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CNC melting Acrylic

Discussion in 'CNC Routers & Engravers' started by 0igo, Mar 7, 2018.

  1. 0igo

    0igo Active Member

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    I got a new CNC and Im trying to cut a 1/8 thick acrylic sheet but I can't seem to cut a piece out without it melting the acrylic. Any tips on spindle and depth speed?
     
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  2. henryz

    henryz Member

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    You are going to have to do some test to see what works best with your spindle also the router bit that you use, I found that for acrylic an aluminum bit leaves a clean cut. We run ours at around 16k rpm 80ipm. Something is wrong if you are getting melting on 1/8th we do up to 1" in 1 pass. Onsrud are good bit for low cost.
     
  3. ewded

    ewded Member

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    Acrylic is a very difficult material to cut. You should experiment with wood before trying to cut acrylic. Try 1/64 deep passes 1500rpm and go as fast as your machine can. If it works try 1/32"
     
  4. GaSouthpaw

    GaSouthpaw Active Member

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    Cast or extruded? In my experience, use cast if you want clean edges. Extruded is good for tenant panels in monument signs, or channel letter faces that are getting trimcap.
    Also, consider using multiple passes on materials thicker than, say, 1/4" to eliminate stressing the bits or the materials being cut.
    As for spindle and feed rates, most of the players who make router bits have a chart that can come in handy. Belin, and Onsrud are common providers. For myself, I stuck with upcut bits and kept the RPMs at 24K. Depending on the material thickness and intricacy of what was being done, I could get as much as 200IPM for cutting speed.

    EDIT: henryzhenryz I'm impressed with cutting 1" in one pass. What size bit?
     
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  5. StarSign

    StarSign Active Member

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    1/4" bit 19000rpm 130ipm
     
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  6. tbullo

    tbullo Superunknown

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  7. henryz

    henryz Member

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    Gasouthpaw for that we would use 1/4" dia. but for 1/8th - 1/4" we can do with 1/8th or 3/16 bit. I think we use a 11hp spindle if I'm not mistaken.
     
  8. GaSouthpaw

    GaSouthpaw Active Member

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    And you can get through 1" in one pass? That's impressive! I've done it, but with no real speed.
     
  9. henryz

    henryz Member

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    Yeah, we never go full speed maybe 50% unless we need it asap. which is only 99% of the time...lol
     
  10. signbrad

    signbrad Member

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    This is true. Cast acrylics are more forgiving when machined. They tolerate the heat of a cutter better and tend to create sawdust rather than melt behind a blade.
    In Plexiglas, for example, Plexiglas G is cell-cast while Plexiglas MC is calendered (extruded).

    Of course, there's a difference in price, too, since cell casting is a more expensive process.

    Brad
     
  11. GaSouthpaw

    GaSouthpaw Active Member

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    Very true, but I always considered the price difference worth it to not have to do a lot of post-cutting clean up!
     
  12. spectrum maine

    spectrum maine Member

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    onsrud or amana bits for cutting plastic is the very first step. a $10 home depot will be impossible to dial in.
     
  13. GraphicsSource

    GraphicsSource Member

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    May 28, 2015
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    Get you a p1-418u bit from cut guru and run it at 84 ipm and 14k rpm...I cut it all the time and don't have melting issues. Sounds like maybe a bit issue.

    Sent from my Pixel XL using Tapatalk
     
  14. mark-s

    mark-s Active Member

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    slow the speed and feed down
     
  15. mark-s

    mark-s Active Member

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    Slow speed and feed down, I cut 1/2 acrylic about 12,000-14,000 RPM speed- with 30% feed.
    Also put some WD 40 on the cut, helps cool the bit.

    mark-s
     
  16. astro8

    astro8 Active Member

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    SIngle flute upcut bit..
    1/8" bit at 150" per minute 24000rpm.
    1/4" bit up to 300" per minute 18000rpm.
    1/8" bit up to 1/2" in one pass.
    1/4" bit up to an inch one pass.

    Using a Biesse Rover Sft.
    If Multicam etc, halve those speeds.
    If Shopbot etc, halve them again.
     
  17. X Edge Tools

    X Edge Tools New Member

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    Jan 25, 2018
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    It depends on if you are looking for the best quality that you can get or just good but fast. I have been machining acrylic for many years and found nothing that worked as well as the Belin until I came to work for X-Edge Tools. Our O series tool for acrylic is hands down the best I have ever used. For the best edges possible use the following: Cast acrylic, X-Edge XO2012 or similar, Climb cut, 60 ipm, 22,000rpm, and lastly do a clean up pass of .06". In other words cut your part a total of .12 larger and on the last pass cut all of the way through and step in .06" to your final size and cut it out. Make sure that you have good dust collection or vacuum or blow before final pass. The results will absolutely astound you! I used those same numbers but no clean up just one pass all of the way through on 1/2" thick and the results were still beautiful. Not quite as good as with the clean up pass but still gorgeous. You can see the XO2012 here. CNC router bits & accessories by X Edge eXtreme Speed eXtreme Quality
     
  18. player

    player Major Contributor

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    What CNC did you get? Size? Specs? Router or spindle?
     
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