In this part we are discuss about Upper Leather Manipulation.
Cutting Methods: The cutting of a skin/hide is a specialized skill, and can only be acquired after many years of practice. Cutting does not only consist in the art of holding a knife or operating a clicking machine, it consists mainly in knowing how to rapidly place the patterns or the knife, and knowing the area to be cut. The difficulty of this work lies in the fact that the skin is irregular structure or value. A good cutter will always be cost minded and get maximum utilization from a skin/hide.
A good cutter must know how to use the maximum the various parts of the skin. Before cutting the skin, the following must be known:
- The defects which exist on both sides of the skin/hide (grain and flesh)
- The direction of stretch.
The vamps and overlays are cut from the bend- these are the main components of the upper which support all the walking flexions, therefore, they must be of the best quality.
Quarters are cut mainly from the belly.
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| Shoe Component |
To cut an upper, the knives must be placed in such a way that the direction of the stretch coincides with the width of the piece.
A skin does not always present the same direction of stretch everywhere and the same quality. A perfect knowledge of the skin permits a good utilization of the skin.
In certain types of skins, particularly suede, there are various shades which should be cut and manipulated by pairs.
To cut a whole skin, it must be placed on the machine, head first, and starting at the left rear legs, working towards the right and placing the knives in such a way as to leave the least possible waste.
The cutter begins the manipulation form the left rear leg, cutting first the quarters. The fronts of the quarters must always converge towards the center of the skin.
The cutting operation in progresses towards the right in such a way, to cut a horizontal strip of the skin, since the quality of skin in this horizontal strip should be consistent.
Before cutting each component, the cutter must insure that the position of the skin leaves a suitable area for the following components. He must position the pieces together, because the smallest amount of abnormal waste often repeated is the cause of important losses.
Bellies and neck areas or those with slight defects, can be cut for inside quarters, which will be reinforced by counters when the shoe is finished. Certain of defects can be in the uppers, provided that they will be part of the lasting margin in the lasted shoe.
Knives: The knives which the cutter uses are manufactured from Swedish steel, are light and easy to Handle, and give very good results. Double edge cutting knives should be sued wherever possible, this minimizes the number of knives required, so reducing cost. The are two heights of knives:
- 19 mm for leather
- 31 mm for textiles and other multi layer cutting
Cutting Block: The blocks on which skins are cut where originally made of wood, but are now usually made of composition rubber or phenolic resin block which last much longer.
The operator should always use the entire surface area of the block to wear it uniformly, this saves knives and improves cutting quality.
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| Leather Cutting Machine |
Safety on Machines: The double control system on cutting machines requires both the cutter's hand to be on top of the machine, so ensuring that he/she cannot get his/her hands caught between the cutting head and the knife
That's all for now. This is the summery cutting method.
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