Scrap at 6.5% cost half a million a year: how an injection molding plant made hidden costs visible

Costs · 3 min read · 21.10.2026

Client

An injection molding plant: 140 employees, 12 presses, production in a three-shift operation. Technical plastic parts for the automotive and consumer goods industries. Capacity was nearly exhausted, so the solution had to be found in the efficiency of the existing presses, not in their number. We present the company anonymously — this is a composite study drawn from several of our projects in this segment, not a single identifiable customer.

The project was initiated by the operations director. He was under pressure from customers on both price and quality and suspected that scrap was eating his money somewhere. He could not find a single figure for it in the financial statements.

Challenge

The scrap rate, consisting mostly of non-conforming parts, had long been stuck at 6.5%. Month after month the same, so the plant took it as a given. The bigger problem was elsewhere: nobody could reliably say what scrap cost in money. It was reported in kilograms and got lost in production costs. Only the measurement within the project revealed the figure — roughly half a million euros a year.

The second problem was shifts. Each operator set up the presses based on their own experience; no standard existed. Differences in parameters between shifts reached up to 4%, so the same order meant different quality in the morning than at night. Regrind was returning to production uncontrolled — without tracking its share and without distinguishing which products it went into. Non-conforming parts from one order found their way into others through the ground material, and problems spilled over into customer complaints. Meanwhile, quality staff spent a large part of the week investigating those complaints.

Approach

1. Mapping the actual state. For four weeks we measured scrap by press, shift and product, and separated planned startup scrap from unplanned. Two figures emerged from the data: monthly scrap costs in euros and the price of one percentage point. When management saw them, scrap became a topic for the boardroom, not just the shop floor.
2. A unified setup standard. Our consultants led workshops with the setters and, together with them, defined setup sheets for every press and product: temperatures, pressures, times, speeds. The standard came from the setup with the best result, not from behind a desk. Piloted on three presses, and a month later on all twelve.
3. Rules for regrind. A maximum share for each product, a marking method, records of returned material. Regrind ceased to be the solution for non-conforming parts — since then, its use has been approved by the quality manager.
4. Shift handover and measuring variation. We introduced a standard for shift handover: setup, press condition, scrap per shift. We measured the differences between shifts weekly and posted them on a board in the workshop. Once operators compared their results with their colleagues', the pressure toward “my own setup” disappeared on its own.
5. Training and setup audits. We taught foremen and setters to work with the sheets and understand the logic behind the parameters. Internal audits have run monthly ever since — 20 minutes per press, with deviations recorded. The first revealed larger deviations on four presses; two months later, only minor issues.

Results

We set the target cautiously at the outset: get scrap below 4%. In the end, more was achieved. The first measurable improvement came in the third month, a stable state after nine. Without investment in technology — everything on the existing presses and with the existing people.

• Scrap rate reduced from 6.5% to 2.4% in 9 months.
• Annual material savings of approx. EUR 320,000.
• Setup variation between shifts reduced by three quarters.

What did not happen along the way: no new press, no new information system. The change lay in setup discipline, in the rules for regrind, and in the fact that scrap began to be reported in money. Today it lives on without us — the foremen run the setup audits themselves and the scrap rate is a managed KPI at the monthly meeting. When the number moves up, they can tell which press and which shift.

We use the same approach — measure, standardize, control — in other projects as well. Where such savings can be found in your production is described in our cost reduction service.

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