1、FORD LABORATORY TEST METHOD BN 102-01 2001 O9 17 POLYMERIC MATERIALS - LOW TEMPERATURE FLEXIBILITY Revised Editorial - no technical change A. Cockman Application This method is used to establish the low temperature flexibility of interior trim materials such as supported and unsupported vinyls, genu
2、ine and simulated leathers, and rubber components such as hoses, fabric- reinforced and unreinforced diaphragms, weatherseals and other applications where the ability to flex at the minimum operating temperature without cracking is required. Scope This procedure is used to evaluate the effects of lo
3、w temperature on flexible polymeric materials when bent 180 O around a mandrel into a loop configuration while at low temperature. It may be performed on materials “as-received“ and/or after any aging or preconditioning requirements indicated on the applicable Engineering Material Specification and
4、Drawings. The bending of hoses is carried out on a specific fixture designed to overcome the problems of the very high effort required to bend some hoses manually. It also gives better control over the bending process and eliminates localized kinking of the hose. Apparatus Required Mandrels Of varyi
5、ng diameters and sufficient rigidity and a suitable support to facilitate rapid flexing of the material while in the cold chamber. Hose-Bending Fixture Refer to Figure 1. The fixture shall be capable of taking a wide range of interchangeable mandrels and shall be securely supported when placed in th
6、e cold chamber so that it does not move or topple during the bending of the hose. Cold Chamber Capable of maintaining a constant and uniform temperature of +/- 2 OC of the temperature specified in the applicable Engineering Material Specification or Drawing. It should be top-opening to minimize the
7、increase in internal temperature when accessed and be large enough to accommodate fixturing as well as providing room to work. I Date I Action I Revisions I Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BN 102-01 Portable Temperature Probe and Indicator Precision of +/- 0.
8、5 C; L.E.D. or L.C.D. temperature indicator with a lead wire of sufficient length to permit location of the indicator outside of the cold chamber. Note: The probe is necessary only when the oven is not equipped with a precision temperature indicator. Gloves To permit handling of hot or cold parts an
9、d/or fixtures. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 OC and 50 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Proce
10、dure A. Materials and Parts (Other Than Hoses): 1. For thin sheet materials, prepare a 50 x 200 mm specimen; for soft materials (e.9. foams, cellular rubber), prepare a 25 x 200 mm specimen; for a thicker slab or for calendared materials, prepare a 12 x 200 mm specimen; for extruded products, cut a
11、specimen of sufficient length to facilitate flexing about a mandrel. 2. Precondition the material according to the applicable Engineering Material Specification or Drawing for the prescribed time and temperature in a controlled environment. 3. Select a steel mandrel that is 1 O times the material th
12、ickness (or 1 O x the nominal outside dimensions if an extruded product) unless otherwise specified. 4. Place the test specimen, mandrel, and gloves in the cold chamber at the specified temperature and maintain for 24 h. Note: Suspend the specimens so that there will be free circulation of air while
13、 conditioning in the oven or cold chamber. If the temperature control is in doubt, locate a temperature probe next to the specimen with a read-out instrument external to the chamber. 5. At the end of the exposure period, open the chamber and, using gloves, hold the specimen on the extreme ends and b
14、end 180 O as rapidly as possible around the mandrel while it is still in the chamber. To minimize temperature fluctuations in the chamber, avoid breathing into the chamber during the test. Page 2 of 4 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BN 102-01 B. Hoses: 1. 2.
15、3. 4. 5. 6. Age or precondition the hose according to the applicable Engineering Material Specification or Drawing. Select a torque wheel (refer to Figure 1 in Appendix A) with a diameter 10 times that of the outside diameter of the hose under test (or as otherwise specified). Clamp a length of the
16、hose equal to 3 times the circumference of the torque wheel to a tangential stub mandrel of suitable size such that the natural curvature of the hose follows the curvature of the torque wheel. Adjust the guide roller so that it holds the hose loosely against the torque wheel and place the fixture in
17、 the cold chamber at the specified test temperature for 24 h. By means of the torque bar, bend the hose 180 O around the torque wheel such that the bending operation is completed within 15 +/- 5 s. Conduct a proof pressure leakage test and burst pressure test as specified in the applicable Engineeri
18、ng Material Specification or Drawing. Chemicals, materials, parts, and equipment referenced in this document must beused and handled properly. Each party is responsible for determining proper use and handling in its facilities. Page 3 of 4 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY
19、 TEST METHOD BN 102-01 POLYMERIC MATERIALS - LOW TEMPERATURE FLEXIBILITY Hose Bending Fixture The fixture shall be constructed from materials of sufficient strength and rigidity to withstand the forces involved in bending the hoses at low temperature. The construction materials shall be either corro
20、sion resistant or be suitably surface coated to prevent corrosion as a result of water condensing on the cold surfaces. Any greases or oils used to lubricate the bearing surfaces shall remain fluid at the test temperatures. Torque Bar ci Shaft 5mm dia. -ame and Wheels Interchangeable Tangential Stub Mandrels I Guide Roller. Slot for Guide Roller Adjustment Figure 1 Copynght02001, Ford Global Technologies, Inc Base Page 4 of 4
