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Aluminium Sand Casting

The process of Aluminium Sand Casting is used for initial prototyping, smaller quantity production castings and larger Aluminium Castings too big to produce by other processes. Alpac Alloys sand casting process equipment is capable of making complex castings from a few grams to 250 kg in weight. Using wood or resin pattern and core box equipment we have 3 moulding lines and 1 large moulding producing unit.

Customers bring their drawings, designs or 3D cad files to us and we design and manufacture the pattern tooling using CAD technology, (DELCAM and PRO ENGINEER). The patterns use the Boxless Moulding technique, so we are not dependant on steel box sizes to restrict our casting scope.

Resin bonded sand is premixed and loaded into the pattern box and allowed to set before releasing for assembly of cores and closing the mould. This method gives accurate moulds which reproduce castings to tolerance. Dimensional tolerances for metal and metal alloys castings to BS 6615:1985, ISO 8062-1984. CT7 to 9.

See casting data sheets for the Aluminium Alloys specifications available for your Aluminium Sand Castings.

Early discussions with our technical staff will ensure the best possible process for your casting needs. We will advise you which process will offer the most economical solution to achieve your casting and component design.

Aluminium Gravity Die Casting

 Gravity Die casting are produced by pouring molten Aluminium into an Iron permanent mould.

The Aluminium Alloys sets in the mould and is then released. The productivity of the process is generally much faster than the Sand Casting process and consequently produces castings more economically. Additionally the ‘chill’ of the metal solidifying in the iron mould can give better strength to the final product.

Advantages of the process include low gas porosity levels, more accuracy and repeatability, finer grain structure, less finishing work is needed than for Sand Castings.

Choice of Process

Sand Casting and Gravity Die Casting

We can help Designers and Engineers to make the right choice of process and Aluminium Alloy most appropriate for their Castings design.

Sand Casting Gravity Die Casting
Production Quantities per Year   1 to 500 250 to 10000
Tool Life   500 to 5000 25000 to 100000
Tolerances 0 to 25mm +/- 0.5mm  +/- 0.4mm
  25 to 100mm +/- 0.8mm +/- 0.55mm
  100 to 250mm +/- 1.0mm +/- 0.7mm
Typical weight range   0.1kg to 250kg 0.05kg to 40kg
Use of sand cores for internal detail   Yes Yes


Further Processes

Heat Treatment of Aluminium Alloys Castings can improve the mechanical properties of the material. Increased strength and hardness compared to the ‘as cast’ condition can be attained by Heat Treating castings made from certain alloys. Improved properties at high temperature operation, higher proof strength or increased elongation can be achieved by the heat treatment process

Additional testing:

Spectrograph analysis: of the material elements can be provided if castings are needed for high specification environments with traceability.

Tensile testing: of samples form cast melts will provide additional documented data when required by the end user.

Inspection: Inspection plans checking documented areas needed to assure the customer the correct interface dimensions, flatness, surface finish, visual features and any other identified special requirements are met.