Ask most injection moulding shops how they document their processes and you'll hear one of three answers:
- "It's on a setting sheet somewhere"
- "Dave knows how to run that job"
- "We've got it in a spreadsheet"
None of these are process documentation. They're process risk.
The cost nobody calculates
When a mould comes back to the press after six months off-tool, how long does it take to get back to a stable process? An hour? Half a day? A full shift of scrap while someone dials it back in?
Multiply that by every tool in your shop, every time it runs. That's the cost of poor documentation — and most businesses never add it up.
Beyond restart time, poor documentation creates:
Scrap and rework — without a defined process window, operators make judgement calls. Some of those calls produce bad parts.
Knowledge walk-out — when your experienced process engineer leaves, they take years of undocumented knowledge with them. The next person starts from scratch.
Failed audits — customers and certification bodies increasingly expect documented, repeatable processes. A setting sheet scribbled on paper doesn't cut it.
Longer mould trials — without good records from previous trials, engineers repeat work that's already been done.
Machine dependency — processes that aren't properly documented often can't be transferred between machines, limiting your scheduling flexibility.
What good documentation looks like
A proper process record for an injection moulding job should include:
- Material specification and drying conditions
- Machine settings (injection speed profile, transfer position, pack pressure and time, cooling time, temperatures)
- The data behind those settings — not just the numbers, but the studies that justified them
- Process window — the acceptable range for each key parameter
- Part quality criteria and how to measure them
- Known failure modes and how to identify them
This isn't bureaucracy. It's the difference between a process you own and a process you hope works.
The shift that changes everything
The shops that get this right have stopped thinking about process documentation as paperwork and started thinking about it as an asset.
Every time a study is run, every time a process is developed, every time a problem is solved — that knowledge has value. Capturing it properly means that value stays in the business.
The investment is small. The return compounds every year.