Starting with the right size and shape based on final part geometry is critical when working with materials like Torlon®, PEEK and polyimides that are inherently expensive. Did you know that an extra .25” on a diameter can add 25% or more to the cost of your raw material? This waste is compounded by a machinist spending time removing extra stock. Add in extra tool wear, especially in glass or carbon fiber reinforced materials, and the unnecessary cost related to using a less than optimal size can exceed 50%.
Drake’s Torlon Seamless Tube is a great example of how to “lean out” parts making. With more than 50 sizes available from stock in most grades, always consider Seamless Tube if your Torlon parts have an ID.
There are performance advantages of Seamless Tube when machining reinforced materials like glass and carbon fiber grades of Torlon. The dominant fiber direction that results from Drake’s unique processing results in high strength and stiffness in the hoop direction. This is helpful for parts under both internal or external pressure or loading. Electrical bobbins, bushings, bearings, containment tubes and even rollers benefit from this flow orientation. Identical parts machined from Drake Seamless Tube have been found to be over twice as strong as parts made from rod or injection molded tubes.
This advantage was realized immediately when Drake offered to machine drop tank fuel and air connects from Torlon 4203 Seamless Tube for the F-16. The 600-gallon tanks extend the F-16’s range by 50%. Field technicians reported that dropping injection molded parts from their former supplier on the tarmac often resulted in cracking or chipping. Drake Seamless Tube parts are literally hammer tough. The two parts are long with very thin walls. Machining them from rod is costly and machining from standard injection molded tubes was not possible because the part length exceeds available tube lengths. Injection molding these parts leaves weld lines from melt fronts that never fully knit back together, resulting in brittleness and the propensity to crack.
Bearings and bushings machined from Drake’s Seamless Tube have inherently improved wear resistance especially at high PVs when the ID of the finished part is close to the as-extruded ID of the tube. The cured skin offers maximum wear and chemical resistance properties, meaning if during machining very little material is removed the need for re-curing after machining can be eliminated.
Machinists report better tolerance control especially roundness and concentricity when starting with Drake’s Seamless Tube over both rod and plate. Often machinists report outer diameters changing once an ID has been machined in a part. Starting with an ID and removing less material from the interior cross section maximizes the dimensional stability of the final part.
Drake’s unique “boutique” approach to Torlon PAI, KetaSpire and Victrex PEEK, Ryton PPS and Ultem PEI extrusion allows for custom diameters with smaller than expected minimum order quantities (MOQs). We have many existing die sizes that can readily be adapted to suit a new part.
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