10 ms·

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

178 points by hughgrunt 2y ago

AnarchismIsCool 2y ago
I remember reading this around a decade ago. Still holds up though
dekhn 2y ago
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.
WillAdams 2y ago
Previous discussions: https://news.ycombinator.com/item?id=41467268 https://news.ycombinator.com/item?id=41467268 https://news.ycombinator.com/item?id=27645605 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.shapeoko.com/ 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/hobbycnc/wiki/index https://old.reddit.com/r/shapeoko/wiki 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/ https://www.cadsketcher.com/ and BlenderCAM has gotten quite a bit more workable - Dune3D was created and is remarkably capable: https://dune3d.org/ https://dune3d.org/ Also a fair number of forums discussing CNC were gathered at: https://forum.makerforums.info/ https://forum.makerforums.info/
- aidenn0 2y ago
  These also had discussions: https://news.ycombinator.com/item?id=4679939 https://news.ycombinator.com/item?id=4679939 https://news.ycombinator.com/item?id=34339459 https://news.ycombinator.com/item?id=34339459
- hnisoss 2y ago
  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..
  - WillAdams 2y ago
    If you want something lighter than FreeCAD I'd recommend trying Dune3D --- it's amazingly easy/nice to use.
    - hnisoss 2y ago
      I ll give it a shot, tnx
- Animats 2y ago
  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.)
- cellular 2y ago
  "GatorCAM for CNC" Instructions to download: https://youtu.be/hqyPzCKGUQc?si=VJ0KRhQOl_-d7Bmm https://youtu.be/hqyPzCKGUQc?si=VJ0KRhQOl_-d7Bmm Download here: https://sites.google.com/view/gatorcam/home https://sites.google.com/view/gatorcam/home Very user friendly. Tab support, v-bit, ATC, sorts toolpaths for faster carving.
sottol 2y ago
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 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).
- hnisoss 2y ago
  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!
- deleted 2y ago
  [deleted]
- mdorazio 2y ago
  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.
  - 2y ago
syntaxing 2y ago
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.
- sottol 2y ago
  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 :')
  - syntaxing 2y ago
    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.
hnisoss 2y ago
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
- ajot 2y ago
  You may also like lcamtuf's current thingy, a substack https://lcamtuf.substack.com/ https://lcamtuf.substack.com/
  - hnisoss 2y ago
    I wish it had an index/tags.
99_00 2y ago
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-mote 2y ago
  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.
- WillAdams 2y ago
  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.
- DannyBee 2y ago
  It depends on the accuracy you are trying to achieve, and with what technology. If you mean FDM, it's absolutely true. If you mean SLA/MSLA these days, i think you could get there. On the first - i have an entirely ballscrew + linear rails driven FDM printer with closed loop servos and proper absolute encoders - I got bored and do lots of CNC retrofits/etc, so had lots of parts around. Think of it as insane version of the Pantheon HS30, if you didn't care at all about costs or practicality. It can position, at speed (IE 300mm/s+), and repeat, the nozzle placement to within 0.0005 inches on all axes, easy. But even with input shaping/etc, you will not get a better surface finish than CNC, and definitely not one good enough for casting. Filaments are just too finicky, even with really really good hotends, sensors everywhere to monitor response and optimize, etc. Now, i did this for giggles, and yeah, i never get misplaced layers, my parts are consistent, etc. But 0.4mm is still a pretty big feature size, and that's the minimum if i don't want prints to take until the heat death of the sun. So I could still machine the same thing on my metal mill and achieve castable surface finish, etc, in much less time and effort.
deleted 2y ago
[deleted]
throwaway81523 2y ago
I'm not too excited by the idea of making little plastic precision gearboxes for robots, so when PLA printing isn't good enough, I mostly want to machine metal. Not car parts or firearms but flashlight bodies, knife blades, small tools, that sort of thing. Nothing wrong with robotics but there are other interesting areas too. I think the article skips over that a little too easily. That said, it's a good article.
- WillAdams 2y ago
  Flashlight body would probably want a lathe, but one of the newer flat ones would be easy in two halves. For an example of a knife blade: https://www.youtube.com/watch?v=G5TYla5x-Nk https://www.youtube.com/watch?v=G5TYla5x-Nk small tool: https://community.carbide3d.com/t/nomad-made-custom-titanium-multi-tool/642 https://community.carbide3d.com/t/nomad-made-custom-titanium...
gaze 2y ago
I read this when I was 25 and now I have a fanuc Robodrill in my garage. CNC is quite the bug
blackeyeblitzar 2y ago
Has anyone here tried using CNC machines for gunsmithing as a hobbyist? Is that even feasible? What about 3-D printing metals instead of plastic? To be clear, I know little about either firearms or metal working, but it seems like it would be an interesting engineering challenge for a hobbyist.
- potato3732842 2y ago
  You can do it but don't expect top notch results. Routers don't have enough rigidity (this is why you don't see gantry mills except in huge sizes) for the kind of work you'll want to do. So much of your stuff will be one off that you're not going to have any speed advantage over a guy with a Bridgeport.
- dole 2y ago
  Current hobby 3d printing of metals usually requires a clay-metal type of filament and sintering, usually by heat or laser to harden the metal, and often needing compensation for shrinking and a lot of other inconveniences. The resultant pieces are "metal" but not strong enough for most internal firearms parts that need to be metal but not necessarily pressure-bearing like a barrel: most notably bolts and carrier groups, fire control group parts like triggers, hammers, sears, disconnectors.
- doe_eyes 2y ago
  You can't easily make a high-quality firearm a hobby mill, chiefly because the barrel needs to be made out of good steel and needs to be rifled. But the quirk in the US is that federally, only the receiver is the regulated part, and many types of receivers can be made out of plastic or aluminum. You can certainly use cheap three-axis CNC with some fixturing to make AR-15 receivers, for example, and many people did. Cody Wilson / Defense Distributed had this whole thing where they were selling CNC mills for cranking out guns. You can also definitely make junk single-use guns using either technology, just like the 3D-printable "Liberator".
eth0up 2y ago
To the machinist/s here: For nearly a year, I've been contacting local machinists for a small[*] project which involves 1) an accurate cut on both ends of a 17" billet of T6061, 2) two crescent cuts, 3) up to 8 threaded holes, but probably, 4) a wee bit o end shaping. All the aesthetic contours, shaping and weight reduction I'd do manually - I hand machine bronze, aluminum and wood archer's thumb-rings, so can wangle that part. This project would result in the world's first ILF asiatic (no shelf), ambidextrous aluminum 17" riser. Though... Every machinist I've spoken to is either friendly at first, implying willingness and ready capabilities, or they simply say no thanks. But all of them ultimately reject the task, typically saying they're too busy. I also have a design for a bow stringer that can handle longbows, recurves and short Asiatic bows safely and efficiently. No one will fabricate it around here. Any suggestions as to why this is such a pariah project? Any suggestions on how I might achieve this? * Not necessarily a good reason/excuse
- potato3732842 2y ago
  Find a hobby machinist. People who aren't trying to expand their business don't want to deal in non-gravy projects from customers who don't seem likely to shovel them a bunch of gravy projects later. Machining is a slowly dying industry in the west so there's far more people not growing their business at any one time.
  - eth0up 2y ago
    Thanks for the insight. I think you're correct... My area is very gravy oriented in general.
- WillAdams 2y ago
  Have you looked at Shapeways or sendcutsend or xometry or 100k Garages? That said, I have an especial interest in archery and multiple machines. Contact me at: https://community.carbide3d.com/u/willadams https://community.carbide3d.com/u/willadams and we can at least work out doing a couple of prototypes.
  - eth0up 2y ago
mvidal01 2y ago
I wish there was an update to these pages. Some of the products and urls are defunct.
- WillAdams 2y ago
  The most likely successor would be: https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z (ob. discl., I work for Carbide 3D)
KaiserPro 2y ago
I wish I had seen this when I was starting out, that would have made life a lot easier!
jwr 2y ago
I followed that guide (it is excellent, if a little outdated) to get really good results. I should really write up and share my experiences, there is so much to learn. In brief: * It's an excellent method of producing very precise parts with fantastic mechanical properties (the next step up is aluminum, but you don't need it in most cases). * It is much more difficult than just throwing something at a 3d printer. * It is not comparable with 3d printing at all. I use both methods: FDM printing for most stuff, resin casting for parts that need to be strong, dimensionally precise, or nice. * Yes, you can use your resin printer to produce originals or master molds, but you will have two problems: 1) precision, 2) silicone cure inhibition. * Tips for those in the EU: Sika Biresin F50 is fantastic, Rencast 5146 is slightly worse (higher viscosity), but works very well, too. Both are relatively easily available. For silicones, BLUESIL RTV 3450 is unbeatable. * For desktop CNC machines, there are good options now: Makera Carvera (either the full model or the "Air" scaled down version) are really nice and precise machines. Software is crappy, but hopefully will get better. I had a Nomad 3, but switched to Carvera. * Don't buy a cheap CNC. There is simply no way to produce a desktop CNC with good precision for less than, say USD $2000. You will be disappointed. Perhaps if one day a Bambu Lab arrives with experienced engineers and a lot of money, they could mass-produce something cheaper, but right now this is roughly the cutoff. * Autodesk Fusion, much as I hate it and the company behind it, is pretty much the only game in town if you want integrated CAD+CAM. Again, I hate the software with a passion, but there is simply nothing else that is as well integrated, works well, and is reasonably priced. * Achievable precision: ±20μm is doable with a little care, things get difficult below that. This is roughly 10x better than what you can get from FDM 3d printing. Note also that this is the limit of what most people can measure: your calipers have an error of ±20μm if they are good. I also noticed that the 3d-printing crowd often has no idea what precision means, so you'll see crazy numbers thrown around. * Mechanical properties of produced parts are way better than what you can get from FDM printing. I laugh at those "strong filament with carbon fiber" youtube videos.
- dylan604 2y ago
  > It is not comparable with 3d printing at all. Not just not comparable, but totally opposite. Subtractive vs Additive. CNC is like chiseling the David out of single block of stone by removing bits. 3d printing is starting with nothing and adding material.

178 points by hughgrunt 2y ago

I remember reading this around a decade ago. Still holds up though

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.

WillAdams 2y ago

Previous discussions: https://news.ycombinator.com/item?id=41467268 https://news.ycombinator.com/item?id=41467268 https://news.ycombinator.com/item?id=27645605 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.shapeoko.com/ 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/hobbycnc/wiki/index https://old.reddit.com/r/shapeoko/wiki 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/ https://www.cadsketcher.com/ and BlenderCAM has gotten quite a bit more workable - Dune3D was created and is remarkably capable: https://dune3d.org/ https://dune3d.org/ Also a fair number of forums discussing CNC were gathered at: https://forum.makerforums.info/ https://forum.makerforums.info/

aidenn0 2y ago
These also had discussions: https://news.ycombinator.com/item?id=4679939 https://news.ycombinator.com/item?id=4679939 https://news.ycombinator.com/item?id=34339459 https://news.ycombinator.com/item?id=34339459
hnisoss 2y ago
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..
- WillAdams 2y ago
  If you want something lighter than FreeCAD I'd recommend trying Dune3D --- it's amazingly easy/nice to use.
  - hnisoss 2y ago
    I ll give it a shot, tnx
Animats 2y ago
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.)
cellular 2y ago
"GatorCAM for CNC" Instructions to download: https://youtu.be/hqyPzCKGUQc?si=VJ0KRhQOl_-d7Bmm https://youtu.be/hqyPzCKGUQc?si=VJ0KRhQOl_-d7Bmm Download here: https://sites.google.com/view/gatorcam/home https://sites.google.com/view/gatorcam/home Very user friendly. Tab support, v-bit, ATC, sorts toolpaths for faster carving.

sottol 2y ago

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 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).

hnisoss 2y ago
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!
deleted 2y ago
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mdorazio 2y ago
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.
- 2y ago

syntaxing 2y ago

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.

sottol 2y ago
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 :')
- syntaxing 2y ago
  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.

hnisoss 2y ago

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

ajot 2y ago
You may also like lcamtuf's current thingy, a substack https://lcamtuf.substack.com/ https://lcamtuf.substack.com/
- hnisoss 2y ago
  I wish it had an index/tags.

99_00 2y ago

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-mote 2y ago
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.
WillAdams 2y ago
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.
DannyBee 2y ago
It depends on the accuracy you are trying to achieve, and with what technology. If you mean FDM, it's absolutely true. If you mean SLA/MSLA these days, i think you could get there. On the first - i have an entirely ballscrew + linear rails driven FDM printer with closed loop servos and proper absolute encoders - I got bored and do lots of CNC retrofits/etc, so had lots of parts around. Think of it as insane version of the Pantheon HS30, if you didn't care at all about costs or practicality. It can position, at speed (IE 300mm/s+), and repeat, the nozzle placement to within 0.0005 inches on all axes, easy. But even with input shaping/etc, you will not get a better surface finish than CNC, and definitely not one good enough for casting. Filaments are just too finicky, even with really really good hotends, sensors everywhere to monitor response and optimize, etc. Now, i did this for giggles, and yeah, i never get misplaced layers, my parts are consistent, etc. But 0.4mm is still a pretty big feature size, and that's the minimum if i don't want prints to take until the heat death of the sun. So I could still machine the same thing on my metal mill and achieve castable surface finish, etc, in much less time and effort.

deleted 2y ago

[deleted]

throwaway81523 2y ago

I'm not too excited by the idea of making little plastic precision gearboxes for robots, so when PLA printing isn't good enough, I mostly want to machine metal. Not car parts or firearms but flashlight bodies, knife blades, small tools, that sort of thing. Nothing wrong with robotics but there are other interesting areas too. I think the article skips over that a little too easily. That said, it's a good article.

WillAdams 2y ago
Flashlight body would probably want a lathe, but one of the newer flat ones would be easy in two halves. For an example of a knife blade: https://www.youtube.com/watch?v=G5TYla5x-Nk https://www.youtube.com/watch?v=G5TYla5x-Nk small tool: https://community.carbide3d.com/t/nomad-made-custom-titanium-multi-tool/642 https://community.carbide3d.com/t/nomad-made-custom-titanium...

gaze 2y ago

I read this when I was 25 and now I have a fanuc Robodrill in my garage. CNC is quite the bug

blackeyeblitzar 2y ago

Has anyone here tried using CNC machines for gunsmithing as a hobbyist? Is that even feasible? What about 3-D printing metals instead of plastic? To be clear, I know little about either firearms or metal working, but it seems like it would be an interesting engineering challenge for a hobbyist.

potato3732842 2y ago
You can do it but don't expect top notch results. Routers don't have enough rigidity (this is why you don't see gantry mills except in huge sizes) for the kind of work you'll want to do. So much of your stuff will be one off that you're not going to have any speed advantage over a guy with a Bridgeport.
dole 2y ago
Current hobby 3d printing of metals usually requires a clay-metal type of filament and sintering, usually by heat or laser to harden the metal, and often needing compensation for shrinking and a lot of other inconveniences. The resultant pieces are "metal" but not strong enough for most internal firearms parts that need to be metal but not necessarily pressure-bearing like a barrel: most notably bolts and carrier groups, fire control group parts like triggers, hammers, sears, disconnectors.
doe_eyes 2y ago
You can't easily make a high-quality firearm a hobby mill, chiefly because the barrel needs to be made out of good steel and needs to be rifled. But the quirk in the US is that federally, only the receiver is the regulated part, and many types of receivers can be made out of plastic or aluminum. You can certainly use cheap three-axis CNC with some fixturing to make AR-15 receivers, for example, and many people did. Cody Wilson / Defense Distributed had this whole thing where they were selling CNC mills for cranking out guns. You can also definitely make junk single-use guns using either technology, just like the 3D-printable "Liberator".

eth0up 2y ago

To the machinist/s here: For nearly a year, I've been contacting local machinists for a small[*] project which involves 1) an accurate cut on both ends of a 17" billet of T6061, 2) two crescent cuts, 3) up to 8 threaded holes, but probably, 4) a wee bit o end shaping. All the aesthetic contours, shaping and weight reduction I'd do manually - I hand machine bronze, aluminum and wood archer's thumb-rings, so can wangle that part. This project would result in the world's first ILF asiatic (no shelf), ambidextrous aluminum 17" riser. Though... Every machinist I've spoken to is either friendly at first, implying willingness and ready capabilities, or they simply say no thanks. But all of them ultimately reject the task, typically saying they're too busy. I also have a design for a bow stringer that can handle longbows, recurves and short Asiatic bows safely and efficiently. No one will fabricate it around here. Any suggestions as to why this is such a pariah project? Any suggestions on how I might achieve this? * Not necessarily a good reason/excuse

potato3732842 2y ago
Find a hobby machinist. People who aren't trying to expand their business don't want to deal in non-gravy projects from customers who don't seem likely to shovel them a bunch of gravy projects later. Machining is a slowly dying industry in the west so there's far more people not growing their business at any one time.
- eth0up 2y ago
  Thanks for the insight. I think you're correct... My area is very gravy oriented in general.
WillAdams 2y ago
Have you looked at Shapeways or sendcutsend or xometry or 100k Garages? That said, I have an especial interest in archery and multiple machines. Contact me at: https://community.carbide3d.com/u/willadams https://community.carbide3d.com/u/willadams and we can at least work out doing a couple of prototypes.
- eth0up 2y ago

mvidal01 2y ago

I wish there was an update to these pages. Some of the products and urls are defunct.

WillAdams 2y ago
The most likely successor would be: https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z (ob. discl., I work for Carbide 3D)

KaiserPro 2y ago

I wish I had seen this when I was starting out, that would have made life a lot easier!

jwr 2y ago

I followed that guide (it is excellent, if a little outdated) to get really good results. I should really write up and share my experiences, there is so much to learn. In brief: * It's an excellent method of producing very precise parts with fantastic mechanical properties (the next step up is aluminum, but you don't need it in most cases). * It is much more difficult than just throwing something at a 3d printer. * It is not comparable with 3d printing at all. I use both methods: FDM printing for most stuff, resin casting for parts that need to be strong, dimensionally precise, or nice. * Yes, you can use your resin printer to produce originals or master molds, but you will have two problems: 1) precision, 2) silicone cure inhibition. * Tips for those in the EU: Sika Biresin F50 is fantastic, Rencast 5146 is slightly worse (higher viscosity), but works very well, too. Both are relatively easily available. For silicones, BLUESIL RTV 3450 is unbeatable. * For desktop CNC machines, there are good options now: Makera Carvera (either the full model or the "Air" scaled down version) are really nice and precise machines. Software is crappy, but hopefully will get better. I had a Nomad 3, but switched to Carvera. * Don't buy a cheap CNC. There is simply no way to produce a desktop CNC with good precision for less than, say USD $2000. You will be disappointed. Perhaps if one day a Bambu Lab arrives with experienced engineers and a lot of money, they could mass-produce something cheaper, but right now this is roughly the cutoff. * Autodesk Fusion, much as I hate it and the company behind it, is pretty much the only game in town if you want integrated CAD+CAM. Again, I hate the software with a passion, but there is simply nothing else that is as well integrated, works well, and is reasonably priced. * Achievable precision: ±20μm is doable with a little care, things get difficult below that. This is roughly 10x better than what you can get from FDM 3d printing. Note also that this is the limit of what most people can measure: your calipers have an error of ±20μm if they are good. I also noticed that the 3d-printing crowd often has no idea what precision means, so you'll see crazy numbers thrown around. * Mechanical properties of produced parts are way better than what you can get from FDM printing. I laugh at those "strong filament with carbon fiber" youtube videos.

dylan604 2y ago
> It is not comparable with 3d printing at all. Not just not comparable, but totally opposite. Subtractive vs Additive. CNC is like chiseling the David out of single block of stone by removing bits. 3d printing is starting with nothing and adding material.