Quest for Support 1

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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