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Is it possible to create a mold of an aluminium motorcycle cylinder head so that you can create an exact replica with melted aluminium?

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  • $\begingroup$ Is it just a prototype or a series production? $\endgroup$ – Sam Farjamirad Oct 28 '18 at 14:02
  • $\begingroup$ Why not - how do you think most of them are made? That is why the fins tend to have a non-smooth surface... $\endgroup$ – Solar Mike Oct 28 '18 at 14:18
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    $\begingroup$ @SamFarjamirad it doesn't make much difference. Either way, you first have to make a "pattern" which is a "3D jigsaw puzzle" in the shape of the cylinder head, so you can extract it after you have made the casting mold around it. This shows the whole process for a simple part: youtube.com/watch?v=D1VgvVcoKDQ. The traditional pattern material was wood as in the video, but 3D printing is a modern alternative. $\endgroup$ – alephzero Oct 28 '18 at 14:37
  • $\begingroup$ I believe most parts like this are die-cast with significant pressure to assure filling the die and minimize porosity. Very expensive for a few parts. $\endgroup$ – blacksmith37 Oct 28 '18 at 21:30
  • $\begingroup$ Do you want a working replica or just a model piece which looks identical on all surfaces? $\endgroup$ – Carl Witthoft Oct 29 '18 at 17:55
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Yes it is but there a a few things you need to watch out for.

You will need to allow enough excess material for any surfaces which need to be machined subsequent to casting.

All castings shrink somewhat so the pattern needs to be a some percentage larger than the finished casting needs to be.

Its not uncommon for castings to have internal voids which are created with cores in the mould these are a bit more difficult to reverse engineer than the exterior.

Finally you need to add the gating (runners and risers) to the pattern. Getting this right is very important as it not only lets the metal in and the air out of the mould, ensuring it fills properly but also controls the cooling rate, which if you don't get it right can cause shrinkage voids, hot tears and other defects.

Cast aluminium is also quite prone to porosity and ideally needs to be degassed if you want to make decent quality mechanical parts.

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  • $\begingroup$ it is really a good answer but may i suggest a little thing ? Sometimes a draft angle is also indispensable. $\endgroup$ – Sam Farjamirad Oct 28 '18 at 19:13

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