Machine Down? Check This First

In my job I get a front row seat to seeing what happens when folks are struggling with a down machine. Typically they immediately start running software tools that make adjustments to the machine on the software side and try to compensate for mechanical inaccuracies. But we need to remember, a machine tool will never function properly if your basic geometric alignments aren’t done correctly. You can only compensate so much, and with this approach you’re just putting a band-aid on the machine. Very often, software tuning does not, by itself, correct the root cause of the problem.

Back to Basics

Back when machine tools were first developed, in the early 1900s, they didn’t have any software. Everything was mechanical. Even today the machine still has a mechanical foundation. So verifying geometric alignments is getting back to basics. You have your basic straightness, squareness and parallelism…all these basic alignments need to be checked if you want your machine to make good parts.

The Real Root Cause

Over the past century we’ve made many improvements and of course added the CNC side of the machine tool—and these have been huge improvements. Today we can put in things like backlash compensation, or use a software tool called the 5-Axis Auto Tuning System, which tunes the machine to be as accurate as possible. Machines have become much more complex, with multiple axes and very detailed software. And when an emergency arises there’s a tendency to jump right into the software side of things and begin troubleshooting there. However the root cause is often in the geometric alignments of the machine tool. The number one thing that should be checked first in most down machine situations is the basic geometries of a square and level machine. 

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Recertification Ensures Good Parts

Of course even better than checking alignments when a machine is down is to never go down in the first place. We recommend setting up a maintenance schedule where alignment is routinely checked. This can be done by someone on your staff, or your distributor can perform a recertification, which makes sure that all the alignments are still within the OEM specification. Some customers will create what they call a “baseline” during a machine installation. Here they check all the alignments and write down the corresponding numbers when the machine is making a good part. Of course the frequency of checking alignments will depend on how much you run the machine, and whether it’s had a little bump or the shop floor has settled, things like that. All you have to do is go in and check and make sure your numbers match the baseline.

Resist the Urge! Check Your Alignments First

So now, if you encounter a down machine hopefully you’ll resist the urge to start checking and running software. That will usually send you running around in circles. Check your geometric alignments first, that’s usually the root cause of the problem.

John Lee is Service Parts Supervisor, Okuma America Corporation.