How many mouldings will a printed pattern survive?

For a sealed PLA pattern handled normally, expect tens to low hundreds of mouldings rather than the thousands a metal match plate gives. That is usually the wrong comparison though: when it wears you reprint from the same file for a few hundred rupees, whereas a worn wooden pattern goes back to a pattern-maker. For genuinely high-volume work, print the pattern to prove the casting and then have metal tooling made.

Can you work from an existing pattern or casting?

Yes, and it is common. We measure the original, rebuild it in CAD, and can correct the things that were annoying about it while we are there. You get the model, so the next copy is a print rather than another measuring exercise.

Do you handle the parting line and core prints?

We will design them if you want us to, but a foundry usually has strong views about where the mould should split, and those views are generally right. Tell us and we will follow. If you would rather we proposed something, we will show it before printing.

What does a pattern cost?

It is priced like any other print, on the volume of material and the machine hours, using the published rate card. A small pattern is often a few hundred rupees; a large sectioned one runs into the thousands. Sealing and finishing is included. Reverse engineering from an old pattern is quoted separately, from ₹1,500.

Casting Patterns and Core Boxes

Printed patterns for sand casting with shrinkage, draft and fillets designed in, sealed and ready for the moulding box. Days instead of the fortnight a pattern-maker quotes, and a revision costs another print rather than another wait.

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Right for

Foundries running short and medium series, one-off castings, and anyone whose pattern needs changing more often than a wooden one can economically be remade.

Not right for

Very large patterns beyond what sectioning sensibly allows, and high-volume production runs where a metal match plate will outlast anything printed.

Why patterns suit printing better than almost anything else

A pattern is a quantity of one. It exists only to make a particular casting, its geometry is dictated entirely by that casting, and when the casting changes the pattern is scrap. That is the worst possible economics for hand pattern-making, where you pay skilled labour by the hour to produce a single item.

It is close to the best possible economics for printing. The geometry comes off CAD you already have or that we build from the old pattern, the machine works overnight without supervision, and a revision costs another print. Patterns are also consumable by nature, so the fact that a printed one will not last as long as mahogany matters far less than it first appears.

Shrinkage is the thing that gets missed

Metal contracts as it solidifies, so the pattern has to be larger than the finished casting by a known factor. Get it wrong and every casting from that pattern is out of tolerance, which is discovered after the melt rather than before.

We apply the allowance as a scale factor in CAD before anything prints, and we state on the job which figure was used so it can be checked against your own practice.

Typical shrinkage allowances

Grey cast iron: about 1.0%
Aluminium alloys: about 1.3%
Brass and bronze: about 1.5%
Steel: about 2.0%
Tell us your alloy and your own figure if you have one, and we use yours

Draft, fillets and the surface

A pattern with no draft drags sand out with it. We put one to three degrees on every vertical face as part of the model rather than leaving it to be filed on afterwards, and we radius internal corners so the sand is not asked to hold a sharp edge it cannot.

The surface matters as much as the geometry. Raw printed layer lines key into the sand and tear the mould on release, so patterns are filled, sanded and sealed with a lacquer topcoat before they leave. This is the step that separates a pattern from a printed shape, and it is included.

What we need from you

The casting drawing or the model is ideal. Failing that, the old pattern or an existing casting works: we measure it, rebuild it as CAD, and you get the file. Tell us the alloy, the parting line if it is already decided, and whether you need core prints or a match plate, and the rest is our problem.