Yet another V2.5 build

After some sourcing work, I got all the parts to build my very first GridBot. Thank you Stewart for all the work!

It’s getting along quite nicely, I’ll have a few ideas for a next iteration, but I guess it will take some more time to finish it and have it working.

Here is an album of work in progress pictures :

My notes so far :

  • laser cut parts are great : acrylic is heat resistant, rigid, quick to cut. I had some 3mm thick handy so that’s what I used. I doubled all the parts that were 5 or 6mm in the cad. I think it would be better to stick to a single thickness, like all parts in 5mm. I don’t know which thickness is most common

  • I built the bed support using extrusions, it’s simpler imho like this and I don’t see side effects. I added some small laser cut parts to attach the bed. This way any hole pattern in the bed can be used. Here I have a bed with 24cm spaced holes in each corner.

  • It could be simpler to have longer extrusions to avoid the support plates in the bottom. I replaced them with simple screws directly “taped’” in the extrusions. I’ll 3d print small foot to be added to the screws.

  • I was suspicious with Klipper, but it’s great. I have it working with a 10€ ramps 1.6 board. You don’t need a powerful board with klipper.

  • My motor current was too low, I upped it to 1.2 amps and now I have faster moves.

  • Belt tension is hard to do correctly, I still need to find a way to handle this without wasting tons of zip ties :slight_smile:

  • It would maybe ease the work if there were “ends” on the frame to help square the gantry.

  • No need to source all the various screw lengths, only the screw that go in the extrusion must have the correct length. This could be simplified imvho

  • I didn’t source enough hammer nuts, I had to remove some corners. They say “don’t cut corners”. I did :slight_smile:

  • I bought low quality rails, I might have to replace them, it’s a shame. Don’t be too cheap on rails, you deserve good quality material when DIY.

Here one picture of the beast :

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And today I finally ended up printing my first cube. Here is the second attempt to check if too fast works (meaning steppers are correctly setted up in klipper). A bit silly, but I’m so happy to have my first corexy printer made with my little hands :slight_smile:

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Just a quick (and late) reply to your concern using maaaaany zip ties. I had the same problem and I’ve tried quite a few different solutions. I ended up going back to keep it simple, these ones works very well for me:

And its really easy sliding them back to change tension. I usually mark the folding point with a marker pen so I know how how many “teeth” I tension.

I use the same from vzbot ( VzBoT-Vz330/Belt_clip.stl at master · VzBoT3D/VzBoT-Vz330 · GitHub )

Works fine and indeed you just tension “per teeth”. I printed the vzbot ones at 105% so they slide in easily (while not getting out too easily) .

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Hello comrades! I have this question. I still can’t get the z-axis to be accurate.

The height of the layers fluctuates all the time. I put backlash-free nuts, nothing has changed. I want to ask how you dealt with it?
I’m thinking of replacing the lead screws with ball-bearing ones.

Random thought: tape a flag to one of the Z screws and watch to see if the screw actually turns through the same amount of rotation for each Z step. For a Z range that should have constant layer height.

I’ve build over a dozen of these and the only time I’ve seen anything like that, it was when bed heating was set to bang bang instead of PID with tuning.

I have seen something like this with belt printers, too, when extruder steps were not accurately calibrated.

Thank you dear. Indeed, when I last calibrated the PID, I did not remove the # in the settings.
Yesterday I calibrated again, turned on the PID, the layers became smoother, but ripples still remain.