Hobby CAD, CNC machining, and resin casting (2015)

 (lcamtuf.coredump.cx)

65 points | by hughgrunt6 小时前

8 comments

  • WillAdams3 小时前
    Previous discussions:

    https://news.ycombinator.com/item?id=41467268

    https://news.ycombinator.com/item?id=27645605

    This was a resource which was mentioned on the Shapeoko wiki --- while it's off-line, it's still on the Wayback Machine: https://web.archive.org/web/20211127090321/https://wiki.shap...

    Since then, some of those pages have been made available on Reddit:

    https://old.reddit.com/r/hobbycnc/wiki/index

    https://old.reddit.com/r/shapeoko/wiki (ob. discl., I work for Carbide 3D)

    And there have been a number of other developments

    - FreeCAD has hugely improved since that was written.

    - Solvespace as greatly improved, adding some basic CAM functionality

    - Blender has had the Solvespace sketcher ported to it as https://www.cadsketcher.com/ and BlenderCAM has gotten quite a bit more workable

    - Dune3D was created and is remarkably capable: https://dune3d.org/

    Also a fair number of forums discussing CNC were gathered at: https://forum.makerforums.info/

    • Animats12 分钟前
      Right. This article is (2015).

      3D printing with PLA has improved in the intervening decade. You can usually get a good print on good modern printers. The first generation of those things had poor extruders, and filament formulation has reportedly improved. There's complicated heat transfer going on in those things. You're welding a hot thing to a cold thing, which is inherently troublesome. I'm told that works better now.

      Machining resin molds is straightforward, because you start with a block of something and machine only its top. So there's no work-holding problem. Trying to figure out how to clamp something that needs to be machined on several sides is usually hard.

      Not sure what's going on in tiny mills today. I've used Tormachs, the whole range of Shopbots, and some strange one-off machines that TechShop somehow obtained. (Never did use the beautiful little Pocket 5-axis machine. TheShop had one just before they went bankrupt.)

    • hnisoss2 小时前
      awesome dump, thanks for sharing. solvespace is cool but until they iron out the chamfer/fillet situation and parametric input I ll have to continue using freecad..
  • sottol3 小时前
    Shameless plug if anyone is interested - I'm working on a $600-ish open-source, reasonably capable, but small and somewhat "tidy" hobby CNC machine with BOM cost around $600 that requires some DIYing.

    It's meant to be an alternative to the Desktop CNCs like Nomad, Carvera, Bantam, ... moreso than a PCNC or other proper entry-level CNC.

    The ultimate goal is to make it hobbyist-friendly, capable of easily cutting alumin(i)um and not taking up a lot space, not being messy or loud enough to require a dedicated workshop. Unfortunately, cutting metal is inherently loud so you probably would not be able to run it in an apartment as I'd hoped.

    I've made a couple decisions around being friendly for people coming from the 3DP space around probing, using roborock CPAP as chipvac, running it mostly dry, fully enclosed. I'm also starting to work on computer-vision-based probing and the idea is to later enable a host of more user-friendly and safety-focused features and maybe integration with Kiri:Moto's CNC mode for "guided" CAM and so on - basically a beginner-friendly CNC that guides newbies using an integrated web-interface.

    More info on Github: https://github.com/thingsapart/mini_nc

    GH is a little outdated but I've been using the little machine to cut alu for a while (mostly parts for itself) and it's working quite well. There's more videos and such on the Discord linked in the GH readme - feel free to ask questions on the Discord, I try to respond as quickly as I can. The full model with all its components is completely open in Onshape (I know it's not ideal but how I learned CAD - link also on GH).

    • mdorazio1 小时前
      What's the advantage of this over a 3018 or 3030 machine? With some basic upgrades (you mentioned needing to diy anyway) you can easily cut aluminum on those for $500 or less.
      • bluGill1 小时前
        Not made in china though since many parts come from china anyway...
        • 49 分钟前
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    • hnisoss2 小时前
      that looks like a nice project, reminds me of the ghost gunner 3 machine. I like the safety note too. might hop into discord sometime next week. thanks for sharing!
    • 1 小时前
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  • syntaxing2 小时前
    Former MechE for a decade and I owned personal CNC routers and on my 6th 3D printer. The biggest issue with CNC is the cost for consumables and accessories. Need a special bit? $$$ Need stock to cut? $$$ Want a nice ER11 or R2 collet set? $$$. A nice vise? $$$ Cut something wrong with a carbide bit? Shrapnel explosion. 3D printing has a bunch of limitations but is a way better machine for hobbyist. But I have been eyeing the Millennium Machines Milo. A very fair price point for a traditional style CNC. You can also decorate it however you want with your 3D printer.
    • sottol2 小时前
      It is definitely more expensive than 3d printing in terms of consumables but china/aliexpress has really good hobby-quality equipment now - if you don't mind the country of origin. Many of their coated end-mills are decent and < $5 depending on diameter.

      Maybe not stuff you would want to run professionally but it works quite well in a hobbyist setting and a mistake won't cost you $50.

      I also looked into the Millenium Milo, only downside for me and kinda why I decided to design my own Voron V0-ish sized mini CNC machine was the really large footprint for about 3x the work volume (work _area_ is ~2x afair). An enclosed Milo would take up about the same volume as two 350mm Voron's side-by-side. So footprint of a small desk.

      Imo besides the price, the other big factor is just how much less forgiving CNC machining is than 3d printing - so many mistakes you can make, zeroing the WCS, wrong WCS, mounting the work different than you had it in CAM, ... bam, at least the work is ruined. That's kind of another longer-term goal with my CNC machine, reducing some of these errors if possible with a web-based UI and maybe some computer vision. But that's far off, I'm currently playing with using a camera for work-probing/WCS-zeroing and it's sloooow progress :')

      • syntaxing1 小时前
        Have you seen the Carvera Air? Not gonna lie, I'm equally tempted but that price point is tough to swallow. Its about $7-800 more than the Milo but has a bunch of things built in that you would probably would enjoy like touch probe leveling and camera zeroing. Its the "Bambulab" of the CNC world.
        • cjbgkagh14 分钟前
          Like many things it’ll depend on your use case. Carvera Air is 200W vs Milo 1.5kW which could make a big difference.
    • Joel_Mckay1 小时前
      A reasonable quality plasma-cutter CNC table offers the speed and low operational cost most fabricators can manage well.

      Having a CNC Router table in a non-industrial zoned area will not work for most people. Services like sendcutsend.com makes life so much easier... =3

      • WillAdams9 分钟前
        I use mine in my (finished) basement, or if cutting tropical hardwoods out on my back deck (I have a machine on a wheeled cart).
      • syntaxing1 小时前
        I was in charge of one of these when I was way younger and they are awesome. Downside is that I don't want to house Argon and they're such a pain to maintain. Getting parts ordered is definitely magnitudes more efficient and significantly cheaper nowadays. You can get really nicely machined and anodized parts from China for the same cost as custom part shipping cost here in the states, it's crazy.
        • Joel_Mckay41 分钟前
          Budget 3D metal printers will eventually enter the hobby market, but I only get to work on my hobby on Saturdays. =3
  • dekhn3 小时前
    With some concerted effort and money spent over several years I was able to more or less reproduce most of this document (but not nearly to the level of detail or variation on process). Eventually I was able to finely CNC engrave a wax block with extremely fine (0.1mm) features, make a mold, and then stamp out as many copies as I wanted. This guide was really helpful in understanding some of the core ideas.
  • hnisoss2 小时前
    oh my! I found this exact page in ~2017. I m something of a tab hoarder and I had around 2k open tabs back then. I loved the page and content and wanted to get back to it, but you know how it goes. Somewhere in early 2018 my browser crashed and I lost the tab. I distinctively remembered losing that page and I tried to find it, over and over again. I actually had one of the pictures saved (blue-red-white wheel), so I opened it in new tab as placeholder until I find the page. 6 years later here we are!!! tnx hughgrunt xd
  • AnarchismIsCool4 小时前
    I remember reading this around a decade ago. Still holds up though
  • 99_001 小时前
    It’s hard for me to believe that using a CNC to mill a model for resin casting works better than 3D printing it and casting it.

    I’d expect that with 3D printing you can even print the spruce and risers.

    • fn-mote1 小时前
      For one thing, IME with cheap hobbyist 3d printers (e.g., Ender printing PLA), the article is dead on about accuracy... people say 3d printers are good for 0.1mm but I don't know how long they spend tuning the machine. I mean, they are... kind of... just not reliably. CNC accuracy of 0.025mm is much easier to achieve (IME).

      If you mean to tell me that I should just have a resin printer to start with, well I agree but I think we should be specific about what kind of 3D printing we are discussing.

      Remember, the guide was written over a decade ago. Certainly 3d printing has gotten better, cheaper, and a lot more reliable. Resin is really strong, though.

    • WillAdams1 小时前
      That was written before resin printers were affordably available or input shaping and so forth had made such a leap in print quality for fused filament printers --- that said, I get much better surface finishes on my CNC machines than my 3D printers, and casting will reproduce even the tiniest imperfection.
  • 1 小时前
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