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Artifact due to initial rotation of blade

I have noticed that when the blade starts cutting a shape, the initial placement of the blade (the place where the tip enters the material) is out of line with the shape. This leads to a small artifact outside the shape. The artifact is especially visible when I use a blade with a large offset (0.7 mm). Since I mostly cut stencils out of acetate, which requires a double cut, this also often leads to a small part that is undercut, and thus still connected to the stencil.

Looking at the behavior of the cutting process, it seams to me that the instructions send to the cutter do not take into account the original angle of the blade. I see the artifact in most cuts (not only the first) so this suggests that the algorithm does not take into account the exiting angle of the blade form the previous shape.

I have noticed, for example, that the Cricut machine straitens the blade before the cut begins, thus the software can keep track of the rotation of the blade at any moment during the cut. Is this not happening in MTC?

Can somebody help me resolve the issue?

I use KNK Max Air for cutting.

Answers

  • Crazy_Mr_ZingCrazy_Mr_Zing Member Posts: 2,920
    The blade orientation cut should not effect any of the other cut shape if you getting shape perimeters not meeting where they begin
    I that was was happening with my Zing I would suspect my  blade offset was incorrect

    What blade are you using and what is the blade offset you have set ?
    I Use Zing Air, Make The Cut - Pop Card Studio, WinXP- Win7 -Win10
    Paper Modellers I Revere Marc Hagan-Guirey ----- Yoshinobu Miyamoto ----- Peter Dahmen
    Gallery ID #26944 ----- Link to My Cloud Have a Look your Welcome to Make Use of the Files
  • Liz_ALiz_A Member Posts: 9,563
    There should only be on "artifact" and that is outside the project cut area and only happens at the beginning of the cut so that the blade is properly oriented. I agree with Crazy, if you are getting other "artifacts" then make sure you using the right offset for the blade.
  • SandyMcCSandyMcC Member Posts: 7,137
    Watch your Maxx Air again at the start of a cut. It will drop once, raise up, move and drop again. That first drop is meant to set the blade direction.  

    However, it sounds like you're carefully testing this, so I recommend taking this issue to the experts.  Please start a support ticket here:

    http://knkusa.com/support-ticket-request/

    Be sure to provide a link to this thread so that they can read what you've already posted. 
    Sandy McCauley
    Cutting with KNK Force, Maxx Air, Zing Orbit
    Need help with your KNK? Visit this link: http://knkusa.com/contact/
    Over 90 free MTC videos: http://www.iloveknk.com/support/mtc-support/
    Latest KNK / MTC User Manuals: http://www.iloveknk.com/Support/user-manuals/
  • vakarelovvakarelov Member Posts: 12
    Thank you for the replies. I am using the eclips blades with .7 - .75 mm offset. I don't think that the offset is the problem, as when it is incorrect, one sees deformations of sharp corners. The max air definitely does not do the drop-and-raise step. Is this controlled by the machine directly, or is it based on commands send by MTC? I have examined the commands send to the machine by monition the USB com traffic, and there is definitely no step to adjust direction.  Here is a picture of the artifact that I am getting at every shape:


  • SandyMcCSandyMcC Member Posts: 7,137
    That's very strange. I checked mine last night before responding to you to make sure I saw it drop once (very quick tap), come up, and move another short distance to drop and start cutting.  I would contact KNK USA for sure.  But one thing... the eClips blades should not have that high of a blade offset.  It should be more like 0.3.  Can you another do test of the same shape, using that offset to photograph? Also, I take it you're using the eClips blade holder, as well?  KNK USA will be reluctant to help you with another brand of blade holder and certainly will advise against using eClips blades in the MA blade holder.   
    Sandy McCauley
    Cutting with KNK Force, Maxx Air, Zing Orbit
    Need help with your KNK? Visit this link: http://knkusa.com/contact/
    Over 90 free MTC videos: http://www.iloveknk.com/support/mtc-support/
    Latest KNK / MTC User Manuals: http://www.iloveknk.com/Support/user-manuals/
  • vakarelovvakarelov Member Posts: 12
    The offset is indeed so big. You can quite clearly see that the blades are bigger. Unfortunately,  the KNK blades are very poor quality steel. They get dull very quickly. I have given up on them.
  • SandyMcCSandyMcC Member Posts: 7,137
    We have many customers who claim the exact opposite! They buy other brands of blades and claim that none of the others last as long as the KNK ones. 
    Sandy McCauley
    Cutting with KNK Force, Maxx Air, Zing Orbit
    Need help with your KNK? Visit this link: http://knkusa.com/contact/
    Over 90 free MTC videos: http://www.iloveknk.com/support/mtc-support/
    Latest KNK / MTC User Manuals: http://www.iloveknk.com/Support/user-manuals/
  • leslie6111leslie6111 Member Posts: 2,348
    edited April 7
    I used ecipls blades in my zing But I used them with a eclips holder in the past and I recall the offset was .45 and I set the holder to 3.5 for most of my cutting needs. I couldn't use the same blades in my zing holder. I then switched to rolland blades with the offset to .25, still at 3.5 even though the blades were slightly longer in the holder. If you look at a different point on your fish like under the tail where the blade turns - I think you will notice a slight divot - thus I agree with Sandy that your blade offset is too high. That artifact piece at the top of the fish could also be a little divot - I can't tell if there is a stray mark without looking at your file.
  • vakarelovvakarelov Member Posts: 12
    edited April 7
    I use these blades and this holder. Originally, I also thought that the offset was around .45, but I was getting clear errors. After some research and experimentation,  I discovered that the offset is between .7 to .75. The shape of the fish is exactly as the vector path (see below).  (The picture was taken at an angle, so the dimension is a but distorted.) I have run the cutter at speed 1, very slowly, to examine what happens to the cutter. The artifact is produced by the blade making the initial contact off the intended curve, and then as the head moves, the position gets corrected. Do any of you know if the direction of the blade is controlled by the hardware or is it controlled by the commands send by MTC? My impression is that the software controls everything. I have observed that all curves are traced with line commands. At the end of each corner point, a sequence of commands is send that trace a circle with the offset as the radius. For this reason, I suspect that the problem is the software. (This is why I posted on this forum.)

    Here is the path of the shape:
    <path id="fish" d="M924.46,810.008c1.36-0.815,2.584-1.632,3.876-2.38c0.34-0.204,0.748-0.408,1.156-0.612 c0.884-0.407,1.156-0.271,1.292,0.748c0.067,0.408,0.067,0.885,0.067,1.292c0.137,1.429,0.272,2.856,0.477,4.284
        c0.136,0.952-0.137,1.292-1.088,1.021c-1.496-0.408-2.924-0.952-4.217-1.429c0.272,0.885,0.681,1.769,0.681,2.652
        c0.136,3.196-1.36,5.304-4.488,5.984c-4.896,1.088-9.86,2.107-14.892,0.68c-0.748-0.204-1.7,0-2.517,0.068
        c-0.204,0-0.407,0.136-0.611,0.136c-0.544-0.068-1.089-0.136-1.632-0.204c0.136-0.477,0.203-1.088,0.543-1.428
        c0.816-1.021,1.021-2.177,0.885-3.4c-0.34-4.012,1.359-7.004,4.76-8.976c0.204-0.137,0.408-0.272,0.68-0.341
     c1.973-0.747,3.944-1.495,5.916-2.243c1.7-0.681,3.265-0.544,4.692,0.68c0.544,0.408,1.156,0.748,1.768,1.02
        C922.896,808.104,923.984,808.716,924.46,810.008z"/>

    Post edited by vakarelov on
  • leslie6111leslie6111 Member Posts: 2,348
    edited April 7
    Are you using the eclips blade holder with the eclips blades? With my zing the path is dependent on the program and not the cutter. You can reverse the path of the cut if you needed. You can also try flattening paths. Do you by any chance have a little node stuck out to create that stray cut. You can either make all the nodes visible or hover over that area with the pencil tool to see if that is the case. You can even use the node editing tool to take out a section and then erase that little part and use the pencil once erased to close your shape, cause it is sometimes difficult to edit out small stray nodes.
  • Crazy_Mr_ZingCrazy_Mr_Zing Member Posts: 2,920
    edited April 7
    @vakarelov Is it possible for you to attach the MTC file



    If you think this issue is software/hardware issue you could put some paper on the mat and exchange the blade for a pen, set the blade offset to zero  and send the project to the machine

    Cutting some basic shapes Square , Circle, Star is a good way of determining the blade offset is correct

    I use a Zing so maybe it works differently But To me the position of the artifact is not where the initial blade direction setting cut would be

    As you mention Cricut I wondering what version of MTC and plugin are you using

    I Use Zing Air, Make The Cut - Pop Card Studio, WinXP- Win7 -Win10
    Paper Modellers I Revere Marc Hagan-Guirey ----- Yoshinobu Miyamoto ----- Peter Dahmen
    Gallery ID #26944 ----- Link to My Cloud Have a Look your Welcome to Make Use of the Files
  • SandyMcCSandyMcC Member Posts: 7,137
    Can you please explain this  in a lot more detail:   "Originally, I also thought that the offset was around .45, but I was getting clear errors. After some research and experimentation,  I discovered that the offset is between .7 to .75."

    What does "clear errors" mean?

    What led you to believe you needed to increase the offset to such a high value?

    Will you please cut a 1" inch square using this offset and the eClips blade and then post a photo of the result?
     
    BTW, the link you provided to the holder didn't work. But I assume it's not the MA blade holder, so it doesn't matter.  

    Sandy McCauley
    Cutting with KNK Force, Maxx Air, Zing Orbit
    Need help with your KNK? Visit this link: http://knkusa.com/contact/
    Over 90 free MTC videos: http://www.iloveknk.com/support/mtc-support/
    Latest KNK / MTC User Manuals: http://www.iloveknk.com/Support/user-manuals/
  • Liz_ALiz_A Member Posts: 9,563
    Can you provide the sources of your research?
  • vakarelovvakarelov Member Posts: 12
    edited April 7
    I fixed the link. It works now.
    @SandyMcC about the research, I found discussion about the blades (on the amazon comment section actually) and somebody said they used offset of .7 (I saw discussion on another forum saying something similar, but I don't remember where ) I tried it with various test patters, and indeed it worked best with .7 (this is what I meant by "errors".) Here is an image comparing the eclips blade (top) and the original blade that came with the cutter (bottom). You can see that the tip is much further out from the center.


    I will cut a square and post it a bit later, ones I go to my shop.

    @leslie6111 I am not sure I understand exactly the suggestion. But, I use illustrator and/or my own proprietary software to generate the svg files that I use for cutting. Since all the shapes I cut are closed curves, the software may decide to start an any point. In fact, there may be a good reason to start in the middle a curve. I have the feeling MTC does that, but I am not sure.

    @Crazy_Mr_Zing I usually do not save the MTC files. I just import and cut. About Cricut, no, I cannot use it with MTC. It only works with its own propitiatory web-based software. I do not like this, so the machine is mostly collecting dust.

    I hope I answered all the comments.


    Post edited by vakarelov on
  • leslie6111leslie6111 Member Posts: 2,348
    I had assumed that you had used mtc and are not just using it for a pass thru. But be that as it may,  I am surprised that the program would put a cut at that location if you didn't have a stray node there so I am suggesting that you look closely and see if there is a stray node at that spot and then delete it. Or try flatten paths before cutting so that MTC would recalculate the paths before sending to the cutter. MTC does make a little tick at the start of cutting but it would be outside the bounding box for the shape and not look integral to the cutting path. eclips blades have 45 degree angle and mine looks slightly different than yours, but it is older and like I said I used .45 as a blade offset. I switched to rolland blades which are less expensive and worked better for me in this same blade holder.
  • SandyMcCSandyMcC Member Posts: 7,137
    edited April 7
    KNK USA has their manufacturer add a cutback to both the 45 and the 60 degree blades to reduce the blade offset. This is necessary for the customers who want to cut very small lettering.  Blades with large offsets do a lousy job on small shapes.

    But having a cutback doesn't affect the longevity of a blade. 

    Sandy McCauley
    Cutting with KNK Force, Maxx Air, Zing Orbit
    Need help with your KNK? Visit this link: http://knkusa.com/contact/
    Over 90 free MTC videos: http://www.iloveknk.com/support/mtc-support/
    Latest KNK / MTC User Manuals: http://www.iloveknk.com/Support/user-manuals/
  • vakarelovvakarelov Member Posts: 12
    @leslie6111 What exactly to you mean by "flatten paths"? Do you mean to remove groups, or remove transformation, or something else. I only work in SVG format, so I am not sure what that means. I am sure that the artifact is not in the graphics. I am getting such an artifact in almost all of the cutouts. I only took a picture of one as an illustration. My problem is that I am not getting the little tick to adjust the initial blade direction. The whole process looks as if the software does not keep track of the position of the blade between cuts at all. Could there be some setting in MCT that I have missed? I will continue experimenting with the offset, but I feel that this is not connected to the offset.
  • Liz_ALiz_A Member Posts: 9,563
    @vakarelovFlatten Paths is a command on the Shape MagicAdvanced menu. MTC makes one initial blade adjustment outside of the area of the project to be cut, first, then does the cut. It does not make any additional marks at any other time to make adjustments to the direction of the blade. I have been using MTC since 2009, and when we see issues you have shown us, it has typically proven to be errors in the offset, an issue with the file, or some other mechanical type of problem. Did you contact KNK USA as suggested by Sandy earlier in this thread? Were you going to post your results of cutting a square or rectangle? 
  • Crazy_Mr_ZingCrazy_Mr_Zing Member Posts: 2,920
    edited April 9
    The Flatten Paths is in the menu under the Wrench Button



    I is often helpful if you can supply the MTC file you having issues with

    I think it also would be helpful if you could cut some basic shapes a Square , Circle and attach a photo of the cutting results

    basic shape are accessed via this button





    If this was you design and the arrow is the direction the mat travels though the machine i would expect the blade direction setting cut to be positioned about with the red dot is to the lower right of the design


    Post edited by Crazy_Mr_Zing on
    I Use Zing Air, Make The Cut - Pop Card Studio, WinXP- Win7 -Win10
    Paper Modellers I Revere Marc Hagan-Guirey ----- Yoshinobu Miyamoto ----- Peter Dahmen
    Gallery ID #26944 ----- Link to My Cloud Have a Look your Welcome to Make Use of the Files
  • MeFlickMeFlick Member Posts: 9,039
    I think that everyone is missing that the OP is not using MTC to do anything BUT import an SVG file she has created outside of MTC and then cut:
    vakarelov said:

    . . .  But, I use illustrator and/or my own proprietary software to generate the svg files that I use for cutting. . . . I usually do not save the MTC files. I just import and cut.  . . . 
    When you say "my own proprietary software to generate SVG files" - can you expound on that?  Is this a program that you wrote yourself?  Is this an issue with files from your own proprietary software only or also from Illustrator as well?  I ask because people have been importing SVG files from Illustrator into MTC and I have not seen this been raised as an issue with others doing so before?

    To note, not everyone who uses MTC has this issue that you are having - like Liz, i too have been using this program since its beginnings and this is not a regular issue with MTC files and cutting them.  Nor when its an SVG file imported and cut. If so, this forum would be full of people with the same issue/concern over the years.  As a result, I wonder if this is something with your particular files and importing them.  It might be helpful to compare your SVG files with other SVG files to see if yours is doing something "odd" that others are not at the start of a cut if you are convinced that there is not an offset issue.  

    I raise this as an area to look at simply since this is the only place I see a "difference" in what you are doing and what others are doing and trying to give a suggest of a place to look for the issue.

    In order to best help resolve this issue, you are going to be best served by logging a support ticket with KNK for help or with MTC support and see if they can help you figure out your issue.  Then, you can perhaps send them copies of your files to look at.  Without looking at your files directly, others testing the cut on their system, etc.  it is only "guessing" at things that could be going on.
    Go Vols!
    image
    Cutting with 18" Silver Bullet and a KNK Force (the rest are collecting dust!)
  • vakarelovvakarelov Member Posts: 12
    @MeFlick This is a program I wrote (am writing). The file I gave an example from was made in Illustrator.  I have attached it. I have seen this issue both in files made in illustrator and in ones generated my the program.

    I will play a little more to see how/when the issue comes up, and I will report. I will play around with both open and closed curves to see if this makes a difference. I will also try if the direction of the previous shape (say a line) affects the issue.
    I will most likely contact MCT first, because I suspect the issue comes from the software. 

    There is also the possibility that the blade, somehow, rotates in the holder between cuts.

    @Crazy_Mr_Zing I found the operation "flatten paths" operation. It converts the path into small linear segments. I am sure this happens before cutting anyways because MCT send all instructions to the cutter in linear commands. The manual says that this is useful if there is an issue with bounding boxes for the object. Very strange, considering how easy it is to compute the bounding box for a bezier curve.

    I need to travel this week for a conference. I will report next week.

    (By the the way, I am a he, but it is a honor to be included among the better sex :smile: )


  • Crazy_Mr_ZingCrazy_Mr_Zing Member Posts: 2,920
    @vakarelov ; I have no knowledge of the technical aspect of the data the MTC sends to Cutters

    This issue still appear to us as a possible incorrect blade offset issue
    Will you cut this file using the blade offset of 0.7mm and attach a photo of the result
     
    Test Shapes 1.mtc



    I Use Zing Air, Make The Cut - Pop Card Studio, WinXP- Win7 -Win10
    Paper Modellers I Revere Marc Hagan-Guirey ----- Yoshinobu Miyamoto ----- Peter Dahmen
    Gallery ID #26944 ----- Link to My Cloud Have a Look your Welcome to Make Use of the Files
  • Liz_ALiz_A Member Posts: 9,563
    @vakarelov - I see a few artefacts in your file. Look at it in Shape Magic => Advanced => View Path Detail. The light gray lines connecting between the waves, which may actually cut, can be removed by choosing Shape Magic => Advanced => Flatten Paths. This process flattened 100 paths in your file. These artefacts are usually from the source drawing program that created the svg file, not MTC. If this was a CorelDraw or other such program, a process done in that source program before exporting to svg would eliminate those artefacts. Can't recall exactly what that it is.
  • vakarelovvakarelov Member Posts: 12
    edited April 11
    @Liz_A No, these are not in the file. MCT seems to show lines between the curve end-points in the shape view window. The best way to see what is in the svg file is to look at it in a text editor, or a browser with develop tools enabled. If you look at the file, the very first path in the first group is the leftmost long waive.

    The flatten path command converts the path into linear segments. This operation is performed before cutting anyways. This is explained on p142 of the manual.
    Post edited by vakarelov on
  • vakarelovvakarelov Member Posts: 12
    Some results from my test. Thanks @Crazy_Mr_Zing for providing the test pattern:

    I cut the pattern twice with .7 offset.  I manually positioned the direction on the blade perpendicular to the first line of cut on the first run and parallel to on the second. Both runs where done at speed of 1 or 2 mm/s. The results where interesting!  I saw a down-up tick on the beginning of the cut. I saw the artifact at the beginning of the cut of all shapes but one. The one shape that did not have the artifact was the first shape of the second run, where the blade was manually aligned with the first cut. The artifact was smallest in the circle, where the end position of the blade on the previous shape, the arrow, is more closely aligned with the initial position. The blade must however rotate180 degs between the two, which may cause some digging into the acetate and some error of offset may also show up.

    The conclusions are: (1) the artifacts are caused by the improper initial direction of the blade. The difference between the two arrows shows this most clearly. (2) The initial tick does not properly align the blade. (3) The blade is not realigned between cuts, shown by the errors on the circle, but especially the square. (The cut of the square starts at the worst possible place in this respect.)

    The illustration shows the cuts and artifacts in order from right to left. (See better on the attachment. I was using the panorama feature of my phone to take the picture, thus the distorted grid. )

    Finally, to settle the large offset issue, I cut one more square (left most on the diagram) with offset of .45 mm. The corners of the square show clear signs undercutting, which is what you would expect if the offset is smaller than it should be. This is because the tip hasn't reached the corner before the direction of the cut changed. This square also showed the artifact, but on the right side, where the cut began. Examining the other shapes more closely, there is a very small undercut as well, suggesting that .75 may be a better offset. This is not viable on the photo.

    I wonder if other people have had a similar problem, but did not notice it with smaller offset blades. I didn't notice this artifact when using the original blades, but I always had unclear disconnects of the cuts, that I could not correct by adjusting the offset. Now I am thinking that this was caused by incorrect blade alignment.

  • Liz_ALiz_A Member Posts: 9,563
    @vakarelov - I think its time to take this issue to KNK. I use MTC and the Maxx Air with OEM blades and I do not have this issue.
  • melmomelmo Member Posts: 102
    @vakarelov I have noticed the same "artifacts" when using blades with large offsets. I ordered some cheap ebay blades with a .9 offset and they were horrible at cutting small objects and always cut the "artifacts". I will only use the KNK blades now and have no problems with very small cuts.
    I don't know what cutter you are using, but on a previous cutter I owned one solution to was to raise the blade holder a bit to help avoid the extra tics.
  • Crazy_Mr_ZingCrazy_Mr_Zing Member Posts: 2,920
    edited April 13
    When the machine first starts cutting it should move close to the pattern lower the blade make a very small cut to set the blade alignment

    Post edited by Crazy_Mr_Zing on
    I Use Zing Air, Make The Cut - Pop Card Studio, WinXP- Win7 -Win10
    Paper Modellers I Revere Marc Hagan-Guirey ----- Yoshinobu Miyamoto ----- Peter Dahmen
    Gallery ID #26944 ----- Link to My Cloud Have a Look your Welcome to Make Use of the Files
  • SBryanWSBryanW Administrator Posts: 5,270
    The initial up/down tick outside the overall pattern is to set the blade direction for the first cut.  At the end of each cut, if there is a cut following, and the blade direction needs to change, then MTC makes a blade correction at end of the current cut before the blade is lifted to move to the next cut.

    Blade direction is a known problem/issue with swivel blades. Short of moving the blade off the project area to set the blade direction before every cut (or in the unlikely event where the blade direction of the next cut is exactly the same as the cut just ending), there will be artifacts on the project.  The bigger the offset, the bigger the possible artifacts.  If there are no blade direction corrections made, then you will still have artifacts and possibly some incomplete cuts.
  • vakarelovvakarelov Member Posts: 12
    edited April 19
    I examined more closely what instructions are sent to the cutter by MTC in the cutting of a 1in square. The KNK protocol is a variation on the HP-GL protocol.

    I initiated a cut with 1mm offset to make the numbers easier to interpret (for this cutter 40 units correspond to 1mm.) I wanted to see if the blade direction gets adjusted before the cut begins. (It turns out, it does not!) After this, I examined if the blade gets adjusted to the correct angle if a slanted line is cut after the square. (Yes, it is! But, the next cut begins at the wrong place.)  I parsed the commands into my software and generated a graph showing all points (scaled to 50%). (I annotated the graph in Illustrator.)  Here are the instructions sent to the cutter with some explanations. All commands are lines, with Ux,y meaning "go to point (x,y) with head Up", and Dx,y "go to (x,y) with head Down" (cut):
    ______________________________________________
    MX;P1;VS28;!FS100;PA;   <--  Initialization, setting coord system, speed, force, etc.

    U-40,-40;D-40,-40; <-- initial click: go to (-40, -40), head down, move to (-40,-40) which is the same point. So no direction adjustment happens.

    U508,1016; <-- move to the point of initial cut with head up.

    D0,1016;D-40,1016; <-- Start cut, moving along X from 508 to 0, and then to -40. (I don't know why the odd move to 0. It should move to -40 directly.)

    D-40,1012;D-39,1008;D-38,1004;D-37,1000;D-33,994;D-28,988;D-22,983;D-16,979;D-12,978;D-8,977;D-4,976;D0,976; <-- Tracing a quarter circle that keeps the cutting tip in place, but changes the direction of the blade for the next line.

    D0,-40;   <--cut next side of square.

    D4,-40;D8,-39;D12,-38;D16,-37;D22,-33;D28,-28;D33,-22;D37,-16;D38,-12;D39,-8;D40,-4;D40,0;D40,0;  <-- Another rotation of blade. A redundant command is sent (D40,0).

    D1056,0;   <-- cut next side.

    D1056,4;D1055,8;D1054,12;D1053,16;D1049,22;D1044,28;D1038,33;D1032,37;D1028,38;D1024,39;D1020,40;D1016,40;  <-- Another rotation.

    D1016,1056;   <-- cut next side

    D1012,1056;D1008,1055;D1004,1054;D1000,1053;D994,1049;D988,1044;D983,1038;D979,1032;D978,1028;D977,1024;D976,1020;D976,1016;D508,1016;D508,1016; <-- Another rotation of blade. A redundant command is sent (D508,1016).

    D388,1016;  <-- cut to end point. This command overcuts by 120 (3mm). This makes sure that the shape is cut fully.

    U0,0;  <-- Go to home position with head up.

    @; <-- end cut.

    _______________________________
    Here is the graph, the square is traversed clockwise form below:



    Here are the commands for the cut if the square is followed by a line on the side:

    MX;P1;VS28;!FS100;PA;U-40,-40;D-40,-40;U508,1016;D0,1016;D-40,1016;D-40,1012;D-39,1008;D-38,1004;D-37,1000;D-33,994;D-28,988;D-22,983;D-16,979;D-12,978;D-8,977;D-4,976;D0,976;D0,-40;D4,-40;D8,-39;D12,-38;D16,-37;D22,-33;D28,-28;D33,-22;D37,-16;D38,-12;D39,-8;D40,-4;D40,0;D40,0;D1056,0;D1056,4;D1055,8;D1054,12;D1053,16;D1049,22;D1044,28;D1038,33;D1032,37;D1028,38;D1024,39;D1020,40;D1016,40;D1016,1056;D1012,1056;D1008,1055;D1004,1054;D1000,1053;D994,1049;D988,1044;D983,1038;D979,1032;D978,1028;D977,1024;D976,1020;D976,1016;D508,1016;D508,1016;D388,1016;D388,1020;D389,1024;D391,1031;D395,1038;D400,1044;U2064,0;D1527,536;U0,0;@;

    (Italics is the adjustment, bold is the line.) Something odd here: Why is the Y coord of the first point of the line 0. There should be a compensation for the offset.

    This is the graph:

    Attached are the svg files for the graphs.

    Verdict: There are two functional bugs: (1) there is no initial adjustment. The correct commands should be U-40,-40;D-80,-40. This will force the blade to align with the first cut. (2) There is no compensation for offset on the start point of the line. There may be a similar problem on the square too, but this is not obvious from the cut. However, considering that 508 is half of 1016, I suspect that the initial point is the mid point of the bottom line. If this is the case, then there is no offset competition. If there was curvature at this point, an artifact would have resulted. The correct placement of the first point should be on the tangent vector from the target point, displaced by the offset in the direction of the cut.

    There may be a few other bugs related to the few redundant commands, but this makes no difference to the cut. 





    Post edited by vakarelov on
  • Liz_ALiz_A Member Posts: 9,563
    @vakarelov - you must be retired to have time to all of this! Amazing!

    On this, "D0,1016;D-40,1016; <-- Start cut, moving along X from 508 to 0, and then to -40. (I don't know why the odd move to 0. It should move to -40 directly.)" is this when the head returns to origin and then moves to the first point?
  • vakarelovvakarelov Member Posts: 12
    Not retired, but trying to start a stencil cutting business, so in effect this is my job. This took me a few hours, so not too bad.

    About the odd point, no, it is the end of the very first line segment. This suggests that the first line and subsequent lines are computed by different operations. You don't see this in the other corners.

    The more i think about this, the more i suspect that the two bugs are one and the same under the hood.
  • SandyMcCSandyMcC Member Posts: 7,137
    Well, I can guarantee you that the developer of MTC will not, unfortunately, be addressing these bugs. This is not a priority for him at this time.  :(

    If you want improved cutting, I recommend you go back to a lower offset blade. I also recommend you download the trial version of SCAL and see how the offset algorithm works for your cuts. I did notice a difference in offset effects when I originally tested SCAL with our cutters. Also, since you're into cutting stencils, SCAL offers a COOL bridge function to easily connect internal shapes with the outside area... exactly what stencil designers need. 
    Sandy McCauley
    Cutting with KNK Force, Maxx Air, Zing Orbit
    Need help with your KNK? Visit this link: http://knkusa.com/contact/
    Over 90 free MTC videos: http://www.iloveknk.com/support/mtc-support/
    Latest KNK / MTC User Manuals: http://www.iloveknk.com/Support/user-manuals/
  • vakarelovvakarelov Member Posts: 12
    Well this is too bad. I'll try SCAL. Eventually I'll write my own interface to the cutter. I may have to increase the priority of this.
  • Little_BerryLittle_Berry Member Posts: 5,759
    Go for it, Dude
This discussion has been closed.