Printing with ABS

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gfeliksdal
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Re: Printing with ABS

Post by gfeliksdal »

Haha, ok I guess a large build envelope it is...

The isolation is the first thing I tried. It definitely helped, but still no solid 110 degC. I'm not an isolation expert, but these are the results I obtained.
The limiting factor is the RAMPS module at this point. I once tried 4x2.2Ohm resistors in parallel and the mosfet melted through the RAMPS module :)...

To give some insights in my efforts:

Test1: 4x4.7Ohm resistors in parallel (default setup of Felix 1.0)
Each line adds extra isolation compared to the previous line.
- baseline, no isolation max temp 70 degC
- bottom isolation, only bubble plastic. to decrease convection losses on bottom. This increased temp of + 10 degC to 80 degC
- bottom isolation, bubbly plastic with alu foil for radiation. + 10degC to 90
- Encapsulating the heat resistors with silicone kit +2 degC to 92degC
- top isolation, aluminum foil. +13degC to 105degC. THis is unusable with foil on top, but gives insight in approx max temp with these resistors.

Test2: 4x3.3Ohm resistors in parallel. Had to include extra heatsink on mosfet to keep temps in check. So not a very safe situation.
- Temp without isolation 82 degC
- Temp with buttom isolationem isolatie 100 graden. When you start printing the temp drops to 94 degC
- Alu foil on top raises the temp 15degC. Up to 115degC
It got pretty close, I hoped a more efficient heater like the foil heater would do the trick, but it is hard to get good specs for it.

Lioric
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Post by Lioric »

4 x 2.2Ohm :) that is 21Amps

In RAMPS specs its mentioned that it has 11A fuse protected heater lines, but seems that this is not the case, as you have tested with 3.30Ohm, that will be 14.5A. Wondering if 5x4.70Ohm (12.7A) might do it (current setup is 10.2A)

I will test with a type of big rubber tape that is covered with aluminum foil on one side (I think it is used in heating or air conditioning ducts) that I used when isolating water lines in my car's turbo installation

Other options, just for the sake of listing them as ideas (I know that you want to keep the electronics as of now)

- Use glass on top to optimize the use of the upwards radiated heat, it has a low thermal transfer rate so it will maintain and store the heat energy (that otherwise will be lost in contact with the air, with the metallic bed only)
- Switch to Azteeg X3, drop in replacement of RAMPS1.4, pin to pin comptaible, made with high current capability for power hungry heated beds in mind
- Drive the heater directly from the PSU 12v rail, with a solid state relay controlled via RAMPS (using the same heater pin that is currently used?)

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gfeliksdal
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Post by gfeliksdal »

Jep indeed 21 Amps :)...
Indeed strange that the fuse didn't really work when connected to the 4x2.2 Ohm, but it was good for the short test.

- I wonder how good the isolation tape will work compared to bubbly plastic.
- Glass is indeed a good option and holds the heat better, but the downside is that it makes the bed substantially more heavy which is bad for dynamics of the system.
- I'm currently in the final stages of development of an own electronics solution. It's done together with an electronics company. They included very efficient mosfets which almost don't get warm even at very high currents. I hope to be able to sell it at the beginning of november.
- The heater option direct connection with a solid state relay would be nice I guess. Is definitely worth a shot.

I also heard about carbon heaters, that might be a good solution as it is lightweight and also able to hold heat very well. It could be a complete replacement for the alu heated bed, must look into it further...

black1q
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Post by black1q »

SUCCESS !!! :D Meanwhile I made a few prints with ABS. I made the ABS solution like described before (some ABS filament in a few drops of Acetone) take an old brush and spread it thin on my Kapton covered printbed. I get the best results with the heated bed and raft, without raft it is very very very hard to remove the objects but it will also work. It is not much work in before and the solution could be removed with more Acetone. So you dont have to change the printer, dont waist money on extra parts or more electrical power, you have a new use for your raft plastic or damaged prints and you can keep the full size printarea. :ugeek:

Lioric
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Post by Lioric »

Nice!, specs please, temps, what slicer settings, size of the tested parts

HLA
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Post by HLA »

Indeed good news :)
Please post some pictures. Want to see the visual proof of concept :geek:
Any issues with oozing, etc?

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Post by gfeliksdal »

Great new! Good to know that the glue is a solid solution. I recently ordered a new foil heater with a 1Ohm resistance before this news, I wonder what the temp will be. If it cannot reach high enough, it is still a good solution for extremely even heat distribution of the table...Hope to test it somewhere next week.

Lioric
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Post by Lioric »

@gfeliksdal:

I'm ordering this heating pads:

https://www.sparkfun.com/products/11289

5x15cm and 5x10cm

120 degrees at 12v with 1.5A (even 6 of them, covering the whole bed and still less than 10A), that will be 8Ohm, hopefully covering the whole bed with this will reach the 110C goal

black1q
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Post by black1q »

@ HLA No I have no issues, its like printing with PLA except that a layer of the solution will still stick on the bottom of the object, but this layer is as even as the printbed. I will make some pictures the next days, meanwhile you can take a look at the high quality section. My blue owl was printed in ABS, sadly with my standard settings as I found out later. (my Pronterface was not installed correctly)

black1q
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Post by black1q »

Ops I forget to say, if you want the print structur at the first layer instead of the solution you only need to print with raft and remove the raft later on.

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