LowRider 3 CNC, LR3 Release notes

LR3 / SKR docs suggest bending the driver’s Diag pin. Anyone else notice the bent pins could end up touching top of the Capacitor below the driver? No idea if that’d cause an issue (?), and didn’t want to find out, so I’ve been clipping off the Diag pin instead of bending. Clipped pins using cutters I usually use on 3D filament. Pins fly off at high speed, usually straight into your good eye. Don’t rely on safety squints, I recommend eye protection and cover/shield with your free hand during the cut so the shrapnel falls close by.

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The diag pin is normally at ground (logic low) potential and raises to logic high if the motor skips a step, in either case being grounded is not a problem, so there is no problem if it does touch the cap casing. If bent at least 90 degrees, it won’t anyway.

I bend mine, in case I someday get the desire to implement sendorless homing. No problems on 2 SKR Pro boards so far. (I realize that’s not a huge sample size.)

The SKR Pro board has a problem in that the diag pin connected overrides the endstop pins, so with the diag pin connected you cannot use stop switches, they will be ignored.

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Anyone have a link for reusable/releasable zip ties that fit the LR3 model’s ziptie channels?

Love the channels integrated into the LR3 models. But they’re just a little bit too narrow for the 0.2" reusable zip-ties I have. Currently working around by trimming width of the zip ties I expect to be remove if/when making future mods.

Asking after seeing @revnull’s observation about zip tie channel in the braces. Neat design feature. I spent ~16hrs building LR3, but I didn’t notice them, LOL.

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LR3 Docs has pic of Struts with holding Tabs for the cutouts.


Currently doing something like…

  • Open downloaded/generated strut .svg/dxf into Estlcam
  • Select menu Automatic functions → Create objects automatically
  • Select all toolpaths (Ctrl + A)
  • Select menu Automatic functions → Create holding tabs
    • Within Create holding tabs popup, update with following settings, then ok.
      • Nominal distance 100mm
      • Min count 2x
      • Max count 15x
  • While all toolpaths are still selected. Edit Holding tab height from Full to instead be 3mm
  • Click on Preview icon (bottom left)
  • Enter cutting depth, stock depth + 0.5mm
  • Click “>” play, speed up and closely watch the planned toolpath.
  • Hold Left mouse button and move mouse to see 3D view, to help understand planned cutting path, and, flight path (dashed red lines) between cuts.
  • Menu File → Save CNC program to create .gcode

Please let me know if there’s a better way.

Edit: Measure your wood, it’s probably not as thick as you think. I set cut depth based on labeled thickness, I should’ve known better by now. Ended up catching loose strut cut-outs with the shop vac.

I have never tried any of the automatic functions. I select them all one at a time and then do the machine order after I finish all the selecting and manually placing tabs.

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@jamiek thank you for creating and sharing a set of strut plates together with a script that folks can customize.

I foolishly spent some time making a video that may help anyone hesitant to try out OpenScad.

Then, sigh… I spent much less time making the video pointless for people that can live with Struts rounded to the nearest 10mm…

I just uploaded Strut Plates .SVG files sized from 480mm - 1700mm, in 10mm increments, to github. Please let me know if they’re wrong.

For example https://raw.githubusercontent.com/aaronse/v1engineering-mods/main/lowrider3/strut-plate-variable/out/lr3-strut-plate-variable_ 780 .svg

Edit number in the URL to the nearest 10mm size you need. So, now folks only need to generate a Custom sized Strut if they need millimeter precision.

Ideally, the LR3 Calculator would provide a link to one of these pre-generated static .SVG files. There’s few enough files, that are relatively small (123 files, total of 2.5mb), that the static files could be webhosted. I don’t think on-demand .SVG generation via Cloud App makes $ense. @jamiek, thoughts?

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OMG! I love it!

I’m going to link the video on the printables page for the strut if you don’t mind.

As for the pre-generated files, it’s got me wondering… it feels a bit weird, but what about 1300 files? As you pointed out, they are small, and github won’t complain (right?). Then the arbitrary strut length is solved period, no asterisks or caveats about adjusting the size a few mm to be multiple of 10. And the OpenScad model becomes even less necessary.

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Thanks Jamie, sure thing, feel free to link/share.

Like the idea of making the video pointless and Strut selection trivial for LR3 builders.

~23mb for 1220 files (480mm to 1700mm for usable cut areas of 1’ to 5’ for gantry). Small size, but Github has 1000 files per folder limit, can workaround by partitioning across multiple folders in way that LR3 Calc understands. I’m happy to attempt LR3 Calc edits if you think it’s worth the effort?

OpenSCAD is very necessary to gen the files. Enjoyed using to make my front Strut, cheers for sharing your script.

Edit: Submitted this pull request extending LR3 Calculator to enable downloading static generated Strut .SVG matching the User’s configured dimensions.

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I would make some joke about men and their tools, but it’s early, and I’ve just started on my first cup of coffee… Besides, whatever you just thought of is probably at least 20% funnier than anything I would have come up with.

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DANG that is some very helpful edit right there. Every 10mm is fine, I made two thinking that would be enough. I was wrong but I am sure most can live with in 10mm.

Thanks guys!

Would you still need to scale the 10mm file in CAM? What about the 1mm? I think that is the main difference. Not having to scale it is with the extra complexity.

And, without making this too complicated, should we also track the script in git, and add versions? In case something changes?

@jeffeb3, @vicious1, sorry for not being clearer earlier, late night.

Short: ALL the Struts have been generated, 480mm…1700mm in 1mm increments, submitted to git (here and here), along with a modified version of @jamiek script. Submitted LR3 Calc Pull request referencing these .SVGs to create slicker than snot SVG download UX for LR3 builders.

Long:
I created https://github.com/aaronse/v1engineering-mods/…/lowrider3/strut-plate-variable yesterday. Made a slightly modified version of Jamie’s LR3-strut-plate-variable.scad in that repo that could be called through command line automation of OpenSCAD.

Generated ALL the Struts, 480mm…1700mm in 1mm increments. Within Windows cmd shell:

for /l %i in (480,1,999) do "C:\Program Files\OpenSCAD\openscad.exe" --D "beam_len=%i" -q -o out_0\lr3-strut-plate-variable_%i.svg LR3-strut-plate-variable.scad

for /l %i in (1000,1,1700) do "C:\Program Files\OpenSCAD\openscad.exe" --D "beam_len=%i" -q -o out_1\lr3-strut-plate-variable_%i.svg LR3-strut-plate-variable.scad

Committed and push the generated .SVG files to /svg_0 and /svg_1 within the v1engineering-mods repo.

Then made some changes to the LR3 Calculator that point Users to these generated .SVG files. Sent this V1E Docs pull request with those edits.

I didn’t stumble onto where Jamie maintains LR3-strut-plate-variable.scad within his git repos @ https://github.com/vector76

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That all makes sense to me. But I would rather keep the source file, the process to create the svgs and the final svgs in the V1EngineeringInc space.

I am fine with it as it is. It is better than what we have.

Thinking longer term, it would be nice to put the script in a new repo, and maybe even add actions to build the svgs. And keep this updated svgs in that repo, or in a release location. Then point the docs there.

This absolutely does not have to be the first iteration. The acceptance criteria for PRs is “better” not “ideal”.

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Agree. Will submit pull request that adds the script and generated .SVGs to the V1E Docs repo where the LR3 Calc (page with script) exists.

Agree auto build time gen would be nice to have (can’t see myself digging into that one right now tho). I appreciate the mindset of accepting improvements now, rather than waiting for ideal to (maybe) turn up later. Cheers!

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I was thinking I would be involved, unless someone dropped the solution in my lap.

I have to remind myself that the Internet is littered with my broken promises. I will get to it all eventually, unless I die first.

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Done, updated V1E Docs pull request

2022/8/30 EDIT: LR3 Calc has been updated to enable downloading Custom size SVG for your chosen build dimensions. Fill out dimensions then click on Download Strut .SVG, cheers!

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anyone have issues with the X tensioner? The nut spins inside, and the whole part snaps when tensioning if you glue the nut. Not sure what I’m doing wrong. I printed it at 30% and then retried at 60% infill.

Hope response in main topic on this helps

Sounds like you might have a galled nut. Try a different screw and nut, make sure to pre thread the nut to loosen up the nyloc a bit. There is very little force on the nut otherwise so it has to be this.

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