June 25, 2019 at 7:07 pm #104392
In process of finishing a 16x26x4 MPCNC with a Mega2560/Ramps1.6 running dual endstop Marlin. Std US EMT, Nema 17 64oz, 12V 20A power supply. Parts are printed with PetG (Amazon Basics). Hardware is mix of metric/standard determined by availability and pricing when I ordered. bearings are all 608RS. I made a couple of additions and am trying a set of belt tensioners from Thingiverse, an additional plate on the outside of the belt pulleys to provide a platform to fasten cable connections and some simple endstops I made.
I am having discrepencies with the dual endstop action on the X axis – no consistency, repeatability when homing – but can manually setup the device and produce the crown drawing. Crown picture attached is the result of running the crown via CNCjs 4 consecutive times with each draw being separated by a move of both the X and Y axis a distance of 40 mm from home before beginning the next iteration. Happy with the level of repeatability I an getting.
Still have some more tape measure to add to direct the Z motor cable, gather more familiarity with EstlCam, CNCjs, etc. Then I should be able to move on making noise and dust.
Attachments:June 26, 2019 at 8:14 am #104430
I am having discrepencies with the dual endstop action on the X axis – no consistency, repeatability when homing
What happens, did you set your drivers, how far off is your machine from square as it sits?June 27, 2019 at 6:25 pm #104547
Machine has a difference of 1/32 in on diagonal measure. DRV8825’s are all in range 0.64 – 0.70. I believe the frame is leveled and squared.
Startup has involved – move arms till endstops are triggered, power the mpcnc, confirm that X/Y axis are zeroed. If I issue at G28 Y0, Y axis will move away form endstop and return to touch both endstops. Movement of the 2 Y motors is in a synchronous movement and both make a soft landing against the endstops. Issuing a G28 X0 also moves in a similar manner. If I issue another G28 X0, the X arm moves away from the stops but the upper/left part of the arm drags behind the lower motor.
I have tried changing the tension bolts to see if I can change this behavior but do not see any difference in the way it reacts.
Future actions: Re-measure and tunein the stepper Vrefs for X1/X2; Replace the ZYX plates (I have reprinted these already; Reprint and replace the XY cages;
Any other suggestions?
Attachments:June 27, 2019 at 6:45 pm #104549
By far the most common issue is a loose pulley.
G28 X Y
Don’t use the zero, no idea if that is good or bad but I never have.
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