1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions Rev. 00 2016 12 20 Released M. Katz, NAControlled document at www.MATS.com Copyright 2016, Ford Global Technologies, LLC Page 1 of 20 DECORATIVE CHROME ELECTROPLATED PART PERFORMANCE WSS-M1P83-E2 REQUIREMENTS, ABS OR PC/ABS SUBSTRATES, GENERAL
2、 EXTERIOR USE 1. SCOPE This specification defines the performance requirements for copper, nickel, and chromium electroplated acrylonitrile butadiene styrene (ABS) and polycarbonate/acrylonitrile butadiene styrene blend (PC/ABS) parts for exterior applications. 2. APPLICATION This specification was
3、released originally where a decorative chrome finish is required for exterior applications, including, but not limited to, grilles, door handles, badges, belt moldings, and mirror caps. 2.1 LIMITATIONS No coating (paint, ink, etc.) may be applied over chrome plating per Ford Design Rule OR-010812-00
4、01. 2.2 REFERENCES Appendix A: Applicable Design Rules Appendix B: PPAP Report Template Appendix C: Reference Images Appendix D: Example SCCAF 3. REQUIREMENTS This specification is performance based and does not have approved sources. All requirements identified for this specification must be met to
5、 achieve acceptable field durability. No one requirement, exclusive of others, is capable of insuring satisfactory performance. Any deviations to the requirements of this specification may be subject to additional performance requirements. Testing at Design Verification (DV), Material Color Durabili
6、ty/Compliance Certification (MCDCC), and Process Validation (PV) must be conducted per Table 7. For MCDCC approval, parts from DV and/or PV testing may be submitted in lieu of separate test parts, as long as the quantity of parts per Table 7 is met. Routine testing for process control shall be condu
7、cted per Table 7, or as directed on the Special Characteristics Communication and Agreement Form (SCCAF). An example SCCAF can be found in Appendix D. The required number and frequency of samples may be changed due to part geometry or production concerns and at the discretion of Ford Design and Rele
8、ase Engineering (D&R) and Supplier Technical Assistance (STA). 3.1 APPEARANCE The plated parts shall be free from surface imperfections and must conform to the color requirements defined by Ford Design Quality, the Ford Color Harmony Team Styling Master and the Approved Boundary Sample. ENGINEERING
9、MATERIAL SPECIFICATIONWSS-M1P83-E2 Copyright 2016, Ford Global Technologies, LLC Page 2 of 21 3.2 MOLDED SUBSTRATES Material substrates used for exterior plated applications and tested to this specification must be approved to the Approved Source List (ASL) for one of the following Ford Material Spe
10、cifications: WSS-M4D836-B1/latest for ABS WSS-M4D813-B1/latest for PC/ABS The decision to use either ABS or PC/ABS shall be directed by the part specific Global Material Strategy located at https:/ and all applicable Ford Design Rules, including those listed in Appendix A. Part geometry must be cond
11、ucive to plating, in accordance with all applicable Ford Design Rules, including those listed in Appendix A. The use of regrind or recycled material for substrates in plated applications is prohibited. Material must be processed per Global Manufacturing Standard W-IMMS - Control of Plastic Injection
12、 Molding Processes, located on the Ford Supplier Portal, STA Global Technical Services, Plastic Molding, https:/ The parts shall be smooth and without flow lines, knit lines, visible porosity, cracks, sink marks, or other molding defects which may detract from the part appearance or performance. Mol
13、ded substrates must also be free of any residual stresses which would impact electroplate adhesion, dimensional stability, or appearance. Mold flow analysis should be conducted to minimize residual stress in molded substrates. Parting lines, flash and other characteristics of molding may impact part
14、 durability and must be minimized. Any rework of parting lines prior to plating must be reviewed and approved by STA before use in the production process. Testing to this standard must be completed on parts with the rework process and submitted to STA for approval. 3.3 FINISHED PARTS Design Verifica
15、tion testing must be completed on geometrically representative parts plated with the production process. Production Validation testing must be done on actual production parts. Where part dimensions limit testing, or other exceptions exist, substitution of surrogate parts or plaques requires approval
16、 of D&R, STA, and Ford Materials Engineering and documentation on the SCCAF. All visible surfaces of the component, including terminating exterior edges visible after assembly shall conform to the full requirements of this specification, unless otherwise specified in the SCCAF or on the engineering
17、drawing. Plated test specimens prepared for investigations according to this specification must be aged a minimum of 2 hours at 23 +/- 2 C prior to testing. 3.4 PROCESS OPTIMIZATION Process development is to be completed prior to any qualification testing to this specification (DV, PV, etc.). Repeti
18、tion of these tests may be necessary in order to optimize molding and plating parameters for successful part performance. Once optimization of all parameters is complete, all testing, including tests in Section 3.4, must be conducted at the production parameter levels. Only results of the final test
19、s, with production levels of all parameters, are required to be submitted as part of the PPAP package. ENGINEERING MATERIAL SPECIFICATIONWSS-M1P83-E2 Copyright 2016, Ford Global Technologies, LLC Page 3 of 21 3.4.1 Residual Stress Test No cracking Residual stresses in molded plastic parts are areas
20、of potential weak electroplate adhesion. Testing for residual stress must be conducted for new parts, when any molding parameter changes, or when adhesion issues may be due to molding stress. Repetition of this test may be necessary in order to optimize molding parameters for reduction of molded-in
21、stresses before all additional testing is completed. Areas with high contrast between light and dark indicate locations of high molded-in stress (Appendix C, Figures 1 and 2). High stress areas should be documented as “adhesion points” or “A-points” in the SCCAF at the direction of the D&R. A minimu
22、m of two “A-points” per part must be indicated. All subsequent adhesion testing per Section 3.5 must be conducted at these locations. Completely immerse the unplated part in glacial acetic acid, 99% purity, at 23o C +/- 3 C for 30 seconds. Remove and immediately rinse the part with water to remove a
23、cid from the surface and allow to dry at room temperature. Review and photograph the part, noting any areas of uneven whitening. Return the part to the glacial acetic acid bath for up to the duration indicated by Table 1 below. Table 1: Glacial Acetic Acid Test Time Substrate TimeABS 120 secondsPC/A
24、BS 180 secondsAfter the specified time has elapsed, immediately rinse the part with water to remove acid from the part surface and allow to dry at room temperature. Review and photograph the part again, noting any areas of uneven whitening. Report must include photos of the part before testing, afte
25、r 30 seconds, and after 120-180 second durations. These photos must be retained for process control validation of the optimized molding process. 3.4.2 Scanning Electron Microscopy (SEM) Report Only In order to document the level of etch obtained on the surface of successfully tested parts, PV testin
26、g submissions must include SEM images at 500X magnification of the etched, unplated plastic surface. Images should be taken in high and low stress areas (whitened and dark areas), as determined by the Residual Stress Test in Section 3.4.1. Examples of under-etched, over-etched and properly etched su
27、rfaces can been seen in Appendix C, Figures 3, 4 and 5, respectively. Improper molding of the part may cause elongated etch sites, which reduce adhesion of the electroplate to the substrate. An example of this condition can be found in Figure 6. ENGINEERING MATERIAL SPECIFICATIONWSS-M1P83-E2 Copyrig
28、ht 2016, Ford Global Technologies, LLC Page 4 of 21 3.4.3 Simultaneous Thickness and Electrochemical Potential Test (STEP) (ASTM B764) The graph of the STEP test, along with the calculated difference of potentials shall be provided with the submission package. An example STEP curve can be found in A
29、ppendix C, Figure 7. 3.4.3.1 Semi-bright nickel to decorative nickel 100 mV min 3.4.3.2 Discontinuous nickel to decorative nickel 20 90 mV 3.4.4 Minimum Discontinuities (ASTM B604, X4) Exterior applications require a discontinuous chromium layer (microporous or microcracked) on a multiple layer nick
30、el system. Microporous systems are the preferred method for corrosion resistance of plastic parts. Microcracked system usage should be limited and pre-approved by the D&R and Materials Engineering. The active sites method shall be the preferred method used to determine microporosity. Images at prope
31、r magnification taken before and after CASS exposure must be recorded. For Satin finishes, the active sites method and a SEM must be used to determine microporosity. Evaluation of microcracks may be done directly by counting the cracks that intersect a straight line with length of at least 1 mm with
32、 a microscope at 100X and calculating to the appropriate units. Plating sources are required to maintain minimum discontinuities as defined in Table 2.Table 2: Minimum Discontinuity Quantities Type Minimum DiscontinuityMicropores 10,000 pores/cm2Microcracks 250 cracks/cmMicrographs used for determin
33、ation of discontinuities and the calculated values must be included in submissions. Example images of discontinuities are available in Appendix C, Figures 8, 9, 10, and 11. 3.4.5 Minimum Plating Thickness (ASTM B487, ASTM B504, ASTM B568) Minimum plating thicknesses are defined in Table 3. For typic
34、al plating construction, refer to Appendix C, Figure 12. Plating thickness should be optimized prior to PV testing to ensure all requirements of the specification are met. To achieve this, electroplated part suppliers must identify the plating thickness distribution for each unique part and rack des
35、ign by mapping the system per Ford Design Rule CPG10801-0032. An example of a single layer analysis of chromium can be found in Appendix C, Figure 13. The plating thickness distribution must be examined for both the production rack and the production part geometry for each plating layer. This proces
36、s is used to demonstrate that the minimum metal plating thicknesses can be obtained for the entire part or to alert Ford to any potential metal thickness concerns. The use of auxiliary anodes is recommended, where applicable. ENGINEERING MATERIAL SPECIFICATIONWSS-M1P83-E2 Copyright 2016, Ford Global
37、 Technologies, LLC Page 5 of 21 Areas of low and high thickness must be documented in the SCCAF on a part and rack level as “pick points”, and submitted to the D&R as part of DV. The lowest thickness part shall also be documented on the SCCAF. Areas with exceptions to the minimum metal thickness req
38、uirements must be approved in writing by the D&R and shown in detail on the SCCAF. Formal deviation is not required. Details must include the area or areas below the minimum and the allowed thickness exception for each. An example of a documented exception can be found in the example SCCAF, Appendix
39、 D, item number 2. Parts with these exceptions must meet all other applicable specification and SDS/CDS requirements. Copper and nickel layer thickness to be determined by Microscopic Examination (ASTM B487). Chromium layer thickness to be determined by Coulometric Method (ASTM B504), or X-Ray Spect
40、rometry (ASTM B568). Table 3: Plating Layer Minimum Thickness Requirements Plating Layer Minimum thickness (m)Copper 18Semi Bright Nickel 15Decorative Nickel 6Microporous Chromium 0.18Microcrack Chromium 0.8The percent of the total nickel thickness which is composed of semi-bright nickel and decorat
41、ive nickel shall be as indicated in Table 4. Table 4: Percent of Semi-Bright to Decorative Nickel Nickel Type Percent of Total NickelSemi Bright Nickel At least 60%Decorative Nickel No more than 40%3.5 PLATING ADHESION All adhesion testing must be completed on the part at the “A-points” in areas of
42、high stress as indicated by Section 3.4.1, Residual Stress Test, unless otherwise noted. Where a single part is produced by multiple cavities, testing at PV must be completed on parts molded from the tool cavity that produces the highest stress conditions, as determined by Section 3.4.1. 3.5.1 Grind
43、-Saw Test (ASTM B571, with modifications below) Testing will be performed using a handheld hacksaw with 6-8 teeth/cm, cutting from the substrate toward the plating. The cut will be made with the plane of the saw 90 degrees to the test area and the blade angled at 45 degrees towards the part (visual
44、representation in Appendix C, Figure 14). A minimum 5 cm cut shall be made at a rate of approximately 1 stroke per second. If part geometry doesnt allow the minimum cut length, the part shall be cut at the maximum length possible. Bandsaws shall not be used for this test. Testing shall be completed
45、in both “A-points” per Section 3.4.1, and in high thickness “pick points” per Section 3.4.5. ENGINEERING MATERIAL SPECIFICATIONWSS-M1P83-E2 Copyright 2016, Ford Global Technologies, LLC Page 6 of 21 All tested samples must indicate no evidence of peeling, flaking, or lifting of the electroplate from
46、 the substrate or between the plating layers. The approving Ford engineer should attempt to peel the plating away from the cut edge with a sharp blade to further evaluate the propagation of adhesion loss. 3.5.2 Peel Strength of Metal Electroplated Plastics (ASTM B533, Procedure A, except production
47、plating layers on parts) ABS 9.0 N/cm curve ave min 7.0 N/cm curve low min PC/ABS 4.5 N/cm curve ave min 3.5 N/cm curve low min Testing shall be completed on a flat section of the part. If no large flat area exists, or if part size prohibits full peel size, a strip of minimum 1 cm X 5 cm can be subs
48、tituted. The resulting values must then be calculated to match the units of the requirement. Testing must be conducted on as large of an area as possible. For each Peel Strength graph, discard the beginning and breaking point of the curve. The average of this center section must meet the curve avera
49、ge minimum requirement. No data point in the center secion of the peel curve shall be below the curve low minimum requirement. Average and low values must be reported for each curve. Test curves must be provided with results. An example curve can be found in Appendix C, Figure 15. Where part geometry or size prohibts suitable Peel Strength testing, results will be substituted with additional test samples of 3.7 Extreme Thermal Cycle, as directed by Table 7. 3.6 CHIP RESISTANCE Tested sp
