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Need a catchy name - enlarging CNC

Discussion in 'CNC Mills/Routers' started by McAdam, Mar 18, 2017.

  1. McAdam

    McAdam Well-Known
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    McAdam published a new build:

    Read more about this build...
     
  2. Serge E.

    Serge E. Master
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    How are you planning to do the transformation between the two modes ?

    I can see a rack and pinion on the 'stretching' axis, like fold down extensions on the longest axis (most likely Y). The short or normal mode would probably use a 750mm length of extrusion (with rack) to give a ~20" woking length. The stretched mode would be done in two stages with 1000mm extensions - one for front and one for rear. These extensions would need a perfect alignment (right and left more than with the base unit itself). This expanding "Y" OX, with both extensions on would reach just beyond the target 8'. X would need to use a full 1500mm, which gives ~52" of working length.

    The approach I took with myOX is to have a fix build and let the work piece slide through working it in segments. So I have a "base" of above machine, capable of working 20.5" in Y at a time. I CNC an alignment marker with each segment to help w/ sliding the work piece throught and align for the next 20.5". As such, my Y is infinite ... just need to support the work piece. ;)

    I plan on changing my Y 750mm extrusions to 1000mm extrusions so I can do 30" segments. The fewer realigment, the easier things get.

    So far, I have used this 'slide through' approach a few times and it works great. I cut croquignole game boards (~36" diameter) from 4'x4' (half sheet) as one piece.

    I am now starting to use this 'slide through' approach to surface long (and large) slabs of oak and such. It gets a bit tricky for a support of overhanging portion given the weight of these slabs, but it gets the work done. This is main reason I want to go 30", does become a pain to slide 8' pieces through. It's 5 "segments", each time to make sure I'm still level to first. I have to attach support "tracks" to the work piece and they become the reference for leveling. Not evident on live edge slabs ...

    The biggest issue I run into with large pieces like a 4x8 sheet, even of 3/4" plywood, is they tend to curl over time (not stay flat) ! The use of a strong vacuum table on the OX should fix that - and suck in saw dust and chips ... especially if you cut through the sheet. Which also weakens the vacuum ... On thinner material, some have some mechanism which pushes down the material about the working end of the tool. But then, your Z axis better be solid to avoid taking this downward force to flex your Z upward. which is not evident with an X of 1500mm in a standard OX design. The gantry needs to be way stronger not to flex. Z assembly itself also needs to be much more solid.

    A few challenges, but all can be addressed as we experiment with our versions of the OX.

    Looking forward to your version.
     
  3. McAdam

    McAdam Well-Known
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    Thats an interesting approach I did consider, but for some things I need it to be millimeter perfect along the length and had no idea how I was going to split the paths up over 3/4 files.

    I have updated the build page with some pictures and a bit more info. Essentially that base will just be doubled (plus a small 250mm one for storage) and they will join together with guide rods in the extrusions, and a single (or two) m10 nut in one sections, and a long 1500mm m10 thread in the other, to kind of really tighten them together.

    I plan on making a vaccum table, but I decided it was easier to make a design then get it cut on the CNC... so for the first version there is no suction and I will be choosing my wood very very very carefully from the supplier.
     
  4. Ron Johnson

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    I need a 1500 x 1500. What will this cost me without electronics?

    Thanks
    Ron Johnson
     
  5. McAdam

    McAdam Well-Known
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    Honestly, putting together everything was a pain in the rear.
    Look for a ready kit. If you're in Europe check out Ooznest or MakerSupplies.dk
    If you're in the US maybe someone else can suggest a good supplier.
    I have ordered from at least 20 different suppliers at different times. I have ended up replacing all the bolts on my machine to get better sizes/cleaner lines.
    A ready kit will save you time, pain & money.

    Only reason i didn't get a ready kit is because i am making a custom build... So i had to put things together myself to match my ever changing needs.
     
  6. Serge E.

    Serge E. Master
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    Check out the OXcalculator. You can tell it the target dimensions and throw in the most recent cost for the listed parts and it should give you an idea of total cost for a base OX. Link should be in my signature (obviously biased, sorry).
     
  7. Serge E.

    Serge E. Master
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    OpenBuilds (now) has just about everything needed to customize your own machine, including two kits which can include just about everything needed short of the spindle/router, bits, wiring, enclosure for the controller ... and the actual spoil board. The extrusion is already cut and tap, so you just need a few basic tools to assemble these kits... Each can be used as a great first machine (assembly required) which can be later customized... It can be up and running in just a few hours, a weekend project where you study the complete assembly video and the parts.

    I started building myOX before these two kits were available. Not finding convincing information about the then existing kits, I played with the OX design, priced from various sources and ended with a large (work volume : 20.5" Y, 52" X and nearly 3" Z) within a reasonable budget but after nearly a year of fiddling and learning. But I can modify it at any time, confident of the new skills learned along the way. For me, it was well worth the experience.
     

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