Test your die-cast part before the tool is built

A die-casting tool costs a lot of money and takes many weeks. If it only turns out afterwards that the part needs to be changed, it gets really expensive. That is why many development departments first have their future die-cast part made as an aluminium sand-cast prototype – from the same data, without a die-casting tool.

This lets you test function, assembly and endurance with real aluminium parts and release the tool only once the part is right. Typical examples from our practice are electronics housings and gearbox housings for test runs in the automotive industry.

Aluminium casting on a technical drawing

How it works

  1. Send your data: 3D data of your die-cast part as STEP or IGES. We can usually adopt the die-casting geometry 1:1, including draft angles. A drawing is not needed to get started.
  2. Review and quotation: We check castability, choose a pattern or a printed sand mould and send you a quotation.
  3. Cast and assess a first part: We usually cast one part first and assess it. We use the same part to set up clamping and the program for machining – so no time is lost.
  4. Heat treatment, machining, inspection: heat treatment in-house, machining wherever possible as 5-sided machining in a single clamping, inspection e.g. by X-ray and measuring arm.
  5. Delivery and testing: Your findings from testing flow into the design – before the die-casting tool is built.

What the prototype can – and cannot – do

  • Material: We cast all common aluminium alloys, including typical die-casting alloys such as AlSi9Cu3 or AlSi12.
  • Properties: We deliberately match the mechanical properties to the later die-casting values. The prototype should not exceed them – otherwise your tests would not reflect the later series condition.
  • Microstructure and surface: A sand casting is not a die casting – microstructure and surface differ.
  • Wall thickness: As a rough guide from about 3 mm. What is possible depends heavily on the adjacent geometry and the flow paths; in individual cases we have also cast 2.4 mm.
  • Long flow paths: They require special casting measures, which we agree with you.

What does it cost?

Rough, non-binding guide values from our invoiced orders (net, as of 10/2026):

  • Pattern equipment (one-off): medium-sized parts approx. 400–8,500 €, large parts up to approx. 20,000 €
  • Unit price including machining: usually approx. 150–700 €; for 3–20 pieces typically approx. 250 €
  • Example: 10 medium-sized housings = pattern equipment + approx. 10 × 250 €
  • By comparison: As a rough guide, the pattern equipment usually costs less than a tenth of a die-casting tool and is ready in less than a third of the time – depending on the part.

All guide values and what affects the price: guide prices for aluminium sand casting

How to make it cheaper

  • Allow 5-sided machining: whatever can be machined in one clamping saves time and rules out re-clamping errors.
  • Homogeneous geometry: wall thicknesses as uniform as possible.
  • Sensible ribbing instead of material accumulations.
  • Machining with few tool changes: for example uniform hole and thread sizes.
  • Tolerances only where needed – mark the important faces in colour in the STEP model.
  • Bundle quantities: we are particularly economical for about 3 to 200 parts.
  • Repeat orders: if the pattern equipment is already with us, usually only set-up costs of approx. 15–200 € apply.
  • Normal instead of express lead time and report changes as early as possible.

How to make it faster

  • Typical lead time: 2.5 to 4.5 weeks.
  • Express: from receipt of data to the cast part approx. 2 calendar weeks. If a drawing or binding dimensions are available, we prepare machining in parallel – the finished part is then with you in 2 to 3.5 calendar weeks. Because we have to coordinate the work closely, an express order costs more.
  • Printed sand mould instead of a pattern for single parts and urgent projects.
  • All details in your first enquiry – this saves follow-up questions.

Frequently asked questions about die-cast prototypes

As a rough, non-binding range: the pattern equipment costs approx. 400–8,500 € for medium-sized parts and up to approx. 20,000 € for large parts. On top comes the unit price including machining of usually approx. 150–700 €, for 3–20 pieces typically approx. 250 €. As a rough guide, this is usually less than a tenth of a die-casting tool.

Typically 2.5 to 4.5 weeks. For express orders, it takes approx. 2 calendar weeks from receipt of data to the cast part; with a drawing or binding dimensions, the finished part is with you in 2 to 3.5 calendar weeks. An express order costs more because we have to coordinate the work closely.

Allow 5-sided machining in a single clamping, design uniform wall thicknesses and sensible ribbing, plan machining with few tool changes, specify tolerances only where needed and bundle quantities – approx. 3 to 200 parts are particularly economical.

Send a drawing or binding dimensions right away so that we can plan casting and machining in parallel, and include all details in your first enquiry. For single parts, a printed sand mould is often faster than a pattern.

We usually cast one part first and assess it; we use the same part to set up machining. If it shows weaknesses, we adjust the casting equipment, usually without significant delay. It only becomes difficult if a third or fourth attempt also fails – this can happen with very thin-walled parts.

Mainly with very thin walls and long flow paths, and with changes that alter the clamping position. We check porosity by X-ray and compensate distortion by straightening directly after solution annealing. Important: microstructure and surface of a sand casting differ from die casting, but we match the mechanical properties to the die-casting values.

For a preliminary estimate, data of a similar part is enough. For a quotation we need 3D data as STEP or IGES; a drawing is not required. Helpful are quantity, alloy, deadline and the important faces marked in colour.

Until production has been run in, we implement changes without significant effort or delay; in the running process there may be minor delays. Changes to the casting as well as to machining are easy to implement. It only becomes more complex if the clamping position changes as a result.

How to reach your goal

Send your 3D data with quantity, alloy, deadline and requirements to info@smp-prototypen.de, subject “Price estimate”. We are happy to sign non-disclosure agreements; your data stays in-house.

More: Aluminium sand casting · Guide prices and enquiries · Quality

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