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Building the Acro 1515 with 1800mm extrusions

Discussion in 'Concepts and Ideas' started by Jeremy Worger, Aug 22, 2018.

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  1. Jeremy Worger

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    Not sure if im posting in the right place on the forum here (first post)
    Could use some help with knowing what parts to order to create this large plotter.

    Im looking to rebuild the acro 1515 but with longer T-slot extrusions, specifically just two 1800mm rails, and two motors (+ pen servo)
    So im doing a T-frame plotter. Like this one for example:
    But its going to be on the floor, with a wheel on one end.

    The extrusions im looking to get are 20 x 20 SlotPro 4 Slot Standard Extrusion
    (hope these are ok?)

    So I am wondering, since I do not need all the parts, which parts do I need from the part list? OpenBuilds ACRO System

    For some reason I don't see:
    ACRO Acrylic Plate Set
    or the gantry: V-Slot Gantry Set - 20mm
    So these too?

    Since I am using 1800mm extrusions, I would need longer belts...so im not sure if this is possible.

    Thoughts? Thanks for reading.
     
    #1 Jeremy Worger, Aug 22, 2018
    Last edited: Aug 24, 2018
  2. Mark Carew

    Mark Carew OpenBuilds Team
    Staff Member Moderator Resident Builder Project Maker Builder

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    Hello Jeremy. Your project is awesome! We checked the Parts List and while the Acrylic Plate set was included, the name didn't match perfectly. We have updated this information added the coordinating link. The ACRO system utilizes the Acrylic Plate set for all of the needed plates.
     
  3. Jeremy Worger

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    Heya Mark, thanks...I hope I can make it work! Ah perfect thanks for updating the part list.
    I don't see the gantry bundle on there, so I assume this is a separate purchase?
    -Are there any other separate purchases?
    Im wondering if you might be able to help me figure out a general idea of which parts I don't need, since I only am building the plotter with 2 rails like the above video and wont be needing all the parts in that list.

    Another question I have is, what kind of belt would I need, since Im doing 1800mm?
    -Would the regular NEMA 17 motors work to drive something 1800mm long with just a wheel on the end?
    Im talking about lying the plotter on the floor like: Plotter

    Cheers
     
  4. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Jeremy,

    I'm not certain the acrylic plates of the of the acro system will offer sufficient strength or rigidity for what you seek to accomplish. This would be my suggestion:

    1800-1.jpg 1800-3.jpg

    It's based on a 200mm x 300mm x 4mm plate which should give you the rigidity you seek. ("Should" being the key word here as I don't recall anyone having built a similar system or having used such long lengths.)
    1800-plate.jpg
    The slim nature of the long 20x20 pen arm may be subject to whip so you may need to slow the system down if it gets to be a problem.

    Sketchup file attached. It was a bit of a rush job so it's not fully detailed or even terribly accurate but sufficient to get the idea. The dimensions shown on the plate can be relied upon however. As to whether the nema 17 stepper motors are sufficient, I really can't say as again, nobody has tried this yet. (Easily replaced though if they're not.) As for belts, GT2 should be more than sufficient for the pen arm but really can't say regarding the other axis. If GT2 doesn't work on that one though, it's easily replaced with GT3.
     

    Attached Files:

  5. Jeremy Worger

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    Hi Rick, thanks so much for taking the time to do this, that looks dead on what I want. !
    Youre probably right, it might whip. Maybe if I had an extra bar attached to make an A-frame it would be better, like the: Plotter
    Where do I get these gt2 and gt3 belts in 6ft lengths though?
    I've never used sketchup, so I'll download it and open up your file.
    So the plate you've designed here and the other parts..these are included in the sketch file?
    Is this a plate I would need to 3d print?
     
  6. Jeremy Worger

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    Ok just took a look at it. So the main side you have the 20x40 extrusion, I guess for extra strength and stability. Super!
    Regarding: Imgur
    What type of belt goes here? And for the second pic, does that belt loop around or are there two belts there? (sorry if a dumb question)
    Im not sure what all these parts are called..nuts, bolts, wheels...etc.. which ones they are from the acro part list.
    As for the electronics....
    My idea is to use the EBB board from EBB Driver Board
    to drive the 2 Nema motors (whether 17 or higher)
    and the pen servo from the same place: Micro Servo Motor
    Not sure how or where I'll attach these, but I don't think that should be too hard, I hope.
    The main goal is to try and drive the whole plotter using Robopaint.
     
  7. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    The video for the Plotter was pretty slick. I especially liked how easily the two parts separated for storage. But at $6500 I can see why you're looking for alternatives. As for the A-frame, I would suggest a wait and see approach. It'll be relatively easy to implement later if whip does turn out to be a problem.

    The part store offers belts by the foot. You will need about 19' worth of belt with 1/3 of that going to the main drive axis and the rest for the pen axis as it requires a full loop around the axis. The belt along the main drive axis is fixed at the ends and runs along the slot beneath the wheels. A small loop is pulled up between the two wheels adjacent to the motor and is looped around the pulley similar to this example.

    The main plate needs to be aluminum as the stresses on the wheels would rapidly wallow out the axle holes if done in 3d printed plastic. You should be able to get the plate pre-cut to size fairly easily and then you'll just need to drill the holes yourself. 13/64" for the typical 5mm screw holes and 9/32" for the larger eccentric shim axle holes. Really not difficult to do just be fairly meticulous with the layout and center punch the holes before drilling. For the big hole,step bits work nicely in aluminum.

    The other plates shown in the example are stock plates from the part store.
    Motor Mount Plate - NEMA 17 Stepper Motor
    Idler Pulley Plate
    V-Slot® Gantry Plate - 20mm

    Beyond the plates you'll need a dozen V-wheels (either regular or Xtreme), a couple bags of 27mm screws, a bag of 8mm screws, a bag of t-nuts, a couple double t-nuts, an idler wheel kit, 6 eccentric spacers (6mm), a bag of regular 6mm spacers, a couple belt clamps, a couple pulleys, a couple steppers, a bag of M3x8 screws, a power supply and a lot of wire. (You should back check though to verify if I missed anything.)

    The board you have shown doesn't put out enough power to run Nema 17 steppers. It's good for 1.25A whereas you may need upwards of 2A. You might check to see if attaching external drivers is a possibility. Otherwise you might check to see if the software you desire will run on an Arduino based system for which higher powered drivers are fairly easy to attach. As far as where to attach the main board there is plenty of room on the main plate. You will need to think through how to get power and signal out to the pen carriage/Z-axis.
     
  8. Jeremy Worger

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    Much appreciated! I don't think I would have figured this out on my own.
    (and im sure to anyone else who comes down a similar path they will find this useful too)
    Yeah $6500 is WELL over my budget haha.
    I think with this kind of approach itd actually be under $1000, which is awesome for a large plotter. (going to use it for drawing mostly)
    So a couple of questions to clarify then...
    The belt by the foot, you say I need 19 feet of belt. How do I order that properly, do I just select 19? (they aren't 19 separate pieces are they?)
    -So 2 pulley plates, and 2 motor mount plates and 1 gantry plate, yes?
    -Should I go with regular wheels? A dozen as in 12 yes?
    -4 belt clamps?
    -2 pulleys or more?
    -Sounds good about the main plate being aluminum, im sure I can find a piece and manage drilling it myself.
    I figure putting this all together will be like an Ikea product, but without all of the instructions.
    I have your sketchup model though, so that's great.

    The EBB board runs the Axidraw plotter though, which is 2 nema 17's and the pen servo ?
    I only want to use the EBB board because it can connect to Robopaint already with fewer issues than another board.
    Robopaint's UI is solid and easier to function, at least for drawing purposes.

    So I guess that's what you mean by a long length of wire, to get the power out to the pen servo.
    Does the part store offer extra long wiring per chance?
     
    #8 Jeremy Worger, Aug 25, 2018
    Last edited: Aug 25, 2018
  9. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    While the belt is priced by the foot it comes as one continuous length so put in 19 and you'll receive a 19 foot length.
    1 pulley plate, and 1 motor mount plate and 1 gantry plate.
    12 yes. You might consider springing for the Xtreme wheels. The plain Delrin wheels can get flat spots if they sit for too long, something which may be amplified by the length of the pen arm.
    2 belt clamps. (Only used on the pen arm, one each side of the gantry plate.)
    2 20-tooth pulleys and 1 idler pulley.

    As for the electronics and wiring I really can't offer much assistance as electronics are truly my weakness. The store does offer wire but I have no idea if it is the correct wire for your needs. Also, not sure what model steppers are used on the Axidraw but they not very big and aren't moving a lot of weight so pulling less than 1.25A could easily be possible in that system. Weight however will be more an issue with what you are building and you will need the power to move it. I suggest delving into the software to determine if the EBB board is the only way to use it or if it can be used on other platforms.
     
  10. Jeremy Worger

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    Perfect. Thanks for all the clarifications. Great to have a proper part list!
    So for the pen axis I would need roughly 6ft and a bit of belt on both sides, and then the rest would be for the main axis yeah?
    I see, I guess they are more durable wheels. I will go with those.
    The Axidraw uses the EBB which uses the nema 17's. But yeah, the Axidraw itself is much smaller in size.
    Hmm.
    Ill have to do some research on how much power I need to cover the minimum. I'll talk again to the guys who make the EBB and see what they have to say.
    Will report back here when I find out more.
    Not sure how ill integrate the pen servo or the wheel...I'll have to figure that out.
    Oh another question I have is, are there such things as stand parts for either end of the 20x40mm extrusion? I didn't see anything on the openbuilds store.
     

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