Electronics > Projects, Designs, and Technical Stuff
Largest Milled PCB yet?
beanflying:
Adding a PI is not a better solution to a 3D printer it does nothing to useful to the G code in terms of the print itself and is not required by the printer to operate. The apps watchdog like functions are of some use but lack in what I want for enclosure control so I will be going somewhere different for mine. A $30 wifi camera looks after my three printers if I want to take a look and at this stage I will be staying with cards for data. My previous post was background to what can be done without attached PC's or additional micros with simple boards.
Adding this sort of functionality to the cheaper or home brew CNC routers needs to take some leads from the 3D printer manufacturers. There is a few forks of Marlin for linking RAMPS style boards in existence but I haven't looked into them much but as far as I am aware they still use a PC in the loop, this is the link that needs severing. PC's are as you point out not needed nor is even a LINUX board what is needed is a simple G code interpreter with some setup controls and interface and the processing needed is no more complex than 3D printers.
My bigger router which I got secondhand with a PlanetCNC board already fitted is getting it's own dedicated mini PC to drive its controller with Windoze auto updating as removed as possible :horse:
The industrial end of the market is another whole can of worms and getting well off topic.
janoc:
--- Quote from: beanflying on January 06, 2019, 07:05:27 pm ---Adding a PI is not a better solution to a 3D printer it does nothing to useful to the G code in terms of the print itself and is not required by the printer to operate. The apps watchdog like functions are of some use but lack in what I want for enclosure control so I will be going somewhere different for mine. A $30 wifi camera looks after my three printers if I want to take a look and at this stage I will be staying with cards for data. My previous post was background to what can be done without attached PC's or additional micros with simple boards.
--- End quote ---
And what "useful things with the G-code" do you want the 3D printer controller to do? (apropos, Octoprint can actually slice models for printing but doing that on a Pi is quite a masochism).
The idea of Octoprint and similar is to add convenience to the machine, nothing else. If your machine has such functionality built-in, then you really don't need it (some printers actually do already) but many don't. My Mendel90 can work from an SD card and can have an LCD + encoder/button connected to it (it doesn't come with one - it was a kit printer) but I still much prefer being able to upload the ready to go G code from my "CAD" PC to the machine over the network instead of messing with cards and then the limited UI offered by the printer.
If you don't find that useful, fine but I think a lot of 3D printer users will disagree with you there.
--- Quote from: beanflying on January 06, 2019, 07:05:27 pm ---Adding this sort of functionality to the cheaper or home brew CNC routers needs to take some leads from the 3D printer manufacturers. There is a few forks of Marlin for linking RAMPS style boards in existence but I haven't looked into them much but as far as I am aware they still use a PC in the loop, this is the link that needs severing. PC's are as you point out not needed nor is even a LINUX board what is needed is a simple G code interpreter with some setup controls and interface and the processing needed is no more complex than 3D printers.
--- End quote ---
Actually Marlin and RAMPS are a fairly terrible solution (even ignoring the design and manufacturing problems some of these boards are notorious for). Those boards are being pushed to their limits by the 3D printers already because the 8bit ATMegas on these are not exactly speed demons when it comes to the math necessary for calculating the movements. There are plenty of printers on the market which "outrun" their controllers - are capable of higher printing speeds than what the poor Arduino-compatible RAMPS board there can computationally handle.
I don't see something like RAMPS being able to drive some serious motors you would find on a CNC neither, the typical "Stepstick" style drivers stuck in female pin headers these boards use simply wouldn't be able to handle the currents. Some poorly designed boards struggle even with the common NEMA 17s already, losing steps or going into overtemp shutdown on the drivers - making you lose your print in the process. Also if your CNC happens to actually use servomotors with encoders, you are out of luck, because most boards targeting 3D printers don't have any support for them. Though I believe there is at least a variant of Marlin (or perhaps GRBL) firmware that allows closed loop control if you want to make your own board.
There are more modern and better boards around - e.g. Smoothieboard (some list here: http://3daddict.com/32-bit-3d-printer-board-comparison/ ) but those generally solve only the math slowness part by using a beefier MCU (typically some ARM), not the other issues. Those don't matter on a 3D printer but may be a problem on a CNC mill.
Kilrah:
--- Quote from: David Hess on January 05, 2019, 02:18:00 am ---Configure the network interface to a metered connection to stop Windows from downloading updates until you do it manually.
--- End quote ---
Even better, flip the "don't update for a month" switch...
beanflying:
--- Quote from: janoc on January 06, 2019, 09:35:06 pm ---Actually Marlin and RAMPS are a fairly terrible solution (even ignoring the design and manufacturing problems some of these boards are notorious for). Those boards are being pushed to their limits by the 3D printers already because the 8bit ATMegas on these are not exactly speed demons when it comes to the math necessary for calculating the movements. There are plenty of printers on the market which "outrun" their controllers - are capable of higher printing speeds than what the poor Arduino-compatible RAMPS board there can computationally handle.
I don't see something like RAMPS being able to drive some serious motors you would find on a CNC neither, the typical "Stepstick" style drivers stuck in female pin headers these boards use simply wouldn't be able to handle the currents. Some poorly designed boards struggle even with the common NEMA 17s already, losing steps or going into overtemp shutdown on the drivers - making you lose your print in the process. Also if your CNC happens to actually use servomotors with encoders, you are out of luck, because most boards targeting 3D printers don't have any support for them. Though I believe there is at least a variant of Marlin (or perhaps GRBL) firmware that allows closed loop control if you want to make your own board.
There are more modern and better boards around - e.g. Smoothieboard (some list here: http://3daddict.com/32-bit-3d-printer-board-comparison/ ) but those generally solve only the math slowness part by using a beefier MCU (typically some ARM), not the other issues. Those don't matter on a 3D printer but may be a problem on a CNC mill.
--- End quote ---
Leaving Octoprint/PI alone as it is off topic and will drag this thread further away from the OP's Post. It deserves it's own thread.
We have been seeing the first 32 Bit boards getting around more and more over the last year or so, using 8 bit as some sort of a argument or point is what exactly? 8 bit apart from the bottom end of the market will be gone fairly soon IMO.
Do not take the words I wrote and try to make them more than they were. I made an OBSERVATION that there were some forks of Marlin to Ramps boards that I was aware of in passing. I didn't suggest them as a solution just that people had done some work on it as I own a Laser Cutter in my tools I was interested in options when I first got it.
Marlin is a fairly well developed and constantly evolving standalone interface to a CNC machine in the majority of cases it is 3D printers. There is no reason I can think of it couldn't be forked for example to a non ramps cnc router board in particular if done from scratch.
At the Hobby end sizes (lets just pick 3020 and smaller) what is needed is a some modification toward a 3D printer standalone solution. Local Data storage, G Code interpretation, Interface for jogging, setup etc. You are making an assumption that the CNC board would use bottom end Chinese step stick drivers like the 5+ year old RAMPS boards to do this would be a really poor choice given what hardware is already in use and available now.
So be it a Marlin, GRBL, Repetier or whatever firmware as a starting point time to lose the PC.
When you leave the 3020 there is currently a large jump overall in requirements and purchase price and you are into the realms of Mach3&4 PlanetCNC etc. so likewise best left alone for another thread.
Mechatrommer:
there is no use of super power mcu if the mechanic cannot handle the speed. once i speeded up my knock off prusa (the china master copy from where i learnt to build another machines at fraction of cost), but the result is poor print mainly due to mechanical reason iirc, so i slow it down. the atmega mcu has more time waiting than compute, i dont see any fault or jittery motion even on fast speed setting that can be narrowed down to mcu bottlenecking, i got a good GUI respond as well, no pause in motion. imho, faster mcu is mostly gimmick on better colorful GUI etc, but i maybe wrong, anyway my prusa works fine in term of mcu processing. the driver stucked in female header is not a good excuse to dismiss OSHW reprap/marlin/ramps as the header is meant to put the right driver on (extendible and configurable) if user see not enough current or missed steps, user should upgrade to bigger version motor driver and the motor, thats the idea instead of buying another new machine that costs another 3-10X. imho as a person who built some proto machines from scratches. i believe we can buy that cheap arduino + ramps shield board and then put another appropriate driver, motor and gearing system to lift a tanker.
the earlier proto-bethan i showed is pretty much a standard OSHW reprap 3d printer build (arduino mega + populated ramps shield, except with different mechanism of and the short Z height and head assembly from 3d printed parts), no need to fiddle with marlin FW, just copy to mcu as is, use FlatCAM OSS to translate gerber to gcode and good to go. i only need to hack GCode for manual drilling process, ie the head will go to drill position (translated from NC Drill file), and then i will correct pcb position and hit enter (encoder button) and head will start drilling. alot better than looking at PC screen to find which hole position and then drill with freehand. 0.5 - 0.8mm drill bit and freehand dont work together nicely, i killed many bits before, before even successfully punching a hole.
there is one word for faster mcu (even OSHW version), its "ex pensive". and close feedback loop motor system? few words... more more expensive than the expensive. a single stepper motor system including the close loop control board can cost few times than my prusa. let alone building complete system using 3 or 4 of that. imho CNC machine only suitable if people want to get serious in substrative CAM such as making mould, aluminium rf shield and enclosure or a some quality metallic pendant for SWMBO etc, but for scratching pcb? i dont think so. anyway a sure way to get a really working machine is go to Hitachi or Toyota factory and ask what CNC they use, buy that.
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