DIY Pen Plotter with Automatic Tool Changer | CNC Drawing Machine

[yifandianzi]

May I ask how to set the tool table above the Y-axis? After setting, the pen position in the tool table is negative, and all the tool tables in the pictures are in the negative direction of the Y-axis

[svenhb]

Tool table positions must be set in machine coordinates - homig of the plotter is needed (or manual "homig" via hard reset on lower left position):

[yifandianzi]

The above image is set by me, and the following image is set by me referring to another producer

[svenhb]

Just change the 277 to 0

[yifandianzi]

1694698454095.mp4

Hello, this is a demonstration set to 0

[svenhb]

You are right, there is a bug and the offset is not shown, but processed during streaming. Will fix it soon.

[svenhb]

You may try this version: https://github.com/svenhb/GRBL-Plotter/blob/master/GRBL-Plotter_Setup_1_7_0_2_i.exe

[yifandianzi]

output_multi_video_1694780403069_1694780417484_VI.mp4

Hello, there is another issue now, which is that it can return to its normal position when returning to zero. When starting to work, the Z motor will rotate in the opposite direction, and then it can surprise the next step normally

[svenhb]

I don't exactly understand this issue. I assume the problem is the servo-position, when PWM is off.
Compare behavior of PWM on/off here:

Compare behavior of PWM low/high here:

[svenhb]

Now I could watch your video on a PC - it's not a servo...
I thing you need to "Zero Z" your Z axis before starting streaming.

[yifandianzi]

Hello, I have reset all X, Y, and Z here to zero, but when starting work, they still rotate in the opposite direction. I think it may be due to incorrect settings elsewhere, and it should not be rotated without selecting a pen

[svenhb]

It is normal that the Z axis move to a save position on start.
Example code after importing a simple line:

Line 14 G00 Z2.00 move Z upwards to save position
Line 17 move to start position
Line 18 G01 Z-1 move Z down, to start drawing
Line 19 draw the line
Line 20 G00 Z2.00 mive Z upwards

[yifandianzi]

Did I make the right changes here

[svenhb]

I don't know your hardware, I didn't saw a servo for a gripper...
Do your gripper opens with M3 S100?

Did you check my site? https://grbl-plotter.de/index.php?id=auto-pen-change&setlang=en

[yifandianzi]

Hello, I have looked at your website and it is slightly different from the position where I lifted and clamped the pen

[svenhb]

Looks like the Z-stepper should turn for a half turn maximum to move from lowest Z to highest Z.
Did you setup $102 correctly?

[yifandianzi]

Should I set $102 correctly to $40?
https://www.youtube.com/watch?v=ZxeStwRespc&list=RDCMUCJHZY4Tl6ovsnBrNocdDbAg&start_radio=1&rv=ZxeStwRespc&t=65
https://www.youtube.com/watch?v=The following link is mine_4S9PE

[svenhb]

Last video is not visible. I don't know your driver settings for micro-steps.
Usually a stepper-motor needs 200 steps for a full turn, If I interpret your design correctly, you have a half turn for about 20mm Z-change. With full-step-mode you may set $102 = 5 (100 steps/half-turn divided by 20 mm)
If you have half-step mode: $102 = 10

If your Z axis is spring loaded to keep it up, you may have a problem with step loss at the Z motor.

[yifandianzi]

https://www.youtube.com/watch?v=ZJZuB_4S9PE
Hello, setting $102=10 and $102=5 will prompt an error, while setting $102=40 will not cause an error

[yifandianzi]

I have set these three places in the firmware

Do you think it's correct

[svenhb]

I don't understand how your z-axis works, in your video time 0.04, the stepper is moving, but the z-wagon is not moving....
Also I don't see an end-switch for z. So you can't use homing for z.
You need to set: #define HOMING_CYCLE 0 ((1<<X_AXIS) | (1<<Y_AXIS)) if you have end-switches there

[yifandianzi]

https://www.youtube.com/watch?v=NDZsdDLbDDo
Normally, it should start working after resetting to zero, and then X Y starts moving to the pen selection position and Z starts lifting. The problem now is that when the start button is clicked, the Z stepper motor has already started working, and then the Z limit is set off

[yifandianzi]

https://www.youtube.com/watch?v=ZxeStwRespc&list=RDCMUCJHZY4Tl6ovsnBrNocdDbAg&start_radio=1&rv=ZxeStwRespc&t=65
The author's point is that the Z-lift motor does not work when starting work after resetting to zero

[svenhb]

The main problem is, that pen selection positions are machine coordinate, which needs homing.
Also the linked video shows a working z-homing - you need to change your mechanics...

[yifandianzi]

Thank you for your great help. When you pointed out the location, I also raised the Z limit position to zero. Now, just as I was preparing to start the work, the Z stepper motor continued to raise and then raised again, triggering a limit fault

[yifandianzi]

https://www.youtube.com/watch?v=QQNdMw_KsNo
After all X Y Z are reset, the execution starts at 0:53, and the Z stepper motor continues to rise

[svenhb]

After Z-homing, Z stays at top position which you may want to have at +2mm in work coordinates.
After Z homing move 2mm down and press "Zero Z".
Also important the choosen travel way for import - small enough for your hardware?:

[yifandianzi]

Hello, where is the white area set and where can I reach the coordinates

[yifandianzi]

https://www.youtube.com/watch?v=qdFgPm4bOkc
This is my complete operation steps, but there are still problems and I don't have a clue now

[svenhb]

Looks good so far.

1. set your travel ranges via $130, 131, 132. https://github.com/gnea/grbl/wiki/Grbl-v1.1-Configuration#130-131-132--xyz-max-travel-mm
   This will influence your homing machine coordinates:
   

After this you go to setup and take over the ranges:

[svenhb]

Here you need a value, close to your homing Y-value = ca. 350:

[yifandianzi]

https://www.youtube.com/watch?v=WWQc27jp7ks
Thank you. After picking up the pen, the servo released it and it got stuck while writing. Where can I cancel this step

[svenhb]

I don't know where the last movement comes from.

• from footer setup?
  

Switch on this check box and watch sent commands:

[yifandianzi]

Hello, I have tried to modify these places, but they still don't work and I will loosen the pen

[yifandianzi]

In this way

[yifandianzi]

https://www.youtube.com/shorts/gHtDPaVl4kA
It's Like That

[yifandianzi]

I am using a special version of firmware with servo support
https://github.com/cprezzi/grbl-servo

[svenhb]

I made a mistake in my last post...You need to use Z axis and disable spindle use.

[yifandianzi]

Hello, is that the case

[yifandianzi]

Hello, I just tried to turn on the Z-axis and disable the spindle like that, but the effect is still the same. I will release the pen

[svenhb]

Can you show the generated gcode

[yifandianzi]

Hello, is that the case This is preparing to write after zeroing
https://www.youtube.com/shorts/GNgGmXgAvh8

[svenhb]

I mean a screenshot like this

[yifandianzi]

In this way

[svenhb]

And the last lines of the code?

[svenhb]

If you watch my video https://youtu.be/tVS8A3_E2IY?t=141
the last action is, removing the pen, then end of program "M30" which causes the servo to move...

[yifandianzi]

Hello, it's from the 27-47 paragraph

[yifandianzi]

Execute M30 only after complete writing

[svenhb]

Try new version https://github.com/svenhb/GRBL-Plotter/blob/master/GRBL-Plotter_Setup_1_7_0_2_k.exe
It removes the final M05 in line 1354

[yifandianzi]

Hello, my version you sent me will still have the same issue after installation

[svenhb]

The M05 should be gone:

There is still M30 which is needed. You can try to edit the code mnually to see what happens:
Set edit mode:

remove last line, then update 2D-view:

[yifandianzi]

Hello, I am trying to delete M3 and the same problem will occur again

[yifandianzi]

https://www.youtube.com/watch?v=9yI0MYlkZ20
This is the process of starting work after resetting to zero, and it is from the process of the image that the servo starts to release the pen holder

[svenhb]

Hello, I am trying to delete M3 and the same problem will occur again

The idea was to remove the final M30

Your code still shows this M3 1000 - this controls your servo after pen change

You must check this box!

[yifandianzi]

https://www.youtube.com/watch?v=zTcfYmqEp1U
Hello, here are my settings. Where else do I need to adjust them

[svenhb]

Sorry, I forget to check with option enabled "Add Tool change command".
I found a bug, please check https://github.com/svenhb/GRBL-Plotter/blob/master/GRBL-Plotter_Setup_1_7_0_2_m.exe
also setup window bug fix

[yifandianzi]

Hello, when writing normally, what should I set for this Z-rise
https://www.youtube.com/watch?v=QgFRFkiDSZA

[svenhb]

When pen is in gripper, move down with joystick an press button "Zero Z"

[svenhb]

BTW: you can set the custom buttons to perform the scripts (right click on desired button):
One button to select pen nr - press this first:

One button to start the script (set the path to your script:

[yifandianzi]

https://www.youtube.com/watch?v=6uB7rexIIOU
Thank you very much for your help. The plotter is now working, but the problem is that the pen clip is not tight enough, and the pen will come up when writing. I am trying to find a way to change the problem with the pen clip

[svenhb]

The problem is, you press the pen down and the pen can't evade. You may invert your mechanics and let the pen press down by the spring and lift by the servo.
My plotters uses gravity to move the pen down: https://youtu.be/7Nvf4UwK_yk?t=112
And evade by an extra linear guide https://youtu.be/XZIN8dHrgjg?t=11