‹ Back to Columns

Investigating the Process

Dave Charbauski

As a casting buyer, I am sure you have been involved in casting quality issues that arise periodically. Whether they are due to an issue with the casting or caused by something with machining or other downstream steps, they can be painful and stressful. Everyone wants to know what caused the problem and how it will be fixed.

Looking back over the years in which I have been involved with the foundry industry, whether as a producer of castings or as an end user, I have noted that the most common cause for problems associated with castings is a failure to follow the defined process to produce them. While this may seem to be an obvious statement, when you are in the middle of trying to solve a problem, the simple task of making sure everyone was following the process doesn’t always come to mind immediately.

I’ll readily admit that there have been occasions where I have encountered daunting metallurgical issues that were difficult to resolve and required hours of met lab review and the use of sophisticated analytical tools to finally arrive at a corrective action. But often, the root cause of the problem came down to something much simpler.  

One obvious example that comes to mind was the production of a thin-wall iron casting that ended up having a large number of scrap castings due to a foundry defect called misrun. The misrun defect can be related to several factors that can be encountered in the foundry, such as an interrupted pour of metal into the mold, trapped air in the mold that won’t allow the metal to fill out the cavities completely, or low pouring temperature of the molten metal. Delving into the problem, the ultimate root cause was found to be a low pouring temperature, but this wasn’t completely obvious at first.  

The foundry was following their process of pouring the metal in a temperature range of 2,500 to 2,570 degrees, which was engineered to be good for the castings they produced. However, when they started pouring castings at 2,530 degrees for example, which was within their pouring temperature range, the metal had cooled significantly during the pouring time, so much so that the last few molds were poured well below the 2,500-degree threshold.  

This finding ultimately lead to the creation of a part specific pouring temperature range being added to the pouring process, resulting in an overall improvement in the scrap rate for many castings the foundry produced. While following and trusting the process is important, there are always opportunities to alter and improve it. This is the importance of engineering the process and then ensuring that everyone follows it.

Why is engineering and following a process important for you as a buyer? Not only is it vital in eliminating quality problems and finding root cause for the problems that do escape the process, but following process steps are involved in almost everything we do on a daily basis. Your shipping and receiving, accounting, manufacturing, and purchasing departments all have processes that need to be followed 

I’ll give you an example from the development of a sourcing process that I wrote about in this column back in the fall of 2022. In that process, I outlined the steps that should be taken to ensure the financial health of a prospective foundry source. So, let’s say you adopt that sourcing process but neglect to dig into the foundry’s financial health because you have known of this company for a long time, and you assume they are financially sound. Do you think you are exposing your company to significant risk by skipping this step?

One of the hardest parts of implementing a process is making sure that all of the people involved follow it when it is put into action. It’s simply in our nature as humans to take a small shortcut or to skip a step. This is the difficulty that can (and does) impact our ability to maintain a manageable scrap rate, make and ship parts on time, and make a profit. Strict adherence to the planned process, as well as making sure that the process is up to date are vital for successful manufacturing.  CS