Maintenance Tips, Case Study
May 23, 2013
For Gosiger technical service specialist David Hoffer, the lack of proper CNC machine maintenance on the part of some manufacturing companies simply doesn’t make sense. “We all know that any mechanical device, whether our own vehicles or a machine tool, requires a certain amount of routine care.” He tells us. “If we never change the oil in our car or truck, for example, we’ll end up ruining the engine. Likewise, if a machine tool is never properly maintained, it can develop serious, costly problems.”
Here’s a perfect example:
"This turning machine has been running continuously for over three years and now requires rebuilding. If properly maintained, this machine will run 10 years or longer without major repairs. Unfortunately, it’s never had any routine maintenance. To make matters worse, it was used to make parts from cast iron, a material that creates highly abrasive chips and dust that can find their way into the moving parts of the equipment. Of course, the machine was designed to operate well even in this harsh environment, having been equipped with a number of features to protect the machine’s components.”
“One of these features is a set of rubber scrapers that help keep the machine bed free of chips, metal dust and other abrasives. Like the oil or air filters in your car, these scrapers need to be replaced periodically so they can do their job properly. They’re relatively inexpensive – perhaps $100 or so depending on size – and are one of the replacement items listed in the preventative maintenance guidelines from the manufacturer. In this case, these scrapers were never replaced and became severely worn, which allowed debris to become trapped between the saddle and the machine bed. As a result, the machine bed had to be removed along with the saddle and completely rebuilt. If the machine bed wasn’t damaged so severely, the repairs would be made and the machine could be up and running again in about 2 weeks. Because of the extent of damage to both the machine bed and the saddle (some of the abrasion to the moving surfaces are 0.030” deep) the surfaces must be milled and recoated with Turcite®. It will take about 2 months to rebuild at a cost of over $135,000.”
“In our experience, CNC machine preventative maintenance is either part of a company’s culture or not. Some shops assign maintenance of one or more machines to an operator or shop maintenance person. This is a good approach as the employee is responsible for making sure the routine maintenance, as outlined by the manufacturer, is followed. Unfortunately, not all shops do this. Some just run the machines until something breaks down and then have it repaired. In this case, that lack of a few hundred dollars in preventative maintenance cost the CNC shop over $100,000.”
A rebuilding case like this one clearly supports Gosiger’s recommendation that customers institute a planned, preventative maintenance program for all of their CNC machines. The frequency of this service depends on the amount of machine use and severity of conditions. Therefore you need to put a daily, monthly and quarterly maintenance program into place. Gosiger can provide training for your internal maintenance staff and design a planned preventative maintenance program for your specific requirements. Moreover, Gosiger offers complete preventative maintenance plan packages for its customers that take the worry out of protecting your investment. Contact Gosiger for more details.