Machine maintenance

Let’s face it: Everything about machine tools and their operation is expensive. If you run your own shop, then you know how much a good machining center or turning center can cost. If you ever have worked for a large company and tried to get capital for a new machine, then you know how many hoops must be jumped through to get the money. Machine tools are not only expensive to acquire but expensive to maintain, and when they go down the results can be catastrophic to budgets and customer relations.

Every minute of downtime costs a shop money, and those lost minutes and dollars never can be recovered. For machinists, engineers and maintenance personnel, excessive downtime creates a stressful work environment and unwanted overtime and generally makes for a less-than-desirable workplace. Preventing unplanned downtime is critical to successful machining operations.

Preventing unplanned downtime can be difficult in the best of times, but the shortage of skilled craftspeople and the increasing complexity of modern machine tools have added an extra layer of difficulty. However, some simple things can be done to help stave off downtime and expensive repairs.

Machines are designed, built and marketed differently based on the work they are expected to perform. High-volume manufacturers like automotive companies often require very robust, heavily built machines whereas smaller shops frequently can suffice with less robust machines. Understanding the capabilities of machine tools is important when preparing the code and tooling for machines.

When I started machining, there was a heavy focus on horsepower, torque and rigidity of guide ways. CNC machines were being purchased in an attempt to automate machining processes, so engineers and machinists were transitioning traditional machining methods to CNC machines. This meant that CNC machines of the time were expected to take heavy cuts in the interest of productivity. Since early CNC machines were controlled versions of old manual
machine designs, this was not an issue.

As the market evolved, machine builders started marketing to smaller shops and lighter, more cost-effective designs appeared on the market, requiring a different approach to programming. Ensuring the longevity of machines requires programmers to adapt to the capabilities of a machine tool and prepare code that does not overburden the machine. Generating toolpaths and cutting parameters that are within the capabilities of a machine prevents premature wear and tear of critical components. Seeing that cutting parameters, such as depth of cut, rotational speed (rpm) and feed rate, are appropriate for a machine is paramount in maintaining a properly functioning machine.

Unintended misuse and abuse of machine tools at the hands of well-meaning craftspeople can significantly shorten the life expectancy of critical components. Ensuring that machine tool operators and machinists have been trained well goes a long way toward extending machine life.

Learning proper setup techniques helps prevent crashes that put undue wear and tear on spindles, servos and guide ways. Correct assembling of toolholders and cutting tools extends the life of spindles and turrets. Learning the right way to load tools into automatic toolchangers assists with eliminating toolchanger crashes. Even the most advanced machines that operate autonomously need trained personnel to keep them operating properly. Also, don’t assume that someone with experience listed on a resume knows what to do. Everyone needs to be trained to operate machines in accordance with the best practices of a company.