Corexy frame rigidity



  • Because I have quite strong frame vibrations when printing with higher speeds I would like to get the frame more rigid. Do you guys have any experiences what's the best way to achieve this?

    Thanks, Martin



  • @MartinNYHC For my printers, I use 2020 and 2040. Drilled clearance holes in the ends for screw access and tapped the ends of the extrusion. Slide the buton head screw into the extrusion slot and tighten via the hole I drilled. Misumi also has self tapping torx screws, HTJ5. When bolted together, it's very solid.



  • post a picture of your frame



  • @Veti Here's one:
    DSC01604small.jpg



  • @Stephen6309 If it was me, I'd probably use 4040 or 2040 for the legs, rather than the 2020. But it doesn't look bad. Some extra cross bracing or rigid panels might help stiffen it a bit more.

    Posting pictures will always invite criticism, so in the nicest possible way, personally I couldn't live with the rats nest wiring but that's another matter.....



  • the carriage seems heavy, unless you want to build a counter like @deckingman.
    this video might be usefull for you.
    https://www.youtube.com/watch?v=y08v6PY_7ak



  • @Veti: this is my frame. I already put an additional extrusion in the top front.



  • @MartinNYHC

    the blv frame is already very rigidt. especially with the additional frame in front.

    try stefans solution for the dampening.

    i use 3 tennis balls for dampening on my delta and it works very well.



  • @Veti said in Corexy frame rigidity:

    @MartinNYHC

    the blv frame is already very rigidt. especially with the additional frame in front.

    try stefans solution for the dampening.

    i use 3 tennis balls for dampening on my delta and it works very well.

    Who is Stefan? 😊

    So just putting tennis balls under the foots?



  • @MartinNYHC said in Corexy frame rigidity:

    Who is Stefan?

    stefan from cnc kitchen. the linked youtube video



  • @deckingman Rats nest is a work in progress. So far, no problem with the 2020, which why there are a few diagonal braces. The printer doesn't move with the wheels unlocked.



  • @Veti No problem running at 100mms. Using a Titan Aero. It's all PLA, except for the brass inserts and wheels.



  • @Stephen6309 Sorry I got confused. I thought the picture you posted was from the OP in response to @veti's request for a picture. The OP was asking for recommendations to get the frame more rigid, and I saw the 2020 extrusion in the picture, put 2 and 2 together and made 5 - hence my suggestion based on the wrong assumption that the OP was using 2020 and wanted to know how to make it more rigid.



  • I think the best way to achieve rigidity, regardless of the size of t-slot you use for the frame, is to add top, bottom, and side panels. That has the additional benefit of enclosing the machine so that you'll be able to add a heater and print ABS (or even higher temperature materials) reliably. This is one reason why I would not build a printer that uses wheels running in the t-slot for the linear motion guides.

    Using larger t-slot will stiffen things up considerably without costing much more. I see a lot of designs made with 2020 t-slot and dozens of expensive corner brackets. I think if the builder spent the same amount of money of larger t-slot bolted directly together without using all the corner brackets they'd end up with a more rigid frame that's a lot easier and faster to assemble.

    A lot of designs, especially the popular corexy type, put the motors and pulleys on top and at the corners of the frame which also makes it hard to add panels to stiffen the frame and enclose it.

    I think it's best to design the machine to be enclosed from the start. The frame will probably be a little bigger than it would be otherwise, but probably not as big a box built around the machine as an afterthought. T-slot is handy stuff to attach things like panels. If you're not going to use it to do that, you're probably better off using square aluminum tubing to build the frame- it's usually cheaper and more rigid that equivalent size t-slot.


  • Moderator

    I added mass to the frame by literally strapping some weight to it such that the printer is strapped down to the table it sits on with some nylon strapping and about 50kg of steel slung under the table. It's not the same as structural rigidity, but it did help a lot with vibration.



  • Thanks for your feedback. As a first step I'll try the tennis balls.



  • @Veti Very interesting video. Thanks for pointing this out.


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