Smallest press on each mold

Each mold's record in the ERP names the smallest press it has run in, and the schedule tries that press first.

Cost	About $930 of staff time
Payback	About 1 month
Limitation	It moves a job only when the smaller press is idle, so the hours freed follow the schedule.

What changes

Each mold's record in the ERP, the plant's planning system, gets one new field: its smallest press.

That is the smallest press the job log shows the mold has run in, so no trial is needed.

The scheduler tries that press first, and moves up one size only when it is booked.

Once a week the scheduler checks the large presses' jobs for small molds.

What it costs and could save

Tagging the 140 molds takes about 23 hours of the scheduler's time, about $930, and nothing is bought.
It could save about $8,900 per year after the scheduler's weekly time, a payback of about 1 month.

Why it works

Mechanism	A mold needs a set clamping force, and more force adds nothing. So the smallest press that holds it shut makes the same part. A tag on the mold tells the schedule which press that is, and the large presses are kept for the molds only they can run. A smaller press also has a smaller pump motor and smaller heaters, so the same job uses less electricity there.
Math	One more running press hour is worth about $55 once an order fills it. We count 70 percent of freed hours as filled, so each freed hour counts for about $38.50. At 300 large-press hours per year, that is about $11,600. The same hours in a smaller press draw about 10 kW less power, which is 3,000 kWh per year. A kWh, a kilowatt-hour, is the unit on the electricity bill. At 10 cents per kWh that is about $300, the smaller part. Together the problem costs about $11,900 per year. The scheduler's weekly check, 1.5 hours per week over 50 weeks at $40 per hour, costs about $3,000. That leaves about $8,900 per year. Tagging the molds costs about $930 once, a payback of about 1 month.
Industry evidence	The usual rule for choosing a press is 2 to 5 tons of clamping force for each square inch of the part's outline, plus about 10 percent. A mold also has to fit between the bars the press closes along, and its shot, the plastic for one cycle, has to suit the barrel. Resin suppliers' guides warn that plastic left hot in a large barrel between small shots can discolor or turn brittle. We found no measured case of what a tag on each mold frees, so the hours are our estimate.
Limitations	A freed press hour is capacity, not cash, until an order fills it. We count 70 percent as filled, because about one order in seven shipped late, so orders do wait for presses. The records do not show that the large presses are the ones orders wait for. A job can move only when a smaller press is idle, and the visit showed two idle presses once, not how often. The electricity is the smaller part, about $300 of the $11,900. A mold in a press too small for it makes bad parts, so a tag is only ever a press the mold has already run in.

Implementation plan	3 steps
Risks	3