FORD WFPP 002-2012 BEST PRACTICES AND COMPLEXITY REDUCTION.pdf

1、 WORLDWIDE FASTENER STANDARD 2012 09 28 Printed copies are uncontrolled Copyright 2012, Ford Global Technologies, LLC. Page 1 of 2 WFPP 002 WORLDWIDE FASTENER PRACTICE/PROCEDURE - BEST PRACTICES AND COMPLEXITY REDUCTION 1. SCOPE This Standard defines the agreements that have been approved by the Wor

2、ldwide Fastener Technical Committee for all new releases. These agreements support best fastener practices and complexity reduction efforts. Carry-over fasteners should be reviewed in line with these policies and strategies. Proprietary features other than those to which a Worldwide Fastener Standar

3、d exists or those approved by the Worldwide Fastener Technical Committee are prohibited and shall not be specified. EXCEPTIONS: Exceptions to the practices and procedures within this document require approval of the Supervisor of the relevant Fastener Engineering Office. Exceptions require the submi

4、ssion of a business case along with the 1217 number request form. The business case shall include the cost and/or technical benefits to Ford Motor Company based on statistically valid data. 2. REFERENCES ISO 4757 Cross Recesses for Screws WB 900 Appendix D Dimensional Requirements for Internal Lobed

5、 Recesses. WB 900 Appendix E Lobed External Drive System for Threaded Fasteners. WD 951 Mechanical and Performance Requirements of Case Hardened Thread Rolling Screws WD 952 Mechanical and Performance Requirements of Through Hardened and Carbon Restored Thread Rolling Screws with Induction Hardened

6、Points WD956 Mechanical and Performance Requirements of Through Hardened and Carbon Restored Thread Rolling Screws for Use in Aluminum Applications WK 900 Hoseclamps Worm Drive 3. AGREEMENTS BOLTS, SCREWS, STUDS, AND SCREW AND WASHER ASSEMBLIES The only property classes that shall be specified for n

7、on-hardened and through hardened externally threaded fasteners are PC4.8, PC8.8, or PC10.9. PC10.9 (10.9 underlined) fasteners are unacceptable. NUTS The only property classes that shall be specified for internally threaded fasteners are PC04, PC8, PC10 or PC12. PC12 shall only be used for yield tig

8、htening applications to ensure that the mode of failure is bolt shank fracture. THREAD ROLLING SCREWS For general steel applications, all thread rolling screws shall be of a trilobular design and meet the requirements of WD951 or WD952. Thread rolling screws M6 and above shall use the Taptite 2000th

9、read form and comply with the requirements of WD952. For general aluminum applications, thread rolling screws shall be of a trilobular design (Taptite 2000“SP) and meet the requirements of WD956. SCREWS FOR THERMOPLASTIC MATERIALS Remformand PTare the only thread forms to be used for screws going in

10、to thermoplastic materials. DRIVE SYSTEMS The hexagon external drive per WA900 and the six lobe drive per WB900 Appendix E are the only approved external drive systems. The six lobe drive per WD900 Appendix D is the only approved internal drive system. The hexagon internal drive system is permitted

11、only for set screws and screw plugs. WORLDWIDE FASTENER STANDARD 2012 09 28 Printed copies are uncontrolled Copyright 2012, Ford Global Technologies, LLC. Page 2 of 2 POINT FEATURES CROSS THREAD PREVENTION POINTS The NP point shall be specified for the reduction of cross threading unless not feasibl

12、e for the given application. In those instances where the NP point is not feasible, the CTP point shall be specified. No other cross-threading point styles are permissible. Some forms of prevailing torque nuts are not compatible with all forms of cross thread prevention points. For example, limited

13、thread engagement and the prevailing torque style of multiple threaded spring nuts makes this nut form incompatible with NP points and may lead to assembly concerns. In this case, the CTP point is recommended. Compatibility of both prevailing torque nut and cross thread prevention point styles shoul

14、d be reviewed before releasing. DRILL POINTS The use of drill points is prohibited for Worldwide fasteners. WORM DRIVE HOSE CLAMPS The only approved design for worm drive hose clamps is the all stainless formed-band type in accordance with WK903. TORQUE VALUES Torque values should be in accordance w

15、ith PT-3 of the Power Tool and Torque Standards. This standard can be found at: http:/ SUMMARY OF REVISIONS 2012 09 28 Para 2: Added WD956 Reference Para 3: Under “THREAD ROLLING SCREWS“ added thread type description for aluminum applications Under “SCREWS FOR THERMOPLASTIC MATERIALS“ revised allowable thread forms Under DRIVE SYSTEMS“ revised allowable internal drive requirement