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New build ideas to #1 - strengthen gantry and #2 increase Z height

Discussion in 'CNC Mills/Routers' started by Joe Geisler, Jan 26, 2020.

  1. Joe Geisler

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    I am in a situation where I have very very limited space but am wanting to be able to process very large projects.
    My workshop is actually a carport that my wife and I park in so anything i have in my shop has to fit in a very narrow area. I have built a steel table that sits over 4' high, 35" wide and over 6' long so that my wood lathe can be stored underneath it when not in use. The lathe and the table are both on wheels so I can pull them out for better access and use.
    The machine I ordered is a 1510 screw drive that will be modified to approx. 890mm Y axis X 1500 x axis. I am having to cut it down to 890mm to fit width of table so cars can still park in carport.
    Ok sorry about the ramble, just giving a visual of the restraints i have.
    Now, my goals and needs:
    #1 I do a lot of small 1/2" to 1" thick plaques, I also do a lot of 24"x30" 3D carvings that are only 1 - 1.5" thick. So far that will all fit within my machine frame.
    #2 I will also do some signs and projects that are 2' - 3' wide and 6' long and 1.5" or less thick. again most will fit.
    #3 I will occasionally work on 36"-38" wide pieces that are 6.5' long and 1.5"-2.5" thick these will NOT fit
    #4 I work mainly with wood but will occasionally i work with aluminum and/or plastic
    #5 I will be using a 1.5kw water cooled spindle both for performance and to keep noise down as this is a residential neighborhood and i am in a wide open carport.
    SO, OK, with the weight of the water cooled spindle and reading about concerns concerning flex and torque of the gantry with that much weight on it, I found an extra heavy duty C-beam through RoverCNC of canada (price isnt bad but the shipping to Hawaii will kill your wallet) this should help with flex and torque in the gantry. I will also use the original Cbeam from the Y to make an extended Z axis (I also ordered additional screw drive and LED light ring from Openbuilds).
    With the extra height I need I have seriously considered buying the extended Y plates from Blue OX on Ebay but once again, I am concerned with gantry movement. And that still wouldnt solve project width issues i will run into.
    To solve all of the height and width problems, I found in the zip file (I think thats where I saw it) for the workbee a file for extended X axis end plates that raise the entire machine 2" higher ... OK, now, that got me thinking. after watching Franco's build on Utube and how he achieved 5" of Z axis travel
    I realized that the extended X axis end plates would allow me to slide my Thick, Wide, Long projects right under the X axis C-beams from the side.
    to take that concept even 1 step further i have modified the extended end plates to a 3 inch extension and will be carving them from 1/2 6061-T6 (assemble machine, use machine to make plates, partially disassemble machine to install new plates, reassemble and screw down to tabletop to restrict movement, vibration, and keep everything square as I will be removing the bed supports to give me that extra depth.

    OK, sorry about writing a book, I am now ready for you all to tell me all the ways I am making mistakes and hopefully offer solutions to help me accomplish my goals.

    attached is a photo of the "workshop" LoL, New Shop Table w lathe.jpg
     
  2. Wallied

    Wallied New
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    Nothing major, mostly the fact that these are always a balancing act of machine travels and rigidity. With that in mind, an X-axis closer to a meter in length starts to be in danger of sagging when paired with a heavy spindle. And raising the height subjects you to more and more deflection as you increase.

    Now, this isn't neccessarily a problem if you mostly work on thin, soft materials like you said you will be doing, but for metals, your cut quality will decrease compared to a more compact machine.

    Also, though the spindle is a lot quieter than a trim cutter, without an enclosure the cutting sound will be easy to hear outside the garage. At least mine is to the point I won't be cutting in the night time to avoid annoying the neighbours. And make sure you have the electrical power available to run all your machinery at the same time.

    Just some pointers to mull over.

    Regards, Will
     
  3. Joe Geisler

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    Thank you for your reply. i agree with the concern for long gantry length and heavy spindle causing sag, thats why i am replacing the existing Cbeam with the extra strength Cbeam from canada. also, with the way my CNC table is laid out I will be cutting my gantry just over 100mm shorter which should also help with sag.
    With the way my shop is laid out the gantry is actually my Y axis, it is the X axis that I am going to extend the plates. (the long 1500mm axis that is only supported at the ends anyways, so raising it even higher should make no difference so long as the plates are thick enough to prevent flex(mine will be 1/2" thick)).
    And in response to your 3rd paragraph, I agree 100%, as soon as I cut my aluminum plates and install them i will start building my enclosure before any other projects are even started. Noise is a very big concern because as you pointed out, it can be heard from the street, ALSO, we take care of my mother-in-law and her living area is theother side of the wall the CNC is next to. she is hard of hearing and very patient but i dont want to start that battle. There is no winning if the wife has to defend the mother-in-law. When "she who must not be named" reaches "wife aggro" of 100 everyone looses!! LoL
    Do you see any issues with the extended legs/feet/end plates and NOT using the metal supports under my spoilboard?? (BUT i will be screwing my machine to the table to try to make up for any lost rigidity from taking out the spoilboard supports).
     
  4. Wallied

    Wallied New
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    My bad, but I'm not totally sure whether you mean to use taller gantry plates (of which there are two), or end plates (of which there are four), but I'm assuming the latter. This, however, I wouldn't do, and instead would use a taller (and personally wider as well) extrusions to achieve the additional height. To avoid losing machining envelope, you could screw the extrusion to the outside of the end plates. But in any case, I can't say without extensive calculations which of the heightening methods would be best, and I don't care enough to do these calculations outside working hours :ROFL:

    On the matter of bolting the machine to the tabletop, I'm of the opinion that it's going to work just fine when we're talking about hobby machines. Just make sure to use a thick enough top. I wouldn't go under 1" of birch ply, and the thicker the better.
     
  5. Joe Geisler

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    Wallied, sorry it has taken so long to return to this thread, been building. yes, i was referring to the 4 end plates. I am thinking that with 1 axis being 1500mm long it would be nice to be able to tile in that direction but the 2 C Beams are definately getting in the way unless I build y system with a very tall bed while would leave me with very little Z travel. Now I can compensate for this by putting on extended gantry plates (2 plates) but I feel that any movement/play/flex in the gantry and/or the V wheels is just going to be amplified by having the gantry even higher off of the 2 C Beam side rails. BUT by raising the 4 end plates using 1/2" or 3/4" aluminum I don't change any of the geometry of the machine as it raises everything equally except the bed, everything is already supported on 1/8" end plates so lengthening them while thickening them should not (I hope) compromise strength or integrity. please feel free to point out any flaws in how I am thinking, this is my first CNC larger than a 3018. I do understand that any increase in distance between the gantry and the working bed will introduce more torque but I am thinking that after fabricating the aluminem extension plates i will be working with wood for the most part and am thinking I could always "raise the bed" somehow if I ever need to work with aluminum again.
    also, I have already built an enclosure as you were suggesting to make sure i don't upset the neighbors.
    Now, as soon as my Openbuilds blackbox comes to replace the chinese arduino clone that I received defective (it fried in the first 5 seconds of testing motion and killed 1 of my USB ports that I still can not get my computer to recognize anymore) 20200208_142619.jpg 20200208_142707.jpg 20200208_191507.jpg , I will finally be able to finish testing, tramming, surfacing, and prepare to cut aluminum unless convinced that I am barking up the wrong tree with extended end plates.
     
    Peter Van Der Walt likes this.

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