The Invisible Process

The process at the heart of manufacturing operations resides inside of equipment, hidden from view. It is extremely difficult to tell the quality of the process by looking at the equipment. The robustness of the process depends on engineering fundamentals like heat and mass transfer, and kinetics (the speed of the chemical reactions). The process must be well designed taking into account these engineering fundamentals.

I’d like to share a story that illustrates the subtlety and invisibility of the process. One day a team leader from a manufacturing scale-up project called me and asked for guidance. The team was working on a project that needed to be in production “yesterday”. However, despite concerted efforts over several months, they were having significant problems with a particular process operation.

This process removed oil from a “green” ceramic part. A “green” ceramic part is a part that has not been fired yet, so it is not yet a stable and solid structure. It was imperative that all the oil was removed from the green part before firing to avoid creating defects during the firing process.

The team had managed to reduce the time to remove the oil from the part, but was still far away from where they needed to be to have an economical process. Their approach was to create vacuum outside the part to encourage drying of the oil from the part. Despite extreme vacuum levels, they still had not gotten close to the desired cycle time.

It occurred to me that the problem might be movement of oil INSIDE the part, so that no matter what vacuum level was present outside the part, the oil could not get to the surface quickly enough. The chemical engineering term for this situation is “internally mass-transfer” limited. I proposed some quick tests to the engineering team to “split the universe” (inside versus outside the part).

The tests showed that the factors limiting oil removal were indeed inside the part. This redirected the teams focus and had significant impact on the equipment required. Slightly elevated temperatures would be very helpful, because they increased the movement of oil inside the part. Expensive and complicated ultrahigh vacuum systems were not necessary.

I learned from this that although the process is invisible, the fundamentals that make it operate must be understood. This fundamental core knowledge of the process is imperative for the creation of cost-effective and reliable high-volume manufacturing processes.

---

YOUR CHALLENGE THIS WEEK

Pick one or two key processes in your operation…

• How well do you understand these processes? Do you understand why they work and how they work in terms of engineering fundamentals?

• Has this engineering data and the resulting process knowledge been documented so others can learn from it?

I’d enjoy hearing about your “invisible” processes, and how your understanding of them has helped you! As always, you can just hit reply to this email and I’ll get back to you promptly.

All the Best, Marty

---