The size of the draw die radius is one of the major factors affecting metal to draw properly. If the radius is too large, wrinkles will occur on the part. If the radius is too small, it will restrict the flow of the material and cause cracking to the part. As a general rule, three (...
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Pinch trimming operation is commonly used in deep draw progressive tool to separate the drawn product from the progression strip. Unlike a conventional metal cutting process, no shearing or fracturing takes place in pinch trimming. Because the metal basically is pinched off, a very sharp burr usually remains on the drawn part; this burr...
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To develop the flat blank contour of a drawn corner for rectangular drawn shell is not an easy task and there isn’t any formula that will produce a flat blank corner contour exactly conform to the print. Extra material will always produce at the edge near the center-line of the drawn radius; this is...
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In my previous blog, I wrote something about drawing lubricants and it selection for drawing manufacturing process. Beside lubrication, the drawing speed is another vital factor greatly affecting the successful rate of the deep drawing process. In general, plain push through draw dies can be operated at higher linear velocities ( faster drawing speeds) than drawing dies equipped with drawn ring or pressure pads. However, the...
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Lubrication is of two main types: The Fluid and The Boundary. Fluid lubrication – This type of lubrication commonly used in bearing system and seldom observed in sheet metal forming. Boundary lubrication is commonly used in most metal forming operation because of the high pressures and low speeds involved. The main function of a boundary...
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