LowRider-inspired Foam Ripper

Actually lost about 140mm in all…100 at the root and 40 at the tip…but it was designed for a specific sized workpiece…balsa wood comes 100mm wide.
Any loss of cutting length from having a wider frame is easily made up by having a longer 2040 (or 2060) beam and I would think a wider frame has to reduce the chance of side to side play.

When I looked at the links from my build log the other day the second link wouldn’t work for me…if you need access to any missing files let me know.

I like the coreXY, that is a nice idea…although it does loose the beneficial counter weight of the two stepper motors hanging off the back of the ‘boom’. Linear rails are of course going to be better than delrin wheels but at a significant cost hit. Will GRBL handle coreXY? I don’t think so, so I guess it is running Marlin - you can just make out the extra burnt edges to the logo he was engraving…nice logo too!
I am sure you will end up with a better design by taking the best bits from many designs…and it is fun at the same time.

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I’ve never tried it but grbl config file does have a coreXY section.

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My zenxy is grbl esp32 and corexy

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Maybe I should start a new build thread for my mish mash design so we don’t stray too far off tangent of dkj4linux thread? I am initially assembling all your parts in fusion 360 so I can understand it a little better. The other design does have 2 motors counter balancing that beam, but connected differently than yours. Not being an engineer, I am not sure which design will support longest reach best? I would not use linear rail, so my reach would be less on his design than what he is getting. His design has the part main_carriage.stl file connected to the 2020 cantilever beam around 66mm out on the bottom and the other connection about center of the 2040. I don’t have anything specific in mind for engraving with a laser, but would like to have it the best compromise of size to function. 2040x500mm for main beam & 2020x400mm for cantilever beam is probably good enough for me to start with. I might go 600mm for main beam. I will probably use eccentric spacers for all the wheels instead of the way you have it if it fits into design easily.

I did find all your parts in that thread as well as the assembly file.

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Go for it! I’m not a mech engineer either so I am not claiming my design is mechanically ‘best practices’ so please feel free to take what you want and modify it… I bet you end up building more than one :slight_smile:
If you use eccentric spacers on all the wheels might you end up with a cantilever arm out of square with the main beam?..might be best to just have eccentrics on one side only.

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I started a new build thread for my remixed design located: Cantilevered Laser Engraver

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I’ve enjoyed playing a little with miniFR but am not happy with my Z-axis. So started looking around on Thingiverse and, remembering how impressed I was with a printed screw-drive linear slide by 3DPRINTINGWORLD, I found that he’d done a belt-driven slide as well. I printed it and put it together only to find that regular GT2 belt was a bit stiff for the slider channel and really didn’t attach securely to the carriage. He printed his belt with TPU, which I’ve never tried… and, on a lark, decided I should. Ordered Overture TPU, got it the next day, and actually managed to print a few belts on my MK3S. But this particular TPU, while flexible, is also quite elastic… and it really skipped teeth easily. So I decided to see what I might do to the carriage to enable regular GT2 belt to be used. I used FreeCAD to create a STEP model of the carriage and then imported that into Onshape, my CAD of choice. I plugged the posts and cavities where the TPU belts fastened and then created toothed channels for the GT2 belt.

So I rebuilt the slide with GT2 belt and now it seems much more robust and positive… and the little 28BYJ-48 is surprisingly strong when set up as a bipolar motor. That’s my bench vise (a couple of pounds) riding back and forth over 70mm range…

Satisfied that the slide looked like it was gonna work, I took a first cut at coming up with a new X-carriage to mount the slide on. The slider is noisy with all the BB’s recirculating in the race tracks with no lube… but of course this machine isn’t going to be doing tons of Z-moves anyway.

The first-cut X carriage plate will mount the “stock” slide but I can already see that I can open the end of the slider rail, remove the small stepper motor, and mount a small NEMA17 and drive pulley just above it and drive it with a more conventional stepper motor…

This assembly will replace the carriage plate in the right background. While I was at it, I also widened the “wheelbase” and placed holes for wheels/axles for either 2020 or 2040, should I ever decide to beef it up a bit more.

Later.

– David

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Looks like your are conquering the Z-axis problem. When you get it working for a nema17, I wouldn’t mind looking at the design. I really do need to make that mod to the 28BYJ-48 motor, but have a mental block against it at the moment.

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More progress…

I printed several X-carriage plates before finally getting all the wheel and belt openings properly located, and X-axis rail modifications made, to accommodate a wider “wheelbase” and 2040 spacings…

Movement in all three axes… Z-axis BB-bearings are noisy but movement is relatively smooth

As I happened to have a length of silver 2020 already cut from the TimSav I dismantled after “retiring” the TimSavX2 hot-wire machine… it fit pretty-nicely between the tractors and on top of the existing X-axis extrusion. So I printed some “joiner” pieces to lock the V-slot together along their length and added it to the existing horizontal 2040 X-axis rail…

There are four of these joiners holding the silver 2020 extrusion tightly to the black extrusion below…

Here a joiner can be seen flush with the end of the added extrusion…

And now, the X-carriage wheel spacing is for 2040 (vs 2020 before) and, with eccentric spacers on the lower wheels, it is much more smooth and stable than before…

I could, of course, do away with the need for the added extrusion by re-orienting the front X-axis rail from horizontal to vertical but I didn’t want to take time to modify and reprint the tractors right now.

Next I need to mount the laser onto the Z-axis and, hopefully, I should be back in business.

– David

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Mounted the laser and proceeded to run Ryan’s focus script and engrave a photo…

Everything seemed nice and smooth…

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You are freaking amazing!! I love to see your posts…
Thank you!!!

Oh, my! Somebody… please help this fella find a cool spot in the shade… :blush:

Seriously, thank you for the kind words… and you’re welcome. I’m just doing and sharing what I love to do and I’m thrilled there are folks like you who are appreciative. Thank you!

Well, I was still not satisfied with the belt-driven Z-axis. It’s doesn’t firmly hold its Z-position when trying to position the laser for a run… and focus is too easily lost. So, I downloaded 3DPRINTINGWORLD’s V2 printed screw-driven stepper slide and printed it off. Unfortunately, a couple of the parts have been revised and inexplicably no longer fit properly. Thankfully, the previous version of the slide shares those same parts and so I was able to download parts that fit… and finish assembly of the slide. No current video, here’s an old video of a previously-built slide that currently resides on my daughter’s laser engraver…

There are two different screws provided with the download… and I used the most aggressive pitch

Now installed on the machine and working nicely…

so it’s back to playing with Lightburn…

Later.

– David

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Finally convinced that a belt-driven Z-axis wasn’t a good Idea because it didn’t hold its Z-position – and thus laser focus – firmly enough while positioning the toolhead… I’ve simplified the X-carriage plate and mounted the new BB-bearing, printed screw-driven, V1 stepper-slider. That, in turn, carries the Eleksmaker 2.5W laser module and danowar’s laser air-assist shroud that I’ve used with this laser module on several machines in the past.

The printed Z-axis slider assembly uses BBs for bearings and works surprisingly well…

The inexpensive (< $2) hobby stepper is hard to take seriously but with a simple unipolar to bipolar conversion actually works quite well for this application. The blue plastic cover is pried loose to expose the small PCB inside…

and the wide central trace is cut to disconnect the middle nodes of the two coils. The red wire is then snipped/removed from the 5-wire bundle…

and the four remaining wires rearranged in the connector to match the stepstick driver pinout… in this case, orange-pink is one coil, yellow-blue is the other.

The air-assist shroud gives a stronger air stream using a small radial fan and printed shroud…

The laser lens focal length (about 55mm) can be adjusted, if necessary, with the ridged nozzle

and fine-focus is acheived using Ryan’s focus script.

The two Charles Bronson image engravings and profile cuts used the exact same gcode file… before (right) and after (left) installing the air-assist shroud.

I’m pretty happy with this machine now and doubt I’ll make any more drastic changes… miniFR lives!

– David

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My neighbor got a laser engraver from universalengraver.com recently & he really needs a better case cover for it since it is in his wood shop. Thought I would see if I could design & print him one. Before starting from scratch, thought you might know a good starting point case for this or what board this is using. Here is what it looks like.

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Ha, ha… don’t need no steenkin’ case! :crazy_face:

I’m the last person you should ask about cases and wire/cable management! Here’s my miniFR setup… looks good to me :stuck_out_tongue_winking_eye: Ship it!

I don’t know that particular board but it appears to be a stripped down Chinese (guessing from the characters printed on the board) knock-off of the Nano/Grbl-based Eleksmaker Mana SE v3.2 2-axis CNC controller…

In fact, that whole machine appears to be a non-Vslot knock-off of the Eleksmaker A3 laser engraver machine that is available almost everywhere online. I got one of those a couple of years ago and my daughter is currently using it. I swapped the 2-axis board shown for a 3-axis board and added a 3d-printed, BB-bearing, screw-driven, Z-axis stepper slide assembly, just like the one on miniFR above. If you need more information about his machine, the similarity is so great I wouldn’t hesitate to use the Eleksmaker A3 documentation as reference and guide.

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If you enclose the board make some provision for forced air cooling for the drivers.

Shame you can’t paste a screenshot of Chinese writing into google translate… :laughing:
Any Chinese readers able to translate it?

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I vaguely remember the google translate app able to take pictures. I bet the website can too.

I didn’t know that!! Tried it but resolution loo low

I found another picture of the same object on the web and it translated as “Dingqi Laser”

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