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CNC milling with open source software

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Re: CNC milling with open source software

#21

Post by gangstead »

nadavami wrote: post #8
cmsimike wrote: post #7

I've been looking for a home PCB machine and would appreciate any recommendations on what to look at or what to avoid. I've been told multiple times that it's easier to just have a service print your board which is probably true, but that would take a lot of fun out of the entire process for me.

I've been using a 3018 CNC with pretty good results. They're fairly inexpensive machines (about $300 I believe) and are decently accurate. I still order boards from China, but for a quick breakout board it's incredibly handy! I also decided to get a 5W laser which is also pretty fun to engrave with. I'm planning on writing a series of blog posts about it if you're interested! As a last note, if you like tinkering, th…

I'm definitely interested. I got into 3D printers and CNC machines at about the same time last year. I figured out the 3D printer right away and quickly went from printing out things on thingiverse to doing my own designs and outgrowing my printer and getting a fancier one.

While I've done about 250 print jobs in just under a year on my 3D printers after 8 months with the CNC I've cut two things. I got an entry level CNC (Millright M3) that runs the same GRBL on Arduino software stack and I've just been stumped after setting it up and cutting a couple rectangles out. The amount of time you have to put into setting up a CNC job is exponentially more and the amount of reference material out there is way less and way more specific to particular work flows / machines / pieces being cut.

Re: CNC milling with open source software

#22

Post by jpm_sd »

HeyLaughingBoy wrote: post #19
cmsimike wrote: post #7

I've been looking for a home PCB machine and would appreciate any recommendations on what to look at or what to avoid. I've been told multiple times that it's easier to just have a service print your board which is probably true, but that would take a lot of fun out of the entire process for me.

It's not just that it's easier, but you can get much finer detail, you don't have to deal with vias, and you can do more than two layers. And (big plus in my book), you don't have to deal with the inevitability of breaking those insanely small end mills. The only benefit over having a board shop do it is the turnaround time, and even that's essentially a tradeoff of time vs money. I just sent a board off to OSHPark.…

This is all true. The biggest deal breaker for any kind of serious work is being constrained to two layers, routing is so much harder that way!

Milled PCBs also have lousy surface quality which is incompatible with fine pitch parts.

Re: CNC milling with open source software

#23

Post by th0ma5 »

opwieurposiu wrote: post #18

CNC is programming "for keeps". Any tiny little error in your gcode has a chance to crash the machine. Unlike a computer crash, a CNC crash results in broken metal flying across the room and anywhere from $5- to $5000 in damage. I programmed for a heavy machine shop for a year before I gave up and went back to making websites. Hobby CNC is fun though, it is amazing what you can make out of wood when you can shape it…

Is there no way to test? Or there is, just not everything?

Re: CNC milling with open source software

#24

Post by Ccecil »

phkahler wrote: post #17
jcoffland wrote: post #5

If you're interested in Open-Source CNC you should check out two of my Open-Source projects. https://camotics.org/ a CNC simulator and https://buildbotics.com/ a CNC controller. I'm somewhat surprised neither of these were mentioned.

Do any of them support the arc or spline gcode? I noticed that most of the 3d printers do not, even though they are essentially 4-axis CNCs.

3d printers typically don't care about arcs or splines since they only use STL files which do not have "real" curves.

Some firmwares support arcs (smoothieware, which is based on GRBL) but it still breaks the arcs down to segments.

Re: CNC milling with open source software

#25

Post by nickpinkston »

th0ma5 wrote: post #23
opwieurposiu wrote: post #18

CNC is programming "for keeps". Any tiny little error in your gcode has a chance to crash the machine. Unlike a computer crash, a CNC crash results in broken metal flying across the room and anywhere from $5- to $5000 in damage. I programmed for a heavy machine shop for a year before I gave up and went back to making websites. Hobby CNC is fun though, it is amazing what you can make out of wood when you can shape it…

Is there no way to test? Or there is, just not everything?

The best shops use simulation tools, but you need the 3D models / configurations of everything to make them work, and then the machinist still needs to load everything correctly. It's very easy to make a mistake.

Check out a simulator here: https://www.ncsimul.com/

Re: CNC milling with open source software

#26

Post by Ccecil »

I work with the smoothieware project (hardware QA). It is an opensource motion control firmware and openhardware control board which works with 3d printers, lasers, mills, etc. Initially based on GRBL and runs on ARM (LPC1769).

The openhardware scene has advanced quite nicely in the last 5 years. There are many very nice projects out there to build from which are largely able to be built at home with parts which can be made locally and/or purchased online. Openbuilds is a good place to start if you are interested.

I always try to remind people...whether it is 3d printers, mills, lasers...the knowledge gain from building/breaking/rebuilding your machine far outweighs the small gain you get from simply operating one. I have never printed an object as interesting to me as it was to create and design an entire working machine from scratch.

If anyone is interested in openhardware projects I recommend checking out reprap.org , smoothieware.org , openbuilds.com as well as several other projects which I am sure you will stumble upon through research on those sites.

There are many opensource CAD/CAM software packages out there which allow you to pick and choose what you like. I personally use Fusion360 for most of my CAD/CAM stuff (I know...not Opensource) and for 3d printing my personal favorite is Slic3r.

Re: CNC milling with open source software

#27

Post by tlarkworthy »

G-code is the most hilariously bad language. Keywords are G + a number, e.g. G01, with wildly different effects, varying arg lists and no standard. E.g. G01 move to position, G20 set the machine units to inches. Its often stateful.

Obviously its coz its old and works, but i chuckle everytime i have to look up the codes at how comically awful it is compared to anything else i see

https://en.m.wikipedia.org/wiki/G-code

Re: CNC milling with open source software

#28

Post by phkahler »

Ccecil wrote: post #24
phkahler wrote: post #17

Earlier quoted context omitted.

Do any of them support the arc or spline gcode? I noticed that most of the 3d printers do not, even though they are essentially 4-axis CNCs.

3d printers typically don't care about arcs or splines since they only use STL files which do not have "real" curves. Some firmwares support arcs (smoothieware, which is based on GRBL) but it still breaks the arcs down to segments.

>> 3d printers typically don't care about arcs or splines since they only use STL files which do not have "real" curves.

I would have thought the printer would support arcs even if the slicer doesn't. There is work going on to support arcs in slic3r (automatic detection of arcs) but it will be irrelevant for printers that don't support it. It's would also be possible for a slicer to import step files and find such surfaces. One can also approximate other curves with fewer gcodes if they use arcs vs lines - splines even fewer.

Re: CNC milling with open source software

#29

Post by sanj »

opwieurposiu wrote: post #18

CNC is programming "for keeps". Any tiny little error in your gcode has a chance to crash the machine. Unlike a computer crash, a CNC crash results in broken metal flying across the room and anywhere from $5- to $5000 in damage. I programmed for a heavy machine shop for a year before I gave up and went back to making websites. Hobby CNC is fun though, it is amazing what you can make out of wood when you can shape it…

"For keeps" is right!

Years ago I was helping a friend model a cam at the heart of a large piece of metals processing equipment for these guys: https://www.butechbliss.com

It was _almost_ right, but had a negative curvature on one surface. The effect was to lift a multi-ton piece of machinery off the floor – which it was bolted to.

My understanding is that the cam is now used as a coffee table!

Re: CNC milling with open source software

#30

Post by Ccecil »

phkahler wrote: post #28
Ccecil wrote: post #24

Earlier quoted context omitted.

3d printers typically don't care about arcs or splines since they only use STL files which do not have "real" curves. Some firmwares support arcs (smoothieware, which is based on GRBL) but it still breaks the arcs down to segments.

>> 3d printers typically don't care about arcs or splines since they only use STL files which do not have "real" curves. I would have thought the printer would support arcs even if the slicer doesn't. There is work going on to support arcs in slic3r (automatic detection of arcs) but it will be irrelevant for printers that don't support it. It's would also be possible for a slicer to import step files and find such su…

Some of the firmware versions do have G2/G3 in them but not all. http://smoothieware.org/supported-g-codes

I assume most of the modern ones do but some of the older 3d printing firmware use a very butchered version of the gcode "standard" which eliminate or rename many of the unused codes.

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