Quest for Support 1

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Currently one of the big problems of the DIY 3d-printers, is that nobody can use support with it so long.  So many objects aren't printable because of too long overhangs and other unprintable features. So it would be good to find a way to use a different material to print support structures which can be removed later. A friend of mine, a chemist, suggested that it should be possible to use PLA as support for ABS and dissolve the PLA later. He has then done some chemical experiments on small parts of filament and found a working solution. He will report over that here on a later date.

So with the chemical solution in mind, I though of ways to create testobjects so we can prove that the chemical dissolving of PLA really works with a actual object . First I made a test to find out, if PLA and ABS would stick together. I printed two cubes, one with PLA and one with ABS on top of each other.

The right one was printed with ABS first, on a heated printed with 110°C, this was obviously too hot. The left one is PLA first on a 50°C printbed, this object looks really nice. And both stick really well together.

Because my two-head Repman is still waiting for new firmware, and the two-head mendel is still in building, I thought of ways to generate test-objects with support with only one extruder. The idea was to print some sort of inlays and use those to support another object by stopping the print, inserting the inlay and letting the print continue.

After I had those test-objects, I traveled to my chemist friend and we started to test dissolving PLA. First we mixed and created the solution he designed.

Then we inserted the first test-object.

The solution was heated via a hot water bath, and put into a ultrasonic cleanser for good mixing.

After about 10 minutes we made a first inspection. You can see, that it started to dissolve, but it needs more time.

After about 45 minutes it looked like this:

Those last strings are probably from when I switched the filament in the print. It was probably ABS mixed wth PLA. The object now needs cleaning with much water, because you shouldn't touch the chemical solution. The chemical solution is now cloudy and should probably not be used anymore.

Here you can now clearly see that it really is possible to make mixed ABS-PLA objects and dissolve the PLA later. So that means we are nearly at the goal to have a good solution to make supported objects with DIY 3d-printers.

The next step is doing more tests with different ABS-PLA testobjects.

 

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  • Guest

    Looks really promising!<br /><br />Laszlo

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  • Wow, this is great!<br />Awesome to see progress in this area!<br /><br />Schöne Grüße aus München,<br />Andreas

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  • Guest

    What kind of chemicals are these? If "you cannot touch them" it seems to me that this is not a real solution, but more polution!

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  • I recently got to play with a Dimension 3D printer, and it prints with ABS, as well as a support material that gets dissolved by sodium hydroxide. I'm not sure what the other material is, but it could be PLA. I'll try to figure out what material they use.

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  • What kind of chemicals are these? If "you cannot touch them" it seems to me that this is not a real solution, but more polution!
    <br /><br />You can touch it, but you should wash your hands within the next opportunity.

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  • Guest

    Both Sodium Hydroxide ( aka Lye aka Drain Cleaner ) and Acetone ( aka Paint Thinner aka Nail Polish remover) are known to disolve PLA. YMMV.

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  • Guest

    Extra... Acetone will Dissolve Both ABS and PLA, so be careful.

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  • Guest

    Sodium Hydroxide is not basic enough to dissolve PLA in an appropriate time - test it on your own!<br />Yes, acetone and ethylacetate dissolve ABS very well, but also harm the PLA. The PLA swells too much, so for a usage as solvent for ABS those solvents don't fit. This was tested for the other way around - ABS as supporting material for PLA - and is proofed to be unsuitable.<br /><br />The "some chemical experiments" were a little bit more than that. Some do less for their bachelor, what I did to get a working concept for dissolving whether PLA or ABS without harming the other one.<br /><br />More information comes later, when I have finished my project documentation.<br /><br />Greetings from the lake of Konstanz<br /><br />BonsaiBrain aka the chemist friend

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