_{1、 Scope of application
All leather (animal leather)
2、 Skin selection
The leather is divided into a.b.c.d grade according to its quality and utilization rate. SATRA leather grading evaluation method can be used to determine the estimated cut-off utilization rate of each grade}

_{3、 Identification
Each piece of leather must be marked with a clear level (e.g. A1; A2; B3; B4; C5;).
Grade I = 100-96% (average utilization rate 97%)
Grade II = 95-91% (average utilization rate: 93%)
Grade III = 90-86% (average utilization rate: 88%)
Grade IV = 85-81% (average utilization rate 83%)
Grade V = 80-76% (average utilization rate: 78%)
Grade VI = 75-71% (average utilization rate: 73%)}

_{4、 Hierarchy
TR level: composed of A.B.C level
Class a = I & II of SATRA (95% average usage of SATRA)
Level B = level III & IV of SATRA (average usage rate of SATRA is 85.5%)
Level C = level V of SATRA (average usage rate of SATRA is 78.0%)
Level d = level VI of SATRA (average usage rate of SATRA is 73.0%)
The quantity of level a must be greater than or equal to the quantity of level C, so as to ensure the utilization rate of level C.
The quantity of level D must be less than or equal to 10% of the total quantity}

_{5、 Inspection procedures and standards
5.1 color and thickness inspection
5.1.1 each purchase order has the same specification, and each incoming material is a batch.
5.1.2 take any one bag of each batch and check its color with the purchasing color card. If the color in the bag is uniform and the same as the shoes or color card confirmed, the color is qualified.
5.1.3 take 20 pieces in each batch, and measure the thickness of the leather material by thickness measurement. The measurement part is the neck, buttock and back two sides (6 points). If there are 2 points on the back and buttocks that do not meet the requirements of the purchase order, the leather sheet is determined to be unqualified.
5.2 grading of leather (appearance inspection)
5.2.1 appearance defects: knife wound, spot, peeling, growth grain, blood vessel grain, trachoma, bumping flower, tendon, hanging wound, rough, branding, loose surface, neck grain, defect, etc.
5.2.2 the inspector shall conduct full visual inspection on all leather materials, and the utilization rate shall be classified as the standard according to the ratio of appearance defects and the grade.}

_{5.3 records
5.3.1 the inspector shall fill in the level on the reverse side of the leather.
5.3.2 the inspector shall fill in the leather material inspection report, which shall be checked and copied and sent to the supervisor for signature and the warehouse keeper for each copy.
5.4 testing
Tear strength, friction fading, yellowing resistance test for white material, aging test for black material.
5.4.1 test by 2.4.2 decolorization. Peel and peel test of cattle patent leather.
(1) The adhesive tape was used to remove the film (5 times at the same position);
(2) The leather surface is repeatedly rubbed with a white cloth for decolorization test (at the same position, rub back and forth for 10 times).
5.5 inspection
Compare the color with the color card (or confirm the shoes).
Visual inspection: grading the percentage of defects such as color card, appearance, wrinkles, scratches, growth lines, blood vessels, neck lines, loose surfaces, spots, etc. by visual inspection, the softness shall be fully checked and felt by hand according to the color card (or confirmation version). When testing leather, pull the leather by hand to see if the non obvious defects will be more obvious after being pulled by hand.
6、 Judgment method
6.1 thickness four points before (head), middle (back 2 sides) and back (tail) of each skin inspection. If there are 2 points that do not meet the thickness requirements, the sheet is unqualified.
6.2 color: it is divided into different color systems according to the leather color.
6.3 appearance and utilization rate: according to the color system of the color, and then according to the utilization rate, it is divided into a, B, C, D levels.
6.4 softness: according to the softness of the color card. If 2 pieces are unqualified, the softness of this batch of leather is unqualified.
6.5 if the utilization rate of leather material reaches below 73%, the head of quality assurance department and manager must judge whether it is a return or a special purchase.
7、 Record
After the leather inspection, fill in the leather quality inspection report and mark the color, number of feet and number of times on the leather.
8、 Machine used
Thickness gauge, pulling machine, measuring machine.
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