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  1. #11
    Quote Originally Posted by Zeeflyboy View Post

    I think your design is better than this one, in this one the Y rails are not optimally placed, would be better on the side or under the table.

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  3. #12
    I can see where the advantage is, in that the gantry arms can be a fair chunk shorter and thus give more rigidity for a given thickness.

    The disadvantages are that it's a potentially a more complicated mounting assembly (especially when ball screws are considered as well), would need extra work to add shielding for the rails and would end up eating into my X-Axis bed area (although actual work area would probably be able to be kept the same with a little careful work, there would be less room for overall material size and clamping.

    So the question is whether I go on the basis that 25mm thick plate will be sufficient for the gantry arms at their current length, or whether I want to take those above mentioned compromises in order to gain a little extra rigidity.
    Last edited by Zeeflyboy; 13-02-2017 at 11:37 AM.

  4. #13
    Bit more time refining the new Z-Axis design.

    I realised I needed the plate that slides down to be slightly slimmer than the unit as a whole, otherwise it would jam on the water/chip tray sides when in the lowered positions so tweaked that along with some more design details and seals, tramming plate etc.







  5. #14
    Nr1 - Cheers. Thing with that suggestion is that the ball screw and mount is actually taking up more depth than the rails and carriages, so would need to do something totally different with the ballscrew arrangement.

    I've been very happy with the pokeys57CNC - setup was easy, the mach4 plugin is great and support has been quick to answer my occasional stupid question.
    You are of course right about the ballscrew placement! So nevermind about that :)

    I'm glad you like the pokey's, might be that Im gonna place an order.. but mach4? Is it working alright as well?

    The new Zaxis is looking sweet, what material are you planning on using for the "seals" in red?

  6. #15
    Red silicone strip for the flat seals and not sure yet for the shaped stuff, either I'll laser cut some thicker silicone strip or 3D print in a flexible rubber.

    Yeah I'm very happy with mach4 - it generally feels much more modern and clean than mach3, and it's far more responsive in terms of reacting to your manual inputs or feed hold etc.

    It is probably a case of burning money somewhat if you've already got mach3, but I just wanted something a bit more future proof since I'm on a new pc running windows 10 pro. I believe that the pokeys57cnc is better supported on mach4, so that's certainly something to consider as a potential extra expense if going the pokeys route (although even the pokeys57CNC + mach4 is cheaper than the smooth stepper + BoB I had).

    If getting mach4, I recommend looking at the pdmx site - even without a joint purchase its slightly cheaper to the tune of 10 bucks or so.

  7. #16
    Looks nice. If you move all 4 z axis blocks down you will gain more travel, or move down the lower ones to increase rigidity at full extension.

    What CAD programme is that?

  8. #17
    Quote Originally Posted by Ross77 View Post
    Looks nice. If you move all 4 z axis blocks down you will gain more travel, or move down the lower ones to increase rigidity at full extension.

    What CAD programme is that?
    Cheers,

    Won't gain more travel by moving them down - it can already travel the full length of the rail so it's limited to rail length minus 2x carriage.

    However it's been pointed out that moving them towards the bottom does put the "fixing" point closer to the work which would reduce the lever arm and increase rigidity. I will probably slide them down a bit and slide the tram plate up to match.

    I'm using fusion 360 for everything these days, the built in cam is awesome.
    Last edited by Zeeflyboy; 14-02-2017 at 10:34 AM.

  9. #18
    For raised X axis I mean something like these where the gantry is mounted directly on top of the X rails, which are themselves raised well above the level of the bed. The raised X axis can then be reinforced and made as stiff as you want. Often they are steel box section, which is x3 stiff as aluminium (like-for-like sizes). This avoids having the long drop down gantry side plates which will not be as stiff.

    It is very difficult to overcome offsets by beefing up/reinforcing the connecting structure. Much better not to have the offset in the first place.

    Click image for larger version. 

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    or

    Click image for larger version. 

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    The example you choose still had gantry sides and the X axis rails were level with the bed so no real advantage and not what I would call raised X axis design.

    Z axis swapped around looks good. I'm adding a pair of tram plates to my new machine so good to see it used on yours.
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  10. #19
    Hi!

    I can recommend the high (X or Y axis depending on what you call it!!) rail approach (my machine is the bottom photo) to give stiffness. My machine munches aluminium and I've even cut (I'll say tickled really) 6mm steel plate. I presume you're the same person who frequents (or possibly did as I've not been on there for a few years now) RcHeliAddict forum, I think the last time I was on there you were just testing your small FPV Quad you designed?
    Neil...

    Build log...here

  11. #20
    (my machine is the bottom photo)
    And mine is the top one. I to was recommended to go down that route
    ..Clive
    The more you know, The better you know, How little you know

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