Process capability failures in the foundry

Editor's Note: This article was previously run in The Crucible magazine, published by NFFS in May 2010, but the lessons remain relevant today. It was originally written by Mr. Ralph J. Teetor III (deceased), President of Foundry Quality Systems and a long-time NFFS supporter, for The Crucible. 

The biggest train wrecks I have ever encountered in the foundry industry have always been associated with process capability. When one of these catastrophes occurs, it quickly becomes an all consuming tornado sucking in every manager in the plant and crowding out all other problems.

The usual scenario plays out to this script:

Sales finds a new customer with a requirement for huge numbers of a casting. The job is run through quoting and the potential profits are large. The job is never put through a contract review process.  Production management and QA are not shown the stringent specifications. After the job is won, a tooling production schedule is established. The tooling arrives in the plant and a sample run is made. QA begins preparing the sample documentation and discovers that a significant amount of the sample run is not compliant. A second sample run is made and enough good parts are found to submit a sample to the customer for approval. The job goes into full production. QA and production management may have voiced some concerns, but were overridden. The customer discovers the discrepancies and rejects large number of castings. A crash engineering program begins in the plant to resolve the problem, usually beginning with re-gating the pattern. The customer is promised the problem will quickly be resolved. The first, second, third and fourth efforts all fail. The customer becomes increasingly disgusted as each lot is rejected, time passes, schedules slip and money goes up in flames. Every manager, engineer and foreman in the foundry is sucked into the affair. Eventually, either the foundry or the customer throws in the towel. The foundry production management breaths a sigh of relief and begins trying to catch up on the other orders they neglected while they were in the whirlwind. The sales manager feels he was let down by production management and never admits or understands that he created the problem to begin with.

Most foundry managers and sales engineers have a very good, but rough, feel for the plant’s capabilities, but a formal process capability study has never been performed for chemical, tensile, hardness or dimensional parameters. This approximate knowledge of the plant’s capabilities causes no problems unless several conditions occur on the same job.

• The foundry top management has never experienced a process capability disaster.
• A process capability study for the parameter has never been performed in the foundry.
• Volumes are big or the part has a very high piece price.
• The customer is military, aerospace, medical, automotive or has very stringent requirements to resolve an unusual customer requirement.
• The sales department is determined to win the job and is willing to promise to meet specifications that they have never achieved before.
• The customer specifications were poorly understood by the person preparing the quote.
• No one ran the specifications past an experienced shop floor production manager.
• There was no ISO-9000 style contract review procedure.
• The customer will not grant concessions on specifications or pricing.

This set of limitations makes a process control disaster quite rare, but when they happen, they can bankrupt the firm or at the least destroy an entire year’s profitability. This happens because:

• The magnitude of the problem is not exposed to QA, engineering or production management until the job has been tooled, production schedules established and the foundry is firmly committed.
• The time lag between the shipment of production size lots of discrepant castings and their rejection is long enough to have permitted substantial production.

The usual result of a process capability disaster is the loss of many tens of thousands of dollars. These stories do not usually have a happy ending, despite heroic efforts by everyone in the plant, because a process capability disaster has its roots in the basic equipment of the plant. It doesn’t matter how many times the job is re-gated, how detailed the part number instructions are written or if the owner of the plant personally watches each production step.

They also result in the permanent loss of the customer, as while this catastrophe plays out, the customer knows about each attempt and its lack of success. This continuing series of failures consumes all of the good will of the customer while convincing them the foundry management is incompetent and unable to meet the commitments they make.

Process capability failures occur in very competent plants run by managers with decades of foundry experience. This happens because until top management understands what happened to them and why, they do not put the proper controls in place to prevent them.

The following case studies detail actual process capability failures that occurred in foundries, including lessons learned and the ultimate solution that was implemented in each case. NOTE: The full case studies are limited to NFFS members. Please log in to your NFFS account for access.

• Case Study 1 – A thirty two year old plant run by an owner with 24 years of foundry experience
• Case Study 2 – A twenty six year old plant run by the original founding partners
• Case Study 3 – A 74-year-old foundry organization run by the 3^rd generation of the founding family
• Case Study 4 – A 12-year-old importing firm which specialized in castings and a 19-year-old foundry run by its founding owner

It is probable that the more experienced readers have found themselves in the center of a process capability disaster during their careers. If you work in this industry long enough in different plants, it happens. The way to prevent these is simple and inexpensive.

• Run regularly scheduled process capability studies on:
  • Chemistry
  • Tensile
  • Hardness
  • Dimensions
  • Heat treatment
  • Welding
• Run each new quote with big volumes through some type of contract review process where the specifications are compared against your process capabilities.
• Do not accept jobs that have specifications you do not understand or for which you have not already performed a process capability study.
• Do not accept jobs that exceed your process capabilities unless you are willing to spend the money to change your capabilities.

It is absolutely worth your time to know exactly what your plant can do on a profitable basis.  The alternative can be catastrophic for your foundry.