Scope of application
All dermis (animal skin)
2. Skin selection
Different grades have different quality and usage. The leather is classified as A.B.C.D grade. SATRA grading method can be used to estimate the expected truncation usage of each grade.
Each piece of leather must be clearly graded (e.g. A1; A2; B3; B4; C5;).
GRADE I = 100-96% (average utilization 97%)
GRADE II = 95-91% (average usage 93%)
GRADE III = 90-86% (average usage 88%)
GRADE IV = 85-81% (average usage 83%)
GRADE V = 80-76% (average usage 78%)
GRADE VI = 75-71% (average utilization 73%)
TR Level: Composed of A.B.C Level
Class A = I & II of SATRA (average utilization of SATRA 95%)
Class B = Class III & IV of SATRA (average utilization of SATRA 85.5%)
Class C = Class V of SATRA (average utilization of SATRA 78.0%)
D = VI of SATRA (average utilization of SATRA 73.0%)
The number of Class A must be greater than or equal to the number of Class C, so that the utilization rate of Class C can be guaranteed.
The number of grades D must be less than or equal to 10% of the total number.
V. Inspection procedures and standards
5.1 Colour and Thickness Testing
5.1.1 Each purchase order has the same specifications and each incoming material is one batch.
5.1.2 One package per batch is selected to check its color by purchasing a color card. If the color in the bag is uniform and identical with the confirmation shoes or color cards, the color will be qualified.
5.1.3 In each batch, 20 pieces were selected to measure the thickness of the skin material. The measuring parts were neck, buttock and back (6 points). If there are 2 points on the back and buttocks that do not meet the requirements of the purchase order, the material will be judged to be unqualified.
5.2 Leather Grading (Appearance Inspection)
5.2.1 Appearance shortcomings: knife wounds, spots, peeling, growth lines, vascular lines, trachoma, touch flowers, tendons, injuries, rough, branding, loose face, neck lines, defects, etc.
5.2.2 The inspector inspects all the leather materials visually and classifies the usage rate according to grade according to the proportion of appearance defects.
5.3.1 The inspector fills in the grade on the reverse side of the leather.
5.3.2 The inspector shall fill in the Leather Inspection Report and send one copy to the supervisor for signature and the warehouse administrator after checking and duplicating.
Tear strength, friction fading, yellowing resistance test for white material, aging test for black material.
5.4.1 was decolorized by 2.4.2. The stripping and peeling test of the cow lacquer leather was carried out.
(1) The adhesive paper was used to test the peeling film (5 times at the same position).
(2) Repeatedly rubbing the leather surface with white face cloth, and carrying out decolorization test (10 times rubbing back and forth at the same position).
Compare the color to the color card (or confirm the shoes).
Visual: All pairs of color cards, appearance, wrinkles, scratches, growth lines, blood vessels, neck lines, loose face, spots, etc. Defect percentages. Visual all check the softness, according to the color card (or confirmation version) to feel by hand. When testing the leather, pull the leather by hand, and see if the imperfection is more obvious after pulling by hand.
6. Judgment Method
6.1 Thickness of each skin examination before (head), in (back 2 sides), after (tail) four points. If two points do not meet the thickness requirements, the skin is not qualified.
6.2 Color: According to the color of the leather, it can be divided into different color systems.
6.3 Appearance and usage: According to the color system, and then according to the usage rate for A, B, C, D.
6.4 Softness: According to the softness of the color card. If 2 sheets are not qualified, the softness of the batch of leather is judged to be unqualified.
6.5 Leather usage rate below 73% must be judged by the head and manager of the quality assurance department whether it is returned or specially selected.
After the leather inspection, fill in the “Leather Inspection Report” and mark the color, feet and series on the leather.
VIII. Machines Used
Thickness gauge, pulling machine, measuring machine.
Post time: Aug-19-2019