Retrofits keep CNC machines in business

It could be the boring mill purchased during the Watergate investigation—the mill that cost $1 million back then but would cost five times that today. Or maybe it’s the commodity machining center that would still produce good parts if you could only make the display turn on.

No matter how old the machine or how much it cost, there could be good reasons for keeping it around. In many cases, doing so can be justified by adding a new control and updating the electronics.

Mach Speed

Dave Eldredge, president of control system provider MachMotion, Newburg, Missouri, said you should ask yourself a number of questions before deciding for or against a retrofit control. “What’s the lead time on a new machine?” he said. “Assuming your old one was kept busy, you probably can’t wait a few months for a replacement. What about the cost? A good rule of thumb is that a retrofit starts to make sense at one-third the price of a new CNC.”

CNC routers, waterjets and plasma tables are just a few of the machine types suitable for retrofitting. Image courtesy of MachMotion

Then there’s the disruption to consider. Say you’ve been running parts on a machine for 20 years. All the tooling is set, the processes are established, and the equipment is sitting in the back of the shop surrounded by newer machines. It’s possible that, by the time you figure in the rigging costs and downtime needed to pull that asset and retool everything, it would be much less expensive to retrofit the existing machine with a new control.

If you’re reminded of the time that you souped up your ’67 Chevelle with a 4-barrel carburetor and high-performance camshaft only to blow up the transmission 2 months later, Eldredge said the analogy doesn’t fit. “As long as the machine is mechanically sound, there’s no risk of destroying the ballscrews or any other components despite the inherently higher performance realized with a replacement control.”

New Dogs, New Tricks

This might be the best reason to breathe fresh life into a weary CNC machine: Eldredge said you can expect a revamped machine to crank out far more parts per hour than it ever did previously and also to be much easier to operate.

“We offer a conversational interface with full 3D display capabilities,” he said. “You can walk up to the control, quickly sketch your part or enter in dimensional data, simulate the toolpaths, post the code, and you’re ready to go. If you want to program with a CAM system, that’s fine too. It’s the same G code you’ve been running for years, but you’re now able to run it on a much more powerful processor, with servos that are far more responsive as well.”

It’s clear that a modern central processing unit and servomotors might take old iron to unheard-of performance levels, but what about newer machine tools? Eldredge said MachMotion recently retrofitted a 3-year-old commodity CNC machine with a new control. The customer was “blown away” by the resulting performance improvement.

“Bringing an old machine back to life is certainly a valid reason for replacing its control and electronics, but it’s still an old machine, and you’re going to achieve only so much with it,” he said. “But taking a relatively new piece of iron, one with a high-speed spindle, for instance, and freshening up the front end with cutting-edge technology—we see that as a very viable ROI for many manufacturing companies.”

Do-It-Yourself Performance

If the machine tool in question is a Fadal and you’re technically savvy enough to plug in a cable TV box, you might want to give Walter Calmette a call. He’s president of Sun Valley, California-based Calmotion LLC, which specializes in improving the performance of the familiar brand of white-and-blue machining centers.