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1. What are the differences between Rough Oversize to Finish (ROTF), Finish Machined and Special Shapes? The high density tungsten alloys shrink considerably during sintering. Depending upon design and configuration, parts may be pressed and sintered close to final size and configuration to minimize machining costs. Special shapes can often be pressed in the die and sintered to near net shape. CMW can provide a finish machined part to your specification or provide an "as sintered" blank ready for machining. If you are purchasing sintered blanks for machining, CMW engineers will work closely with you to keep your cost low through the use of a wide range of available tools or recommend new tooling to reduce material and machining cost. When requesting a blank for machining, please specify your machined size so that the best ROTF (rough oversized to finish) part can be provided. Material up to 4" in diameter is kept in stock for same day shipment. Larger diameters and rectangular cross sections can be provided upon request. Stock diameters are available as sintered (ROTF) or finish machined to a +.010/-.000 tolerance. 2. How are machinable tungsten-based products made? There are several ways to produce our various machinable tungsten products. These various parts can be pressed using a steel die with set width and length dimensions, and a variable pressed thickness. Depending on the size of the die, the parts can be pressed using a hydraulic press or a mechanical press. Generally smaller parts are produced on the mechanical presses and slightly larger parts are produced using the hydraulic presses. Pressing pressure and die box size are the two main deciding factors in which type to use. The third option for pressing is to use a hydrostatic press. This method tends to be used for very large and/or heavy parts. Various sizes and shapes can be produced using these methods, but generally the parts come in standard round bar or rectangular bar form. Other common geometric shapes are also frequently available such as rectangles, triangles, round discs, rings, and ovals. Special tooling can be created to achieve various irregular shapes. However, when an intricate finished part is required, this material is machinable, very similar in characteristics to gray cast iron. Slightly slower feeds and speeds, and no coolant are required during machining. On small, discrete parts up to 2.000", an "as sintered" tolerance should fall between 1-1½ % per inch. As size and weight increase, the tolerance on the part will increase up to about 5%; weight of the part has a large part to do with this. As the part reaches peak temperature during the sintering cycle, the material becomes slightly pliable similar to modeling clay that's been left in the sun; at this point the weight of the part will cause some deformation. This is why parts with a larger cross section will need considerably more tolerance than smaller parts. 3. Are CMW® Tungsten-based Alloys safe to handle? Yes. 4. Which industry specifications do CMW Tungsten-based alloys conform? CMW tungsten-based alloys can be manufactured in accordance with the following specifications:
AMS-T-21014 5. How do I schedule a plant tour? Please contact us at metals@cmwinc.com or call the Metals team directly at 317.634.8884. |
