A little maintenance equals less downtime

If you think that you have more important things to do than perform the recommended maintenance on your CNC machine, think again.

“Even the simple daily checks can lead to findings that could prevent catastrophic failures,” said Brad Cooper, service manager at Farmington Hills, Michigan-based Star Cutter Co., a maker of cutting tools and tool grinders. “This equates to less downtime, less scrap and better-quality parts.”

A little maintenance can make a lot of difference. With delivery times for parts becoming longer due to the supply chain issues that companies worldwide have been facing, preventing the failure of a part by conducting an easy daily inspection could prevent weeks or even months of machine downtime, he said.

Shops needn’t be concerned about the amount of downtime required for maintenance. Adequate machine maintenance can be done in as little as 30 minutes a week, said Bryan O’Fallon, product specialist at Haas Automation Inc., a machine tool builder in Oxnard, California.

Nevertheless, he said, “the temptation is to just run until something happens to the machine and then deal with it. But we’ve shown here over 20-something years that the amount of downtime you have to perform the maintenance is much less than the downtime you have when something breaks because you didn’t perform the maintenance.”

Service Engineer Orville Collins checks the oil level for a machine spindle. Image courtesy of Haas Automation

Today, those wishing to stay on top of machine maintenance are aided by a variety of tools and technologies aimed at making the job easier. For example, most machines now are equipped with sensors that trigger an alarm if the grease or oil level is low, said Orville Collins, service engineer at Haas Automation. But he advises not letting things get to that point. The reason is that the alarm could come at a bad time — say, when the machine is in the middle of cutting a mold.

If that happens, “chances are you could end up damaging that mold,” he said.

Best Practices

To keep things running as they should, there’s no way around regular maintenance procedures. Collins recommends that a number of them be performed first thing every morning, including making sure that machine spindles are warmed up properly, air lines are cleaned out and the coolant level, pressure and concentration are correct.

In addition, O’Fallon stresses the importance of flushing chips out of machines. If this isn’t done, he said chips will get into all sorts of places they shouldn’t and cause damage and rusting.

“So I would say the single most important thing to do is to clean the machine at the end of the day,” he said.

As for less frequent maintenance, fluid lubrication — grease for the ways and oil for the spindle — should be checked at least monthly.

“If you run out of oil for the spindle, you can burn up the bearings and kill the spindle,” O’Fallon said. “If you run out of grease for the ways, you can (damage) linear guides and ballscrews, which are very expensive.”

Whether shops are performing only the required level of machine maintenance or wish to go beyond that, Cooper said they need to document the maintenance and train their people to properly perform it. Another good practice is to use visual aids that show operators what needs to be checked and describe the procedures for making the checks.

“That is what I see in a lot of shops that are doing proper maintenance,” he said. “It makes it a lot easier on maintenance staff and
operators.”

The pictures and descriptions can be placed on the machine next to the operator station and in pneumatics and electrical cabinets.

Once a maintenance plan has been developed, Cooper also recommends “automating” the plan so it becomes routine. This can be done using an enterprise resource planning system that on a weekly or monthly basis triggers the creation of a report that reminds the staff to perform the required maintenance and update the system with the latest maintenance information.

Recent Developments

In addition to good maintenance practices, shop floor operations can get a boost from recent developments that help keep machines in good working order. For example, machines made by GF Machining Solutions LLC in Lincolnshire, Illinois, eventually force machine users to perform critical maintenance. To ensure that the spindle has enough oil, for example, the machine at first will inform the operator when the oil level in the container is becoming low.

A machine operator checks and replaces rotary and linear encoder filters. Image courtesy of Star Cutter” data-entity-type=”file” data-entity-uuid=”03410a7d-4316-4377-884c-4c8af80472ad” height=”472″ src=”/wp-content/uploads/legacy/inline-images/Image%205%2020220201_141422_0.jpg” width=”628″ />

If the required maintenance isn’t done in a certain amount of time after that, the machine “will alarm you out completely and lock you up so that you don’t destroy your spindle,” said Eric Ostini, head of business development.