1 Topic by parto

  • parto
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  • Registered: 2015-04-22
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Topic: XY printer resolution issue/question in Marlin

Hi, I have built and been running successfully a home designed reprap cartesian printer based on a Gen 7 main board with Marlin 1.1.x firmware. I have been looking to improve the resolution on my X and Y axis. My current steps /mm is as below:

#define DEFAULT_AXIS_STEPS_PER_UNIT { 11.94, 13.93, 500, 129.7 }

Taking my X axis for example, this should translate to 1/11.94 = 0.083mm/step. In my host controller - which is Simplify 3D – I tried finding the smallest X movement I could get the printer to move. I assumed this would be 0.08 mm since that would be one single step of the motor. I moved the X axis to 100mm from the home position and then sent a G1X100.1 F1 (the F value was set as low as possible so I could roughly count the steps the motor moved. ) I found that I had to increase the move to 100.4mm before I got any movement of the motor and then the motor moved about 3 or 4 steps to travel from 100mm to 100.4mm. Further increasing the move distance resulted in no movement until G1 X100.8 F1 and then the motor moved the same distance as before.
I don’t understand why the smallest distance I can resolve to is about 0.4mm. I would have expected 0.08mm. Also why is the movement, when it happens more than 1 step? Is there some setting in marlin that is preventing the resolution from going below 0.4mm?

2 Reply by yizhou.he

  • yizhou.he
  • yizhou.he
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  • Registered: 2017-07-05
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Re: XY printer resolution issue/question in Marlin

I think your acceleration too slow, and with low motor current, moving distance too short give it no time to acceleration. try increase F value and see if it will move for small distance.

(Da Vinci 1.0, Jr. 1.0 RAMPS, miniMaker) X4, (Creality CR-10S, CR-10 mini, Ender-3) X4, Anycubic MEGA X4, Anycubic Chrion X1, ADMILAB Gantry X2 (MonoPrice Maker Select V2, Plus, Ultimate)X4--Select mini X1, Anycubic photon X4, Wanhao duplicate D7 X1.
iNSTONE Inventor Pro X2, CTC Dual X2, ANET-A8, Hictop 3DP-11, Solidoodle Press, FLSUN I3 2017X1

3 Reply by IronMan

  • IronMan
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Re: XY printer resolution issue/question in Marlin

Your steps/mm seem way too low...what is your drive method for X & Y?  Most systems using belts and drive pulleys are set at around 80 Steps/mm...and that assumes your stepper driver is set at 1/16.

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4 Reply by yizhou.he

  • yizhou.he
  • yizhou.he
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Re: XY printer resolution issue/question in Marlin

IronMan wrote:

Your steps/mm seem way too low...what is your drive method for X & Y?  Most systems using belts and drive pulleys are set at around 80 Steps/mm...and that assumes your stepper driver is set at 1/16.

I agree, it is very strange, but I don't know anything about his printer and he states "built and been running successfully".

It is also very strange the X and Y step/mm are also very different. may result in distortion of the prints. If his correct step/mm is 80 Steps/mm, then it totally make sense the minimal resolution become 0.4 instead of 0.08 (about 5-7 times difference).

(Da Vinci 1.0, Jr. 1.0 RAMPS, miniMaker) X4, (Creality CR-10S, CR-10 mini, Ender-3) X4, Anycubic MEGA X4, Anycubic Chrion X1, ADMILAB Gantry X2 (MonoPrice Maker Select V2, Plus, Ultimate)X4--Select mini X1, Anycubic photon X4, Wanhao duplicate D7 X1.
iNSTONE Inventor Pro X2, CTC Dual X2, ANET-A8, Hictop 3DP-11, Solidoodle Press, FLSUN I3 2017X1