Custom Castings: The Production Process Step by Step

Custom castings are made in several stages: from the design and pattern, through mold making, to casting, machining and inspection. Below we describe each stage using the example of aluminum alloy castings, which we produce at our foundry.

Casting design

During casting design the first step is gathering customer specifications. This is a key stage, because the entire production process depends on it custom castings. It is necessary to define precisely requirements for the shape, size and quality of the casting.

The next stage is creating the model of the casting according to the specified parameters. This process uses modern technologies and precision toolsto ensure accuracy and compliance with the customer's expectations.

Once the model has been created, verification of its correctness and accuracyfollows. If necessary, corrections i adjustmentsare made to ensure a perfect match with the customer's expectations.

Another important element of casting design is technical analysis and cost-effective. This allows the production process to be optimized, taking into account costs and the possibilities technical requirements.

Casting pattern and core boxes

The pattern reproduces the shape of the casting, enlarged to allow for metal shrinkage and machining allowances. For sand molds it is made of wood, resin or steel: wood and resin work well for prototypes and short runs, steel for large runs. Holes and internal passages in the casting are formed by cores made in core boxes.

Patterns are now usually designed in CAD systems and made on CNC machines or by 3D printing. If documentation is missing, an existing part can be scanned and its model recreated. At our foundry, patterns, core boxes and permanent molds are made in our own pattern shop – we describe the details on the page modeling and prototyping.

Wax patterns are used in investment casting by the lost-wax process: the wax is melted out of a ceramic shell and metal is poured into the resulting cavity. This is a separate technology, used mainly for small, highly accurate castings – our foundry does not use it.

Making the casting mold

The type of mold depends on the casting technology:

• sand mold – single-use, made of molding sand compacted around the pattern in molding flasks; after pouring it is broken up,
• permanent mold – a durable metal mold made of cast iron or steel, reused for runs of castings,
• die (high-pressure die casting) – a tool steel mold for high-pressure casting, cost-effective for large runs.

Every mold is designed with a gating system that feeds metal into the cavity, plus risers and vents, so that the metal fills the mold without misruns and no shrinkage cavities form in the casting. We describe mold construction in the article casting molds.

Casting and Finishing

Molten alloy is poured into the prepared mold – by gravity or under pressure – and left to solidify. After removal from the mold, the gating system and risers are cut off, and the casting is ground and cleaned.

Functional surfaces – fits, holes, threads – are machined to size, most often on CNC machines. On request, the casting undergoes heat treatment, polishing or powder coating. Finally, dimensions and quality are checked according to the agreed acceptance conditions. At our foundry, machining and finishing are carried out at the same facility as casting – see CNC machining.

Key questions about custom castings

• What are the benefits of ordering custom castings?

  A custom casting is made to the customer's drawing, so its shape, alloy and tolerances are matched to the specific application. A complex shape – with ribs, holes and passages – can often be made as a single piece instead of being assembled from several parts.

• How long does it take to produce custom castings?

  Making a pattern or mold usually takes from a few days to several weeks, depending on complexity. Add to this trial castings, their inspection and series production – so it is worth agreeing the lead time already at the request for quotation stage.

• What materials can be used to produce custom castings?

  Foundries work with aluminum alloys, cast iron, cast steel and copper alloys, among others. Our foundry makes castings exclusively from aluminum alloys per PN-EN 1706 – in permanent molds, sand molds and by high-pressure die casting.

We describe what to prepare for a quote in the guide foundry quote request.