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  for Metal Finishing since 1989
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The looks of die cast aluminium

May 29, 2009

Hi,

I am a student at the University of Technology at the faculty Industrial Design Engineering in Delft, and I am designing a kitchen product (hand-driven blender). One of the parts consists of an aluminium alloy which is being produced using high pressure die-cast technology.

I am wondering if you could give me some information on the surface quality of untreated aluminium castings. It is important that the product has a smooth surface finish and a uniform color. I know there are some finishing processes available, but the budget of the project is very limited and it is hard to get an insight in polishing and plating costs.

- Is the color of a die-cast product uniform across the entire product?
- What is the best process to get an evenly colored product (low budget)?
- Can you give me an indication of the costs of this process?

Product info: It weighs about 0.8 kilograms and measures approximately 0.27 x 0.25 x 0.12 m. The product has a uniform wall thickness of 2.5mm, with no tight corners. It will be produced about 10000 times and only the outside has to look evenly colored.

Yours sincerely,

Jan Paul Hagg

Jan Paul Hagg
Student - Delft, Zuid-Holland, The Netherlands

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June 3, 2009

Hi Jan,

Without knowing more about what you will expect the piece to do, addressing what types of plating or finishing you may want to look at would be problematic at best. One thing to be aware of is that - aside from something like powder coating - castings do offer more problems for finishing than machined parts due to the higher surface content of non-aluminum alloying ingredients. If you search this site, you'll find many letters addressing ways to minimize the impact and achieve a coating that ALMOST looks as good as what can be achieved with a machined part.

If the part is going to be in food contact, you'll probably want to look at an un-dyed anodize sealed in hot water - that being the case you will get MUCH better results with machined parts than with cast parts (you can check anodized aluminum cookware for examples of what this might look like). If the part is not going to be in food contact - say, somewhere on the outside - you could look into powder coating, which will give you the same color consistency as paint and is often used on aluminum (check any aluminum patio furniture - for example - and you will almost certainly see powder coating).

Good luck!

Jim Gorsich
Compton, California, USA