Re: I designed a polar printer July 12, 2013 03:17PM |
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Re: I designed a polar printer July 21, 2013 03:04PM |
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Re: I designed a polar printer July 21, 2013 03:26PM |
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Re: I designed a polar printer July 21, 2013 03:42PM |
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Re: I designed a polar printer July 26, 2013 04:15PM |
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Re: I designed a polar printer October 27, 2013 02:23AM |
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Re: I designed a polar printer November 09, 2013 02:57PM |
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Re: I designed a polar printer November 29, 2013 01:31AM |
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Re: I designed a polar printer November 29, 2013 11:46AM |
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Re: I designed a polar printer November 30, 2013 01:14AM |
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Re: I designed a polar printer December 12, 2013 09:35PM |
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Re: I designed a polar printer December 13, 2013 03:25AM |
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Re: I designed a polar printer December 13, 2013 07:07AM |
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Re: I designed a polar printer December 14, 2013 05:19PM |
Registered: 14 years ago Posts: 43 |
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A2
Very cool!
Looks like you could rotate the table and print 2 colors on one part?
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Fabricate
Very nice project, looks really cool! Have you already started modifying the firmware?
I would also like to build a polar printer, quite similar to the PiMaker and the R-360. Although they claim the projects to be open source, I could not find the firmware they are using. Does anyone know if they really published their firmware?
Re: I designed a polar printer December 15, 2013 12:18PM |
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Re: I designed a polar printer December 20, 2013 11:50PM |
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Re: I designed a polar printer January 08, 2014 05:55AM |
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Re: I designed a polar printer January 08, 2014 10:24PM |
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Re: I designed a polar printer January 09, 2014 09:11AM |
Registered: 11 years ago Posts: 72 |
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unlimitedbacon
The math is all worked out and documented here [github.com] . I also wrote a program in python to simulate the motions and help me understand how it will work [github.com] .
I've been playing with various firmwares, trying to wrap my head around them, but it turns out to be much more difficult to read other people's code than to write your own. Thanks, MattMoses. I looked over ttsalo's patch a little. Having an example to go by will make things much easier.
Re: I designed a polar printer January 10, 2014 07:04AM |
Registered: 10 years ago Posts: 60 |
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Kenzu
Don't know much about firmware myself, but next project is a bipolar printer, so when i have the hardware build I will try to port firmware for it. But kind of hoped that you have got some firmware working just a bit. ;-)
Re: I designed a polar printer January 10, 2014 04:44PM |
Registered: 11 years ago Posts: 72 |
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Fabricate
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Kenzu
Don't know much about firmware myself, but next project is a bipolar printer, so when i have the hardware build I will try to port firmware for it. But kind of hoped that you have got some firmware working just a bit. ;-)
bipolar printer? You mean with two hotends?
I think (although I did not run any experiments) the big problem atm is that the arduino has not enough computing power. For this reason I am going to wait for the RAMPS-FD or RADDS boards to be available, as the Due seems to have a lot more power!
Calculating the polar coordinates from x and y positions should not be to complicated (http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_polar_and_Cartesian_coordinates), if the device is powerful and the libraries exist.
But I am not quite sure if we shouldn't apply specific slicing for the polar bots and have some new G-Code commands (and have some G-Code Preprocessors in the meantime). So instead of G92 X10 E90 you could say G92 R10 P36 E90. R, S, T, U, V, W could be 6 extruder positions, P is the angle in degrees and Z and E, F, H, I, J, K (G is not allowed here I think) are the extrusion rates for these extruders. This would allow to have multiple extruders working simultaneously.
Re: I designed a polar printer January 11, 2014 05:35AM |
Registered: 10 years ago Posts: 60 |
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Kenzu
No bipolar as both rotating table (polar) and a rotating/sving arm with the hotend. (also polar) There for bipolar. Se the doc linked by Unlimitedbacon [github.com]
Re: I designed a polar printer January 11, 2014 11:38PM |
Registered: 14 years ago Posts: 43 |
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Fabricate
I think (although I did not run any experiments) the big problem atm is that the arduino has not enough computing power. For this reason I am going to wait for the RAMPS-FD or RADDS boards to be available, as the Due seems to have a lot more power!
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Fabricate
@unlimitedbacon: what kind of bearing did you use for the rotating axis? Do you have plans for upgrading your bed with a heatbed?
Re: I designed a polar printer January 12, 2014 07:42AM |
Registered: 12 years ago Posts: 1,236 |
Re: I designed a polar printer January 12, 2014 08:52AM |
Registered: 10 years ago Posts: 60 |
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unlimitedbacon
Computing power does not seem to be an issue (yet). As it turns out, the trig functions provided by avr-libc are extremely fast. We ran a test and found that tan() executes in about 13 cycles. An examination of the source code shows that this is because they are using some hand optimized assembly and lookup tables.
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unlimitedbacon
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Fabricate
@unlimitedbacon: what kind of bearing did you use for the rotating axis? Do you have plans for upgrading your bed with a heatbed?
Funny you should ask. We just upgraded it with a heated bed. The electrical connections are passed through a slip ring [www.adafruit.com] which also acts as the central bearing. The heater is a big round kapton heater thats made for delta printers [trinitylabs.com].
Re: I designed a polar printer January 13, 2014 03:25AM |
Registered: 11 years ago Posts: 72 |
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unlimitedbacon
Good news, everyone!
Now theres firmware! [github.com]
Here it is printing an octopus [youtu.be], and the final product [imgur.com].
This print took about 1.5 hours. The feedrate was 20 degrees/second which is roughly 55 mm/s. I think that the machine is capable of at least 40 degrees/second.
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Fabricate
I think (although I did not run any experiments) the big problem atm is that the arduino has not enough computing power. For this reason I am going to wait for the RAMPS-FD or RADDS boards to be available, as the Due seems to have a lot more power!
Computing power does not seem to be an issue (yet). As it turns out, the trig functions provided by avr-libc are extremely fast. We ran a test and found that tan() executes in about 13 cycles. An examination of the source code shows that this is because they are using some hand optimized assembly and lookup tables.
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Fabricate
@unlimitedbacon: what kind of bearing did you use for the rotating axis? Do you have plans for upgrading your bed with a heatbed?
Funny you should ask. We just upgraded it with a heated bed. The electrical connections are passed through a slip ring [www.adafruit.com] which also acts as the central bearing. The heater is a big round kapton heater thats made for delta printers [trinitylabs.com].
Re: I designed a polar printer January 13, 2014 07:58PM |
Registered: 14 years ago Posts: 43 |
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Fabricate
I also found the slip ring you are using, but I am not quite sure if it can be used for this application. They say that it is rated for 2A each wire, but I think this is an absolut maximum rating for quite a short period of time (sadly I found no datasheet specifying everything precisely). I think the main problem are the very small wires, that are never rated for 2A. Anyway, nice to hear that it works for you! Also the heatbed looks great!
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Fabricate
I never thought about using the slipring as a central bearing! This is a great idea, how well does it work? I am worried about wobbling on the bed resulting in differences on the Z axis.
Re: I designed a polar printer January 14, 2014 05:00PM |
Registered: 10 years ago Posts: 60 |
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unlimitedbacon
We're doubling up the wires to let us pass more current. That slip ring has 12 connections total, so we can use 5 for each connection on the heater and the other 2 for the thermistor. This brings the limit up to 10A (120W). The slip ring hasn't melted yet, so it seems to be working.
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unlimitedbacon
The wind turbine slip ring is probably a better solution in the end. I don't think you need to do the temperature sensing wirelessly. That one has 3 connections. You could combine the ground for the heater and thermistor, then use the third connection for the sensor.
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unlimitedbacon
Wobbling is a big problem at the moment, but it was like that before we added the heated bed. So its not because of the slip ring. I think I can fix it by changing the arrangement of the support rollers.
Re: I designed a polar printer January 27, 2014 06:18AM |
Registered: 11 years ago Posts: 72 |
Re: I designed a polar printer January 09, 2015 11:17AM |
Registered: 10 years ago Posts: 56 |