Household Laser Cuts | Hacker News Reader

Household Laser Cuts

cceckman.com

52 pointsevakhoury18 comments

For more on this in spades see boxes.py

For my part, I've been working the CNC router angle, so have a much larger kerf to cope with (and the added advantage of controllable partial depth and no char):

https://community.carbide3d.com/t/full-blind-box-joints-in-c...

https://github.com/WillAdams/gcodepreview

I really love boxes.py, and have contributed several designs. The flexbook, shadowbox, coinbanksafe, and frameloom are all mine :)

I'm really proud of the loom.

https://boxes.hackerspace-bamberg.de/FlexBook

https://boxes.hackerspace-bamberg.de/Shadowbox

https://boxes.hackerspace-bamberg.de/CoinBankSafe

https://boxes.hackerspace-bamberg.de/FrameLoom

Recently I've been on a kick making bracelets with that frame loom. The rotating heddle bar makes it super quick to warp up. I've written about how to go from woven rectangle to bracelet here:

https://ojensen.net/musings/bracelet-on-frame-loom

There is a FreeCAD workbench for this, and it seems to have been restarted recently:

https://github.com/execuc/LCInterlocking

Like some of the other older pre-TNP-mitigation plugins it's possible its interaction with those mitigations is quite limited, though my limited understanding is some work has gone into extending the mitigations into objects generated by the Python API in the next version of FreeCAD (26.3 — CalVer now).

I've had great success designing durable objects using the sheet metal modeler in OnShape[0] and have them fabricated with SendCutSend[1]

[0]www.onshape.com [1]www.sendcutsend.com

I've been using onshape for 3d printing and it never occurred to me that this kind of thing was a possibility. My mind is being blown, thank you for this comment!

Can anyone recommend a home CO2 or high-wattage diode laser cutter which can cut 3-4mm ply? We run an Epilog machine at my local makerspace, but I wonder if consumer machines have gotten reasonably good recently?

My 50W Omtech Polar Plus (since discontinued) can do 3mm in one pass and 6mm in two passes (or one pass near max power but I prefer two for reduced charring and to extend the lifecycle of the laser).

Basically any 50W Chinese laser should get you what you want. But at that price point you can't adjust the mirrors, no red dot to guide cuts, poor camera calibration etc. It's worlds away from what I expect you get with an Epilog.

I bought one of the 60W Chinese Laser cutters, 40cm x 40cm, with RUIDA controls for the steppers. It's a decent machine and it runs with Lightburn. I get shocked a little bit from the HV supply when touching fluid in the cooling loop, and there is no interlock preventing the laser from firing with an open hood, but it cuts well and the mirrors are adjustable. It was about 700$ for the machine and 700$ for shipping to Europe in 2023.

Just keep in mind this is not a desktop machine to run in a flat. You need some infrastructure like a cooling loop and air exhaust, so this thing best lives in a basement or hobby room.

Being in the EU, VEVOR looks like they have a 400mm x 600mm 60W CO2 laser for ~1600 EUR* (somehow with free delivery to Denmark). I've never bought anything from VEVOR though.

*Back to School special, since everyone has to get a new 50W machine each school year.

Before you go deep on OpenSCAD, consider JSCAD: https://jscad.app/

Roughly similar capabilities, but you get to use javascript or typescript instead of the linguistic abomination that is OpenSCAD.

I'm actually rather fond of OpenSCAD --- it has the advantage of being completely safe in terms of security/execution, so no worries about downloading a random .scad file and wondering what it might do.

If one wants a full-fledge programming language for this, I found Python a lot more comfortable:

https://pythonscad.org/

I found that Figma is really good for designing SVG laser cuttable designs. Had to fix a few things with exports, units etc. but solid. Here's a little plugin I built if it's helpful:

https://www.heyraviteja.com/post/portfolio/laser-cuts/

> To add a little pizzazz, I constructed a cat’s head silhouette from an ellipse and two triangles, then randomly scattered them

Ooh! A scattering that avoids overlapping punching might benefit from another recent item on Poisson Disk Scattering [0]... Although on a boringly-practical level, I guess rejection sampling would make more sense for this need.

Calculating kerf is the worst. :(

Can you not just cut a 1" square, measure it accurately then use that as the kerf correction (option to add in software like Lightburn).

I do something similar: trace a rectangle and subdivide it into 20 smaller rectangles. Then I slide the smaller rectangles to one side. The part that's missing (divided by 19) is the kerf.

Yes.

This is exactly what you do.

But, in metric :)

> overlapping circles and rectangles

Just hull() two circles. It's a cheap operation in 2D.

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