Are You Making the Same Changes?

Most of us have heard the definition of insanity: "to keep doing everything the same and expect different results." It makes sense that if you want different results, something is going to have to change.

Foundrymen always are involved in projects to change--they make changes to reduce scrap, lower costs or improve specific aspects of the operation. Sometimes, however, the changes they make aren't really changes.

How can changing something be keeping it the same? If the changes are those that always are made, it may be keeping things the same. Believe me, it happens--more than most people even realize.

Repeating Changes

An example is a foundry I've helped with some small jobs. My visits usually are with the president, but, naturally, I also know the superintendent.

It seems every time I ask about the superintendent, he's working with a patternmaker to re-rig a problem job (expecting the patternmaker to drop off a revised pattern in a few minutes), or is going over some revisions at the patternmaker's shop. He certainly thinks he's making changes, but is he really? In my mind, he isn't.

He has been so busy changing the same things he has in the past that he didn't have time to make the changes that were really needed. If some of the time the foundry spent on changing patterns was devoted to better controlling its processes, it wouldn't need to make all of the pattern changes.

As with so many things in life, it's always easier to see someone else's faults than our own. When I started thinking about how he is working so hard to make the same changes, I realized I've been guilty of the same thing. I also recognized how difficult it can be to know what to change.

One Man's Solution

My way of solving foundry scrap is by improving the control of processes. If you're experiencing hard castings (having either hardness readings that exceed the specified limits or chilled edges), improve your metal control. If you're experiencing misruns, improve your temperature control or rigging process. If you're experiencing sand inclusions, improve the control of your sand properties. I recommend process improvement because it works most of the time.

One of my clients wanted to take his quality to another level by reducing scrap. I immediately set to work thinking about how to improve the plant's processes. I looked at its metal control and devised an improved system that allowed the foundry to control its iron to an even greater degree. Customers felt the greater control improved casting machinability, but the scrap didn't go down.

Looking at the records of the operation, it was no surprise that improving the metal control didn't reduce scrap. Metal control wasn't causing scrap. Process improvements could have eliminated all variation in the metal, and the scrap wouldn't have gone down noticeably.

Sand inclusions were a problem, so that was the next area we attacked. The foundry tweaked this and tightened that, and the control charts showed that the control of the sand properties improved, but the scrap didn't go down. Once again, the records showed why the "improvements" hadn't worked. There was scrap to correct this time, but statistical analysis didn't show any correlation to where the sand properties were being held or to the amount of variation the properties showed in the ranges they were held. Sand control had improved, but the foundry really didn't have any reason to expect that the improved control would reduce scrap.

We were stumped. We were about to start another program of improving the sand control when a small fire occurred that required one of the molding machines to be rebuilt. After that, it took only a couple of months worth of data to notice a reduction in the inclusions. A couple more months of data proved that the decrease wasn't a fluke.

We then analyzed what happened and made a change that has kept the inclusions down since that time. The change wasn't another program to reduce sand property variability, nor was it periodically setting fire to the machine. A change was made in the maintenance practice. Far more checks are made now, and no longer are the preventative maintenance checks treated like something to do if nothing is broken, A real change had been made, and different results were achieved.

Making the Right Decision

Don't misunderstand me. I am not condemning improving sand control or changing rigging. Obviously, both are important. If the sand wasn't well-controlled, even with the improved maintenance, the inclusions would have been high. Similarly, if the gating was causing erosion, the best maintenance in the world couldn't have prevented inclusions. Nor would improved maintenance solve all your problems. However, the next time you're changing something in order to improve, ask yourself if the change you're about to make is really a change. Have you already done this before? If so, should you really be expecting this same change to achieve the improvement you're seeking? Maybe you need to find something that really is a change.