Calculation question
Posted by chipspencer
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Calculation question March 30, 2019 05:22AM |
Registered: 5 years ago Posts: 3 |
Hi. I am building what I feel is an over engineered Prusa i3 clone. I am using 1/2-10 single start (10 turns per inch) acme leadscrews for all three axes. My z-axis leadscrews are driven buy a single stepper motor with a 30 tooth gt2 pulley on the motor and a 60 tooth gt2 pulley on each leadscrew. The steppers are 127oz-in nema23 with 0.9 degrees per step (400 steps/revolution.)
To round out the hardware description, the build surface is 1/4 inch forged aluminum tool & jig plate from MidWest Steel. Genuine E3D v6 all metal HotEnd with Bowden tube and a Bondtech QR extruder, Ramps 1.6 plus/mega2560 sandwich with Trinamic 2130 drivers, Nema 23 0.9 degree/step steppers and a 24v power supply. Final build volume will be 250mm x 350mm x 200mm.
I am starting to configure Marlin for my ramps 1.6/mega2560 sandwich. The question I have is for the mm/step calculation. Do I include the desired microsteps in the formula or just use the base steps per rev? 1/16 microsteps for example.
So my calculations say ( 400 steps*16 microsteps) per revolution / 2.54 mm per revolution = 2,519.685 steps / mm for x & y. I invert that answer to get mm per step. 1/ 2,519.685 = 0.000396875 mm per step.
For my z calculation I divide my x/y by 2 or multiply by 2? Remember, the 30t pulley is on the motor & 60t on the leadscrews. Do these numbers seem accurate or is my math flawed?
Edited 1 time(s). Last edit at 03/30/2019 10:39AM by chipspencer.
To round out the hardware description, the build surface is 1/4 inch forged aluminum tool & jig plate from MidWest Steel. Genuine E3D v6 all metal HotEnd with Bowden tube and a Bondtech QR extruder, Ramps 1.6 plus/mega2560 sandwich with Trinamic 2130 drivers, Nema 23 0.9 degree/step steppers and a 24v power supply. Final build volume will be 250mm x 350mm x 200mm.
I am starting to configure Marlin for my ramps 1.6/mega2560 sandwich. The question I have is for the mm/step calculation. Do I include the desired microsteps in the formula or just use the base steps per rev? 1/16 microsteps for example.
So my calculations say ( 400 steps*16 microsteps) per revolution / 2.54 mm per revolution = 2,519.685 steps / mm for x & y. I invert that answer to get mm per step. 1/ 2,519.685 = 0.000396875 mm per step.
For my z calculation I divide my x/y by 2 or multiply by 2? Remember, the 30t pulley is on the motor & 60t on the leadscrews. Do these numbers seem accurate or is my math flawed?
Edited 1 time(s). Last edit at 03/30/2019 10:39AM by chipspencer.
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Re: Calculation question March 30, 2019 06:25AM |
Admin Registered: 13 years ago Posts: 7,002 |
you have to include the micro stepping in your calculations
X/Y seems fine with 2,519.685 steps/mm but this is going to overload a mega, way to many steps for a little 16mhz 8 bit processor.
Z you would multiply by 2, the 30 tooth has to go around twice for 1 revolution of the 60 tooth
Edited 2 time(s). Last edit at 03/30/2019 06:34AM by Dust.
X/Y seems fine with 2,519.685 steps/mm but this is going to overload a mega, way to many steps for a little 16mhz 8 bit processor.
Z you would multiply by 2, the 30 tooth has to go around twice for 1 revolution of the 60 tooth
Edited 2 time(s). Last edit at 03/30/2019 06:34AM by Dust.
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Re: Calculation question March 30, 2019 10:12AM |
Registered: 5 years ago Posts: 3 |
Thanks for the clarification. For now, Marlin is just a test platform until I get the hardware working. I am ultimately going to run Klipper on a raspberry pi which will handle all of the processing. The ramps/arduino stack will just be the glue to the motors, thermocouples and limit switches.
Edited 1 time(s). Last edit at 03/30/2019 10:26AM by chipspencer.
Edited 1 time(s). Last edit at 03/30/2019 10:26AM by chipspencer.
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