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OpenBuilds OX CNC Machine

Discussion in 'CNC Mills/Routers' started by Mark Carew, Dec 15, 2013.

  1. DiggerJ

    DiggerJ Journeyman
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    If you lift your separator to sit on top of the barrel and put a piece of plastic around it, you will get much more room for dust, and can see when it is getting full. The Thiens sure work great don't hey!
     
  2. Nigel King

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    What is a good multipass depth for mdf with a 6.4mm and 3mm bit?
     
  3. Robert Hummel

    Robert Hummel Custom Builder
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    In mdf with the right feed you should be able to do half depth passes IMO
     
  4. Paruk

    Paruk Journeyman
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    #1684 Paruk, Oct 25, 2014
    Last edited: Oct 25, 2014
    GrayUK likes this.
  5. GrayUK

    GrayUK Openbuilds Team Elder
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    Thanks Paul.
    I think they are very informative so I've added them to the Helpful Tool Section in their own thread. :thumbsup:
    I tried to add them to the Resources Section, but I couldn't work out what all the URL business was about, and wasn't able to!
    Too complicated for me. :banghead:

    Adding a new thread, adding funny faces and colouring it is about as far as my Forum skills go! :D

    Thanks again.
    Gray
     
  6. Paruk

    Paruk Journeyman
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    You're welcome! Found also a video of LMT Onsrud (they sell a lot of good bits) in which they explain the principles and refer to their catalog, in which they have tables printed. Get that catalog!:)

     
    Serge E. and Mark Carew like this.
  7. David the swarfer

    David the swarfer OpenBuilds Team
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    half the bit diameter is the usual starting point.
    what is more important is the load per tooth and feed speed, which all hang off the RPM and recommended SFM for the material. get those numbers right, and then set the depth according to what you machine can handle.

    but also think about this.....

    in multipass you are doing (material thickness * overcut%) / passdepth = number of passes.
    lets say you are cutting 10mm sheet with 1mm passes, and 105% overcut.
    so total cut depth is 10.5mm and the final pass will be .5mm, making 11 passes.

    so, to save one extra pass it may be better to cut slightly slower, but slightly deeper, and get 10 equal passes.
    10.5 / 10 = 1.05mm per pass.

    over an entire sheet that one saved pass can be a significant amount of time (-:
     
  8. Paruk

    Paruk Journeyman
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    I'm just reading a very comprehensive piece of work about the issue here http://www.cnccookbook.com/CCCNCMillFeedsSpeeds.htm. There seems to be a lot to speeds and feeds as it appears to be called. I think we should add this link to the Helpful tool sections. Although I'm sure the guy behind it did a lot of work on his g-wizard calculator, but paying $ 79 a year for a subscription to that software is a bit too much asked. The Cookbook is very informative though. ;)

    The link is added to Helpful Tools!

    The CNC USB controller software also has a build in calculator that can be used. Not as comprehensive as the g-wizard, but still very useful and a good starting point.
     
    #1688 Paruk, Oct 26, 2014
    Last edited: Oct 26, 2014
  9. Paruk

    Paruk Journeyman
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    According to the CNC USB Controller software a 0.25" 2 flute with a cutting speed of 250 feet/min, 12000RPM, 0.013" chip load will give a feed rate of 312 in/min. The 3mm bit gives a feed rate of 156 in/min. And I think this is with (as David already indicated) half the bit diameter (or a full bit radius if you prefer) in mind.

    Remember: these are just a starting point from which you'll have to fine tune the feed rate. Listen to the sound of the tool and observe your machine to adjust accordingly. If it doesn't sound or look good, stop and find out what the problem is. Too slow is not good, too fast neither. It has to be about right (not exact, although preferred) for the best results.

    Hope this helps a bit (no pun intended).:)
     
    #1689 Paruk, Oct 26, 2014
    Last edited: Oct 26, 2014
  10. SlyClockWerkz

    SlyClockWerkz Well-Known
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    Hey everyone,
    I've been working on making some garolite plates (originally recommended by kram for the OX) to offer to the fine folks on here wanting to build the machine. I made a few modifications, including a recess for the steppers so spacers are unnecessary (increases the rigidity of the plates as well with them being flush mounted). I also removed unnecessary holes on the front gantry plate to retain as much strength as possible (compatible only with 2060 z axis). Also, if anyone is wondering why they are orange ish is because the same stuff in black is much more expensive. I went with this color to keep the cost down and painted my set black very easily. Check them out here:http://clockwerkmech.weebly.com/ox-cnc--garolite-plates.html

    [​IMG]
     
    #1690 SlyClockWerkz, Oct 27, 2014
    Last edited: Oct 27, 2014
  11. Tweakie

    Tweakie OpenBuilds Team
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    Very nice work with those plates Sly :thumbsup:

    Tweakie.
     
  12. SlyClockWerkz

    SlyClockWerkz Well-Known
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    Thanks Tweakie :D
     
  13. Mark Carew

    Mark Carew OpenBuilds Team
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    Nice work @SlyClockWerkz
    I will add a link to your plates on the first post
    Mark
     
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  14. KerryH

    KerryH New
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    Very nice work @SlyClockWerkz!

    That will be a great lower cost alternative to the aluminum plates being offered.
     
  15. SlyClockWerkz

    SlyClockWerkz Well-Known
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    Thanks! These were my thoughts as well. They also perform admirably in everything ive used them for from plywood all the way to aluminum.
    made by the ox, for the ox
     
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  16. Mark Carew

    Mark Carew OpenBuilds Team
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    I use them for my video build OX as well :)
     
  17. Serge E.

    Serge E. Journeyman
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    Very nice ...

    I see you take custom orders as well. This could come in handy for those wanting to tweak the design for their first build.
     
  18. SlyClockWerkz

    SlyClockWerkz Well-Known
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    Yes, website is a work in progress, but im planning on trying out some custom orders (depending on the scale of the job of course) if people want something special
     
  19. Paruk

    Paruk Journeyman
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    Yippie! Just received a bunch of router bits I can test. After all, what good is a Buffalo without teeth? Some ball noses, v grooves, roughing and finishers and an engraving bit. Let's go outside and play! :)
    IMG_1171.JPG
     
  20. JWhitten

    JWhitten New
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    I have finally finished the mechanical assembly of my system. You can see the videos of the first couple of movement tests here-- I have an eager assistant helping me out in the first video :) . I still have to get the Mach3 software set up and hook up the computer to the machine. But I'm getting there!



    First Test of CNC Router (X & Z Axis Only)




    Second Test of CNC Router (All Axis and Router Spindle Attached)

    I noticed the Z-axis is wobbling a bit. When I checked into it, it turns out the lock-ring has slipped and the lower bearing is just hanging. I need to get that re-seated and tightened back up.

     
  21. Paruk

    Paruk Journeyman
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    A question for whoever can answer it. It's about speeds and feeds.

    Material MDF
    Bit: 1/4" Upcut Spiral 4 flute carbide
    Chip load between 0.006" and 0.008" per flute.
    RPM of Router 18,000

    Feed rate (according to Onsrud formula) should be RPM (18,000) x #flutes (4) x chip load (0.006") = 18,000 x 4 x 0.006" = Feed rate of 432 ipm at cutting depth of 1 x Diameter. This would be a feed rate of (432 imp x 25.4mm)= 10,973 mm/min. To me, that seems to be extremely fast and I'm afraid the Buffalo will fall apart at that speed or the bit will fly thru the wall (and maybe me!). Even at half that speed I doubt nothing will break.

    Does this speed "looks" normal to the "experienced" machinists here? Or do I have it all wrong in the calculations?:confused:
     
  22. Paruk

    Paruk Journeyman
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    And out of that question another one popped up; how fast can you go with the nema 23 steppers on an OX? Max feed rate for this setup?
     
  23. Tweakie

    Tweakie OpenBuilds Team
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    Unfortunately this is where compromise has to come into the equation.

    The ideal speeds and feeds assume a rigid, industrial type of machine (no disrespect intended here) rather than our hobby type machines.

    When working with wood / MDF it may pay to reduce the spindle speed (and in my case changing to single flute cutters) as the feed rate has to be kept high enough to avoid burning / overheating the work / cutter whilst still keeping within the available torque envelope of the axis stepper motors controlling the motion.

    Bit of a balancing act really but some trial and error will soon show the best settings for any particular design of machine.


    Hope this helps.


    Tweakie.
     
  24. GrayUK

    GrayUK Openbuilds Team Elder
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    Hi JWhitten.

    I'm impressed with quietness of your Steppers! Normally they can make a hell of a racket. Yours sound smooth and classy. If you know what I mean. :thumbsup:

    I see what you mean about the Z wobble! Glad it was a small problem. :)

    Gray
     
  25. JWhitten

    JWhitten New
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    Hmm, all the steppers I've ever heard sound like they're singing when they get going. Is that what you mean?
     
  26. Paruk

    Paruk Journeyman
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    "Unfortunately this is where compromise has to come into the equation."
    You have a formula for compromise? LOL

    "The ideal speeds and feeds assume a rigid, industrial type of machine (no disrespect intended here) rather than our hobby type machines."
    That's what I also thought, those speeds just seem to fast for the OX.

    "When working with wood / MDF it may pay to reduce the spindle speed (and in my case changing to single flute cutters) as the feed rate has to be kept high enough to avoid burning / overheating the work / cutter whilst still keeping within the available torque envelope of the axis stepper motors controlling the motion."
    Is there a way to work out the torque on the steppers, so the maximum possible feed speed can be calculated?

    "Bit of a balancing act really but some trial and error will soon show the best settings for any particular design of machine."
    The trial part is ok with me, but the error part I like to keep to the minimum since getting new quality cutters is a nightmare here in Thailand. Everything has to come from abroad (time and money factor!).


    "Hope this helps."
    Yep, to become more aware of all factors involved but not in getting closer to the answers. LOL

    Maybe you can share the feeds and speeds you are using with the OX on various materials? At least we can have an idea where to start.
     
  27. JWhitten

    JWhitten New
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    Is it possible to get V-Slot rails of a length about 3300mm (approx 10-1/2 feet) ?
     
  28. GrayUK

    GrayUK Openbuilds Team Elder
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    On some videos you can hear every step as a clunk, so to speak.

    Gray
     
  29. Paruk

    Paruk Journeyman
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    No, this is not a model of the new high rise buildings in Beijing but a bunch of V-slot connectors for the X axis. They go in there to connect them together and will contribute to a stiffer X axis (that's the plan!).
     
    Balu likes this.
  30. Balu

    Balu Well-Known
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    Please also make a video that shows us how it works :).

    Did you design the connectors yourself?
     

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