I wrote an article a few months ago about manufacturing processes and their control. I illustrated this with the process of making a cup of coffee. A lot of things go into it:

How to make a good cup of coffee? By using:

• The right amount of energy (not too hot, not too cold)
• The right water (pure enough, clean)
• The right coffee powder (right taste, properly stored, before expiry date…)
• The right milk (not expired…)
• The right sugar (right amount, properly stirred…)

All of these are the process controls behind a good cup of coffee.

Now, let’s say you use a coffee machine to pour 500 cups of coffee a day. Part of the process controls is to ensure that machine remains in a “as new” state. That’s when preventive maintenance comes into play.

This article list all the preventive maintenance actions that are recommended on an expresso coffee maker. Some routines need to be done daily (cleaning with a special detergent), every 3 months (replacing group gaskets and shower screens, testing switches…), every 6 months (replacing the valve…), and every year.

If you don’t do this, you cannot get consistently good coffee!

The same thing applies to every valuable piece of equipment (including the tooling) in a factory.

Which is why, in a factory relying on equipment, process control includes preventive maintenance.

I wrote a long guide on this topic on the CMC website: How A Preventive Maintenance System Cuts Costs In Chinese Factories.

Here is what I wrote about process control and preventive maintenance:

A worn-out tool or a machine functioning abnormally creates unacceptable products that have to be reworked or scrapped. Poor quality often accompanies high equipment downtime. They are both indicative of insufficient maintenance.

Let’s take a simple analogy. If the brake system on your car wears down and is not replaced in time (maintenance), what happens? The car is no longer able to stop as expected (quality).

There is actually considerable overlap between these two preventive activities:

• What maintenance staff call cleaning, inspecting, adjusting/repairing, and replacing
• What quality staff call process control

If this is of interest to you, I strongly suggest you go to that page and download the e-book.