Aluminium sand casting

For high-quality prototypes and single parts made of aluminium, we use the sand casting process. We mainly work with aluminium alloys such as AlSi10Mg, AlSi9Mg or AlSi7Mg0.3; special alloys are available on request. In our own foundry we produce prototypes as well as pre-series and small series.

Casting series or single parts in sand moulds is a traditional casting process that allows precise and economical production. We work with the so-called core block method. A major advantage of this method is that any necessary changes can be made quickly. The required pattern equipment is made in-house, which ensures a high degree of flexibility. For single parts, complex geometries or time-critical projects, we use 3D-printed mould parts.

What sets us apart: we carry out every step of the casting process in-house – from design to analysis and machining. This allows remarkably short lead times. One of our specialities: we turn welded sheet-metal assemblies into aluminium castings – many individual parts become one single cast component. Problem solving and short-notice changes are no particular challenge in this environment.

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SMP production hall with robots and parts

From welded part to casting

Welded sheet-metal assemblies consist of many individual parts and come with many challenges: every weld seam introduces heat and causes distortion, and production is hard to scale.

We turn such assemblies into a one-piece aluminium casting. As a sand-cast prototype, the new component can be tested quickly – and it forms the basis for later series production in die casting.

Even at the sand-cast prototype stage, cost savings are around 25 %.

Have your welded design checked

Sand casting at SMP

To produce your prototype, we need a 3D data set of the finished part (STEP or IGES), including holes and mounting surfaces. We work pragmatically and start directly with your 3D data: we take tolerances from colour-coded surfaces in the STEP model or from a comparable drawing, for example of a predecessor or similar part. Adjustments are implemented during production – saving you weeks. Based on your finished-part design, we design a casting blank for making the sand mould. The aim is to create a castable part from your data, which includes closing holes and adding draft angles and machining allowance.

Once the casting blank is ready, we create a negative mould of your prototype and set up the pattern box – traditionally with a cope and drag. We make pattern equipment from PUR-based block materials. Depending on service life, part complexity and function, materials of different densities are used. For cavities or undercuts we use cores and corresponding core boxes.

We fill the pattern box with moulding sand made of quartz sand and water glass. We deliberately work exclusively with inorganic binders – for the sake of the environment and the health of our employees. All mould halves and cores are formed from the positive pattern boxes (drag, cope, …) and further system components such as sprue, risers, feeders and chills. Put together, they form the mould with the negative part cavity. The sand is then cured by gassing with CO2 – and the castable sand mould for your prototype is ready.

Two melting furnaces are available for the casting process. We pour the liquid aluminium into the sand mould manually with ladles using the core block method. We specialise in complex geometries and thin-walled components. After cooling, we remove your casting and start the further processing.

Machining

Based on your requirements, casting is followed by machining on our 5-axis CNC machining centres. Our pattern makers also take care of assembling sub-assemblies or complete prototypes.

CNC machining

Further processing

To improve the material properties of your prototypes, we carry out common heat treatments such as T6, T64 and T7. Surfaces of sand-cast parts can also be finished by painting, powder coating or ESD coating.

Further processing

Quality assurance

Throughout the process, we inspect all sand-cast parts in an X-ray inspection system (first article, sampling, 100 % inspection). On request, we also carry out further tests such as leak tests or assembly checks.

Quality assurance