Built on a coffee maker. And on a budget. No precision rails or bearings. True Delta Kinematics. Great prints.
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Here are two useful links for understanding delta kinematics:
Kinematics explained:
http://forums.trossenrobotics.com/tutorials/introduction-129/delta-robot-kinematics-3276/
Online calculator based on above equations:
https://www.marginallyclever.com/other/samples/fk-ik-test.html
I seem to recall that the labels for the dimensions in the calculator are a little misleading, so be sure to double check the drawings in the first link.
Here's where you can enter those parameters into my modified marlin code on github (originally modified from an early version of the firepick-delta firmware). Starting around line 198 in Configurations.h:
#define DELTA_E 50.8//172.0//131.636 // End effector length
#define DELTA_F 158.3//152.4//81.4//190.526 // Base length
#define DELTA_RE 163.5//114.5//270.000 // Carbon rod length
#define DELTA_RF 50.8//77.0//86.000 // Servo horn length
The un-commented values above are the dimensions used on this printer (in mm).
The coffee maker hotplate has a significant delay which causes control problems....
By the time the sensor sees a temperature change, enough energy has been put into the plate that it shoots up to a very high temperature. The process does not seem to stabilize with just PID control.
To correct this, we edited the PID algorithm. Now the hotplate is pulsed on between 0 and 1 seconds every 10 seconds according to the PID algorithm.
More details coming....
To correct for distorted prints. Print a 1 in cube, measure dimensions, calculate transformation matrix to correct and update firmware.
Pretty straight forward here: Arduino Mega + Ramps 1.4.
Generic hotend/extruder.
SSR for hot plate control.
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Seriously. I am located in CT USA. Can i just buy one . . . ?
Really would like to make this project. Where can I find the instructions to make this happen?
Do you have any plans for incorporating the Mechaduino into this printer - even just for fun? Would that allow you to use cheaper motors other than the typical NEMA 17's?
A similar machine with Mechaduinos is in the works. The motors wouldn't necessarily be cheaper, but you would get some combination of improved resolution or a larger build volume depending on how you dimension things. You would also avoid losing steps.
Cool!
What's the printing area?
There are an aluminum bar on motor, right? (I think) on the other end there are a bearing? (on the joint mount)
Thanks!
This looks great! Please tell me it has a heated bed thanks to the coffee machine internals :) Also, are those steppers geared down?
ooh, found http://tropical-labs.com/index.php/mechaduino - think that answers my second question :)
Thanks for commenting!
Yes, a solid state relay controls power to the coffee maker to regulate the bed temperature. The coffee maker itself did not need to be modified, so you can actually slide the delta assembly off and make a pot of coffee!
You are a step ahead of us on the motors though! We are using standard 400 step/rev NEMA 17 stepper motors to directly drive the delta mechanism on this printer. We've also built a second, larger delta printer where the steppers are geared down 5:1 with GT2 timing belts. Next up, we will be building a closed-loop version featuring our Mechaduino stepper based servo motors!
Mechaduino is also on hackaday.io:
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Gotta say... I love it. Somehow I missed this gem. You combined two of my favorite things. :)