1、 FORD LABORATORY TEST METHOD EU-BI 007-01 Date Action Revisions 2001 03 13 Revised Editorial no technical change A. Cockman 1994 02 28 Printed copies are uncontrolled Page 1 of 6 Copyright 2001, Ford Global Technologies, Inc. CHIP RESISTANCE TEST FOR PAINTED PANELS Application This test method is us
2、ed to determine the chip resistance of painted panels and body parts and painted plastic panels and parts. Apparatus Required Gravelometer The Gravelometer (see attached sketch) consists of an elongated box with a hopper and nozzle system on one end and a slot for the insertion of a test panel on th
3、e other end. Steel shot is poured into the hopper where a stream of air propels the shot onto the test panel. The nozzle system consists of - beginning from the main line air supply side - a 200 mm, 1/2 inch (12.5 mm) air inlet pipe with an inner diameter of 11.5 mm, a tee-piece to fix a pressure ga
4、ge with a range of 0 to 1.6 bars, a 150 mm, 1/2 inch (12.5 mm) air inlet pipe with an inner diameter of 11.5 mm, and a nozzle which is exactly described in an additional drawing. To guarantee a laminar air stream during the test, all pipes have to be polished on the inner surface. From the inlet to
5、the outlet of the air the inner diameter of the pipe system must be exactly 11.5 mm. The joint from the main line air pressure to the pipe has to be made by a two meter, 25 mm metal hose. The test air pressure will be adjusted by a ball cock. This cock is fixed behind the main line air pressure gage
6、. This gage has a range of 0 to 16 bars, and it is used to control the static pressure at closed cock. During the test the flow pressure must be controlled by this gage all the time. A second gage of a range from 0 to 6 bars must be fixed immediately behind the ball cock. By this gage it is possible
7、 to control the pressure which is reduced only by the position of the cock. All gages must be tested every 6 months. It is recommended to have a primary pressure of 7 bars. It is not permitted to deviate from the dimensions of these specified components. Source: Messrs.Erichsen or Pearson-Panke Equi
8、pment Ltd. 5870 Hemer Sundwig 1-3 Halegrove Gardens Germany London NW7 3LR FORD LABORATORY TEST METHOD EU-BI 007-01 Page 2 of 6 Copyright 2001, Ford Global Technologies, Inc. Steel Shot 13.6 kg of SAE 780 shot with the following additional requirements: Size 100 % to pass through a No. 7 screen (2.8
9、 mm) 100 % to be retained on a No. 10 screen (2.0 mm) Shape To be as near 100 % round as possible. Hardness 90 % to be RC 42-48 One litre of water containing 5 g of potassium dichromate is used to wet the steel shot and then dried to prevent rusting of the shot in storage. Source: Messrs. Nolten 420
10、0 Oberhausen Europahaus Germany Steel Test Panels Steel body skin panels 100 x 300 mm, prepared according to the requirements of the relevant material specification. Evaluation Standards 4 black and white photographs. Source: Central Laboratory Ford-Werke AG 5000 Koln 60 West Germany Calibration of
11、the Gravelometer For calibration of a Gravelometer a master nozzle and specially prepared calibration panels are required. These panels prepared with three different test enamels which give after shot rating 0, rating worse than 3 with particular chipping of enamel and rating worse than 3 with compl
12、ete chipping, can be obtained from Materials Laboratory Product Engineering. The Central Laboratory Cologne is in possession of the master nozzle which can be obtained on request for the calibration exercise. FORD LABORATORY TEST METHOD EU-BI 007-01 Page 3 of 6 Copyright 2001, Ford Global Technologi
13、es, Inc. The calibration panels will be tested per para 2 through 5 of the procedure as outlined below in the Gravelometer to be calibrated. After the procedure replace the complete nozzle system with the master nozzle and repeat the test. If the corresponding panels of both series are equivalent in
14、 appearance, the Gravelometer may be considered standardized. Note: If it is not possible to achieve equivalent appearance in spite of pressure adjustment according to para 4 of the procedure below, the procedure system must have a defect or the inner surfaces of the nozzle system are worn out and t
15、he failed part must be replaced. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise
16、 specified. Procedure 1. Prepare the panels with the paint to be tested as outlined in the material specification. Test results are extremely sensitive to total paint film thickness. Thickness determination shall be made on each part tested per FLTM BI 117-01 and recorded. 2. After ageing insert the
17、 part into the Gravelometer as shown in the sketch. 10 - 15 mm of the upper edge to be above the top of the holder. 3. Pour 13.6 kg of shot retained on the No. 10 screen (2.0 mm) into the hopper with the plug in place. 4. Main line air supply should be at 7 bars prior to and 4.8 to 5.0 bars during t
18、he test. Open the line valve. Note the open line pressure at the indicating gage. This pressure should indicate 0.5 to 0.6 bars. 5. Pull the plug allowing the shot to fall into the air stream. When the panel has been abraded with the full 13.6 kg of shot, shut off the valve, remove the panel, rinse
19、in warm water and blot dry. FORD LABORATORY TEST METHOD EU-BI 007-01 Page 4 of 6 Copyright 2001, Ford Global Technologies, Inc. Evaluation Compare the test panel with the standards and report the number of the closest comparison panel or evaluate as required by the relevant material specification. 7
20、.0 bars = 7.0 atmospheres = 101.5 psi 4.8 bars = 4.8 atmospheres = 70.0 psi 5.0 bars = 5.0 atmospheres = 72.5 psi 0.5 - 0.6 bars = 0.5 - 0.6 atmospheres = 7.25 to 8.70 psi Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsi
21、ble for determining proper use and handling in its facilities. FORD LABORATORY TEST METHOD EU-BI 007-01 Page 5 of 6 Copyright 2001, Ford Global Technologies, Inc. FORD LABORATORY TEST METHOD EU-BI 007-01 Page 6 of 6 Copyright 2001, Ford Global Technologies, Inc. CHIP RESISTANCE TEST FOR PAINTED PANELS Rating 0 Rating 1 Rating 2 Rating 3
