I've been working on the drawings for the chimney and dome on my 5" Stowe locomotive. My son printed a chimney piece in plastic which looks really good and I wondered if there are any companies that can do the same printing in brass or stainless steel?
Polly did a brass 3D printed casting for me of a reverser stand (Very reasonably priced), but they are currently going through a sale and I'm having trouble getting them to answer any questions.
Does anyone have a recommendation for a supplier that can print in brass or stainless steel in small quantities?
There are a number of bureaus that offer 3D printing in stainless steel, brass, titanium etc eg craftcloud3d.com and www.hubs.com/ I have used them for plastic with production in both Europe and china both have been very good. For 3D printed parts in steels they are going to be pricy!
Do I understand this right? When 3D printing in a metal, like brass and stainless, there is no plastic involved it is purely metal, so the resultant part would react to heat exactly the same as if machined from solid metal?.....Like Oilite bearing bushes, but without the oil?
3D printing in metal by laser sintering is possible, but with some important caveats.
Stainless steel and aluminium are the cheapest materials, and are widely available, almost certainly because that is where the industrial demand is. They may be "non-traditional" in ME, but if you can work with them, why not?
Mild steel is problematic. To make it print satisfactorily the powder must contain a large fraction of bronze which acts as a sort of "flux". The resulting part looks more like bronze than MS and has a physical strength comparable to bronze. It is more expensive because of the post-processing - it has to be kilned after printing. For those reasons it is not very popular.
Brass and other copper alloys are feasible but today it is hard to find anyone who will print it. Read the fine print - companies that claim to print brass almost always use a combination of printing and casting. Send them a solid model and they will first 3D print it in plastic, then use that plastic to make a rubber mould in which the brass is cast. Rubber moulds wear out and you should ask how many castings they expect before making a new mould. Alternatively they 3D print in wax and use that for an investment cast. Investment casting usually gives a better surface finish, better dimensional accuracy, better physical properties, but is more expensive. Some companies may accept your own prints but will impose requirements about shape and surface finish (particularly for the rubber moulding process), so a preliminary discussion is essential. You may find you don't save much, because most of the cost is in the casting process.
I suggest doing a web search - there are many companies that offer these services and their number continues to grow. Many offer on-line quotes, so upload your solid models to know the price. But if you want to use brass, before committing to buy, phone them and ask enough questions to understand exactly what they offer.
To partly answer Bob's question: casting done this way will machine just like any other casting. I have a few directly printed brass components (by a company that no longer offers that particular service) and I've done light machining on them (opening up holes to size) without any problem. I don't know how they react to heat, because I havent; had a need to find out! But the advantage of a 3D printed part is that it shouldn't need much or any cleaning up.
I think clarification is necessary molten brass is poured at around 1100°C and I don't know of any "rubber" mould that could take such a temperature. In fact the rubber mould is used to form wax copies which are then investment cast. If I am wrong please let me know of this completely new to me technology. Dan.