When to Move From a Short-Run Shop to a Production Molder

The usual way to think about this move is as a number. Sell enough units and you graduate to a big molder. The number matters, but on its own it is a poor guide. Move too early and you pay for hardened steel on a design that is still changing. Stay too long and you pay a short-run price for every part of a product that no longer needs a flexible shop.

The time to move is when three things hold at once: the design has stopped changing, demand is steady enough to forecast, and the cost of each part now matters more to you than the cost of the next change. When all three hold, a production molder will usually make your parts for less. When one of them doesn't, it usually won't.

What a short-run shop is built for

A short-run shop is built for change. Its molds are built to be adjusted, and a run of a few dozen parts is a normal job. Between 2020 and 2025 the shop's molding runs went from tens of parts to tens of thousands.

That flexibility carries a price on each part. It is worth paying while you are still learning what the product needs to be.

How production molders cut the cost of each part

At high volume, the cost of each part is driven by two things: how long each cycle takes, and how many parts come out of each cycle. Production molders build for both. They run hardened steel molds with several cavities, often with hot runners that keep the plastic molten right up to each cavity so there is no runner to trim and scrap, and often with robots taking parts off the press. Their presses are sized to the job.

A mold like that costs more and takes longer to make, and changing it is slow and expensive. Once the design is frozen, none of that matters much, because the cost is spread over a very large number of parts.

Signals you can check

• Your change log has gone quiet. Nobody has asked for a dimension, a feature or a material change in recent runs.
• Your reorders arrive at a size you can predict, and you could commit to a volume if the price was right.
• When you read a quote, the price of each part bothers you more than the setup.
• Your mold is showing wear on a part that hasn't changed.

If some of these are true and some aren't, I'd wait. Freezing a design to save a little on each part, and then having to change it in hardened steel, often costs more than the saving.

A different question from local or overseas

Moving to a production molder is a separate decision from moving overseas. Where a mold is made and shipped from turns on freight, duty and minimum orders, and Dan covers it in the local or overseas section of our guide for products with proven demand. This post is about when a short-run shop stops being the right shop at all.

Why we say so

A shop that holds on to work it isn't built for costs its client money. When a product reaches this point, we say so. There is no fixed number for it. How long a mold lasts, and when moving makes sense, depend on what the client needs, the resin, the use and the care the mold gets, so it is settled in an honest conversation with the client's needs first. The move is the client's decision, made on cost. If the client would rather we keep running the job, we do.

One example. The shop proved a concept for a client, and the client began needing runs of 20,000 and more. The shop opened talks with a production molder, helped the client see that a steel mold was now the economical choice, and handed the client to a partner in its network.

The shop has built its network of specialist shops over three decades, and that introduction is part of the service.

Not every product gets here. Plenty sell steadily at volumes a short-run shop handles well, and never need to move. That is a perfectly good place for a product to be.

If you think you are close, put your change log and your last few orders side by side. If both have gone quiet and steady, the conversation about an introduction is worth having now.

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