Mod Squad: 5-Axis Machining

If you use a pair of machinist’s vises bolted to the bed of a vertical machining center and laboriously replace jaws for each new job or build fixtures from scratch and stick them on the shelf until the order repeats, listen up: Modular workholding saves time and money.

Irregularly shaped parts, such as this casting, can be clamped directly to a modular baseplate. Image courtesy Carr Lane Manufacturing.

Merriam-Webster defines modular as “having parts that can be connected or combined in different ways.” But to Colin Frost, chief business development officer at Carr Lane Manufacturing Co., St. Louis, modular means the ability to quickly and easily fixture most any job that comes through the door.

“For us, modular starts with a superaccurate, grid-style baseplate, tool block or angled plate that contains a series of bushed holes,” Frost said. “We use a hardened-steel threaded insert with a locating bushing over that, so customers can clamp and locate in the same hole.”

The company’s offerings include a seemingly endless assortment of mounting blocks, locating pins, adapters, clamps, stops, risers, rests and supports that either bolt directly to the baseplate grid or to one other. These components are available individually or in one of several “starter sets.”

“Modular fixturing kits are popular with shops that manufacture a variety of low-volume, complex parts on an infrequent basis, when a vise is unsuitable,” he said. “For example, we have a customer in Iowa that makes repair parts for agricultural equipment. Some of this is quite old, and, since they obviously don’t want to keep tooling on the shelf for 30 or 40 years, they use modular components to build whatever fixture is needed at the time, then tear it down when the job is done.”

Modular workholding extends to 5-axis machining as well, such as this a zero-point system that’s used to attach a quick-change vise. Image courtesy Fixtureworks.

Frost said the fixture design for each part is recorded by photographing the complete assembly or laying it out in a CAD system. Each part is referenced on the baseplate’s “hole address,” so if a customer orders that part again 5 years later, the fixture doesn’t have to be recreated from scratch. “This is one area where modular fixturing really shines.”

Modular kits are the Tinkertoy sets of the toolroom and can cost $20,000 or more. Because of the large number of parts and the myriad ways to assemble them, Frost said it’s important that somebody understands what all the pieces are and how to use them and properly manages the investment.