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1、 E I A CB34 93 3234600 0507343 bTb Ropmduced y GLOBAL ENGINEERING DOCUMENTS Nith Thr hmtukn ol EIA d unda RwJtl Almmant EIA ENGINEERING BULLETIN Contact Lubrication CB14 JUNE 1993 ELECTRONIC INDUSTRIES ASSOCIATION ENQINEERINQ DEPARTMENT Copyright Electronic Components, Assemblies & Materials Associa
2、tion Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A CB14 93 3234600 0507144 532 m NOTICE EIA Engineering Standards and Publications are des
3、igned to serve the public interest through eliminating misunderstandings beween manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence o
4、f such Standards and Publications shall not in any respect preclude any member or nonmember of EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than EIA
5、 members, whether the standard is to be used either domestically or internationally. Recommended Standards and Publications are adopted by EIA i n accordance With the American National Standards Institute (ANSI) patent policy. By such action, EIA does not assume any liability to any patent owner, no
6、r does it assume any obligation whatever to parties adopting the Recommended Standard or Publication. Technical Bulletins are distinguished from EIA Recommended Standards or Interim Standards, in that they contain a compilation of engineering data or information useful to the technical community, an
7、d represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering practice, or that may be acceptable to, or have been accepted by, appropriate bodie
8、s. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in future revisions of this Bulletin are encouraged to do so. It is the intention of the formulating committee to revise and update t h i s Bulletin from time to time as may be
9、occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. (Formulated under the cognizance of the EL4 CE-2.0 Committee on National Connector Standards.) Published by 0 ELECTRONIC INDUSTRIES ASSOCIATION 1993 Engineering Department 2001 Pennsy
10、lvania Ave., N.W. Washington, D.C. 20006 PRICE Please refer to the current Catalog of E U & JEDEC STANDARDS & ENGINEERING PUBLICATIONS or call Global Engineering Documents, USA and Canada (1-800-854-7179) In tema tional (303-7!n-2 18 1) All Rights Reserved Printed in U . S . A . Copyright Electronic
11、 Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A CB34 93 3234600 0507345 479 Copyright Electr
12、onic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A CBL4 93 3234b00 0507L4b 305 = CB14 Page
13、1 The purpose of this document is to review contact lubricants used in signal contact systems for electronics. Factors affecting the use of lubricants will be discussed including those areas requiring further study. Applicable advantages, limitation and cautions are indicated. A bibliography is incl
14、uded if further investigation is desired. It is not the intent of this document to make a conclusion or forward a recommendation. Due to the wide variation of available lubricants (both generic and proprietary), the specific situations briefly discussed herein may not be of issue contingent on the l
15、ubricant formulation which may have been designed to resolve a specific problem. In considering the use of a lubricant, the reader is advised to assess the specific areas of interest and chose a lubricant which best fits the application after proper evaluation techniques have been performed. The inf
16、ormation contained herein has been based from various publications and papers as indicated in the bibliography contained at the end of this document. information, these publications should be researched as applicable. For more specific Copyright Electronic Components, Assemblies & Materials Associat
17、ion Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A CBL4 93 3234600 0507147 241 CB14 Page 2 Two surfaces in contact w i t h each other appea
18、r t o form a relatively large continuous contact area. area of contact is formed by contact asperities (commonly called la-spots). contact w i t h each other and represent as low as 1% of the apparent contact area. In reality the real These asperities are actually metallic peaks in When a contact fo
19、rce is applied these peaks contact each other and may actually enlarge dependent on the magnitude of the applied force. This may result in localized cold welding and/or potential galling. d wem is defined as the solid state bonding between atoms of the metallic surface areas in contact. Contaminatio
20、n free surfaces are required for this t o fully occur. of contaminants on the surface can minimize cold welding. The presence u is defined as a wear condition resulting from friction between the asperities of the contacting surfaces. This can result in localized welding and subsequent metal surface
21、disruption, metal transfer and/or further roughening of the mating surfaces. In addition, when one of the two, or both contacting surfaces are moved relative t o each other, any localize cold welding between the asperities has t o be broken or sheared. is a function of a numberof variables such as c
22、ompressive forces, surface conditions, cleanliness etc. This shearing force Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networ
23、king permitted without license from IHS -,-,- , E I A CB34 73 = 3234600 0507348 188 CB14 Page 3 S I C PHENOMENON - ontinuea When a lubricant is applied t o a surface, the fluid generally forms small droplets. When surfaces are brought into contact, these droplets are spread over the entire surfaces
24、i n the form of a thin f i l m . The f i l m is thin enough t o be penetrated in several areas by the material asperities thus not affecting electrical resistance. welding, reduces shear forces involved and hence reduces wear, galling and frictional forces. The impact of this f i l m results in mini
25、mizing cold C. 1. WEAR: The term “wear“ indicates the “forced“ removal of contact material during the sliding action which occurs. This removal may be a result of the transfer phenomena, loss of loose particles (debris), pushing material aside, etc. The following are the basic wear mechanisms which
26、exist. a) ABRASIVE: Wear resulting from rough, sharp hard materials or a combination thereof in contact w i t h a softer material. An example of this is a lead-in chamfer of a mating pcb against a gold or t i n (ally) plating of the mating contact. these situations. Lubricants may not be effective i
27、n b) BRITTLE FRACTURE: This is the cracking of a plated surface perpendicular t o the direction of sliding. strength materials or a poorly controlled plating process. not prevent this type of wear from occurring. This type of wear can occur on low Lubrication by itself w i l l Copyright Electronic C
28、omponents, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A CB14 93 W 3234600 0507149 O14 c CB14 Page 4 UT
29、ES AFFECTED BY LURRICATION - ontinued Cl 2 . 3. ADHESIVE: This is the most common type of wear common t o connectors. Basically this type of wear results from cold welding and/or the transfer phenomena. significantly reduced when a lubricant is used on the surfaces. This type of wear is The rate of
30、wear sharply increases from “mild“ t o “severe“ usually when a specific load is achieved. Use of a lubricant w i l l result in this transition t o occur at higher force levels with all other factors being equal. Lubrication w i l l also allow thinner gold plating t o be used due t o the reduction of
31、 the wear rate. CORROSION : A lubricant can l*seall* off reactive surfaces from the surrounding atmosphere. It can also significantly reduce pore corrosion as w e l l . mixture of wax and an oil are effective in this case. Microcrystaline wax or a Fretting corrosion may be inhibited by the use of a
32、fluid lubricant. as w e l l as inhibiting frictional polymers in palladium (alloy) systems. It w i l l reduce fretting wear on of gold platings LOWER MATING FORCES: reduces coefficient of friction and this decreases the mating force of a connector system. This can be an important feature for high de
33、nsity connector currently evolving. reduction may be as great as 80% contingent on contact configuration (entry geometry) , surface, conditions (eg . roughness, cleanliness, etc.). This reduction may be achieved without reducing normal force and may allow an actual increase in this attribute without
34、 adversely affecting the resultant mating force. A lubricant by its inherent nature Said Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduct
35、ion or networking permitted without license from IHS -,-,- E I A CB14 93 3234600 0507150 836 M CB14 Page 5 Typical coefficient of frictions are as follows: Clean surfaces : 0.3 t o 1.0 Lubricated Surfaces : 0.15 t o 0.2 There are two basic equations which may be used in understanding frictional forc
36、es: a) F = (KN/H)S F = Frictional Force K = Constant, Proportionality N = Normal Force H = Hardness of the soft material S = Shear Strength of the soft material b) F = p N F = Frictional Force p = Coefficient of Friction N = Normal Force In essence, frictional forces is a function of cold welding. C
37、old Welding is a function of the adhesive bonding of metals i n contact relative t o the “real“ area contact and the shearing force required. “real“ area of contact. It also exhibits a much lower shear force and as a result of these factors, the frictional forces are reduced. A lubricant w i l l min
38、imize the D. CONDITIONS TO BE EVALUATED 1. COSTS: the manufacturing process and as a result represents additional costs. the technique. The addition of a lubricant is an additional step in This cost can greatly vary contingent on Copyright Electronic Components, Assemblies & Materials Association Pr
39、ovided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without license from IHS -,-,- E I A CBL4 93 m 3234600 0507L5L 772 m CB14 Page 6 ITIONS TO RE PIvaZsBTEp - 2. 3. 4. 5. 6. E. CLEANI
40、NG: If a lubricant is applied by the connector manufacturer, cleaning will remove the lubricant and, hence, no advantage will be gained. PARTICULATE RETENTION: A lubricate can increase the retention of particulates from the environment. This can be in the form of dust and/or fibers. Recent studies h
41、ave indicated that dust does not adversely affect the function of a lubricant. Further study is required relative to fibers. CONTAMINATION OF ADJACENT SURFACES: Certain lubricants and the volatile carriers can transfer to adjacent surfaces. Non-spreading, low volatility lubricants are, however, unli
42、kely to transfer. A lubricant reduces mating forces. It will also reduce unmating forces. Thus, to prevent “walk out“, connectors with a lubricant should be “locked“ together by jackscrews or other hardware locking techniques used in its application. Fluid lubricants contingent on their formulation
43、may evaporate. dependent. should be researched prior to using. The rate of evaporation varies and is temperature Lubricants used in applications beyond 65OC ON CONTACT LUBRICANTS The following are typical contact lubricants available: a) Polyphenylethers : 5-PPE and 6-PPE b) Hydrocarbon oils : Miner
44、al Oils c) Perfluroalkylpolyethers d) Polyolef in Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproduction or networking permitted without lic
45、ense from IHS -,-,- E I A CBL4 93 323qbOO 0507152 b0 D CB14 Page 7 For additional information relative to generic or proprietary contact lubricants, the following companies may be contacted: Moncanto, St. Louis, MO William F. Nye, New Bedford, MA Dow Chemical Corporation, Midland, MI Tenneco Chemica
46、ls, Piscataway, NJ R o h & Haas, Philadelphia, PA Electrotube Corporation, Syosset, NY Copyright Electronic Components, Assemblies & Materials Association Provided by IHS under license with ECA Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/30/2007 03:06:29 MDTNo reproductio
47、n or networking permitted without license from IHS -,-,- E I A CB14 93 3234600 0507153 5Y5 CB14 Page 8 The following is not a complete listing of all reference work published in the area of contact lubrication. references. Additional references are contained with the publications listed. It does lis
48、t key 1. 2. 3. 4. 5. 6. 7. 8. * 9. 10. 11. 12. S.J. Knunbein, Mort Antler, “Inhibition of Corrosion and Wear on Gold Plated Contacts“, NEP/CON, 1967. L.P. Solos, “Fundamental Study of Gold Plating and Dry Film Lubricant System for Long Life Sliding Contacts“, Nat. Aerospace Electronics Conf. , NAECON, 1964. G. Steinberg, S. W. Chaikin, “Lubrication of Electrical Contacts with Solid Thin Films of Organic Compounds“, Holm Conf., 1966. M. Antle