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If I were to take a delta machine and change it from being belt driven to spectra line what are the changes that need to be made in the firmware? I have searched and cant seem to find a definitive answer. I'm pretty sure you have to input things like the pitch and such but where do you do it and how would you figure the pitch for spectra line since there are no teeth? This may seem like a silly question but I would like to know all I can about 3d deltas down to the firmware and all. If anyone knows I would really appreciate an explanation of what should be changed and why it needs to be changed if its not too much trouble. Thank you!!

check this guy out

https://plus.google.com/+SteveGraber/po ... erid=gplp0

I went through a few of the pages of posts but didn't see anything about setting up the firmware for the drive system or anything.

Check out the firmware for Richrap's 3DR. I believe it uses spectra

http://richrap.github.io/3DR-Delta-Printer/

just curious, but is there a specific reason you're interested in making the switch?

cope413 wrote:just curious, but is there a specific reason you're interested in making the switch?

I wanted to ask that too. Is there a problem that this fixes?

It's been discussed before, and a quality toothed belt has long fibers in it to keep it from stretching. That negates the usual reason that people are drawn to spectra. The only arguable improvement (aside from the obvious cost and spare parts availability) would be in "step inertia" because it would reduce the moving and rotating weight for each stepper motor. With Nema 17's it's arguable that this is negligible too though.

I'm all for creative and innovative solutions, but if it ain't broke don't fix it

No, nothing is wrong with my Max, its going great, I'm actually getting some of my best prints ever out of it now. I'm curious about what it is that needs to be changed in the firmware in respect to the drive system weather it be belts or spectra line or whatever because I'm in the middle of designing my own derivative of the Kossel but have a different idea for the drive system and am trying to figure out what in the firmware needs to be adjusted.

Dont worry I'm not reinventing the wheel on something working well, lol.

AndThenSome09 wrote:No, nothing is wrong with my Max, its going great, I'm actually getting some of my best prints ever out of it now. I'm curious about what it is that needs to be changed in the firmware in respect to the drive system weather it be belts or spectra line or whatever because I'm in the middle of designing my own derivative of the Kossel but have a different idea for the drive system and am trying to figure out what in the firmware needs to be adjusted.

Dont worry I'm not reinventing the wheel on something working well, lol.

I'd think it would just be a matter of recalibrating the steps/mm for each axis once you had it all figured out. You should be able to calculate it based on the circumference of the spool on the stepper, then confirm/fine-tune it with empirical measurements.

#define DEFAULT_AXIS_STEPS_PER_UNIT {80, 80, 80, 760*1.1} // default steps per unit for Kossel (GT2, 20 tooth)
#define DEFAULT_MAX_FEEDRATE {500, 500, 500, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {9000,9000,9000,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for retracts

Would those settings be here in the firmware? If so how do I figure out the ratio on DEFAULT_AXIS_STEPS-PER-UNIT? SAYS 760*1.1, how do I come up with those numbers?

AndThenSome09 wrote:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80, 80, 80, 760*1.1} // default steps per unit for Kossel (GT2, 20 tooth)
#define DEFAULT_MAX_FEEDRATE {500, 500, 500, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {9000,9000,9000,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for retracts

Would those settings be here in the firmware? If so how do I figure out the ratio on DEFAULT_AXIS_STEPS-PER-UNIT? SAYS 760*1.1, how do I come up with those numbers?

That's X, Y, Z, and E, so the 760*1.1 value is your extruder value; probably not the number you want to adjust for this exercise.

What you're looking for is the number of steps needed to move the belt, screw, or in this case fishing line one millimeter.
If your Spectra is attached to the stepping motor with a spool that has a circumference of 20mm, that means one full revolution of the motor would move the Spectra 20mm.
Assuming you have a 1.8 degree stepping motor using 1/16 microstepping, that's (360/1.8)*16=3200 microsteps per revolution.
So, 3200 steps per 20 mm = 160 steps per 1 mm. So 160 would be your calculated value.

The empirical method is simply to make a mark on the Spectra, turn the motor an exact number of steps, then make another mark. Measure the difference, then redo the math to fine-tune your calibration.

That's the concept, anyway. You'll have to create the correct facts for your scenario, of course.

Thank you! That's perfect, exactly what I was looking for! Thank you for the help guys!

Again dont worry my Rostock Max is staying as is for now, only upgrade I foresee in the near future is a new E3D hot end so I can try my hand at some nylon. Other than that my Max is absolutely perfect at the moment!