Dozens of part numbers invite mix-ups: HR for rubber gasket makers

Half past six on a busy day. The clicker press operator has run twenty-odd jobs since morning, and a pump maker wants a set of flange gaskets by tomorrow. He pulls a steel-rule die from the rack. The outline is right, and so are the bolt-holes. The die is meant for thicker sheet, though, and he cuts it from the neoprene roll nearest the press. Two hundred gaskets go into a carton that still holds a few from the previous job. The customer's fitter finds out the next week, when a joint seeps.

That first strain on our page for rubber gasket makers is the daily reality of a unit that cuts and moulds many small orders. Wrong die, wrong sheet, mixed bins. Most owners see carelessness. Usually it is a system that leaves each step without an owner.

• Look-alike dies. Two steel-rule dies with the same outline and hole pattern but cut for different sheet, sitting side by side in the rack.
• Faded rack labels. Marker numbers on the die board rub off, and the operator picks by shape.
• Unmarked sheet stock. Cork, fibre, EPDM and neoprene sheets stacked together, with thickness known only to the stores clerk who received them.
• Shared bins and cartons. The last few pieces of one job lie in the bin when the next job starts.
• Waterjet and nesting changes. A nest re-run for a different sheet, without anyone telling the operator.
• The evening call. A workshop rings at four for parts by morning, and the changeover is rushed by the people already tired from the day.

When a mix-up is traced, the person who ran the press usually takes the blame. That feels like accountability. It is the opposite. The operator learns to keep quiet about near misses, the faded label stays faded, and the next operator makes the same mistake. Nobody owns the rack, the sheet marking or the bin rule, so nothing upstream changes.

Many gasket units also mould seals and rings beside the cutting presses. Here the trap is compound rather than sheet. Two black compounds of different hardness look identical on the rack, and a mould with several cavities can be loaded from the wrong strip. A hardness reading on the first lift, a lot tag carrying compound and cavity numbers, and separate shelves for each compound family close most of that gap. The moulding operator signs the same start-of-job card, with a line for compound in place of sheet.

• Stores clerk: issues sheet against the job card, measured with a thickness gauge, with the thickness written on the sheet edge.
• Toolroom die maker: keeps the die rack in order, with stamped die numbers and the sheet each die is meant for.
• Press or waterjet operator: signs the start-of-job check before the first cut.
• Inspector: checks the first-off against the drawing, including hole pitch and thickness.
• Packer: one job per bin and per carton, labelled before the first piece goes in.

Job card number and part number: ________.
Job card and the drawing at the press show the same revision: yes or no.
Die number taken off the rack, plus the sheet stamped on it: ________.
Sheet material and thickness measured with the gauge: ________.
Bin and carton empty, labelled with this part number: yes or no.
First-off checked against the drawing by: ________.
Operator signature and time: ________.

1. 1

   Write the check into each role

   The start-of-job check belongs in the job description of the operator, the stores clerk and the packer, not on a poster. Role design for gasket makers shows how.

2. 2

   Test drawing reading before anyone inspects

   A short practical test on reading hole pitch, inner and outer sizes and thickness against a drawing. Repeat it when drawings or gauges change. The learning plan for gasket units can hold it.

3. 3

   Train new operators on die setting

   A written ladder for die setting, press stroke and sheet feed, with practice on offcuts rather than live sheet. Trial and error on real stock is an expensive teacher.

4. 4

   Review mix-ups weekly, by cause

   Fifteen minutes with the crew, the toolroom and stores. Log each mix-up by job, cause and step. A reporting view for gasket makers puts it on one page.

5. 5

   Set a cut-off for evening calls

   After a fixed time, urgent orders need approval, and overtime goes by a fair rota. The shift rules for gasket units can carry it.

• Pick one busy day and count the part numbers run and the mix-ups found.
• Walk the die rack. How many dies have readable numbers and a sheet thickness stamped?
• Check whether sheet in stores shows its thickness without anyone measuring it.
• Read the last three mix-up reports. Do they name a cause, or only a person?
• Count last month's evening rushes and who stayed for each one.

The people issues across the trade, from hot presses to hand finishing, are mapped on our overview of rubber plants. For the rate side of trimming and sorting work, see paying finishing teams fairly. For building a second die maker, the questions in protecting tool room knowledge apply directly.