On-Demand Injection Molding

What it changes

Traditional molding asks you to commit to a production quantity so the molder can plan a single long run. That produces the lowest possible unit cost and the highest possible inventory risk, because you are paying to store, insure, and possibly obsolete parts you have not sold. On-demand production inverts that: the tool is held ready and parts are made against a call-off schedule.

Where it fits

Product launches where real demand is unknown and forecasting is guesswork.
Seasonal or campaign products with uneven demand across the year.
Spare and service parts that must remain available for years at low annual volume.
Designs still maturing, where a large committed run risks obsoleting stock at the next revision.
Cash-constrained programs where inventory tied up in finished goods is the binding constraint.

What it costs

Being honest about the trade: per-part price on a small call-off is higher than on one large run, because setup, material changeover, and quality checks are amortised over fewer parts. The comparison that matters is not unit price against unit price. It is unit price plus the carrying cost of inventory you do not need yet, plus the risk of obsoleting it.

Cutting steel is the long pole. Quotation, design review and sampling are measured in days; the tool build is measured in weeks and is largely fixed by the number of cavities and the amount of hand finishing. On-demand supply attacks the queue around the tool, not the tool itself.

What has to be true for it to work

Tool ownership and storage are documented. You should know who owns the tool, where it is stored, who insures it, and what notice is required to move it.
Tool maintenance is scheduled. A tool sitting idle between runs still needs cleaning, protection from corrosion, and periodic inspection.
Lead time for a call-off is stated. On-demand only helps if the response time is shorter than your planning horizon.
Quality is consistent between runs. Same tool, same resin grade, same process parameters, with any change notified rather than made silently.

Questions worth asking any supplier

Who owns the tool once it is paid for, and what document proves it?
Where is it stored, and who insures it?
What is the lead time from call-off to dispatch?
Is there a minimum order quantity, and is there a minimum annual volume to keep the tool active?
What happens to the tool if we stop ordering?
Is a material or process change notified before parts ship?

How we handle it

Trumould runs production against call-off with no minimum order quantity, so you can order the quantity you actually need. Specifics on tool storage, maintenance, and call-off lead time are stated on the how it works page rather than left to be inferred.