I would like to print parts (e.g. jewellery) for use which I don't want to look or feel like a plastic, but metal-like, so briefly people won't see much difference.
Are there any specific type of home-printers that can achieve that? Or it's rather kind of filament that you should use?
If you'd like to print on RepRap like FDM printers, you cannot print from metal, but you can use some filament that tries to look like metal. I have good experience with Bronzefill, but there are plenty of others, just Google for metal filament 3d printing. Note that sometimes the parts need to be post-processed with a rock tumbler. There are several open source DIY tumblers you can build and use.
If you actually want to print from metal, you would need SLS (Selective laser sintering) printer, which is much more expensive.
Especially for smaller parts, I would suggest looking into electroplating. You can get a really nice, copper, nickel, or even gold finish using it.
The biggest issue is that to electroplate something, it must be conductive, but there are many conductive paints on the market which you can use to apply a very light coating to make the plastic conductive. I heavily suggest priming well (2-3 coats) before applying the conductive paint, as it will help to minimize the amount of conductive paint needed.
Here is an instructables link on a cheap, diy, electroplating solution. It's assuming you are doing it on a metal, but once you apply the conductive paint, it's effectively the same thing.
Also here is an amazon link to a fairly well priced conductive spray paint which would do the job just fine.
The Colorfabb metal filaments are the most metal-like filaments I've used (copper, brass, and bronze) and probably the ones that would make the most sense for jewelry. While not as dense as solid metal, it's about 3 times as dense as regular plastic and when polished the metal shows through. Print at 100% infill to make it heavier. Bronzefill is about 3.9g/cm³, about 80% metal by weight, maybe 30-40% by volume. I wouldn't say the polished result feel like solid metal, but it feels even less like plastic.
There's also Filamet, which promises to be almost entirely made of metal and can be sintered into solid metal, but it hasn't been released yet.
parts ... I don't want to ... feel like a plastic
This is harder than looking like metal. Plastic doesn't have nearly the density of metal, nor the thermal conductivity of metal. So by touch people will be able to tell the difference between almost any metal item, and a plastic item that looks similar.
For jewelry, as long as the wearer doesn't mind that it's not metal (they will be able to tell) you can fool most viewers with proper finishing. Sanding/smoothing, and then painting the printed part will work for most things.
For things which dangle significantly, the swinging and action of the item may give away its density, but some objects people expect to be hollow metal can be printed in solid or high density plastic and give the same weight, though they are lower density.
Are there any specific type of home-printers that can achieve that?
For things which feel metallic, no, except for very small items where the weight and thermal conductivity won't be significant. A laser sintering printer could make real metal parts if this is needed, but these don't fall into the category of home machines.
If you don't mind a multi step process, you can make molds of the printed object, then cast real metal, or very high density epoxies, to accomplish your goal.
Beyond that, a high resolution machine with a lot of hand-finishing work is going to get you as close as you'll get to looking like metal.
You have several options:
Printing with filaments made up of plastic and metal powder mix. Bronzefill is one example.
While most may argue it doesn't look much like bronze or copper and rather clay, it can made to by some automatic polishing methods:
Some don't like the idea of having a plastic and metal powder mixture and they say if it's not pure bronze/some other alloy it might as well be painted. Which is the second option:
Spray painting an ABS or PLA print with metal color spray paint. You might need to sand or acetone bath the print first for the paint to be applied evenly.
Metal plating can be done for more realstic texture.
The 3d print should again be sanded/polished first.
The first method of getting actual metal object from a plastic object: Printing with a metal clay, then firing it in a kiln. You'll need an appropriate extruder which can extrude paste instead of filament:
There are 3D printers that can do that officially.
You'll need a kiln...
Second method of getting actual metal object from a plastic object, via metal casting ("lost polymer casting"). From all the above options this is the most dangerous if you're not experienced, skilled and careful.
In addition to the aforementioned enriched filaments which give an excellent result, ABS can be plastered, painted and even chrome plated.
There's also an interesting discussion of printing with specially-designed solder alloys, at RepRap: Blog - A new approach to printing metals.
The author settled on 57.5%Sn, 41.3%Bi, 1.2% In, which begins to melt at 130 °C and finishes by about 170 °C. This has much better viscosity after melting, so it doesn't just drip away or bead up, and whose melting point is low enough that it can be applied directly on top of PLA or ABS.
Brass nozzles corrode quickly, however, so another material is needed (anodized Al was an improvement). It sounds difficult but feasible.
