FAQ's

Why Casting?

One of the oldest methods of producing a shape in metal is that of casting. Casting involves the melting of the metal in a furnace or ladle and pouring this molten metal into a hollow mould. Casting offers the designer the opportunity to achieve near net shape solutions to a huge variety of problems. A wide range of materials are available, in quantities from one to millions, and in sizes from tiny, for example a washer, to 280 tonnes. The gravity dies used at Skaigh are made from cast iron and produce rapid solidification of the metal. This produces castings with excellent mechanical properties, generally sound and hold good dimensional tolerances.

Why Aluminium?

Aluminium has been recycled in the UK since the metal first began to be used commercially in the opening decades of the 20th Century. Aluminium and its alloys can be melted and recast repeatedly without loss in quality with today's technology. The recycling of good quality aluminium scrap back into new ingot takes place with an energy saving of 95% of the energy required to produce the same weight of aluminium through the primary smelter route. Secondary aluminium refiners convert most of their materials into foundry ingot, generally based on the aluminium-silicon alloy system, with additions of other metals such as copper and magnesium. These ingots, to BS EN 1676 or LM Series, other international specifications, or to aerospace specifications, are used to produce aluminium castings.

Aluminium's advantages may be summarised as lightness, rapid machinability, corrosion resistance and suitability for volume manufacture. The UK uses around 140,000 tonnes of aluminium foundry alloys per year.

For further info download fact sheet here. UK Aluminium Industry Fact Sheet 5 “Aluminium Recycling”

Why gravity die-casting?

For low volume, very large or very complicated castings, sand casting is the usual route, where a pattern is (relatively) cheap, but the casting is expensive. For very high volumes pressure die-casting is the answer, as high tooling costs are offset by much lower unit costs. Gravity die-casting falls in the middle ground where tooling is not prohibitively expensive, but savings on casting costs can bring the break-even point down to as low as 200 units.

Why Skaigh?

Skaigh has been Aluminium Gravity Die casting for almost 50 years. Our on-site services include Sand Cast Prototypes, Die and Tooling Manufacture, Sand Cores manufacture, Heat-Treatment, various surface finish treatments and the ability to fully machine the casting as required. All these services are in-house; this allows us to react quickly to your needs and respond promptly to your requests. We believe in the principles of excellent communication, great quality and providing the customer with a higher level of service than found elsewhere.

Casting Tolerances

Process	Tolerances on Critical Dimensions				Tolerance across part line	Taper		Minimum casting wall thickness		Ability to use sand cores
	Up to 25mm		Each Additional cm			Min.
Gravity Die Casting	± 0.4mm		± 0.02mm		± 0.25mm	1°		3.5 **		Yes
Sand Casting	± 1mm		± 0.40mm		± 1mm	2°		4.0		Yes
** Smaller wall thickness possible in certain situations.

 

 

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