Print & cut | contour cutting

Software / Firmware
1

Hello All,

Its been a long time! I made a lot of mods to my MPCNC (Attached a laser diode / Worked out a foam cutter for cutting out RC plans)

I thought If you could help me with something which is related to electronics and programming.

I do not have a clue about how programming works

I make a lot of stickers of my art, I’m searching for a diy contour cutting/print and cut alternative which could help me with this. (something which cricut and silhouette machines do very easily)

Basically if a camera is mounted tool / laser head which detects 3 - 4 reg marks on printed paper and scales, skews, orients the cutting file / artwork the right way. Thus the cutting results are accurate.
Something like this

The current method I’m using to cut stickers involves a setup like this.

Something close to what I’m looking for can be found here:
http://openpnp.org/

Its a pick and place machine used prominently for placing minute components on a lot of PCBs.

But there’s no way I can use it for print and cut function as I require, as the software isn’t built for that purpose.

Please let me know if you have any leads regarding this or if you could point me in the right direction.
Thanks :+1: keep up the great work!

2 Likes
2

I can say, this is very interesting. There are a lot of neat solutions you could do for this.

For example, on a pi, you could have a usb camera, attached to the gantry. You could use a python program to read the images in, determine roughly where a fiducial is relative to the camera, and send small movements over gcode to the machine to line it up to the image center.

Mechanically, this would be pretty simple, you just need a camera with a good set focal length, and rigidly mounted. It can be off center, and any difference between the camera center and the tool can be calibrated out.

From the algorithm perspective, if you could install opencv for python, there are some easy steps to capture the image, and find the image coordinates of specific shapes. Then you would need to be able to send corrective movements to the firmware. Determining the amount to move can be a simple proportion to avoid any calibration problems.

The user interface is another part, and you can’t forget that. If you wrote the python script, you can get by with hacking or command line arguments. If you want this to be more universal, you would need to have a web interface, or something similar. That can be relatively easy (compared to the past). Something like the flask library for python would be a good fit.

The last part is that once you have the measurements (the XY for each corner of the printout), you need to adjust the gcode sent to the machine to compensate or else configure Marlin for correction. Either will require some work.

This is a decent sized job, and this custom software will probably end up being useful, but I just do not have time to do it. It is super interesting though.

3 Likes
3

My standalone vinyl cutter software kinda has something like this built in. You use it to print from an ink printer, then the same software also runs the fudicials and cutting. You do manually indicate it is on the target though (I did not pay for the camera). It will move to where it thinks teh marker is and you fine tune it.

Making new software would be freaking amazing. The vinyl master software is not fun for me to use.

4

@jeffeb3 Thanks for the amazing input! Your method could be the right way to implement this feature. Do check out how this plotter captures the reg marks:


They first show how the plotter is calibrated. Then the print and cut operation is shown. Calibration is necessary only once or when you feel that the contur cutting is shifting or producing errors.

You need to place your printed sheet and bring the cutting head closer to the first reg mark, when you press start, the tool head offsets and the camera activates and scans the reg mark.

After scanning the first reg mark, it then travels to the other 3 marks to do the same operation. The travel distace to scan each mark is based on size of the file which we are working with.

After scanning all the 4 marks the dimension and scale is calibrated and then it is cut.

I’m really surprised that there are not a lot of DIY resources pertaining to CNC PRINT & CUT / CONTOUR CUTTING or SOFTWARE BASED OPTICAL REGISTRATION MARK DETECTION.

This feature is niche but quite revolutionary and would be a game changer if someone implements it!

@vicious1 there are a lot of plotters and laser cutters too, which have this feature. Earlier plotters used to do this by scanning the reg marks with laser, the new ones which are coming out are doing so by scanning the reg marks with a camera:



But this feature can be implemented universally on to the DIY builds like MPCNC too.
Also, machines with the feature are very costly, and it would be great if we can spend a few bucks and have this feature into our existing ones.

1 Like
5

Heck yes!

6

Hi

Has anyone figured this out yet?

Would be interested

7

For what exactly? Laser is easy if you have the right material, printing with an inkjet though…not so much.