Isostatic Molding to Produce Thin Wall membrane PTFE Tubing
PTFE Schlauch – Manufacturers regarding seals and other components employing Teflon (PTFE) quickly end up sweeping most of their particular profits out with the machining chips when producing elements from traditionally compression shaped rods and tubes.
PTFE resins are expensive, and making parts from compression-shaped rods or even tubes usually yields only 10-20% of the material purchased to the finished pieces. Since PTFE, once sintered, cannot be reground and reused, 80% of the material cost end up in the particular trash. The answer is to use isostatic moulding techniques to produce thin-walled tubing.
Isostatic creating was developed by the W. T. Shamban Company in the 1954s and 60s. Initially, while missile nose cones warmth shields were manufactured from PTFE, a technique was needed to consistently compress PTFE powder through the bullet-shaped surface of a nose cone.
This was produced by placing PTFE powder within a nose cone-shaped lightweight aluminium plug, then covering the powdered ingredients with an elastomeric bladder. The pin, powder and bladder were often placed in a new pressure vessel, and highly pressured water was pumped in to gain the compression of the powdered ingredients into the preformed shape looking forward to oven sintering.
As a helpful side note, as rockets grew and the nose cones became too large to fit in pressure vessels, the bladder-covered plugs with powdered resin ingredients sandwiched inside were easily lowered into the ocean into the appropriate depth to achieve the ideal compression pressure.
Modern isostatic moulding machines have come to challenging ways from the missile nasal cone days. Now they work with oil instead of water with cylindrical pressure vessels. Isostatic moulding machines generally start using a hydraulic pressure system providing a custom intensifier to help kick the pressure right up from the standard 3000 psi hydraulic system components to the more considerable forces needed to achieve suitable physical properties in the formed PTFE.
The better designs employ interchangeable mandrels to make the system adaptable to many sizes connected with tubing, polyurethane stop pieces, and outer dimension forms to transfer the particular hydraulic pressure from the urethane material bladder to varying lengths of tubing.
The soft urethane acts as a smooth to move the specific hydraulic pressure to the compressed powder resin. By using quiet end bells, ending belling common with earlier models is eliminated so that the complete length of the moulded tube will be usable.
Minimal hydraulic regulates are required, and most of the hydraulic components needed are available off the shelf. The exception is the étendre, which must usually be designed from scratch to achieve the necessary pressure boost and quantity makeup requirements of this kind of powerful, flexible hydraulic method.
The only problem with isostatic creating is there are no machines you could purchase off the ledge. Each needs to be custom designed and tailored to meet the specific measurement ranges and the required material contained required parameters.
This commonly ends up meaning there is a hefty investment in engineering in addition to hardware costs. It usually takes quite a few months to have an appliance designed, fabricated, installed and tested. Once that expenditure is made, the commission times are relatively short, often way less than four years.
Having isostatic capability will allow smaller seal, bearing, and custom machined PTFE makers to compete with their more substantial competitors by drastically lessening their scrap rates and allowing them to bid on significant volume applications competitively.