This standard specifies the test materials and apparatus, test methods, presentation of test results and test reports for the feed direction stability test method of household sewing machines when sewing without threading. This standard applies to household sewing machines driven by electric motors, as well as household sewing machines driven by hand or foot. GB/T 4517-1995 Test method for feed direction stability of household sewing machines GB/T4517-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Household sewing machines
Test method for feed direction stability
Household sewing machines
-Determination of directional stabilityGB/T4517-1995
Replaces GB4517-84
This standard adopts the international standard ISO 4817 "Test method for feed direction stability (deviation) of household sewing machines" in a non-equivalent manner. 1 Subject content and scope of application
This standard specifies the test materials and apparatus, test methods, expression of test results and test reports for the test method for feed direction stability of household sewing machines when sewing without threading. This standard applies to household sewing machines driven by electric motors, as well as household sewing machines driven by hand or foot. 2 Reference standards
GB406 Technical requirements for natural cotton fabrics
QB/T1514 Needles for household sewing machines
3 Test materials and apparatus
3.1 Test materials: 10 pieces of 130 medium plain cloth are cut into wrinkle-free test materials, which are 200mm long and 60mm wide. The long side must be along the warp direction, and a marking color line is drawn in the center of the test material, parallel to the long side of the test material. Note: Other test materials similar to the specified test materials are allowed, but they should be noted in the test report. 3.2 Needle: Nm80 needle as specified in QB/T1514. 3.3 Coordinate paper: No. 4 coordinate paper in millimeters, with a hole in the center to ensure that the feeding action of the feeding mechanism and the presser foot is not hindered. 3.4 Apparatus: Vernier caliper with an accuracy of 0.02mm. 4 Test method
4.1 Test principle
Each sewing machine to be tested shall be tested five times. For household sewing machines capable of forming a zigzag seam, first test it five times with a straight seam, then adjust it to a zigzag seam and test it five more times. Calculate the average offset P for each. 4.2 Test conditions
4.2.1 Install the needle plate and presser foot supplied with the machine in accordance with the manufacturer's instructions for use corresponding to the seam. 4.2.2 Adjust the pressure of the presser foot in accordance with the manufacturer's instructions for use. a. If no specific value is specified in the instruction manual, and there is a presser foot pressure adjustment device for adjustment during use, the pressure when the presser foot is in the lowered position should be adjusted to 18±1N; b.
If there is no adjustment device, or if there is an adjustment device but it is not adjusted by the user, keep the original fixed value when the manufacturer ships. 4.2.3 Expand the working surface of the test sample so that the coordinate paper and the test sample must be placed completely flat on the working plane. The coordinate paper is fixed on the working plane with its longitudinal lines parallel to the theoretical feeding direction. 4.2.4 Adjust the stitch length to the following values;
a. Straight seam state: 1mm±0.1 mm; b. Z-shaped seam state: straight stitch length 0.5mm±0.05mm; horizontal stitch length 4mm±0.4mm.
4.2.5 Before each test, the needle must be replaced. 4.3 Test procedure
4.3.1 Place a single-layer test material on the coordinate paper between the feed member and the presser foot, and turn the upper wheel by hand to make the needle pierce the color line in the center of the test material. In the Z-shaped seam state, use the left side as the first needle to pierce the color line (see figure), make the long side of the test material parallel to the longitudinal line of the coordinate paper, and then put down the presser foot.
4.3.2 Feed the test material 150mm at a sewing speed of 700±35 stitches/min. If the sewing speed does not reach 700 stitches/min, test it according to the highest stable sewing speed that the sewing machine can achieve. Theoretical feeding direction
Operator-side
Marking color line
Sewing machine operationbzxz.net
Z-shaped seam test
Needle position at the end
No. 4 coordinate paper
Working surface
During the test, the operator is not allowed to touch the test material, and let it move forward naturally. 38
Z-shaped seam state
Actual direction
GB/T4517-1995
4.3.3 Use a vernier caliper to measure the vertical distance between the last needle hole of the machine needle piercing the test material and the color line. 5 Display of test results
5.1 Measure the result value A or B shown in the figure (error <±0.25mm), see the schematic diagram for details. 5.2 Measure the offset A...As or B.Bs obtained from 5 tests and calculate the arithmetic mean value P or PB6 Test report
The test report should include the following contents:
The number of this standard;
The model and number of the sewing machine under test;
The test speed of the sewing machine;
The specifications of the test material and the machine needle;
The test result value PA or PB under the straight seam state;
The test result value PA or P under the zigzag seam state;
The manufacturer's name
The test year, month and day,
The name of the tester.
Additional remarks:
This standard was proposed by the China Light Industry General Association.
This standard was drafted by the National Technical Committee for Sewing Machine Standardization and the Shanghai Sewing Machine Research Institute. The main drafters of this standard are Fang Yuming and Guo Meizhu. 39
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