Preventive Maintenance

Most manufacturers know the value of maintaining their machinery and tools. Substantial amounts of time and money are spent to acquire the proper manufacturing equipment. The results of a regular preventive maintenance program helps to protect and prolong equipment life and performance.  Additionally, far greater returns on investment are gained for each piece of equipment maintained.

However, even the best intentioned tend not to perform preventive maintenance until the problem occurs. Often it’s simply because on a day-to-day basis production output tends to trump maintenance. Many manufacturing facilities commonly place more emphasis on production rather than machine maintenance. They must stay focused on production output to maintain company profitability. This strategy works just fine until that day the machine breaks down.

A failure never happens at a convenient time. Most often it’s at the most inopportune time… i.e. the middle of an important production run on a weekend. In the service business we are constantly tasked to respond to emergency breakdowns that could have been prevented by simple preventive maintenance.

IF a PM program is your plan it will enable the production planner to make informed decisions about the production schedules based on pre-planned maintenance outages. This approach can substantially minimize unexpected machinery downtime by allowing management to actually schedule the downtime instead of the machine scheduling it for them.

Implementing a PM Program

First, implementing a PM program requires information gathering and planning. Begin by assembling pertinent information on every piece of equipment in your building. It must be cataloged, organized, reviewed and then stored in an accessible location. Develop a database that includes all of the maintenance and service records for every piece of equipment. This can help identify maintenance issues by individual machine. Based on this database, timetables can usually be easily identified on perishable components, which can then be used to pinpoint specific weaknesses associated with a component or a machine. This information can enable informed purchasing decisions regarding the projected maintenance needs.
Economic conditions indicate that most companies are not quite back to full throttle. Now is an ideal time to institute a preventative maintenance program and bring equipment back into good working order.

One question is whether an “annual” or “semi-annual” PM program should be put in place? To determine the need, follow a common sense rule. Typically a year of machine life is based on a single shift operation for one year. If there are two shifts operating it is equivalent to two year wear on the machine in one calendar year. If your company has more than one shift operating per day then consider a semi-annual plan.

A PM Program primarily begins with a detailed inspection and cleaning of each machine. Some examples of places to begin are;

• Pulling back those way covers once a year and clean out the chips. Chip build up can destroy ways, way wipers, linear guides and ball screws.

• For those who use water soluble coolants be aware that these coolants can build up on the machine surfaces over time (they are designed as a  rust preventive). If the machines are not cleaned
periodically limit switches will begin to stick and “other” failures will occur i.e. unable to reference axes, tool changers will fail and etc. Also do not use solvents to remove the coolant that has built
up on the equipment – use HOT WATER. Remember it is WATER SOLUBLE.

• Clean and inspect the fans in the electrical cabinets. It can keep electronic component temperatures cool and will go a long way in preventing those expensive electronics from failing.

• Replace hydraulic oil and filters in machines once a year as it will help lower oil temperature and keep hydraulic lines from leaking or blowing out. Inspect, repair, or replace hydraulic pumps and
test their performance, pressure and flow. Replace leaking or damaged hydraulic hoses.

• Verify that the proper amount of lube is getting to the spindle, ways, ball screws, and lead screws to prevent costly repair and rebuilds. Inspect and replace worn ball screws and lead screws.

• Discuss the machine and its operation with person who is runs it on a daily basis. Educate employees and get them involved in the process. Alert machine operators can often point out problems
to maintenance personnel long before a sudden stoppage happens. Have them cycle the equipment and listen for any odd noises such as bad bearings or worn belts.

• Many manufacturers have implemented certification programs for their equipment to satisfy internal as well as external traceability requirements such as ISO and QS certification and compliance.

• Before checking the positioning and repeatability on any machine first check that the equipment is leveled properly. Any twist in the base of a machine (as caused by settling over time) can cause
erratic positioning readings. Check and maintain the proper alignment of all axes. Verify the linear positioning and repeatability. Set the compensation i.e. pitch error comp and verify with a laser
interferometer system. Machine calibration services are available and sometimes required to verify performance. Prepare for planned maintenance rather than having to react to a sudden non-
compliance condition. Calibrating machines with precision laser measuring equipment will provide peace of mind that the parts produced on the machine will meet the tolerances
customers demand.

• Once the positioning has been verified maintain a calibration library on all equipment and then plan to re-calibrate annually. A machine’s dynamic / interpolation performance can be inspected
using a ball bar. The ball bar tool is the optimum method for inspecting or verifying the machine tools function and dynamic performance during operation.  Many equipment “downtime” hours can
be avoided by early detection of problems. A routine inspection helps to expose potential issues before they become critical. The benefit is both in extended production time and avoidance of
premature component failures.

Maintaining the PM Program

Monitor maintenance activity with software technology. Software will enable maintenance managers to quickly and easily schedule and review recurring maintenance tasks while reducing the time needed to administer service requests. Use it to automatically generate work orders when preventive maintenance is due. Use email and text messaging to distribute work orders to your maintenance staff, as well as preferred service vendors and suppliers. Documenting these activities makes it easier to analyze trends and spot recurrent problems.

There are some cases where a PM program will be of little value. This occurs when it’s implemented on equipment that has been severely neglected and is in poor condition. Addressing and correcting known problems, can, over time restore the machinery to its optimum operating condition.  Preventive maintenance is an idea being adopted by manufacturers around the world and plainly put, preventive maintenance saves money!

Electric Power and Your Company Equipment

Every company requires electric power to function. However, manufacturing requires and consumes larger amounts of power to operate the high tech CNC equipment and other machinery within those facilities.   The utility that supplies electric power has a plus and minus voltage tolerance. Sometimes that incoming power can vary beyond the stated tolerance of the power company (seasonal overloads, weather, and etc.). Those variances come with consequences for the end user.   When the power “anomaly” occurs, the most noticeable effects show up as component failures.

When a variance occurs your company may experience excessive maintenance issues.  If you’re noticing that your machine service company is visiting more often than usual as shown by your outlay of money to them and you are blaming the machine supplier for your breakdown experiences it might be time to check the power.

Review your repair and maintenance records and remember that any power variance can and will affect EVERYTHING in the building.

To determine IF there is a problem, first review the expenses related to service and electrical problems.  To resolve the issue:

1. Request that the power company place a “chart recorder” on the input lines for a week or so.
If the power problem is occurring in certain seasons have the recorder placed on the lines during that time.

2. Review the recorder findings with them. You might find that it was them all along. If that is the case, request the
power company issue a rebate or provide some other type of resolution.  After all, they are providing a service
that you are paying for.

Contact us as we may be able to assist you with a solution.