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Cricut

Discussion in 'Members Lounge' started by 3v0, Dec 12, 2008.

  1. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    A cricut is a XY machine with knife blade on Z axis. The X is a slider and the Y is a paper feed roller. Think of a plotter with a knife instead of a pen. It is designed to cut 2 dimensional objects for scrapbooking using font cartridges.

    To get the unit to cut you have to adjust cut depth, pressure, and speed. When you get that it seems to work well. I only played with it for about an hour.

    The unit can also be controlled with USB. One company reversed engineered the USB interface and is selling software that allows you to use TT fonts from you PC. They are not sharing the info.

    Others are talking about using it to make PCBs. I would like to use it to cut stencils for applying solder paste.

    EDIT: I have no clue regarding the accurcy of the unit. It seems well built and uses steppers. I expect that is should be good enough for stencils.

    They can be had for $130 on sale. I was not looking for another project but I was offered on for free and could not pass it up. Maybe someone publish the interface specs or code. The rest would not be too hard.
    [​IMG]
     
    Last edited: Dec 12, 2008
  2. HiTech

    HiTech Well-Known Member

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    You know you're an engineer when a Cricut is what's posted above.

    You know you're a normal person when Cricut is this: [​IMG]

    You know you're a bloke when a Cricut is this:
    [​IMG]
     
  3. blueroomelectronics

    blueroomelectronics Well-Known Member

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    At first I thought 3VO misspelled Circuit :)

    That's a pretty cool cutter. Too bad the marketing types locked the communications protocol down.
     
    Last edited: Dec 12, 2008
  4. dave

    Dave New Member

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  5. HiTech

    HiTech Well-Known Member

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    I have a machine like the one above but connected to my 'puter. I use it to make custom lettering and insignias. It works quite well and quickly. Amazing to watch it cut out a complex insignia.
     
  6. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Aren't they called 'vinyl cutters'?.

    They use them now instead of sign-painting on vans etc.

    The first one I ever saw was at a Sunday Market in Sherwood Forest (watch out for Robin Hood! - he had a small generator, a laptop, and a vinyl cutter, along with various colours of vinyl. Basically he was selling stickers for cars, and would 'print' out any logo you wanted - he had a pretty extensive database.

    It was a while back now, it all ran in DOS :D
     
  7. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Update, getting there.

    It was not my intent to work on this but some things sort of draw me in. I have made some progress.

    Eagle
    Changed the cream layer so it had no fill.
    Checked black and pdf in print dialog.

    Inkscape
    Import the pdf from eagle and save as a SVG (scalable vector graphic) file.
    I used the finest setting for details when importing the pdf but I do not know that it had much of an impact. The file was 8K. To see the graphics I needed to do a VIEW>DISPLAY_MODE>OUTLINE.

    Sure Cuts a Lot
    Loaded the SVG file from inkscape and hit cut.


    That much worked but the scale was off by about 2x. Attempts to rescale it in inkscape did not go well. I am thinking about adding a 2 inch line to the graphic in eagle. I can compare the actual length of that line in the cutting software and then use print scaling in eagle to get things right.

    I did try rescaling it in SCaL but the cutting program hung up part way through the file. The SCaL program is $75 so I will use the demo version up to the point where I know this works.

    So far I have been making the cuts in a single pass. It looks like the SCal program has the option to make several passes. That would let me reduce the cutting pressure which would be kinder on the knife and maybe a little cleaner.

    3v0

    This is fun.
     
  8. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    That is an awfully good price for a vinyl cutter compared to what I paid for a Roland Dr. Stika several years ago. But then, I also remember paying $$$ for a laser jet.

    It looks like it uses the "standard" triangular knife. Is the feed straight enough to handle a PCB?

    John
     
  9. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    It has a straight feed path. It is setup so the feed rollers run on a carrier (cutting matt), the carrier is sticky.

    With the knife out I stuck a sheet of .02 SS PCB stock to the carrier and ran it in and out without a problem.

    You may be right about the knife. The replacements from cricut are 2 for $10.

    The unit is limited to a width of six inches.

    I have had the 3rd party software "sure cuts a lot" hang twice so far. That sounds like trouble. Not a show stopper yet.

     
  10. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    It think I have it.

    I used this method to cut a solder paste stencil on copy paper using the SCAL demo software. I have not tried to use it yet. I expect I may have to switch to mylar. It illustrates how to get graphics from Eagle to the Cricut.


    To cut a top layer solder paste stencil. :) VERY PRELIMINARY :)

    Eagle
    Layout PCB as usual.

    Change the tcream layer to no fill and color to black.

    Add a 2 inch line to the tcream layer.

    In the print dialog check black and print to pdf box.

    Inkscape
    Import the above pdf and save as a SVG (scalable vector graphic) file.
    I used the finest setting for details when importing the pdf but I do not know that it had much of an impact. The file was 8K. To see the graphics I needed to do a VIEW>DISPLAY_MODE>OUTLINE.

    Sure Cuts a Lot
    Loaded the SVG file from inkscape. SCAL has its own idea regarding what size the graphic should be. Using the scale on the onscreen cutting board shrink the graphic such that the 2 inch line is again 2 inches. To do this I first zoom to 400%. Move the graphic so the left edge is on a inch line. Then resize it so that it is 2 inches long.

    Save the SCAL project. Load the project again and hit cut. If you try to cut without saving and loading (or maybe just undoing the zoom) SCAL will crash.
    Thats it. Not much to it.

    "Sure Cuts a Lot" is a 3rd party program intended for use with the Cricut. It is $75 and can be found at Craft Edge.

    Is it worth it. The machin can be had for $135 or so on sale. The SCAL program is another $75. That totals to $210. Clearly it is not a beer budget solution. But if your SO is into scrapbooking that will offset the cost.

    Pololu lasercut stencils run $20 each time you have them made. In that light this method could pay for itself. Especially if the SO already has the machine.

    EDIT: According to the flap on the Cricut forum the software hang was introduced by the latest firmware used on the Cricut. I did not see anyway to downgrade the cricut firmware. Possibly a effort by Cricut to protect their investment.

    I do not have mylar but found a unused laminator pouch and managed to cut a stencil on it. I had to increase speed to get the plastic to cut instead of stretch.

    3v0
     
    Last edited: Dec 13, 2008
  11. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Image of stencil and PCB with paste

    The pictures were taken with a Digital Blue microscope.

    The mask was cut from half of a laminating pouch that I purchased with a wimpy Harbor Freight laminator. (not good for PCB work) The sheet was .003 inch. Note that the holes are not exactly square. I think this is due to the rotation of the knife when cutting direction is changed.

    The mask was cut with the demo version of SCAL which added cuts through the work to make it unusable. These is a wee bit of extra paste due to that but it will not matter. The picture was taken after the stencil was used. I cleaned it but it looks like there are a few bits of paste on it.

    Mostly it worked well. I still have to add the parts and pop them in a fry pan (ala Sparkfun). I am a bit worried there is not enough paste but 3 mil mylar is what Sparkfun and one other source suggested.

    EDIT: I melted the paste for the resistors and caps using a Teflon pan on a gas range. About 2 minutes. Added pictures

    3v0

    FWIW: This is a hybrid board. It uses 805 resistors and caps along with a through hole processor. The processor is soldered to the PCB top and bottom so its pins can act as vias. It worked well in that I only have 3 vias where I need to solder wires, mostly to pin the top and bottom gnd pours together.
     

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    Last edited: Dec 13, 2008
  12. Karbos

    Karbos New Member

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    One problem you may/might have is when the knife blade is first inserted into the material, it will create a slight dimple as it will begin cutting. This happens to our Vinyl cutter at work.
     
  13. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    The stencil is pushed against the PCB by the scqueege/scraper. It does not have to be dead flat.

    So far it worked well but I have only tried it with 805 parts. I am not sure how it will do on SOICs and such. I have doubts.

    3v0
     
  14. HiTech

    HiTech Well-Known Member

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    This is the unit I have made by Bepop. It interfaces to a computer.

    [​IMG]
     
  15. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    28 pin SOIC

    Today I cut a working stencil for a 28 pin SOIC. The Cricit did a very nice job. It is suprising how little paste is required to make a connection. I am also suprised how fast the process is. If there is interest I will post more pictures.

    I have yet to try TQFP packages of any size. That still worries me. If the Cricut can not cut these I will make a new part with an altered cream layer. Have the paste cover all the pins on each side. I am fairly sure the paste will be attraced to the pins when heated just as it does when applied with the syringe.
     
    Last edited: Dec 23, 2008
  16. HiTech

    HiTech Well-Known Member

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    My little unit cut out the image shown below, with no problems. Final decal image size was about 7"x7" and the wolf's head was amazingly accurate, despite the details in the fur. I use release paper to apply it to the final surface and a wallpaper seam roller to smooth it out.

    [​IMG]
     
  17. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    This is my SVG and PDF file if you want to try it on your cutter. The SVG file is zipped.
    [​IMG]

    EDIT:
    It looks sloppy in the png image but the spacing is quite even. The single line beside the cuts is two inches long, the cricut rescales the image and I need this line to force the size back to normal.

    3v0
     

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    Last edited: Dec 23, 2008
  18. HiTech

    HiTech Well-Known Member

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    It should be interesting to try that out. I do remember one of my lettering/graphics projects having some rather tiny bits to etch. It did them cleanly.
     
  19. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Inscape to "Sure Cuts a Lot" scale workaround.

    I have no idea if anyone other them me gives a rip but it is still a good place to record the info.

    A member of the "sure cuts a lot" forum posted this about preserving the scale between inkscape and the "sure cuts a lot" program. I have imported and scaled a file but have not yet cut it. It looks like it should work well.

    I placed the object size in the file name
    paste_W1p88xH1p78 as in 1.88 wide by 1.78 high.

    EDIT: When you set the size in sure cuts a lot they do not agree in regard to proportion. The Height (X) axis is too large. The correct size can be obtained by choosing keep proportions an setting the width axis.
     
    Last edited: Jan 29, 2009
  20. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    Actually, I find your ventures into this area interesting and refreshing. Please continue to keep us updated.

    John
     
  21. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    I would think this should be of more general interest. Even people who have their boards made still have to build them.

    Maybe it speaks to how few people are building SMD project on PCBs.
     
    Last edited: Jan 29, 2009

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