Injection Molding Job Costing Review Checklist
Most margin leaks in molding come from a short list of omitted costs: runner weight, a rosy cycle time, the wrong press rate, packaging and tool maintenance. This checklist walks through them in order so an estimator or controller can review a quote before it goes out, or a finished job before it is repeated.
0 of 38 items complete
11 critical items still open - these are the highest-risk gaps.
Material
Process and press
Tooling
Packaging, quality and freight
Overhead, margin and terms
Count the checked items. Fix every unchecked critical item before the quote leaves the building. Below 80 percent complete, expect margin surprises. After the first production run, repeat the checklist against actual costs and feed corrections back into your standard assumptions.
Quote versus actual cost report
Optional: talk through a read-only ERP agent that compares quoted and actual cost per molded job.
Optional. The tool and every export work without this. No spam.
How to use it
Work through the five groups with the quote worksheet open. Tick items that are covered and documented. Any critical item left open should be resolved before sending the quote, since those are the ones that most often turn a profitable-looking job into a loss. Use it again after the first production run, comparing actual material usage, cycle, scrap and packaging against the quote.
Where molding quotes go wrong
Material and cycle time dominate the error budget. Cold runner weight can be 10 to 30 percent of the shot on small parts. Scrap during start-up and purging is usually higher than the final inspection reject rate. Cycle time estimates from tool makers are often optimistic by a few seconds, which on a short cycle is a large percent. Press rate errors come from using a plant average when the job needs a large tonnage machine.
- Runner and sprue not included on cold runner tools
- Cycle time taken from the mold maker proposal
- Average press rate used for all machines
- Packaging and freight omitted from the piece price
Using it with your cost tools
Pair this review with the quote cost build-up worksheet for the numbers, the cavitation optimizer to confirm the tool decision, the press selection worksheet to confirm the press, and the resin price impact calculator to understand exposure. The checklist ensures nothing is missing, and the tools check the arithmetic.
After the job
Compare actual cost to quote on each repeated job. Record the cycle time, scrap, material usage and press hours from production reporting and update the standards in your ERP item and routing. Over a few jobs this closes the gap between quoted and actual cost and makes the next quote more accurate.
Frequently Asked Questions
Which items are most often missed in molding quotes?
Runner and sprue weight on cold runner tools, start-up scrap, realistic cycle time, a press rate for the right machine size, and packaging and freight. Together these usually explain most of the gap between quoted and actual job margin.
How should I treat tool amortization?
Spread tool cost over the volume the customer commits to, not the volume you hope for. If the customer owns the tool, quote it separately and leave it out of piece price. If you own it, add maintenance and cost of capital.
How often should I review actual cost against the quote?
After the first production run, and then at least annually or whenever resin, labor or press rates change significantly. Feed the differences into your standard costs so new quotes reflect real conditions.
Does the checklist apply to captive molding plants?
Yes. Even if no price is quoted externally, the same costs apply, and the review shows whether a molded part is cheaper made in-house than purchased. Replace margin with an internal transfer rule.
Netray can build a read-only agent over your ERP and shop floor data that compares quoted versus actual cost per molded job and highlights the lines that drifted.
Related Tools
Molded Part Quote Cost Build-Up and Margin Worksheet
One row per part: enter weight, cavities, cycle time, resin price, press rate, tool cost and target margin. The sheet builds cost per 1,000 parts, quoted price and annual gross profit.
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Enter part weight, runner, scrap, regrind reuse and old and new resin prices to see the per-part cost change, margin erosion, annual dollar impact and the price increase needed to hold margin.
Engineering & PLMInjection Mold Cavitation Optimizer (Total Cost per Part)
Sweeps the number of cavities from 1 to 32 and shows machine cost plus tooling cost per part, so you can see where adding cavities stops paying for itself.
MES & Shop FloorInjection Molding Press Selection Worksheet (Tonnage and Shot Utilization)
List each mold with projected area, cavities, cavity pressure and the press you plan to use. The sheet computes required tonnage, clamp utilization and shot utilization for every row.
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