Starting big, making a SLS with Linux CNC
- tommylight
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22 Aug 2016 13:51 #79250
by tommylight
Replied by tommylight on topic Starting big, making a SLS with Linux CNC
I have tested an EPSON head in a ROLAND plotter ( CMYK, had been left for a long time so the ink got dried in the nozzles, had to clean them, took 4 days, ouch )and i know for sure up to 2mm far the printing quality was perfect, up to 5mm it would get blurry, but i think for what you need it would still be usable !
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22 Aug 2016 14:03 #79251
by andypugh
Replied by andypugh on topic Starting big, making a SLS with Linux CNC
Actually, this has reminded me of another type of printer that I would like to build.
I would like to make a printer to print sand casting moulds:
The hard part is the printing head and binder chemistry.
I would like to make a printer to print sand casting moulds:
The hard part is the printing head and binder chemistry.
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22 Aug 2016 14:14 #79252
by wyattwic
Replied by wyattwic on topic Starting big, making a SLS with Linux CNC
So apparently SLS is capable of doing that too.
www.researchgate.net/publication/2580270...tive_laser_sintering
www.researchgate.net/publication/2580270...tive_laser_sintering
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22 Aug 2016 15:10 #79255
by andypugh
Though I imagine that the special sand isn't all that cheap.
I was thinking that ordinary sand and standard sodium silicate (CO2) binder might be possible.
Replied by andypugh on topic Starting big, making a SLS with Linux CNC
So apparently SLS is capable of doing that too.
www.researchgate.net/publication/2580270...tive_laser_sintering
Though I imagine that the special sand isn't all that cheap.
I was thinking that ordinary sand and standard sodium silicate (CO2) binder might be possible.
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29 Aug 2016 12:57 #79650
by wyattwic
Replied by wyattwic on topic Starting big, making a SLS with Linux CNC
Hey guys, making progress the last few days. Welded together a heavy steel table, now I just need to level and sandblast it, then start building.
I came across a very strange, small, cheap, high torque motor I rebuilt years back and I'd love to know if LinuxCNC could possibly control it. This motor has two leads for power at 12v and a three leads for a photo optic sensor on the back. The sensor changes high/low every ~8.5 degrees. I forgot to test if it can run in the reverse polarity.
I think I may need to solder together a board that could accept direction and run, then take the sensor back to the LPT. Any better ideas? How would that get programmed into LinuxCNC?
My design is still loose, but I was thinking about using these motors to aid with the fresh powder feed. The design for the unit is still up in the air, as the original working area I thought I had has changed.
I came across a very strange, small, cheap, high torque motor I rebuilt years back and I'd love to know if LinuxCNC could possibly control it. This motor has two leads for power at 12v and a three leads for a photo optic sensor on the back. The sensor changes high/low every ~8.5 degrees. I forgot to test if it can run in the reverse polarity.
I think I may need to solder together a board that could accept direction and run, then take the sensor back to the LPT. Any better ideas? How would that get programmed into LinuxCNC?
My design is still loose, but I was thinking about using these motors to aid with the fresh powder feed. The design for the unit is still up in the air, as the original working area I thought I had has changed.
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29 Aug 2016 14:24 #79654
by andypugh
Normally you would run such a motor with a variable voltage. LinuxCNC would output PWM and direction and the driver would convert that to the requisite power level.
However, with only a single channel encoder you have no way to know which direction the motor is travelling, so it can't really be used for a servo system.
Replied by andypugh on topic Starting big, making a SLS with Linux CNC
I think I may need to solder together a board that could accept direction and run, then take the sensor back to the LPT. Any better ideas? How would that get programmed into LinuxCNC?
Normally you would run such a motor with a variable voltage. LinuxCNC would output PWM and direction and the driver would convert that to the requisite power level.
However, with only a single channel encoder you have no way to know which direction the motor is travelling, so it can't really be used for a servo system.
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29 Aug 2016 14:52 #79663
by tommylight
Replied by tommylight on topic Starting big, making a SLS with Linux CNC
For moving the sand , you would need it to go from one side to the other, without stopping anywhere except the end points, right?
For that you can use that motor, and 2 switches, one at each end that would stop the motor, plus 2 diodes wired to those switches, so when it gets to one end point it wont move further even if you command it, but it can move in the opposite direction to the other end.
see attached image.
For that you can use that motor, and 2 switches, one at each end that would stop the motor, plus 2 diodes wired to those switches, so when it gets to one end point it wont move further even if you command it, but it can move in the opposite direction to the other end.
see attached image.
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29 Aug 2016 14:53 - 29 Aug 2016 14:54 #79664
by wyattwic
Replied by wyattwic on topic Starting big, making a SLS with Linux CNC
With that information Andy you just gave me an idea.
Currently the design is to have multiple pistons - work surface and powder feeds. I could have that work area much larger if I could have the powder provided by an auger assembly. Then with these motors I don't need direction, I just need to turn them on for a set amount of time while the laser is doing its part.
I realize this whole thread has been me rambling off ideas. As soon as I have the table, gantry and laser mounts finished I need to sit down and get the internals to a T.
Currently the design is to have multiple pistons - work surface and powder feeds. I could have that work area much larger if I could have the powder provided by an auger assembly. Then with these motors I don't need direction, I just need to turn them on for a set amount of time while the laser is doing its part.
I realize this whole thread has been me rambling off ideas. As soon as I have the table, gantry and laser mounts finished I need to sit down and get the internals to a T.
Last edit: 29 Aug 2016 14:54 by wyattwic.
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29 Aug 2016 14:55 #79666
by wyattwic
Replied by wyattwic on topic Starting big, making a SLS with Linux CNC
I see what you mean Tommy. The problem I have at the moment, with the gear ratio in these motors, I have no clue if it can run in reverse. Ill find out.
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29 Aug 2016 15:03 #79668
by tommylight
Replied by tommylight on topic Starting big, making a SLS with Linux CNC
almost all of the do run in reverse, find a drill battery and test it, no matter what Voltage the battery, try it and then reverse the wires to the battery. It should work.
The only gearings i have seen that don't work in reverse are from old photocopy machines, they have a system of braking in reverse as the old bikes had (30 years ago, on bicycles you would pedal and move normally, but when moving the legs in reverse, it would brake to a halt(not break down))
The only gearings i have seen that don't work in reverse are from old photocopy machines, they have a system of braking in reverse as the old bikes had (30 years ago, on bicycles you would pedal and move normally, but when moving the legs in reverse, it would brake to a halt(not break down))
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