Low-volume batch production: 10–500 parts without tooling

You need 50 enclosures, 200 brackets or 30 assembly jigs. It's too many to make by hand, and nowhere near enough to justify injection mould tooling. Toolmakers quote four figures and six-week lead times before the first part exists; machinists price every part individually and the numbers barely improve with quantity. This is the gap that low-volume 3D-printed batch production fills.

We run batches of 10 to 500 parts from our Bicester workshop: no tooling, no minimum order, and most jobs dispatched within days rather than weeks. Here's how the economics work, what a typical job looks like, and — just as usefully — where this approach stops making sense.

No tooling changes everything about the economics

Injection moulding is cheap per part and expensive to start. A simple single-cavity tool for a small component typically costs £3,000–£8,000 and takes four to eight weeks to cut. Spread over 50,000 parts, that's pennies. Spread over 100 parts, the tooling alone adds £30–£80 to every unit before any plastic has been moulded.

3D printing has no equivalent cost. The first part costs the same to produce as the hundredth, which is why the technology became the default for rapid prototyping. The same economics apply at 10 parts or 500: you pay for machine time and material, not for the right to begin.

There's a second effect that gets less attention: design freedom mid-batch. If part 40 of 200 reveals a fit problem, we amend the CAD and every subsequent part prints to the new revision. With a mould, that same change is a tooling modification — more money, more weeks. For parts whose design is still maturing, this alone can justify printing the batch.

Speed is the third leg. A moulded part cannot exist in under a month, however urgent the job. A printed batch can start the same afternoon the order lands. When a production line is down or a launch date is fixed, that difference is worth more than any per-unit saving.

A worked example: 120 brackets, one week

A representative job: an equipment installer needs 120 wall-mount brackets — a 45-gram functional part, in a material that won't creep under load. In PETG that prices at roughly £4–5 per unit at that quantity: around £550 all in. The mould route quoted £4,600 for tooling plus a per-part price, with the first parts arriving in six weeks.

We pack the brackets onto build plates, run the first plate for a fit check, then run the rest continuously. The first 40 dispatch inside 48 hours so installation can start; the remainder follow within the week. Total lead time: five working days, and nobody carries tooling risk.

Materials that survive real service

Batch parts are almost always functional — fixtures, housings, brackets, jigs — so material choice matters more than it does for prototypes. For general indoor fixtures, PETG offers a solid balance of toughness and cost. For anything outdoors or under a bonnet, ASA handles UV and heat that would degrade cheaper materials. And for parts that need real stiffness — machine guards, sensor mounts, load-bearing brackets — carbon-fibre-reinforced grades add rigidity without a weight penalty.

One honest caveat: printed parts are anisotropic — weaker across the layer lines than along them. For most fixtures and housings this never matters. For parts under sustained bending loads it's a design consideration, and we'll orient the part (or suggest a geometry tweak) to put the strength where the load is.

Consistency across the batch

The reasonable question about printed batches is whether part 1 matches part 200. Modern FDM machines are far more repeatable than their hobbyist reputation suggests: dimensional consistency of ±0.2 mm is routine, and we've held tighter where a job demanded it — see the DAC bracket job, where printed precision beat what could be fabricated by hand. Our process for batches is a first-article inspection before the run starts, then sample checks across plates as it progresses.

Where injection moulding still wins

We'd rather tell you this before you order. Beyond roughly 500–1,000 identical parts with a settled design, moulding's unit price usually undercuts printing, and the gap widens from there. Moulding also wins on high-gloss cosmetic finishes, and on certified food-contact and medical applications we don't cover. If your volumes are heading that way, we'll say so — and printing still earns its keep as the bridge.

How to brief a batch job

Send us a STEP or STL file, the quantity, the material (or the operating conditions, if you'd rather we recommend one), and any dimensions critical to fit. That's enough for an accurate price — usually the same day, often within the hour. If the design isn't quite finished, our CAD team can take it the last mile before the run starts.

Quantity matters to the quote, so tell us the real number — and if you're weighing 50 against 150, ask for both prices. The difference is often smaller than you'd expect, and unlike moulding, ordering the smaller batch now doesn't penalise you if you come back for more.