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CNC plotter with drag knife + CAM software

drzasiek 5385 34
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  • CNC plotter with drag knife + CAM software
    Today I present a CNC machine - a plotter with a drag knife which I made for my own use (for my spouse).
    The spouse designs and cuts out decorations from paper. So far, he uses the Brother Scanncut plotter. The machine works quite well, although after cutting, I think that already thousands of decorations show some wear. In addition, it works quite loudly, which is a bit disturbing because the studio is at home (the engines probably work at full speed, the housing vibrates a lot) is slow and the working area sufficient for an A3 sheet has started to be insufficient.
    A decision was made to build a new machine with a larger working area.
    Initially, the idea was for a laser. Despite my concerns about inserting the laser into the house (need for extraction, flammable material, etc.), I took the first steps. I bought a 30W laser and to speed up my work a bit, I also bought a 165 x 85 cm frame according to the openbuilds project. In the meantime, however, it was decided that a drag knife would be the best solution for this application. The already purchased frame, a bit too flexible for a drag knife, but for the one without the Z axis, I decided to use it. I made the Z axis myself, a trolley with a head holder printed on a 3D printer. I strengthened the frame and mounted it in the reverse position. Initially, I wanted the axle to be light and I wanted to use a modeling servo as a drive (see the photo), but I quickly found out that it was a bad idea. Finally, the Z axis drives the stepper motor, the pressure of the knife by a push back spring.
    The housing is mainly plywood and MDF (used scraps and waste that I had) and 0.5mm steel sheets as covers. There is also a table with shelves for mats and paper.
    The paper mats are 6mm foamed PVC with scales engraved on the milling machine to make it easy to arrange the paper.
    Controls are GRBL and CNC Shield, on Universal gcode sender computer.
    Since it was hard for me to find a tool that would be simple, easy and quick to generate the toolpath, I did my job. This is the program I called CuterCam and it was this stage that took the longest (about 1.5 months).
    The program loads a dxf or svg drawing, detects the shapes itself, determines the order based on the algorithm. Shapes can be moved, rotated, duplicated, deleted, hidden, grouped etc. and arranged freely on the selected mat. In fact, it takes just a few clicks and the g-code is ready for a very complicated drawing. The program has a wizard of post-processors, you can create and save many of them. Shapes are cut out according to one of 3 algorithms:
    - internal first
    -external first
    -nearest shape
    In addition, the program allows you to control the angle of the knife entry. After completing the previous shape, the program saves the knife setting angle (angle of the last vector of motion) and starts the next shape from the place where the angle of the first vector of motion is as close to it as possible. This allows the knife to be lowered immediately to the cutting direction, it does not have to turn back in place, so there is no risk of breaking it or tearing the material out when turning.

    Below are some photos that have survived from the construction and a video of cutting out and the work of the CuterCam program.
    CNC plotter with drag knife + CAM software
    CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM softwareCNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software CNC plotter with drag knife + CAM software

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    About Author
    drzasiek
    CNC specialists
    Offline 
    drzasiek wrote 2168 posts with rating 3157, helped 106 times. Been with us since 2009 year.
  • #2
    miszcz310
    Level 20  
    I don't know anything about it, but wouldn't an ordinary servo (control 0, 1) be enough for the Z axis? The advantage would be to reduce the weight of the ambulance.
  • #3
    CMS
    Administrator of HydePark
    How did you solve the knife contact pressure adjustment and cutting depth for different materials?
    Typically these applications use a coil and you have a stepper motor.
  • #4
    drzasiek
    CNC specialists
    Gentlemen, I don't think you've read it :)
    Originally there was an idea to use a servo (you can see it in the photo) but it was too slow and too weak (you killed yourself by lifting the head pressed by the coupling up). In addition, the servo has a potentiometer that has a long service life, I started to fear whether the servo would have to be replaced too often.
    The head pressure is realized by means of a spring. The spring pressure is adjustable. The motor serves only for lifting, when it lowers it, the belt is loose and the spring presses the head.
    The cutting depth is regulated by the head itself by adjusting the knife protrusion from the head (adjustment on the screw). With us, the cut is made in the same material all the time (cardstock 170g), so the adjustment is one-time.
    The best application here would be an electromagnet, but a few that I tested turned out to be too weak in this range of motion and were too hot. The engine works reliably, quietly and is unimaginable in this application.
  • #5
    Przybyłek
    Level 13  
    Write something more about underlays, how the underlay sticks to your table and how the undercoat sticks to your table.
  • #6
    drzasiek
    CNC specialists
    The mat is made of 6mm thick foamed PVC. I have mats in sizes A3, A2 and A1. The mat is simply placed on the table against the base stops (Left and Bottom). On the right and top there are locks with butterflies. The lock is pushed against the mat and locked by tightening it with a butterfly screw. The entire block is 6mm high and made on a 3D printer. A light temporary adhesive is applied to the mats, the paper is stuck to the mat and cut. It detaches from the mat after it is cut.
  • #7
    Przybyłek
    Level 13  
    Please write me what is this glue? Could this foundation be thinner? Do you buy ready-made ones with measuring cups, or do you somehow mill the measuring cups yourself?
  • #8
    drzasiek
    CNC specialists
    Temporary glue for paper, on but ... it's full of it.
    The backing could be thinner and it could be thicker :) I chose 6mm because I thought it would be thin enough not to be too expensive and thick enough not to bend like paper when being moved. I engraved the scale myself.
  • #9
    CMS
    Administrator of HydePark
    drzasiek wrote:
    The cutting depth is regulated by the head itself by adjusting the knife protrusion from the head (adjustment on the screw). With us, the cut is made in the same material all the time (cardstock 170g), so the adjustment is one-time.


    And everything is clear.

    When it comes to holding the paper, I repaired the plotter (drawing in ten different colors with pens) several times, probably Roland, where the worktop was made of "electrifying" material, and there were electrodes on the bottom. It was enough to put a sheet of paper, press a button and the electrostatics literally sucked the paper to the table top.
  • #10
    drzasiek
    CNC specialists
    I have to be interested in this because it sounds interesting. The glue is good and reliable, but every few dozen sheets of mate you have to clean and apply glue. When drawing, the forces on the paper are smaller than when cutting.
  • #11
    Przybyłek
    Level 13  
    CMS wrote:
    drzasiek wrote:
    The cutting depth is regulated by the head itself by adjusting the knife protrusion from the head (adjustment on the screw). With us, the cut is made in the same material all the time (cardstock 170g), so the adjustment is one-time.


    And everything is clear.

    When it comes to holding the paper, I repaired the plotter (drawing in ten different colors with pens) several times, probably Roland, where the worktop was made of "electrifying" material, and there were electrodes on the bottom. It was enough to put a sheet of paper, press a button and the electrostatics literally sucked the paper to the table top.


    I have exactly this Roland, and I have the same frame as the author. That is why I am asking, because the PVC would stick electrostatically thin and the paper with glue.
  • #12
    CMS
    Administrator of HydePark
    Looking at the date of your joining the group of our forum members, I do not exclude that your plotter could also be hosted on my operating table at one time. :) . Unfortunately, I had the last case of this model about 10 years ago ... I hope that I repaired it so well that it is still in use today, not that it was scrapped.
    But after all, the patent with electrostatic paper holding is sweeping.
  • #13
    Przybyłek
    Level 13  
    I am 32 years old and have known the stories of this plotter since almost I was born. He was at the Lodz University of Technology, he had a converted holder in which you put a marker pen and drew PCBs designed in Autotrax. Then, somewhere around my 12 years old, he came home and drew my TDA7318 preamplifiers and TDA7294 amplifiers and 89S52 controls ;-) Then he went to the wardrobe and recently, when I was at my parents' house, I saw him there. I think I'll take it because my girlfriend also cuts flowers, but with scissors :P
  • #14
    drzasiek
    CNC specialists
    I do not know what model you have, but somewhere I saw Roland's plotter drawing, he was murdering himself terribly, in the sense he drew all the gaps with lines and he slowed down terribly. Additionally, I don't know if you know, but you can't just attach the drag knife to the pen and cut it as if you were drawing. The drag knife runs behind the axis of rotation, in sharp turns you need to turn in an arc so as not to break the knife and you need to trim shapes. Of course, in the short term, it can work like this, but there will be some shortcomings and a significant risk of breaking the knife and thinning the paper on sharp turns.
  • #15
    Przybyłek
    Level 13  
    I associate the number 980 in the name with something. That's right, when I drew a PCB in protel99 and it was controlled by the Windows driver, it was a bit like that. But with the Autotrax, or rather the addition, PLOT seemed to be walking like a storm, curves, arcs, points with a hole in the middle.
    As for the knife, I know, but the issue of CAM, the plotter does not deal with it, neither this nor any (unless CAM is in it) The plotter probably gets Gcode, but I think that it also had direct driver control via LPT and after RS GCODE.
  • #16
    Slawek K.
    Level 34  
    Great performance ;) I am planning to make such a plotter for cutting stickers for models in a 1:14 scale. In my concept, it will be a cutting plotter on a roller because the foil is rolled up and it is not as stiff as your bristol. Good inspiration, thanks a lot and a well-deserved splash flew ;)

    Greetings
  • #17
    drzasiek
    CNC specialists
    There is no shortage of plotters that cut the foil from the roll. I don't know if it will pay off wasting time building your own, unless there are specific requirements that trading plotters do not have.
  • #18
    Slawek K.
    Level 34  
    I know, but I do all the machines myself, such a deviation ;) I don't need a plotter for profit and hobby purposes, so the economy doesn't matter here :D

    Greetings
  • #19
    Przybyłek
    Level 13  
    It's not about earnings, but you'll probably get one for free or for PLN 100-200. I had two old A1 cars and they were scrapped last year because there were no volunteers.
  • #20
    Slawek K.
    Level 34  
    Ok, I suggest you respect your friend's thread and not drag on Offtop ;)

    Greetings
  • #21
    bojkot
    Level 9  
    Great project, congratulations. What did you write your C # program in?
  • #22
    drzasiek
    CNC specialists
    C ++ program with Qt.
  • #23
    hacker_ice

    Level 24  
    Great project :) will you share the soft and maybe some details as if to make a similar plotter?
  • #25
    drzasiek
    CNC specialists
    I do not provide source versions. However, if someone needs help, advice on building something similar, I do not make any secrets, I will gladly answer, advise.
  • #26
    SilverGTA
    Level 22  
    Is it possible to cut with a similar device in soft materials, but fixed in some way so that they do not move? For example, for example, a thick non-woven mat, synthetic wool or just felt?
  • #27
    drzasiek
    CNC specialists
    Certainly many materials can be cut in this way. After all, the drag knife is used in industry. These types of plotters are also dedicated to tailoring purposes where various materials are cut, the question of the right knife (size, angle), processing parameters and the right glue (there are many temporary adhesives, stronger and weaker).
  • #28
    koczis_ws
    Level 27  
    I did something similar once, but I took the easy way. I have adapted the Roland A1 plate plotter to cut the self-adhesive foil. I designed the knife and made it myself. All the fun was writing the program because without it the cut looked terrible, the drag knife didn't cut exactly what I drew.
    I did it like this. I was exporting a drawing to HPGL. Then, with the written program, I corrected the vectors for the knife offset and generated the HPGL again, which I sent to the plotter.
  • #29
    drzasiek
    CNC specialists
    Vectors alone are not enough. If you send the program in the form of motion vectors, the machine will shred all the arcs. My program finally converts vectors arranged in an arc into arcs.
  • #30
    koczis_ws
    Level 27  
    There is no such thing as an arc in digital technology. It is always broken, only it has more or fewer lines depending on the accuracy required. Real bows are analog only.