games working casting process

[slirgy]

I've been thinking about the casting process games workshop use, and is it possible to use casts that use metal (wood elf eternal guard) and if the wood ef release ever comes out wood it be possible to use these moulds to make plastic versions of the same models.
thanks all in advance

[Spectrar Ghost]

Not exact duplicates; plastic models have no tolerance for undercuts like resin or metal, thus the models would have to be modified at the least. Fortunately this is not a terribly difficult process - take a 3d scan of the model and with the resulting file many CAD programs have pug-ins that automatically detect undercuts. It would then be a matter of finding the most efficient orientation of the model in an injection mold, and cutting the model into suitable components.

It could be done, but more realistically you'd find the models resculpted to keep them fresh and use the medium to it's fullest istead of bodging models into a medium htey weren't designed for.

[slirgy]

thank you i quite like the eternal models though

[Mr Ogre]

Far more likely they'll be a resculpt in plastic. More and more units are being shunted into plastic. And in Fantasy, you're even getting characters (including named ones) released in plastic.


Wouldn't surpriise me at all if Finecast is a kind of stop gap on the way to a fully plastic range. And that's a move I for one would welcome! Conversion opportunities alone are grinsome!

[Trasvi]

(Talking generally here) Most models are cast in either Resin, White Metal, or Plastic.
Resin uses very flexible rubber moulds and a gravity or pressure cast process. The moulds are quite easy, quick and cheap to make - essentially you just pour silicone rubber over the master model and then cut it in half. However, the mould rapidly deteriorates through use - pieces of rubber are easily torn off, the heat from curing resin can also harm the rubber. Because the mould material is so flexible, it allows more interesting shapes including undercuts, and resin typically has lower viscosity and shrinks less whilst it sets resulting in casts which are closer to the original. Resin typically is used for small production as the moulds are CHEAP, but labour for each production is expensive.

Metal uses much less flexible rubber which is able to withstand the heat of liquid metal. The mould making process is reasonably similar to resin casting, but typically many masters are laid out in a wheel for spin casting (though pressure casts are still possible). The two halves of the mould are put into a spin casting machine, the metal is injected in the centre, and the centrifugal force pushes the liquid out to the extremities of the mould and sets. Metal is more viscous than resin so doesn't always make it all the way into the details as they are sculpted, and shrinks slightly as it cools. Metal allows for some undercuts, but typically small ones. Compared to resin, metal moulds are more expensive, the casting material is more expensive, but involves much less labour so tends to be cheaper for medium sized runs.

Plastic casting is an entirely different matter. Plastic moulds are made from machined steel. This means that there is zero flexibility in the mould and thus no undercuts are allowed. Typically, the master is sculpted at 3x scale, and is scanned into the machine (or, these days, the entire model is digitally sculpted). Plastic is injected at very high pressure into the mould and rapidly cooled. This process is highly automated and casts can be produced vary rapidly. Due to the nature of plastic and the moulds used, you do end up with a little less detail than is possible in metal or resin. The machined steel moulds are very expensive, which means that plastic only makes sense for very high volume items. GW is one of the very few companies which has extensive ranges in plastic.

With this information taken into account, you can see why it is extremely unlikely to see a metal model being directly moved to plastic. A metal model simply isn't designed to be cast using plastic techniques as it will have undercuts, doesn't exist in a 3-up form, etc. It also shows why GW was able to switch easily from metal to resin (as the sculpting procedure is very similar) and why many people are surprised that GW moved from metal to resin (higher labour cost).

[paddyalexander]

The higher labour costs of resin casting are offset by the fact that both the material and molds cost much less than casting in metal. Other companies like Mantic also moved from metal to resin on some of their minis and doubled the contents of those boxes while leaving the price the same.

Also there are plenty of other manufacturers out there whom have large portions of their model ranges in plastic. The difference is that gwPLCs' plastic casting (including mold tooling) are all in house (so much cheeper) while manufacturers like Mantic, Warlord and the Perrys have to go to a third party caster which is a lot more expensive.

Otherwise I agree with Trasvi, moving a model directly from metal to plastic would be difficult to impossible. Digitly scanning and altering the model to work with plastic is a possiblity.

[orlanth1000]

Send Mechanicalhorizon a PM, his knowledge of GWs manufacturing processes is very good.

[carlisimo]

It also shows why GW was able to switch easily from metal to resin (as the sculpting procedure is very similar) and why many people are surprised that GW moved from metal to resin (higher labour cost).

I don't think that many people were surprised. Tin prices were through the roof!

http://www.indexmundi.com/commoditie...tin&months=240