GB 4518-1984 Test method for creepage of seam material of household sewing machines

The method specified in this standard is applicable to measuring the creepage generated when two layers of sewing materials are combined for sewing. This method is applicable to household sewing machines driven by electric motors, as well as household sewing machines driven by hand or foot. GB 4518-1984 Test method for creepage of sewing materials of household sewing machines GB4518-1984 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Household sewing machines
Test method for creep of one ply of material over another1 Introduction
UDC 687.053
.001.42
GB 4518---84
1.1 The method specified in this standard is applicable to the measurement of creep produced when two layers of sewing material are stacked together for sewing. 1.2 This method is applicable to household sewing machines driven by electric motors, and also to household sewing machines driven by hand or foot. 1. This standard is formulated with reference to the international standard 1S04818-198 "Test method for creep of one ply of material over another for household sewing machines". 2 Nouns and terms wwW.bzxz.Net
2.1 Creep: When two layers of sewing materials are stacked together and sewn on a sewing machine, one layer of sewing material gradually shortens relative to the other layer of sewing material.
2.2 Creep: After two layers of sewing materials of a specified length are stacked together and sewn together, the distance that one layer of sewing material shortens relative to the other layer of sewing material. 3 Principles
On the long side of the same sample stacked together, two cuts are cut at a specified distance, and then they are sewn together at a specified sewing speed. The mutual displacement distance of the upper and lower layers of the sample at the second cut position is measured, which is the creep. Carry out the same method four times, measure the creep of each result, and calculate the arithmetic mean, which is the creep of the sewing material layer of the sewing machine being tested. 4 Test materials and apparatus
.1 Test materials: 6 pieces of unwashed, wrinkle-free cotton fabrics specified in the appendix, 90mm wide and 600mm long, with a color line parallel to the long side and along the warp in the center of the test material. 4.2 Sewing thread: three-strand cotton thread as specified in Appendix A (Supplement). 4.8 Needle: Nm80 needle as specified in CB4521-84 "Needle for Household Sewing Machines". 5 Preparation before testing
5.1 Install the needle plate and presser foot corresponding to the seam as specified in the manufacturer's instructions. 5.2 Adjust the pressure of the presser foot as specified in the manufacturer's instructions:. If the specific value of the presser foot pressure is not specified in the instruction manual, and there is a presser foot pressure adjustment device for adjustment during use, the pressure of the presser foot when it is lowered should be adjusted to 18±1Nb. If there is no presser foot pressure adjustment device, or if there is one but it is not adjustable by the user, it should be adjusted to the original state at the factory. 5.3 Expand the working surface supporting the test material so that the entire test material is always placed flat on the working plane during the test. 5. Adjust the sewing machine to form a straight seam. 5.5 Adjust the stitch length to 2.5mm±10%. 5.6 When sewing two layers of material, adjust the tension of the needle and thread so that the needle and shuttle threads are interlocked between the two layers of material. Issued by the National Bureau of Standards on June 23, 1984
Implemented on March 1, 1985
6 Full test sequence
GB 4518--84
6.1 Align the two layers of test material and place them between the presser foot and the needle plate. Turn the upper wheel by hand so that the needle pierces the color line in the center of the test material, and then lower the presser foot.
6.2 Sew forward along the color line for about 20mm.
6.3 Spread the test material flat, and cut a 3mm long incision on the right long side of the test material as shown in the figure as a mark, and then cut another incision 500mm away from the first incision as a mark (see the schematic diagram). 6.4 Gently guide the test material with your hand, and continue to sew along the color line to the end of the test material at a speed of 700spm ± 5%. If the maximum sewing speed cannot reach 700spm, the test is carried out according to the highest stable speed that the tested machine can reach. 6.5 Repeat the test three times in the above sequence.
?Representation of test results
After each test, measure the mutual displacement distance of the upper and lower layers of the test material at the second incision position, that is, the creepage L1, L2, L3, L4, and obtain their technical average value P (), which is the creepage of the sewing machine under test. Test Report
The test report shall include the following contents:
The number of this standard
The creep amount L1, L2, L3 measured after each testc.
Average creep amount P,
GB 4518-84
If the sewing speed does not reach the speed specified in this standard, the actual test speed of the sewing machine under test shall be stated; d.
If the test material and sewing thread do not meet the requirements specified in Appendix A of this standard, the specifications and reasons of the substitutes must be stated; e.
and the differences with the provisions of this standard; f. The model and number of the sewing machine under test;
The name of the manufacturer;
The year, month and day of the test;
The name of the tester.
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A.1 Test materials
The cotton fabric used as the test material should have the following characteristics: GB 4518-84
Appendix A
Test materials and apparatus
(Supplement)
． Fabric state: bleached, unsized, colored Warp: Composition: pure cotton,
Original yarn number: warp 290 dtex,
weft 290 dtex
Density: warp 275.5 ends/dm,
weft 267.5 ends/dm2
Dry weight without pulp: 161.4 g/m2
Weaving: plain cloth
Note: Textiles shall comply with the provisions of GB406-78 "Technical Requirements for Natural Cotton Fabrics" and GB411-78 "Technical Requirements for Printed and Dyed Cotton Fabrics". A.2 Sewing Threads
The sewing threads used for testing shall meet the following requirements; a
White,
mercerized,
Z twist direction,
Specifications: 50/3Sz (125dtex3).
Note: For the provisions on sewing threads, see FJ491--8 "Cotton Pagoda Sewing Thread". Additional Notes:
This standard was proposed by the Ministry of Light Industry of the People's Republic of China and is under the jurisdiction of the China Sewing Machine Industry Standardization and Quality Inspection Center. This standard was drafted by the Shanghai Sewing Machine Research Institute. The main drafters of this standard were Jiang Chengqing, Pan Xiji and Fang Yuming. 43
Also standard logic requirements
Also low line section
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