A leading extruder manufacturer has recently purchased a Lesitritz machine for its new $1.5 million state-of-the-art manufacturing facility. The Leistritz machine will manufacture feed screws utilizing the whirling and milling processes.

A producer of screws for the extrusion, injection mold and blow mold industries, faces the same time pressures today as mold makers. In order to be compatible, speed is a factor, to reduce the amount of time and man hours it takes to produce a screw."

A screw is made by selectively removing metal from the shaft. Because whirling removes much more material than traditional milling, cycle times are about three to four times faster. Whirling uses a doughnut shaped cutting tool that cuts screw flights by spinning rapidly, usually at about 1,000 RPM, around the top of the shaft. The screw also turns to expose fresh steel to the tool. The computer controlled whirling head pivots to cut angles in the screw.

Using traditional manufacturing techniques, screws has to be transferred to at least three different machines in order to become a finished part. Now using a single CNC controlled Leistritz machine, the whirling tool first roughs the screw, then a separate milling tool finishes the job in just one set-up.

It typically took 6 to 12 weeks to make a screw after receiving an order. Since the German-made machine sold by Leistritz Corporation of Allendale, NJ, began turning out screws, the company has been able to reduce its production time to 6 to 8 weeks; some priority jobs have been completed in 2 to 3 weeks! The combination of the new Leistritz whirling machine and the newly built 3,200 square foot building could cut development time more dramatically, down to 24 hours.

Whirling's higher output and greater consistency also helped this producer win contracts to make injection molding screws for customers where price was previously too high.

What Leistritz has been able to do is integrate the CNC and CASEM software technology into the demanding process of whirling. Leistritz has always had an extremely reliable machine, but now coupled with CNC and CASEM , the process has been made very simple.