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Author Topic: Print to Cut functionality & Mach3 on router  (Read 15792 times)

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Offline Tweakie.CNC

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Re: Print to Cut functionality & Mach3 on router
« Reply #10 on: April 28, 2013, 01:36:43 PM »
Ahhh - non-linear distortion - Thanks Ian.

I will crawl back under my shell.  ;D

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Print to Cut functionality & Mach3 on router
« Reply #11 on: April 28, 2013, 03:28:49 PM »
Hi Guys,

It is brilliant that that some smart minds attending to my problem. The question of linear and non-linear distortion is not as important to me as the fact whether the whole process could be automated in Mach3 as Ian described in his post to produce 10s/100s/1000s. The automated production is the key problem.

It is true that when you print on vinyl and mount it on substrate that non-linear distortion occur. It occur less so if flat bed applicator is used as you effectively roll the print with same force on substrate. If you wet apply or if you skilled enough dry apply the sheet vinyl with strokes of squeegee you create obviously more non-linear stretch. Non linear distortions only happen when you print on roll media. If you have flatbed printer and you print directly on substrate only linear distortions occur.

It is quite normal in signmaking to add bleed (additional colour to extend the image over the vector cut line) to contour cut image to avoid white non printed borders in case of vinyl print being contour cut on plotter. It is to create shaped sticker.

The packages as i-Cut and Optiscout can compensate for non-linear distortion and therefore the graphics designer is not required to add any bleed to combat the white borders. But as I sad earlier we are relatively small sign company which can benefit from automated cutting of sheet material where the design was printed on roll media and mounted hard substrate. We would not mind to spend little more time designing the artwork if only we can then mount it on sheet and cut it in one operation on our router in similar fashion we produce shaped stickers on vinyl plotter.

Keep the good work.

Petr.

Re: Print to Cut functionality & Mach3 on router
« Reply #12 on: June 04, 2013, 11:31:03 AM »
I worked for over 35 years in the printing industry, and saw many changes in technology over the years. (From letterpress printing, to web offset printing of telephone directories). The most advance system I personally worked with, was a computer-controlled registration system. (CCR for short). It involves the use of registration dots which were printed onto the web travelling at speeds up to 2500 feet per minute, for each of the four process colors used. CMYK, a television camera was mounted onto a linear rail system, which allowed the camera to travel across the web, driven by a servo motor and toothed belt. The camera would make a scan across the moving web, under computer control and photograph the programmed location of the registration dots on the web itself. A specific pattern arrangement of the dots (I.E. the distance from Cyan to the Magenta, Cyan to the Yellow, Cyan to the Black, and so on, relative to each of the 4 colors) was the "Target" to be maintained by the CCR. This was accomplished, by electric servos, which manipulated the registration of the plate cylinders for each color on the press itself. To be sure, the system was a multi-million $ system. And further improvements which included a computer controlled ink density scanner and closed loop control (to control dot gain) made that particular printing press the most advanced system I ever worked on. So, I can see where it could be possible to develop a similar application for what you are trying to do. However, I don't think that Mach3 (as it is) could accommodate such a system, since it would require constant re-writing of the G code during program execution.

Offline stirling

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Re: Print to Cut functionality & Mach3 on router
« Reply #13 on: June 08, 2013, 10:26:45 AM »
Petr

Just a couple of thoughts which may or may not make your task easier. Non-linearly distorting an existing toolpath strikes me as being quite a complex task. However creating a new toolpath from scratch for each image as it's loaded onto the cutter bed may be easier. Compared to the time it takes a tangential knife setup to actually cut - the processing time to create a toolpath for each image should be negligable. Typically you'd just need to photograph it of course, and then use an edge detection algorithm to create the toolpath. If your contrast between the white space and the image is good then the edge detection could even be trivial.

Also if your machine has good accel you could get away with generating gcode with just short lines and no arcs and let CV do the smoothing. This would make the gcode generation fairly trivial also.

Anyway - just a couple of thoughts.

Ian