1、 ENGINEERING MATERIAL SPECIFICATION Material Name Specification Number Date Action Revisions 2003 06 13 Revised Para 3.0 inserted; Para 3.5, 3.6, 3.7, 3.8, 3.10, 4 deleted 1994 06 30 NGA1E10370437006 Released A. Vallabhanath Printed copies are uncontrolled Page 1 of 5 Copyright 2003, Ford Global Tec
2、hnologies, Inc. EPOXY POWDER, ELECTRICAL INSULATION WSF-M3L72-A2 ELECTROSTATIC FLUIDIZED BED APPLICATION, FUEL RESISTANT 1. SCOPE The material defined by this specification is a finely ground epichlorohydrin bisphenol epoxy resin in dry powder form. It is applied to the surface of a part at room tem
3、perature from a fluidized bed by means of electrostatic action. 2. APPLICATION This specification was released originally for material used as a coating on metal for electrical insulation and corrosion protection, such as on the alternator stator and windshield wiper motor armature for slot and end
4、insulation. 3. REQUIREMENTS 3.0 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.1 TEST BAR To be run on each lot of material 3.1.1 Preparation of Test Bars Six square
5、steel bars (12.7 x 12.7 x 150 mm) having all significant surfaces ground to 0.75 1.25 micrometer) rms shall be thoroughly degreased in at least two successive baths of trichloroethane. They shall then be electrostatically coated at room temperature with 0.30 0.46 mm of resin on the flat surface. The
6、 bars shall then be cured for 10 minutes at 210 C in an air circulating oven. This time and temperature may be deviated provided the actual time and temperature data accompany the bars at the time of submission. Test bars which do not meet the above requirements for thickness and coverage may not be
7、 reworked for submission to this specification. 3.1.2 Hardness Knoop 20 - 25 (ASTM D 1474, 100 g load) ENGINEERING MATERIAL SPECIFICATION WSF-M3L72-A2 Page 2 of 5 Copyright 2003, Ford Global Technologies, Inc. 3.1.3 Particle Size On 60 mesh None Through 60 on 80 mesh, max 1.2% Through 80 on 325 mesh
8、 Balance Through 325 mesh, max 37.0% 3.1.4 Differential Scanning Calorimetry The DSC thermogram for this material shall match the standard thermogram curve on file at the appropriate Materials Office of the affected Product Engineering Office. The thermogram shall be generated at 20 C/minute in air
9、at 101 kPa and shall show the Tg and the heat of reaction. 3.2 To be run for initial approval and as specified by Quality Control. Since the above tests are required on each lot, these results will also be included as part of this testing and results reported. 3.2.1 Cut Through Temperature, min 300
10、C (Average of 2 tests) All bars must pass Test Method: See figure 1. Mount the bar by means of clamps on a ring stand. Place a loop of 26 gage bare copper wire over the resin coated area 13 mm from the coated end. Attach a 227 g weight including any clamps or leads to the wire and place the test ass
11、embly in a forced air circulating type oven. Attach one lead from an 8 Va-c power supply alarm circuit to the cutting wire and one to the bare end of the steel test bar. Include this lead weight as part of the 227 g load. Attach a thermocouple to the steel bar by placing in the 3.2 mm drilled hole i
12、n the bar. Secure with tape. Start the oven and increase the temperature at a rate not to exceed 208 C/h to allow uniform heating of the test bar. When cutting wire penetrates the resin and contacts the steel bar surface the circuit will be closed and the buzzer alarm activated. Immediately record t
13、he temperature of the test bar. This temperature shall be defined as the cut through temperature of the resin. Repeat the test and record the average of the 2 tests as the cut through temperature. 3.2.2 Thermal Shock Resistance Must pass the following on 4 bars Place part in a circulating air oven a
14、t 154 C for 30 minutes. Remove and quench in cold water. Dry and immediately place in alcohol-dry ice mixture at -40 C for 10 minutes. Remove and inspect for signs of cracking, crazing, or loss of adhesion. Repeat above cycle 9 more times. At the end of the 10 cycles there must be no cracking, crazi
15、ng, or signs of adhesion loss on any of the 4 test bars. ENGINEERING MATERIAL SPECIFICATION WSF-M3L72-A2 Page 3 of 5 Copyright 2003, Ford Global Technologies, Inc. 3.2.3 Dielectric Strength, min 20 kV/mm (ASTM D 149, short time, test 6 bars) Except use the bar as one electrode and a 12.7 mm wide alu
16、minum foil wrapped completely around the bar on the resin as the second electrode. All bars must meet or exceed the minimum. 3.2.4 Fuel Compatibility Epoxy coated test samples 25 x 100 mm shall be immersed in ASTM D 471 Ref. Fuel C at 60 C for 336 h. 3.3 FINISHED PART 3.3.1 Thickness To be specified
17、 on engineering drawing 3.3.2 Dielectric Strength, min 20 kV/mm (ASTM D 149, short time) 3.3.3 Cut Through Temperature, min 300 C Test Method: See para 3.2.1. This requirement is only specified when the part is of a configuration which permits testing such as the slot tooth on the alternator stator,
18、 the windshield wiper motor armature, etc. 3.3.4 Adhesion Must pass the following Using a bent point scriber (such as a Starrett #67), scribe a line through the resin coating to the metal substrate in an area when insulation is not required, if possible. The resin shall cut cleanly with no flaking,
19、crazing or chipping away from the scribed or chiseled line. This requirement may be deviated when an appropriate impact test, approved by the Product Engineering office, is employed as a substitute. 3.3.5 Thermal Cure The differential scanning calorimeter (DSC) thermogram on cured resin removed from
20、 a significant surface of a production part shall have a maximum Tg of 117 C and evidence of 3% maximum heat of reaction when thermally evaluated at 20 C/minute in air at 101 kPa. 3.4 Powders of different manufacture, process, blend or chemistry shall not be intermixed in the electrostatic fluidized
21、 bed without prior approval of the Product Engineering Office. ENGINEERING MATERIAL SPECIFICATION WSF-M3L72-A2 Page 4 of 5 Copyright 2003, Ford Global Technologies, Inc. 5. GENERAL INFORMATION The information below is provided for clarification and assistance in meeting the requirements of this spec
22、ification. 5.1 TOXICITY This material shall be considered as relatively nontoxic compared to liquid epoxies. However, since it is an epoxy, care should be taken to avoid prolonged exposure to the skin. This material should be used in a closed system to reduce the possibility of breathing the powder.
23、 5.2 EXPLOSION HAZARD As stated, the material should be used in a closed system because of the possibility of dust explosion present in powdered materials. 5.3 STORAGE LIFE The resin shall be used on a first in first out basis. All containers shall be sealed and prominently show the date of manufact
24、ure; the batch number; the 6 month expiration date. No material may be used beyond its expiration date or from damaged containers without the approval of the Product Engineering office. Caution must be employed to insure that this material is not exposed to unnecessary heat or other sources of energy which will affect storage life. Maximum allowable storage temperature is 38 C. From May 15 to September 30 all material must be shipped via refrigerated vehicles. ENGINEERING MATERIAL SPECIFICATION WSF-M3L72-A2 Page 5 of 5 Copyright 2003, Ford Global Technologies, Inc.
