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Topic: Polishing ABS Prints

I want finished prints to look like injected moulded parts.
1 step is printing at lower layer heights, But from what ive read so far, the settings and info required to do this consistently is not there at the moment. Im sure as time goes on and more people get there printers better settings and profiles will be created.

Untill that time, Why dont we discuss the best way to polish up our prints to make them look a million bucks.

Personally, Im very interested in using a tumbler.
Because we're not tumbling metal parts we need to be very careful what "media' we use in the tumbler with our prints to make sure they dont get destroyed.
At the moment im looking at this vibratory tumbler
http://www.allthingsshooting.com.au/product/HSS400-200

And using these hardwood cubes as the media.
http://www.aussiesapphire.com.au/index. … ts_id=2875

Site states that the hardwood should be perfect for tumbling plastic. You could also use nutshells but from what ive heard they might not be heavy dut enough for the ABS.

Anyone have any experience tumbling, tumbling plastic or polishing up ABS prints?
What im hoping to avoid is sitting here for hours sanding little 3d prints by hand :-)

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Re: Polishing ABS Prints

I saw a post somewhere from a guy using nut shells with abs, he did indeed say that they were not tough enough and turned to dust pretty quickly.

They have some interesting options on ebay as well. http://www.ebay.com/sch/i.html?_trksid= … p;_sacat=0

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Re: Polishing ABS Prints

I've heard from someone who tried a barrel that it didn't do much for ABS or PLA.  However Shapeways and Redeye use vibratory tumblers, so I would take that as a solid recommendation.  I wonder if Shapeways would be willing to say what media they use, of if they would consider that a trade secret.

McMaster has a 10" model for about $250.  I don't know how big a part you can put in there, but I would think that tubs should take bigger parts than barrels.

There are also automatic buffing machines that are a little like putting your part through a car wash.  I imagine those are way more expensive.

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Re: Polishing ABS Prints

Acetone works nicely for cleaning up parts, I tested it on a part I had around.

http://i376.photobucket.com/albums/oo204/captainkeewl/8e9ec3e2.jpg

I didn't do it quite right, I'll have to play around with some different techniques. However, it really shined up the part and in some areas got rid of the grain completely.

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Re: Polishing ABS Prints

Thanks Kyle.
Looks great.
Below is a recipe for ABS glue that ive found. Useful for this sort of application.

1. Empty and Clean Nail Polish Container

Acetone is the active ingredient in nail polish so a good rinse at full concentration should do an effective job of cleaning it out. Once clean, fill container approximately half full and seal the cap. (Acetone is highly volatile and will quickly evaporate away if the cap is left off for too long)

2. Fill container approximately half full with Acetone and seal.

Acetone is highly volatile and will quickly evaporate away if the cap is left off very long

3. Snip filament into pieces

4. Drop into Acetone until container is about 3/4 full

5. Swirl and wait

If your impatient like me you'll go back and check it EVERY 5 MINUTES to see if it's done...it won't be. Light concentrations can be ready to use in under an hour, heavy mixtures can take as long as day to be fully suspended.

6. The mixture should be ready when it is relatively free from lumps and of the desired consistency. Add more Acetone or filament to get needed thickness (if you filled it only 3/4 full there should still be room).

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Re: Polishing ABS Prints

The ABS cement actually works great as a polisher as well.  After a few prints for each color, you will have enough strands of ABS to make a little touch up cement for every color you print with.  I paint a little on and then dip a paper towel in the cement and sort of buff it on.  You want to be careful on delicate parts because it can actually eat into the ABS very quickly.  For polishing, I make the cement very thin, and for glueing I make the cement much thicker.

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Re: Polishing ABS Prints

We have an intern who is working on this problem. We have tried sanding , ABS Glue, and acetone washes. We have encountered some successes, but we haven't elevated this to the art form it should be. We are aware that some printers use a "fume bath" method to finish pieces. This is a bit dangerous so we don't recommend it.

Perhaps we can start sharing pictures of results from various finishing projects? This would accomplish something.

Former Solidoodle employee, no longer associated with the company.

8 (edited by Soli_Intern 2012-08-08 21:57:55)

Re: Polishing ABS Prints

All about Acetone: Safety and finishing techniques, an unofficial guide

Safety first!  Acetone is flammable, and any spark can ignite the fumes (much like gasoline).  Never work with acetone in the same room as your printer, or in your kitchen!  A hot acetone bath is dangerous.

Acetone is heavier than air, which means the fumes tend to sink and slowly fill up a space.  Work somewhere well ventilated.

Acetone can irritate your skin and the fumes can give you headaches.  Keep your containers tightly sealed.

Acetone melts through many kinds of plastic, so look for containers that are meant to hold solvents.  Safe containers include polypropylene, metal, and glass with tight fitting lids.  2-part lids on jam jars are not great - it is hard to see if the jar is completely sealed.

Acetone will strip finishes from shoes, shelves, floors, and pretty much anything else you might spill it on. 

Acetone can only do so much.  A professional hot acetone bath and a smooth print can come out quite nicely, but a regular print and brushed acetone might never look like an injection molded part.
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Acetone finishing techniques, Part 1: Using a brush

Before you start:
0. Save your thin misprints and piles of extruded threads to make acetone "glue".  Extruded threads dissolve more easily than solid filament. 

1. Get some cheap brushes to dedicate to this.  Melted acetone will accumulate between the strands. 

2. How will you hold the piece while you are working?  Use caution if you are using a plastic or rubber-coated clamp, acetone drips may eat away at them.  If you plan to hold it, use gloves.

3. Make sure you are in a well-ventilated area away from heat sources, and cover your work surface, floor, and clothes.   Pouring your acetone from a large container into your small working container is a potential splash zone.  At the end of a brush stroke, the acetone may splatter - much farther than you imagine it could!

4. Evaluate your piece - are there any very thin or loosely filled areas?  The acetone may completely melt through them. 

5. Ready a small, easy to seal container of acetone.  You want to minimize evaporation, and as you brush the piece your brush will pick up plastic and make your acetone dirty. 

-------

Brushing your print:
1. Dip brush into acetone and re-cover your supply. 

2. Brush gently across piece.  Brushing hard will cause drips and splatters.  You only get a few strokes before all the acetone evaporates, so plan to so small sections at a time.  Brushing a "wet" area with a dry brush will make unpleasant streaks.

3. On your final pass, keep brush strokes all in the same direction, preferably in the direction of the layers - brushing top to bottom is likely to leave grey streaks. 

4. Do not touch brushed areas until they are dry

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Cleaning up:

Do not dump acetone down the drain!  Save whatever is left for next time. 
Clean your brushes as well as possible.  With gloved fingers, squeeze out plastic from between the strands, then swish in acetone. 
Make sure your acetone containers are TIGHTLY SEALED.   
Go get some fresh air


That's all for now!  Happy polishing

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Re: Polishing ABS Prints

There is the option of a room temperature vapor bath.  I put a yoda on an upside down shot glass inside a paint can with about an inch of acetone, put the lid on and left it overnight.  When I checked it the next morning, Yoda's head had fallen off.  So overnight is too long, but maybe a couple of hours would be right.

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Re: Polishing ABS Prints

That sounds pretty good Ian, just need some tweaking for how much acetone & how long etc

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Re: Polishing ABS Prints

Ian, what was the quality of the detached head? Did it look smoother?

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Re: Polishing ABS Prints

I think with the vapor, the amount of acetone wouldn't matter as much.  Maybe surface area, air pressure, I don't really know what factors affect the amount of vapor.  Basically what happens is the vapor condenses on the part, and that is what does the smoothing so maybe the most important thing is the temperature of the model.

It is basically the same as dipping or brushing, but the advantage is that coverage will be even, probably no dripping and no worry about brush strokes.  A problem I would have with acetone washes is that if there was a flat top, the acetone would pool and evaporate a little more slowly so the effect wouldn't be even over the whole model.

If you have layer lines, acetone will mostly give you shiny layer lines.  To smooth out the layers it needs to sit on the surface long enough to melt the plastic enough for it to begin to run together.  Maybe gravity has some effect, maybe it is reducing surface tension enough, I don't know.  But by the time it has melted the ridges enough, it has probably also gotten inside, melted the fill, and is well on its way to turning your model into something out of a Salvador Dali painting.

For the pro smoothing machine, they recommend several applications of about 30 sec exposure to vapor followed by 45 minutes of drying.  I don't know what the room temperature equivalent of that would be.  You can get a head start by sanding it down first so the texture isn't so deep.  Leaving the plastic dust on might help fill in.

The other option is using some concentration of ABS/Acetone.  The plastic melted in the acetone can fill in the texture, rather than relying solely on melting it smooth.  It's hard to figure out thick to make the mixture, and get it applied evenly.  If you dip it, there will be runs and drips and you can't really control how much plastic gets left on the surface vs. running down the sides.   You could use it as an alternative to the initial sanding.  Brush on a light concentration of ABS/Acetone to get the layers mostly filled in, then use the vapor or some washes to smooth out the brush strokes.

The parts of Yoda that hadn't fallen into the liquid or molded itself to the cup had the shiny layer lines.

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Re: Polishing ABS Prints

The Persistence of Yoda by Salvadore Dali-

http://solidoodletips.files.wordpress.com/2012/08/yoda-1.jpg

http://solidoodletips.files.wordpress.com/2012/08/yoda-2.jpg

The area on the back of his head where you can still make out the layers would probably be smooth with some advance sanding.

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Re: Polishing ABS Prints

Ian:
I know you're aware, but just for the community I should make it known that putting Acetone vapor in an enclosed space like this is somewhat dangerous. Acetone has the ability to explode under the right conditions. I've seen some amazing results with the pro finishing machines, but I'm not 100% sure of the mechanism they are using. They may very well have some tricks up their sleeves.

Former Solidoodle employee, no longer associated with the company.

15 (edited by MeshMoth 2012-08-09 17:51:16)

Re: Polishing ABS Prints

Just wondering, would something like this work?

http://www.rustoleum.com/CBGProduct.asp?pid=11

It says spray filler so maybe it will fill up a good amount of the grooves?

I was thinking of printing>spray with that stuff>sand>spray again (if needed)>paint.

Edit:

And if that stuff eats plastic maybe spray this stuff first?

http://www.rustoleum.com/CBGProduct.asp?pid=379