Measure Your Workholding!

You probably use a number of performance metrics throughout your manufacturing facility. These metrics might measure sales, inventory, gross margin, spindle up time, quality, etc., but are you measuring the performance of your fixtures and workholding?

I believe you should be using Overall Equipment Effectiveness (OEE) to measure your workholding. Knowing your OEE will allow you to measure the performance of your fixtures and workholding and also determine where you are losing the most productivity or which area of concern you should look at first when improving your workholding.

The loss factors involved with OEE speak to the fundamental purposes as to why you would look to improve your workholding. The three loss factors used to calculate OEE are:

Availability: All events that have interrupted or stopped planned production. Examples could include missing components or incomplete systems to catastrophic fixture failure or “throwing parts”. Workholding that doesn’t repeat well will always cause a stoppage.

Performance: Anything that causes production to slow down or not run at full speed. An example is adjusting manufacturing speeds and feeds or depth of cut because you lack confidence in your workholding.

Quality: Any manufactured parts that don’t meet yours or your customers quality standards. The list of quality related workholding failure is a long one, poor surface finish, out of tolerance, too much vibration, etc.

Once you have identified your loss of productivity, simply formulate them;

Availability = Actual Run Time/Planned Production Time

Performance = (Ideal Production Time X Total Pieces)/Actual Run Time

Quality = Good Parts/Total Workpieces

Once you have these metrics, simply multiply them together; Availability X Performance X Quality = OEE

Consistently measuring the performance of your fixtures and workholding will ensure that these systems contribute to your overall efficiency and profitability.

Remember the old saying, “if you can’t measure it, you can’t manage it.”

Eric J. Nekich