1、FORD LABORATORY TEST METHOD BN 115-07 Date 2001 O9 11 1999 o1 19 COMPRESSION SET OF POLYURETHANE FOAM Action Revisions Revised Editorial - no technical change A. Cockman Application This procedure is used to determine the constant deflection compression set expressed as a percentage of the original
2、deflection of seating grade polyurethane foam. Apparatus Required Steam Autoclave Equipment necessary to maintain required temperature and pressure. Bandsaw Saw Blade (Regular bandsaw with a double beveled scalloped edge band knife blade may be used.) Dial Gage Model #35B-30 (range O - 50 mm, 1 divi
3、sion = 0.02 mm) mounted to a stand gage having a 25 mm circular diameter circular indenter foot and used exclusively for compression set measurements by having the shaft spring removed. Source Federal Products Corporation 1144 Eddy Street, P.O. Box 9400 Providence, Rhode Island 02940 Phone: (401) 78
4、1-9300 Fax: (401) 941-5280 Compression Device This consists of two flat plates 1 O0 x 200 x 13 mm steel plate. The two steel plates must be held parallel to each other by bolts and the space between the plates must be adjustable to the required deflection thickness using spacers or shims. FORD LABOR
5、ATORY TEST METHOD BN 115-07 Conditioning All test specimens or parts (from which test specimens will be obtained) shall be preflexed twice to 80 - 90 % (IO - 20 % compression) of their thickness then conditioned (post cured) at 23 +/- 2 “C and 50 +/- 5 % relative humidity for seven days minimum prio
6、r to testing and tested under the same conditions. The post cure time shall commence from time of demolding part or from time of slab bun cure. When test specimens are submitted to Ford Motor Company for evaluation and if the test specimens (or parts from which test specimens will be obtained) have
7、previously been post cured seven days at the suppliers plant, then the test specimens (or part) need only to be preflexed twice (80 - 90 %) as above and conditioned 2 h at the above temperature and relative humidity prior to testing. Samples Size and Selection All test specimens shall be selected fr
8、om an area that is directly below the IRGL circle, (Indentation Residual Gage Load) or as specified on the engineering drawings. The test specimen shall be free of skin, voids, hard spots, striations and densifications or knit lines. These specimens shall be cut 50 x 50 x 25 mm with the mm dimension
9、 perpendicular to the part top surface, and the top surface of the cut specimen, parallel to, and 6 mm below the top surface of the part. Specimens less than 25 mm thick shall be plied up, without the use of cement, to a 25 mm thickness. Three test specimens per part shall be tested. The computed Cd
10、 values reported shall be the mean of those observed. If any value deviates more than 20 % from this mean, two additional specimens shall be tested and the mean for all five values shall be reported. Preparation After selection and cutting to the required size, all specimens must be dust free and sh
11、all be conditioned for 1/2 h at 23 +/- 2 “C and 50 +/- 5 % relative humidity. Procedure 1. Using the Federal Products dial gage, take height measurements at each of the four corners and at the center of each sample, average the five measurements, and record as original height. The outer circumferenc
12、e of the indenter foot shall be approximately 3 mm in from each edge of foam specimen when measuring corners. 2. Place two specimens in the compression device at least 38 mm apart, and deflect 75 % using spacer bars, and shims. Page 2 of 3 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY
13、 TEST METHOD BN 115-07 3. Within five minutes, place the deflected specimens and the clamped device in a mechanically convected oven at a temperature of 70 C +/- 2 OC for 22 h, then remove the device and unclamp and remove the specimens immediately. 4. Remeasure heights (as in para 1 above) after a
14、30 - 40 minute minimum recovery time. 5. Calculations: Calculate the constant deflection compression set, expressed as a percentage of the original deflection as follows: Cd = TO - Tf x 1 O0 TO - TS Where Cd = Compression set expressed as a percent of the original deflection. To = Original thickness
15、 of sample. Ts = Thickness of spacer bar and shims used. Tf = Final thickness of sample. 6. Steam Autoclave Aged: Measure the heights of three test specimens and then determine the normal compression set, defined herein, after the specimens have been steam autoclave aged for 3 h at 19 +/- 2 kPa and/
16、or 104 +/- 2 OC, then dried 3 h in a convection oven, or as specified in the material specification, followed by 16 h conditioning at 23 +/- 2 “C and 50 +/- 5 % relative humidity. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities. Page 3 of 3 Copynght02001, Ford Global Technologies, Inc
