Scara Problem

JoergS5

@Mauxx is there a difference you send the command of the simplify 3D jog control and later at 5.00, how to you send this command? Are the methods different?

For me it seems like after testing and starting the move at 5:00, the printer changes to normal x-y coordinates and interprets y0 as not moving the distal arm. Is there maybe some reset by Simpliy3D or something similar?

As a test, could you start with Simplify3D jog control with a G1 X300 movement? Does this work without a curve? And then testing go back to 0,0 and make a G1 X300 Y0 move with Simplify3D. If this is also ok, there must be a difference between the jog control and the later movements.

Mauxx

@JoergS5
at the beginning of the video there are 10mm shifts

while at 5:10 minutes it is a single G1 X300 command from X0Y0, yes I was trying to draw the same line

JoergS5

@Mauxx did you make the 5:10 command with this tool also?

Mauxx

yes G1 X300

JoergS5

@Mauxx to really understand: if you press many times X +10 in jog control, it draws the line correctly, but if you put G1 X300, it draws a curve?? In the same tool and without any special actions like leaving the tool, resetting or other things?

The Simplify3D has the Communication register, could you check it for unusual commands like resets?

Mauxx

Exactly, you understand!!! (for communication register i'll check on monday)
Look also central cube, 2 sides are arc, i don't know why!!!

JoergS5

@Mauxx can you show me what Simplify3D has in his communication window after you made the moves?

JoergS5

@Mauxx Ok. Let's proceed on monday. I'm curious about the reason. I am sure, we will find the reason.

Mauxx

@JoergS5 i'll show you on monday, when i go in my "lab"

Mauxx

@JoergS5 I hope!!!

Mauxx

@JoergS5 everything works except this thing

JoergS5

@Mauxx I have an additional idea: (removed, this was not the reason)

Mauxx

I try to work with 800x800 area with 0,0 at centre of tower (X-400,X400; Y-400,Y400) and this problem is in all 4 central axis
Probably you're right, so how i can set my config?

JoergS5

@Mauxx is the angle limit a physical limit or can you change the limit in the configuration?
If it's a physical limit, you could place the printer nearer to an edge and/or further away from the print bed. This should give you a bigger print area.

For optimal placement I cannot give a recommendation, but it's worth to search, e.g. this document: https://www.researchgate.net/publication/298430720_Optimal_Placement_of_a_SCARA_Robot_-_Lab_Report

Mauxx

@JoergS5 Yes, max angle is physical limit
Sorry for my bad english...

Mauxx

@dc42 have you ever encountered this issue?

Danal

We've all focused on the stuff happening along X while Y=0.

None of that explains what happens at 3:10 or so in the video, the move from X90Y220 to X60Y220 also draws an arc. An arc that falls outside the printable area as specified by M208. None of the joints are anywhere near a limit.

Mauxx

it's really very strange
thank you all for your help!!!

JoergS5

@Danal said in Scara Problem:

We've all focused on the stuff happening along X while Y=0.

None of that explains what happens at 3:10 or so in the video, the move from X90Y220 to X60Y220 also draws an arc. An arc that falls outside the printable area as specified by M208. None of the joints are anywhere near a limit.

That's a valid point. Maybe multiple reasons.

My ideas for things to analyze:

the communication log of Simplify3D
belt connection between steppers and Axes: maybe slipping or other problem. Slipping belt could explain curves at strange positions. => one more idea: maybe acceleration and speed too high, so belt starts slipping. You can test setting speed and acceleration lower

Is it a toothed belt or a non-toothed one? If it doesn't have teeth, you can check whether the belt slips at the stepper pulley when the printer makes a curve. The pulley itself could slip also (pulley on the stepper axis). You use a method which I know as ServoBelt, this produces high tension, needs high torque and may lead to slipping pulley.

@Mauxx which Duet hardware, firmware versions are you using?

Mauxx

Scara give same issue also with Arduino IDE and with RepetierHost draw a Triangle...

I'm sure the belt doesn't slip, i have GT2 toothed Belt

I'm using RRF Lpc on Skr V.1.3 board

When printer draw arc Y motor doesn't move at all