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Question: Still new to vinyl cutting. Sawtooth or jagged edges on Vinyl Cuts?

Discussion in 'Newbie Forum' started by gwizah, Dec 30, 2020.

  1. gwizah

    gwizah New Member

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    Jul 30, 2020
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    Greetings,

    I am still fairly new to vinyl cutting, and everyday I learn something new. Im using a Mutoh Kona 1400 and Oramask 813 film to make stencils. I recently noticed I am getting more "sawtooth" edges on curves where I was previously printing smooth, clean curves. How should I handle this issue?

    I have read that changing the pressure of the blade or even removing the tool holder and making sure there is lubrication can fix this. I was wondering if this is common after several cuts. This machine was a "hand-me-down" from a generous vinyl shop I've worked with so it had a good long run.

    Should I be replacing the blade-? Is it something more serious? Any help is appreciated!

    Ive uploaded an image comparing the two. The one on the left (partially obscured by transfer tape) is the clean one that I cut about a month ago. The one on the right is the new cut from today.
     

    Attached Files:

  2. Texas_Signmaker

    Texas_Signmaker Very Active Signmaker

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    I've never seen that before...that is odd.
     
  3. Notarealsignguy

    Notarealsignguy Very Active Member

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    Maybe your blade holder is worn out? Pop the blade out and put in a drop of lube. Then replace it
     
  4. Jburns

    Jburns Active Member

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    check your blade holder - looks like its really loose - also pinch rollers and make sure media is unrolled
     
  5. letterman7

    letterman7 Very Active Member

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    Yep, all of the above. I've even seen static do that on my own machine (buildup affecting the head - rare, but it happened). Could be the head is on it's way out as well.
     
  6. signheremd

    signheremd Member

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    We had something similar happen on an old Graphtec - the rails needed to be cleaned as well as the wheels that ride in them (that allow the machine to move the blade left and right). Pull some covers off and look around for signs of dirt or graphite - unplug first... check the pinch rollers to be sure they are clean and their drivers are clean. May just need a good cleaning.
     
  7. JBurton

    JBurton Signtologist

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    Looks like the plotter blade holder may not be fully seated. On my graphtec if the blade isn't fully seated, the blade eventually stops cutting from being pushed upward, but what you have here definitely looks like the blade is physically not rigid enough.
    If you are unfamiliar with the plotter, I found a pdf, may be worth a moment to read through replacing the tool in the tool holder. Here's a link:https://docplayer.net/62359041-User-s-guide-kona-cutting-plotter-760-1400-1650.html

    upload_2020-12-31_9-54-50.png
     
  8. bob

    bob Major Contributor

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    All of the above is good advice but anytime a plotter starts flakey behavior such as you have shown, remove any dust cover from the tool carriage and blow all of the dust and crud out of the carriage. Pay particular attention to the blade up/down mechanism.
     
    • Agree Agree x 1
  9. gwizah

    gwizah New Member

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    Jul 30, 2020
    Miami, FL
    Hey all,

    Thank you for the responses. I just cleaned the heck out of the machine, making sure to remove any dirt from the platen and pinch rollers, and generally clean the cutter head. I did not find any buildup of residue on the knife holder end and added some thin oil to the blade holder tip to make sure it turns smoothly. I added a little white lithium grease to the "up and down" rail for the tool holder as well.

    I checked the height of the blade, and it just barely leaves a mark on the backing on oramask 813. The force is set at 120 grams. Drop Speed is 60 (i dont know if these settings affect the cut quality)

    Attached is a close up pic of my blade tip.

    I feel like I am slowly weeding out the issue...but after another test cut, it seems to not be as bad as before, but still showing up towards the edges of the cuts.

    Im kind of stumped...Could it be tension on the belt?
     

    Attached Files:

  10. XtremeXccessories

    XtremeXccessories Member

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    Have you changed the blade recently or changed the knife offset setting? Cut strip in good shape?
     
  11. balstestrat

    balstestrat Active Member

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    Between the bits
    Turn down the speed and take a slow motion video of this issue. Most new phones can do for example 720p 480fps.
     
  12. JBurton

    JBurton Signtologist

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    Looks like the blade has a few miles on it but it doesn't tend to do this once dull.
    How fast are you running the plotter?
    Does it do the same thing on straight cuts?
     
  13. gwizah

    gwizah New Member

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    XtremeXccessories:
    So I changed out the old blade today. Same issue.

    Below is the test I ran. I also ran an offset test in VinylMaster Cut 4.0 which is what I am using. The test is below, but I believe the machine offset is currently set at 0.54.

    Balstestrat:
    I have linked a video here showing the machine in slo-mo for twenty seconds that I shot on my iphone: http://gwizone.com/mutoh/mutoh_slowmo.MOV

    Jburton: The settings panel on the plotter reads "down velocity" at 60. I am guessing that's the speed that the knife drops? I dont know where the setting for the overall speed would be. Is that something that can be modified via the cutting software?
     

    Attached Files:

  14. TammieH

    TammieH Very Active Member

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    I think its something to do with the handshake between your plotter and computer,
    or you changed some of the settings on the plotter by mistake, "Offset" for example
     
  15. balstestrat

    balstestrat Active Member

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    Between the bits
    I just had a quick look of the video, sadly it's a bit short and dark but to me it seems like it's doing a little jagged move. Like there is something wrong.
    Not sure if it was the exact spot where you have the issue.
     
  16. unclebun

    unclebun Very Active Member

    In the video starting at about 10 seconds you can see the cutting carriage visibly wobbling front to back as it moves left to right. I would look at the nylon wheels that bear it along the track. I bet one or more is loose, broken, or worn.
     
  17. JBurton

    JBurton Signtologist

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    Agreed. I didn't see that in the video at first as I was staring at the blade, but it does appear the carriage has some sort of slop in it.
     
  18. gwizah

    gwizah New Member

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    Wow, good suggestions. I am going to disassemble the cutting head tonight and take a close look at the wheels.
     
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