite weld buttons, the selection is most usually IPC-140 nickel plated. Other materials employed are IPC-151 (nickel Silver), IPC-180 (monel) or IPC-210 (Grade A nickel). These materials offer more resistance to corrosion, but at a higher cost.

Composite contact rivets employing tungsten faces and the platinum family materials normally are made on nickel-plated steel. Since these materials are used in relatively low current applications, the low conductivity of steel does not present a heat rise problem. In
the use of silver and silver alloy face materials, the normal selection is copper or brass materials for the backing. Where precious metal plating over a base metal is sufficient in the contact application, IPC-130 (ETP copper) is a typical choice.


Properties of IranPlatin Base Metals

Iran Platin Material Number	Composition % by Weight	Density T.o/cu.in.	Hardness Range R 15T Scale	Electrical Conductivity % IACS	Melting Point % IACS
IPC-140	C-1008 Steel	0.284	79 - 88	14.5	2800
IPC-287	B-1113 Leaded	0.284	75 - 85	12	2750
IPC-130	ETP Copper	0.321	50 - 84	100	1981
IPC-133	OFHC Copper	0.323	50 - 84	101	1981
IPC-137	Sulfurized Copper	0.323	52 - 85	95	1922
IPC-120	Cartridge Brass	0.308	55 - 91	28	1680
IPC-122	Free Cutting Brass	0.307	67 - 85	26	1630
IPC-210	Grade A Nickel	0.321	73 - 93	18	2615
IPC-180	Monel	0.319	80 - 92	4	2380
IPC-151	Nickel-Silver	0.314	77 - 90	5.5	1930
Note: Hardness values are for comparative purposes only should not be used in design specifications.

Properties of Elements Used in Electrical Contact Applications
Please select an element below to view its properties.
Aluminum
Beryllium
Cadmium
Carbon
Cobalt
Copper
Germanium
Gold
Indium
Iridium
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Osmium
Palladium
Platinum
Rhodium
Ruthenium
Silver
Tellurium
Tin
Tungsten
Vanadium
Zinc
 

Contact Materials

Contact Material Applications

Below is a list of materials that have been used in the typical applications shown. These are recommend for initial design and testing in similar applications. The IranPlatin Material Number is linked to the actual material page to provide additional information.

Aircraft                                          IranPlatin Material #

Jacks                                             262      30    213     214
Relays                                           100      41      43       44
Thermostats                                   10     271      31     227
Toys                                              133      50       51      10
Traffic Signals                                 10      20       91      82
Vending Machines                           20      51      10       91
 

Contact Materials

Types of Contacts

Solid Rivet Contacts
Direct Melt Composite Contacts
Economet Composite Rivet Contacts
Brazed Composite Rivet Contacts
Tungsten Composite Rivet Contacts
Duell Head Composite Contacts
Solid Weld Contacts
Composite Weld Contact
Composite Screw Contacts
Special Composite Contacts
Contact Stampings
Precision Four-Slide Formed Parts
Microminiature Precision Metal Stampings
Contact Weld Tapes
Specialty Products

Solid Rivet Contacts

IranPlatin solid rivet contacts are available in a wide range of sizes, offer superior electrical performance, and are economical. In addition to cost savings, high speed cold heading provides a solid rivet contacts of greater strength due to unbroken metal flow lines as well as uniform, high quality.

Although silver and silver alloys are still the most widely used metals for solid rivet contacts, IranPlatin manufactures millions of contacts in a variety of other precious and base metals.

Solid contacts are usually supplied with a solid shank, but are also available with indent, tubular, chamfer or other special configurations.

In some cases, the selection of a typical size will speed production and keep costs down. However, a contact that IranPlatin-designs to meet the need of a specific application provides the optimum blend of performance and economy.

Head: Flat, radius, button, conical
Shank: Solid, indent, tubular, chamfer
Material: Silver, gold, palladium, platinum, precious metal alloys, silver or gold plated base metals
 

Type of Contacts

Economet Composite Rivet Contacts

IranPlatin's Bimetallic Economet Rivet Contact was developed to produce an economical composite contact and to overcome the limitations of other methods of manufacturing composites. Economets are precision headed at high speeds from wire on specially designed equipment.

There is no intermediate brazing material in metallurgically bonded Economets. Thus these composites perform more reliably, even at high operating temperatures, than composites produced by brazing. Backing is typically OFHC copper; facing is fine silver or silver alloy. Being mostly copper, the composite has superior thermal and electrical conductivity. Only a small percentage of the Economet contact is silver, so in many applications it becomes economically feasible to choose larger contacts that have the advantages of superior heat absorption, heat dissipation and high electrical capacity.

Since the IranPlatin Economet is headed, it can be made at tolerances closer than can be achieved by brazing. Uniform consistency of close tolerances facilitates feeding and staking on high speed automatic assembly equipment. Economet parts are also available with tubular shanks.

Head: Flat, radius, conical
Shank: Solid, indent, tubular, chamfer
Facing: Silver, silver alloys
Backing: OFHC Copper
 

Type of Contacts

Brazed Composite Rivet Contacts

Iran Platin brazed rivet contacts offer an excellent variety of contact sizes and configurations. The advantages of a brazed composite rivet are economy (by the replacement of precious metal with less expensive base metals) and the strength gain inherent in the use of certain base metals.

Brazed composite rivet contacts can be provided with virtually any contact face material that will withstand high temperature brazing. The wide choice of backing materials enables the designer to pick a metal with high electrical conductivity for heat dissipation or to select a metal which has the greater physical strength necessary for mounting or assembly. So, the contact engineer has great latitude in material and size selection.

The most generally used backing material is CDA102 OFHC copper which is relatively inexpensive, and has excellent thermal and electrical conductivity. In many applications, copper, nickel or silver-plated steel is selected as the backing material because it is strong and economical. Plating improves resistance to corrosion.

Since brazed composite rivets are made from several components, dimensional tolerances are greater than a solid counterpart. These tolerances can be improved by such secondary operations as coining.

Head: Flat, radius
Shank: Solid, indent, tubular, chamfer
Facing: Silver, coin silver or other silver alloys
Backing: Brass, bronze, copper, monel, nickel, steel
 

Type of Contacts

Duell Head Composite Contacts

The Duell Head composite contact is a contact for double-use in double throw applications This type of contact has the economic advantage of replacing silver with less expensive copper. How much silver is saved depends upon the size and configuration of the contact.

Head: Flat, radius. Certain head configurations will require a tapered sidewall
Shank: Solid
Facing: Silver, coin silver or other silver alloys
Backing: Copper
 

Type of Contacts

Solid Weld Button Contacts

Generally formed by cold heading, Iran Platin solid weld contacts offer the metal strength of unbroken flow lines, eliminate any problems due to bonding, and are high speed, precision manufactured to close tolerances. Contact resistance is lower than that of the composite. In addition to these advantages, in certain sizes or depending on quantities, solid weld contacts are more economical than composites. Silver and silver alloys are the most widely used metals, although in certain applications other precious metals or their alloys are used. Solid weld contacts are made in sizes ranging from .062 to .500 head diameter. If your design varies substantially from the standard or typical sizes show in the size charts on solid weld contacts please check with our engineers to be sure that the particular contact can be headed economically or if, possibly, a composite should be used.

Head: Flat, radius, conical
Material: Silver, silver alloys, palladium and palladium alloys, gold and gold alloys
 

Type of Contacts

Composite Weld Contacts

Iran Platin composite weld contacts offer the economy of using precious metals for the contact facing plus the following advantages: a strong, permanent bond; low electrical resistance; dependable operation at high temperatures; and the ability to with stand sever arcing.

This type of composite weld contact is made by metallurgically fusing fine silver or a silver alloy facing directly to a base metal backing. Fusing or puddling provides a positive bond, eliminates any intermediate bonding material and problems caused by use of any bonding material, and eliminates high resistance because of a loose contact.

Fused contacts can be coined to provide a smoother, dense, hard, wear-resistant precious metal contact face with improved dimensional accuracy to the radius desired. Nickel-plating the steel backing reduces the possibility of corrosion.

In yet another method of manufacturing, the silver or silver alloy facing is brazed to steel or some other base metal backing. Then, as in fusing, the composite contact can be coined to harden the precious metal facing, and aid in forming a dimensionally accurate steel welding projection.

This facilitates automatic feeding and the accurate welding of the composite weld contact directly to blade or bracket.


While each method of manufacturing composite weld contacts has certain advantages, the optimum contact is a compromise between the plus factors of various materials, dimensions, manufacturing processes and the electrical and performance requirements of each application. Iran Platin engineers will be glad to work with you in determining which particular contact, size, materials and method of manufacture will be most economical for you while meeting or exceeding your performance requirements.



Head: Flat or radius, either natural or coined
Facing: Fine silver, coin silver and other silver alloys. Other precious metals available depending on application.
Backing: Monel, nickel, nickel-plated steel, nickel-silver, etc.
 

Type of Contacts

Composite Screw Contacts

In many applications, Iran Platin composite screw contacts offer greater economy through minimal use of costly precious metals, using the contact for more than one purpose, choices of designs and materials and a reliable bond.

Composite screw contacts are used in applications that require one or more of the following:

a. quick, easy adjustment or replacement in the field,
b. in-manufacture or field calibration,
c. where the screw economically serves as
both the electrical contact and fastener.

These contacts are normally made by fusing or brazing, depending upon size, materials, electrical requirements and cost. When fused, backing is usually nickel-plated steel because of its strength, low electrical resistance through proper bonding and excellent resistance to corrosion.

Since such composite screw contacts can serve so many functions, the size charts list only several standard or typical sizes. When you have an application that may involve a composite screw contact, Iran Platin engineers will work with you to determine that particular design, combination of materials and manufacturing process best suited and most economical for your specific application.


Head: Flat, radius
Facing: Silver, silver alloys, gold, gold alloys, platinum, platinum alloys, tungsten, powder metals
Screw: #4 to ½ " and specials
Backing: Bronze, copper, nickel-plated steel, brass
 

Type of Contacts

Special Composite Contacts

Not all contacts fall into a convenient category. For lack of a concise name or readily identifiable classification, many have to be called specials. Often, specials are composite in construction. Special composite contacts serve as regulator contacts, rotary switch terminals, toggle switch terminals, starter and window lift contacts in varied applications involving automobiles, trucks, gas engines, material handling equipment, appliances and military.

Designing the optimum special composite contact requires a thorough knowledge of contact engineering, contact manufacture and the may factors involved in each specific application. Many times a decision cannot efficiently be made as to whether the contact is standard or special, solid or composite, until the potential or existing application has been carefully studied and evaluated. Iran Platin engineers are at your service and will be glad to work with you in developing the contact best suited to your needs at the lowest cost consistent with required reliability.
 

Type of Contacts

Contact Stampings

Many electrical devices being manufactured today employ contacts of precious metal manufactured on punch presses from strip material. Typical of these parts are:

1.Bridging contacts of solid or overlayed precious metal
2. Stationary terminals of inlay strip
3. Laminated slip rings
4.Rotary switch terminals

All of these require expert design and die layout to insure a minimum of scrap generation to produce the lowest possible cost.

Our complete staff of engineers, designers and toolmakers will be glad to work with you in determining the optimum design, materials and die construction best suited to your requirements.
 

Type of Contacts

Microminiature Stampings and Other Precision Parts

Iran Platin also produces microminiature stampings and small precision parts for electronic as well as non-electronic applications. These products, like our contacts and assemblies, are backed by decades of design and manufacturing expertise. Small presses using either progressive type or single stage tooling are used to make miniaturized components in small or large quantities.

Iran Platin is capable of producing in high volumes C and S bends, headed leads for semiconductors, fine wire parts, finger contacts, slip ring, wipers and spring-leaf type wire contacts. These are made from such precious metals as gold, platinum, palladium and silver and their alloys as well as from other materials such as copper, copper alloys, stainless steel and nickel silver. Typical applications are potentiometers, timers, transducers and various instruments and recorders in which good electrical contact on a non-filming surface is essential.

Iran Platin's production facilities can accommodate most customer needs. Through its four-slide capabilities, it can offer increased cost savings in automated contact-blade assemblies because tooling for this manufacturing process is normally less expensive than that used in progressive-tool type production.
 

Type of Contacts

Contact Tape

Some years ago, Iran Platin expanded its capabilities by adding a line of electrical contact tapes and tape assemblies. These tapes are normally composites of a backing base metal and a capping contact material.

Capping materials are usually gold, silver, palladium, platinum or alloys of these precious metals, as well as alloys of noble metals. A wide variety of backing materials includes nickel, nickel silver, monel, low-carbon steel and other base metals to meet your requirements.

Contact tapes come in a range of weld projections, including single and multiple rail, cross-hatch and diamond projections.

Tapes may be purchased in coil form on reels for customer assembly on their own welding equipment or in lengths cut to customer specification for tweezer (resistance) welding.
 

Type of Contacts

Specialty Products

Iran Platin's vast experience in close-tolerance cold heading makes it possible to apply the method to make base metal parts that are more economically produced than by screw machines.

Although some of these specialty products are current carrying members without silver, most of them are not contacts. Mostly made from copper, they are however used as terminals; for example, as shunts in ground-fault devices.

Iran Platin does not normally compete with commercial cold-heading houses because our customers want tighter tolerances. Customer prints of screw machine parts are continually being evaluated to determine whether tolerances, configuration and materials will lend themselves to conversion to the more economical heading processes. Also, in many cases our modern punch press department performs secondary operations on such headed parts-and all done at lower cost than by any other means.
 

Type of Contacts

Assembly Design

The Iran Platin assembly equipment mentioned in this section consists of state of the art high speed machines that have been designed and built by Iran Platin engineers to automate and speed production of economical, high-quality contact assemblies.

With this equipment, completed contact assemblies can be produced by welding, staking, double heading or a combination of these processes.. resulting in an assembly that meets your print.

This equipment has proved particularly valuable in long, high-production runs where unit cost is an all-important factor.
 

Type of Contacts

Choosing the Contact Assembly

In addition to individual contact points discussed in the Contacts section,
Iran Platin is fully equipped to produce contact assemblies (staked rivet, weld tape, or wire weld).

The next step after production of the contact itself is attachment to some carrying member. These carriers may be in the form of thin spring stampings (blades), copper bars, intermediate size terminals, screw machine parts... the variety is almost endless.

Since no single attachment is best in all applications, each application should be evaluated from a performance and economic standpoint. For these reasons, users of contacts and contact assemblies find it advantageous to consult with Iran Platin engineers while their products are in initial design stages, or if a redesign is being considered.

When a contact assembly is manufactured by Iran Platin, you eliminate the hidden cost of contact scrap and inventory. Through experience, Iran Platin has developed many methods of keeping precious metal scrap at a minimum during production both at Iran Platin and at the end-user.

Iran Platin's state of the art assembly equipment can produce contact assemblies utilizing manufacturing processes such as staking, double heading, resistance wire or tape welding, and furnace brazing.

As the contact specialist, Iran Platin concentrates its efforts on originating, developing and perfecting the manufacturing process that provides the optimum contact and contact assembly. Iran Platin will provide the entire assembly or attach its contacts to your components, whichever best suits your requirements for efficiency and economy.
 

Type of Contacts

Assembly Processes


Riveting and Staking
Resistance Tape Welding
Resistance Wire Welding
Furnace Brazing
Blade and Terminal Assemblies

Riveting and Staking

In-die riveting and/or staking contacts to a current carrying arm or mounting bracket is a widely used method to produce contact assemblies. Tubular contacts are riveted or rolled, while solid shank contacts are staked or upset. Both methods lend themselves to high speed production. Virtually unsurpassed in economy, these assemblies are used with light to medium electrical loads.

Tubular shank contacts are used on thin materials where staking a solid shank might cause distortion. They are also utilized for fragile plastic materials. Solid shank contacts are used on heavier, less fragile materials.

Since the solid shank contact can be produced at higher rates of production than tubular types, it is the more economical. In either case, the resulting assemblies will be of consistently high quality.

A rule of thumb for hole size in the carrier or arm for a given contact shank diameter is S.D. x 105%. Hence, for a contact shank of .078 diameter, the hole size would be .078 x 1.05 or .082 diameter.

The shank length of the tubular contact is obtained by adding the total thickness of the material(s) it must penetrate plus 55% of the shank diameter.

Example: Contact shank diameter is .078 and the spring arm to which it will be attached is .012 thick.
S.L. = (Material Thickness) + (55% x S.D.)
S.L. = .012 + .55 x .078
S.L. = .012 + .043
S.L. = .055

The shank length of the solid shank contact requires the addition of the material thickness plus 33% of the shank diameter. Example: the contact shank diameter is the same .078 in. and the blade the same.012.

S.L. = (Material Thickness) + (33% x S.D.)
S.L. = .012 + .33 x .078
S.L. = .012 + .026
S.L. = .038

With proper tooling, both solid and tubular contacts can be riveted or staked as assemblies on riveting machines or bowl fed into stamping presses.
In all such contact setting operations, it is important to keep setting tools cleaned and polished in order not to mar the contact face or embed impurities that could lead to contact failure in the electrical device. It is also important that the contacts be firmly seated on the carrier to obtain optimum electrical and thermal conductivity.
Iran Platin is equipped to provide a riveted or staked contact assembly stamped to meet your print requirements.
 

Assembly Processes

Resistance Tape Welding

Next to riveting, staking, and double-heading, the most common method of contact attachment is resistance welding a contact tape.

In tape welding, the contact is placed against the carrier between the two electrodes of a resistance welder. With proper pressure and current flow from the electrode thru the carrier and contact to the other electrode, a weld nugget is obtained due to the localized heating and ultimate alloying of the weld projection and carrier material.

Either a single or double throw contact arrangement can be achieved by welding. Very high production rates can be obtained on automated welding equipment. Resistance welding is yet another process adaptable to Iran Platin assembly equipment.

Normally a spring arm or carrier to be welded does not contain the locating hole that is present for rivet assemblies. To obtain the proper contact location, piloting of the strip and fix turing is required to register the contact to a feature of the carrier.

Resistance tape welding also requires the proper selection of electrode materials and the proper weld projection for the type and thickness of carrier material. Our engineers will assist in this selection.

Iran Platin is specially equipped to handle both low and high volume weld assemblies and is a leader in this technology.

A variation to Resistance Welding is Resistance Brazing. The process is identical to welding except a braze alloy is used as a backing on the tape rather than a high resistance material. This configuration typically yields a higher bond area and lower electrical resistance under load.
 

Assembly Processes

Resistance Wire Welding

Resistance wire welding is the most economical means of attaching a contact to a carrier (blade or terminal). This technique does not require the separate manufacture of a contact rivet or weld tape. The wire welding process is also high speed when compared to riveting or tape welding. The limitations to this process is the requirement that the wire be made from a weld able alloy such as fine silver, coin silver, silver nickel, etc. Alloys such as silver cadmium oxide or silver tin oxide can not be wire welded since these materials are designed to resist welding.

Iran Platin has developed a very robust and high speed automated wire welding process that encompasses a strip take-off, a pilot press, a weld head and final stamping and forming of parts at very high speed. The finished parts can be either collected as discrete parts or wound onto reels of subsequent operations. In-line cleaning of parts is available when needed. The use of SPC and contact bond strength and integrity are verified during sampling on a real time basis.

All of the advantages of tape welding are also available with wire welding with the added advantage of economy. Double contact welding (either on the same side or opposite sides of the blade or terminal) is very common in Iran Platin's process. Also, many materials are routinely used as blade and terminal material to meet customer needs or specifications.
Iran Platin offers customer assistance in choosing the optimum contact and blade/terminal materials for their devices. Experience has proven that Iran Platin having early involvement in the design process pays dividends.
 

Assembly Processes

Furnace Brazing

In addition to the individual brazed contacts described in Section l, IranPlatin offers a wide variety of furnace brazed assemblies.

Brazed contact assemblies offer the greatest latitude of contact material selection combined with greater area bond to the carrier. For these reasons, brazed contact are the ultimate in the higher current applications.

In this process, the contact and carrier are positioned in a fixture with the proper type and amount of brazing material between them. As they are passed thru the atmospherically controlled, high temperature brazing furnace, the brazing material alloys with the components and upon solidification, a strong, metallurgical bond is produced.

High brazing temperatures will cause annealing of most materials. This, if it is detrimental, can be compensated for by the subsequent cold working of the parts or the selection of heat treatable carrier materials.

The ability to fixture 2,3, 4, and 5 components and complete the assembly in one operation can produce generous cost savings.

Iran Platin can either use customer or supplied backing or produce the complete assembly of backing and contact.
 

Assembly Processes

Blade and Terminal Assemblies

The Iran Platin assembly equipment mentioned in this section consists of state of the
art high speed machines that have been designed and built by Iran Platin engineers to automate and speed production of economical, high-quality contact assemblies.

With this equipment, completed contact assemblies can be produced by welding, staking, double heading or a combination of these processes. resulting in an assembly that meets your print.

This equipment has proved particularly valuable in long, high-production runs where unit cost is an all-important factor.

Quality Policy: Iran Platin is committed to meeting or exceeding our customer's requirements.

Please send inquiries to info@iranplatin.com or phone: IranPlatin at 0098-021-8590014 or 8590006 fax to 0098-021-8090460.
 

Assembly Processes