How to finish printed objects

[Michiel950]

Hi,
I am Michiel from Dremel and I have a question. I am interested in how you finish printed objects. Or perhaps I need to take it one step back: do you finish printed objects at all? If you do finish objects, how do you do this and are Dremel tools and accessories used? I am very interested in your experiences. Many thanks for sharing your knowledge.
Michiel

[old man emu]

The goal in finishing 3D printed objects is to remove the striations produced when an object is built up by layers. As well as removing these striations, one wants the end product to have a smooth surface, as if it had been injection molded. In general, Dremel tools finish objects by grinding away the surface. This would result in a rough surface. The current method of producing a smooth, glossy surface is to expose the object to an atmosphere of a solvent which slightly melts the surface and allows the melted material to flow into the striations to smooth them.

Old Man Emu

[Vanguard]

In the early days you might have seen somebody sanding or possibly using a Dremel, but even in the early days the resolution was high enough you really never seen anybody grabbing a Dremel. That is unless they were really globing. Just not needed or done.

What I see the most is fogging, with acetone, I personally don't like doing this, it STINKS ! I can live with the resolution on most prints. Some of the Professional display prints are finished, but it looks to me like they are using body shop type of finishing.

Hope that helps some. Not much use for Dremels at the moment. Why don't you put your big $$$ to work finding one ?

[Michiel950]

Thanks for the input guys!

[dddprint]

I am cooking my prints in acetone vapour. The result is awesome: http://www.thingiverse.com/thing:191495
If you want to use a gas stove to boil the acetone then make sure there are no acetone vapours around (no stink) when you ignite the flame or you will make a HUGE fireball all around you. It's harmless but scarry.
The idea is:
1: boil some acetone to make vapour
2: let the vapours soak into the model
If you mix up the steps (soak acetone into the model and THEN boil it) you will get bubbly surface: http://www.thingiverse.com/make:54865 which is awesome too!

[Michiel950]

I know about using acetone, but I have not gotten in depth with it. I will check it out. Thanks.

[Geoff]

Here is a very simple method.

1. Get 2-3 Tablespoons of acetone, place in glass jar.
2. Get a piece of wood, place it in the bottom of the jar with the acetone, you are using the wood as a base. The wood surface needs to be higher than the surface of the acetone, we dont want the bottom of the model to get wet.
3. Place the glass jar on your hot bed of your 3d printer, heat the hot bed to 110c, wait a minute.
4. Place the 3d printed object in the glass jar on the piece of wood for about 10 seconds. Pull it out, check it if it needs more repeat for 5 seconds at a time.

[old man emu]

I am cooking my prints in acetone vapour.
If you want to use a gas stove to boil the acetone then make sure there are no acetone vapours around (no stink) when you ignite the flame or you will make a HUGE fireball all around you.

Whoa there, pardner! Let's look at the safety aspect of what you are doing.

Acetone's Flash Point is -18C. At any temperature above that there is sufficient acetone/oxygen mix to sustain fire. Since most of us are working with acetone in micro-environments where the ambient temperature is about +10C, there is always potential for a flash if the acetone/oxygen mixture comes into contact with an ignition source.

Therefore: always work with acetone in a well ventilated area and limit sources of ignition by grounding metal containers; using static free containers and by locating ignition sources (pilot lights, electrical relay switches and radio frequency transmitters [your cell phone])

Acetone's Boiling Point is 56.5C, so there is no need to use a gas stove to evaporate the acetone to create an acetone rich atmosphere.

My suggestion is to obtain an old glass fish tank that has a cover so it can be sealed. Then obtain a thermostat kit from an electronics show (Radio Shack?), and a 60W soldering iron.

Attach a metal crucible to the hot end of the soldering iron and place both into the tank, being sure that the power cord of the soldering iron come out of the tank. Fill the crucible with acetone. Place the temperature sensor from the thermostat kit into the acetone in the crucible and connect the sensor to the thermostat which should be outside the tank. Put your 3D printed object into the tank, and cover the tank to seal it. Then create a means for the thermostat to be able to cut the power to the soldering iron when the temperature of the acetone in the crucible gets to 60C. Switch on the power and monitor the tank until your printed object has reached the desired smoothness, and you can switch everything off; let it cool, then remove the object.

Old Man Emu

[nka]

Here is a very simple method.
3. Place the glass jar on your hot bed of your 3d printer, heat the hot bed to 110c, wait a minute.

If I dont have a hot bed, can I use the oven (I mean, the circle on the top... dont know the name in english) in a cooking pot? It has fan I can start to get the vapor out. I guess I could just place it at "high" (or medium?) and as soon as it boil stop it ? and then do step 4 ?

[old man emu]

If I dont have a hot bed, can I use the oven (I mean, the circle on the top... dont know the name in english) in a cooking pot? It has fan I can start to get the vapor out. I guess I could just place it at "high" (or medium?) and as soon as it boil stop it ? and then do step 4 ?

Please. please, please take note of the words I have written in BOLD lettering in my post. This process must not be carried out in a domestic space, unless you want to spend all of 2014 3D printing a new house and contents for you and your family.

By the way, the circular heated area on top of a cooking stove is called a hotplate.

(Please don't flame me for that last sentence)

Old Man Emu