Start by working out whether you have a capacity problem or an allocation problem, because the two look identical from the outside and have different solutions. Calculate what your tool can theoretically produce (cavities multiplied by 3,600, divided by the cycle time in seconds, multiplied by running hours) and compare it with what you actually receive. A large gap means the press is not too small, you are simply not high enough in the schedule. Only when the arithmetic shows the tool is genuinely at its limit do you choose between more cavities, a second tool, or a second manufacturer.
How do I tell a capacity problem from an allocation problem?
With one calculation. Take a six cavity tool running a 25 second cycle. That is 864 units an hour, so roughly 86,000 units a week on two shifts of 100 running hours. An annual demand of 500,000 units fits into six weeks of press time.
If your yearly volume fits into six weeks of machine time and you are still short every month, the tool is not the constraint. One of these four is:
- You rank low in the schedule. The press rarely runs for you alone, and the customer with the higher margin per machine hour gets the slot.
- Changeover time is high relative to your call off size. Frequent small orders mean frequent changeovers, which makes your job the easy one to postpone.
- A component or resin is the bottleneck, not the moulding.
- Scrap has crept up, so more has to be made than you order.
Ask for three numbers: the actual cycle time, the running hours your tool logged last quarter, and the scrap rate. If they are not available, that is already an answer.
Why has my factory stopped prioritising my orders?
Usually because the economics of their press changed. A manufacturer allocates machine time by contribution per machine hour, and three things move you down that list: a long cycle on a low value part, small irregular call offs that force changeovers, and a forecast they cannot plan against.
Two of those three are yours to fix. Consolidating call offs into fewer, larger batches removes changeovers from their week, and a rolling twelve week forecast, even an imperfect one, lets them block press time in advance. Both are free and worth trying before you commit to tooling.
If that does not move the needle, the constraint is commercial, and no scheduling discipline on your side will outrank a customer with better economics on the same press.
More cavities, a second tool, or a second manufacturer?
It depends on whether you are short of output, short of security, or both. Four routes with their real price:
| Route | Investment | Lead time | What it solves | What it does not solve | | --- | --- | --- | --- | --- | | More running hours at the current site | None | Weeks | A temporary peak | Dependence on one site | | Convert the tool to more cavities | Low to medium | 4 to 8 weeks | Output and unit cost together | Your position in their schedule | | Second tool at the same manufacturer | Tooling investment, driven by cavities and volume | 6 to 12 weeks | Output and single tool failure | Dependence on one site | | Second manufacturer with its own tool | Tooling plus qualification | 3 to 8 months | Output, priority and supply risk | Nothing, but it costs the most attention |
Going from two cavities to four halves machine time per unit and doubles output in the same hours. At EUR 22,000 for the conversion and EUR 0.21 off the unit price, break even arrives at roughly 105,000 units, which on 300,000 a year is inside five months.
A second manufacturer is the most expensive route and often the right one anyway. What you buy is more than output.
What does a second chain buy you besides capacity?
Control over your cost price. The moment two parties can make the same part you have a reference point: you know what a unit costs elsewhere, and your pricing no longer rests on one quotation. You can also place volume where it runs best, long flat runs with one party, small call offs and variants with the other.
Underneath that sits a larger point. The route you have was chosen at the volume you had then. Cavity count, resin purchasing, packaging, transport mode and inspection were fixed on assumptions that held at 40,000 units a year and not at 300,000. Optimising inside that route then runs into a ceiling: taking a cycle from 40 to 36 seconds helps, but the setup itself does not scale with you.
A worked example on invented assumptions: a unit price of EUR 2.40 at 300,000 units a year. Take 4% out inside the existing route through a faster cycle and less scrap and you save EUR 29,000 a year. Rework the chain itself, cavities, material, packaging and where assembly happens, for 15%, and it is EUR 108,000, every year, against a one off investment in tooling and qualification.
That also makes it a different kind of decision. "We need more capacity" is a purchasing question you settle this quarter. "Our chain was designed for a volume we have passed" is a design question, and the answer keeps paying for years.
How do I bring a second source online without a stockout?
In six steps, with the stock build before the transition rather than during it.
1. Write down the specification. Current drawings, material grade, the tolerances that are genuinely functional, cosmetic requirements and the scrap limit. Without that document you qualify on opinion. 2. Build stock covering the new source's lead time plus a buffer. At 6,000 units a week and a ten week lead time that is 60,000 units. This is the cash peak of the entire project and it arrives early. 3. Have the new party review manufacturability before steel is cut. A second tool is the moment to remove design compromises you have carried since launch. 4. Sample and run a first article inspection with a dimensional report against the written specification, plus a functional test. 5. Run both sources in parallel for one to three months. Split the volume deliberately, for instance 80 to 20, so the new source does real production rather than trial shots. 6. Compare scrap rates between the two sources before you shift the split.
One brand whose annual demand went from 40,000 to 180,000 units in two years started the stock build only after the new tool had been ordered, so inventory cost and tooling invoice landed in the same quarter. The technical work went fine; the project still slipped a quarter, for cash reasons alone.
What changes about quality control when two sites make the same part?
Everything that was implicit has to become explicit. Two sources always produce slightly different parts. The question is not whether they differ, but whether the difference falls inside a limit you have defined.
In practice: tolerances on the functional dimensions, a first article inspection per source and per tool change, scrap reported per source rather than in total, and samples measured the same way at both sites. Agree in advance what happens on a deviation: who stops the run, who assesses it, and within how many hours.
Be straight about the trade off. A second source lowers your supply risk and raises your management load. You split volume, so you lose some scale at both sites and maintain two processes instead of one. On a product carrying a large share of your revenue that is worth paying for. On one that is 5% of revenue it usually is not.
Production Heroes takes products from design to series production, from feasibility and cost price to sourcing and supply chain, and supplies moulds and tooling to manufacturers across Europe, from the Netherlands and its own presence in China.
Sources: production volumes from our own project history; the capacity, saving, payback and stock figures are worked examples on invented assumptions, not a quotation.
Frequently asked questions
- How quickly can a second manufacturer be producing my product?
- Three to six months if an existing tool can move, four to eight if a new tool is needed. Tool build takes six to twelve weeks, sampling and first article inspection four to eight, and you then run both sources in parallel for one to three months before shifting volume.
- What does a second tool cost?
- It varies widely, driven by cavity count, side actions, steel grade and the volume you design for, so always ask for it alongside the piece price. Converting an existing tool from two to four cavities costs a fraction of a new tool and raises output and unit economics together.
- How much stock do I need to cover the transition?
- At least the new source's lead time in weekly demand, plus a buffer for the first runs. At 6,000 units a week and a ten week lead time that is 60,000 units before you start, which is the largest and most frequently forgotten cost in the whole project.
- Is optimising with our current factory cheaper than adding a second one?
- In the short term, yes. A few percent usually remains inside an existing route, in cycle time and scrap. The ceiling is the setup itself, which was chosen at a lower volume. A second chain also gives you a reference price, and that is what makes the saving hold.
- Does my unit price drop as volume goes up?
- Only if the setup changes with it. Volume alone mostly buys better material pricing and fewer changeovers. The real step comes from more cavities or a shorter cycle, because both cut machine time per unit, which is where the money sits.