Preventative Maintenance

Preventative maintenance (PM) can be defined as a planned maintenance program that has been established to prevent unscheduled machine downtime. Of course, not all machine downtime can be prevented, but with regular checks of critical items, you can prevent some major catastrophies. A good PM program will have floor level checks and skilled trades checks as well as a method for determining what to check and how often.

Floor Level Checks

Prior to using any machinery, the operators can and should be checking certain items as part of a preventative maintenance program. The items to check will vary based on the type of equipment and the skill level requirement. If at all possible, emergency stops should be a priority. There needs to be an extremely high level of confidence that the machine will shut down with the push of the right button (or switch) in case of an emergency.

Other items that can be checked by operators include pressure gauges, fluid levels (i.e. hydraulic oil), filters, grease on moveable parts if required, no oil leaks, etc.. These types of checks validate that the machine is operating properly. If one of these checks does not meet the pre-determined criteria (between min and max levels), the correct support group is called to correct the problem prior to the operation of the machine. This helps prevent larger maintenance issues in the future.

Skilled Trades Checks

There should be certain areas in a preventative maintenance program that only skilled trades or qualified people will be able to perform. Machine calibration would be one such area. Any work that requires dis-assembly and re-assembly should be done by a certified technician.

Again, this is not work that is taking place due to an issue. This should be regularly scheduled maintenance, much like an oil change on your car.

In shops where dies are used, the tools should be checked on a regular basis to ensure all parts of the tool are functioning as originally designed. A small amount of wear that goes undetected could lead to even bigger problems in the future.

PM Frequencies

The key element to your preventative maintenance program will be determining the frequency at which certain checks are performed.

Floor level checks would consist of shift to shift checks, daily checks, bi-weekly or weekly checks. Items such as the emergency stop should be verified prior to any use of the machine if possible. Oil checks may be done daily or weekly. Filters could follow the same frequency as oil.

Skilled trades PM checks would be performed less often. Regular checks such as bearings or seals on machines can be done weekly or monthly depending on the amount of wear it sustains.

The important aspect is how to determine the frequency. When setting PM schedules, you want to have the check prior to the machine going down. Tracking history of a particular issue will give you insight on how often to check. For example, if a bearing tends to wear within 6 months, the PM frequency will be set at 5 months. The bearing should be replaced regardless of the condition. If it is not changed, the bearing will wear and result in unscheduled downtime.

The ultimate frequency will depend on your knowledge of the equipment, skill of the people and age of the machinery. Keep in mind the main purpose is to prevent unscheduled downtime through monitoring of the machine condition.