TPT September 2013

Technology News

The best draw tooling IN tube drawing, the key to producing the finest quality tube starts with having the proper draw tooling. Draw tooling is the heart of the process. Without proper tooling, tool life, productivity and profit margins may all be compromised. unique application. Tube drawing is accomplished in the die box on a draw block or drawbench, where the draw tools work in conjunction with a lubricant in effort to affect change on the tube – most notably, the surface finish, the outside dimensions, the wall thickness and the length of the tube. The draw tooling in the die box is comprised typically of carbide dies, plugs and mandrels. Glen Carbide focuses on the grade of carbide, tooling design and tooling quality as the essential elements in making the ideal draw tooling for each

As a tool maker, Glencarbide first looks at utilising the proper grade of carbide for the application. Different metals respond differently to each set of tools. Soft metals such as copper and aluminium can be drawn using harder grades of carbide, whereas hard metals such as steel and stainless steel work better with tougher grades of carbide. The objective is to find the grade of carbide that works best for your application. It is important to find a grade that is tough enough that it will not break, but hard enough to last as long as possible. With more than 50 years of experience the company has developed a good feel for what performs the best in most tube drawing applications. The design of the draw tooling may be the most important of the three elements. The key is to provide suitable tool geometries that will promote proper lubrication, which in turn will help provide better tool life, longer production runs and superior quality tubing. When designing the draw tooling, Glencarbide works with the customer to determine the shape and dimension of the incoming tube and develop a die design that will transition the tube from either a round to round, round to shape or shape to shape finished product. Each die is custom designed to transition the metal into its final shape, accounting for stresses unique to that shape. When designing the geometry of the draw plug, it is vital to keep in mind the lubrication flow. There must be a gap between the inside diameter of the tube and the major diameter of the plug. The gap will allow the lubricant to pass into the transition angle and be drawn into the bearing land of the plug. This will provide a thin film barrier for the plug. Direct contact will damage the carbide tooling, which in turn will scratch the walls of the tube. The transition angle of the plug is also critical. It must work in conjunction with the die angle to create a wedge that will effectively control the wall thickness as the tube is being drawn. An effective wedge will help minimise the draw force required to form the tube. A mandrel is often used in drawing round to shape or shape to shape tube.

Glencarbide – USA Website: www.glencarbide.com

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S eptember 2013