MACHINING PLASTIC IS AN ART

AS THE PRICE OF METALS CONTINUES TO RISE, MORE AND MORE product designers are looking for ways to replace machined metal parts with plastic parts, and machine shops are getting more opportunities to bid on jobs that call for machining plastics, and they are finding it profitable.

The equipment

is essentially identical and, for the most part, so are the tools and techniques. But even with the similarities, cutting plastic is not the same as cutting metal. For that matter, cutting one plastic is often not the same as cutting another plastic, and shop operators need to do their homework if they want to avoid costly mistakes.

"The decision to get into machining plastics should not be taken lightly," said Kevin Delk, president of Delmar Company, a plastics machining and fabrication business in Lakeville, Minnesota (www.delmarcompany.com). "You need to get the wildcards out of the process. Since most of the plastics are sensitive to changes in temperature and humidity, keeping humidity low and temperatures stable in your facility is important. You also need good people. Most runs are low-volume so you need operators who can do set up and think on their feet. Speeds and feeds are just as dependent on the operator as they are on the material.