Shop Solutions: Tool Clamping for High-Speed Plastics Milling
Samvardhana Motherson Peguform (SMP), one of Europe’s leading plastic component processing companies, was looking for a new tool clamping system that would solve a problem the shop was experiencing when milling combined composite plastic components for the automotive industry. What they found was the powRgrip tool clamping system from Swiss precision tool manufacturer Rego-Fix Tool Corp. (Tenniken, Switzerland; Indianapolis, IN), which improves balancing precision and concentricity compared to heat shrinking.
SMP is a system partner supplier to the automotive industry and a worldwide supplier of plastic parts and complete systems and modules for vehicle interiors and exteriors. Typical product applications include bumper and front ends with emphasis on crash management and pedestrian protection, body panels, door panels, and rocker panels with emphasis on lightweight construction, and cockpit and instrument center consoles.
As a group of companies, SMP includes several facilities in Germany (company headquarters are in Bötzingen near Freiburg), as well as plants in Spain, Portugal, Brazil, Mexico, and China. In 2011, the 302 employees at the company site in Meerane, Germany, generated sales totaling around €73 million.
High-quality and cost-effective manufacturing are top priorities for the plastics specialist, especially in the milling of combined composite plastics. For one such component, a plastic sill cover, the challenge was the different properties of the various plastic materials that made up the combined composite plastic. These very different materials had to be machined in a single pass using a solid carbide and single-flute cutter. The cutter was required to generate a perfect cut from the plastic carrier material (PCABS) through the intermediate layer of PUR rigid foam to a tough PVC skin that had to be cut cleanly. The final product requires no further machining or finishing and is passed directly on to the final assembly stations in the factory.
Volker Große, application engineer in the plastics milling and welding department at Meerane, said, “When servicing our machine tool spindles, we noticed above-average spindle wear. This was caused by the tool clamping system we were using at the time. As a result of toolholder imbalance, vibrations were being transferred into machine spindles. This resulted in exceptionally high tool wear and chatter marks on finished products. In particular, for high-speed machining at speeds of 38,000 rpm, the toolholder balance played an even more critical role. We needed a solution—fast. We decided to test our heat-shrink fixtures against Rego-Fix powRgrip toolholders that clamp tools without having to heat holders.”
During the comparison, powRgrip displayed the obvious strengths of its system advantages. The powRgrip holders offered the lowest overall imbalance, and even after multiple clamping and unclamping cycles, these values remained constant.
“In the past, we noticed wear on the tapers of our heat-shrink holders, and after repeated heat-shrinking cycles, the result was increased imbalance,” said Große. “Now that we have made the switch to powRgrip, concentricity is far more precise. Plus, the service lives of our spindles have been noticeably extended, and cutting tool consumption has dropped considerably.”
In addition to more precise concentricity and excellent balancing precision, powRgrip tool clamping also impressed plastics processors, such as SMP, with the ease and simplicity with which tools can be changed using the system’s automatic clamping unit. With just a push of a button, the tool is hydraulically pressed securely and accurately into place within seconds. There is no heating, and holders are ready for immediate use.
The investment in the powRgrip tool clamping system has quickly paid off for SMP. For instance, there is now no longer any need to replace the several HSK-E 25-type heat-shrink chucks that used to wear out every year. The company has also managed to lower costs within its three shifts of operation because a lot of time is now being saved thanks to a reduction in the number of required tool changes.
“The Rego-Fix powRgrip system is the perfect solution. Since we introduced the new system, our work has been cost-effective and user-friendly,” said Große. “The good balancing properties, precise concentricity and the noticeably longer service lives of tools and machine spindles were the key factors that won us over to powRgrip.” ME
For further information from Rego-Fix Tool Corp., go to www.rego-fix.com; or phone 317-870-5959.
This article was first published in the January 2014 edition of Manufacturing Engineering magazine. Click here for PDF.
Published Date : 1/1/2014