Patterson Mold supplies the die cast industry with quality built tooling, design and excellent service and has been doing so for over 19 years. The company, which employs 90 people, is based in St. Louis, Missouri and works out of a 36,000 square foot custom-built building under the direction of Mike Whalen.
Not long ago, Patterson Mold used conventional workholding devices such as mechanical vises and toe clamps. Although these are commonly used throughout the industry, the vises were found to restrict the workpiece size. The toe clamps also limited the five-sided machining necessary in the tooling and molding business.
Patterson Mold first found out about magnetic workholding products from Tecnomagnete (Morrisville, North Carolina) after reading an article in a trade magazine about Tecnomagnete's electro-permanent magnets and then visiting a shop where the magnets were already in use. At that point, Patterson decided to host a demonstration of Tecnomagnete's workholding magnets. During the demonstration, the staff was able to evaluate the time saving methods and the increased machining capabilities that the magnets could offer.
At first the operators were skeptical about the holding power of the magnets during heavy cuts and chip evacuation on drilling cycles. After trying out the machinery, they were no longer concerned. In fact, a recent survey of the operators showed that they unanimously felt that the electro-permanent magnetic chucks offered greater workholding power than conventional workholding techniques. In one example, the operators actually stalled a cutter on a 30-hp machine to test the effectiveness of the magnet and succeeded in moving the magnet before the work-piece moved.
Some of the improvements they have seen since they began using the magnetic workholding system includes shorter set-up times and unrestricted five-sided machining. This unrestricted machining is where they have made their biggest gains. They presently use five magnets dedicated to four machines, one each on the two vertical machines, another on one of their horizontal boring mills, and two on their other horizontal boring mill. Their latest application of the electro-permanent magnets was to install two 400 mm by 1000 mm on the angle plates for one of the horizontal boring mills. The magnets are hard wired in tandem and have the optional partial set controller to aid in set-up. Patterson says they machine most of their mold base with this setup.