I was thinking about this lately:
How hard would it be to build a CNC machine controller that has a micro SD card slot, so when I want to debug the G Code and make a test part, I control the CNC machine with a computer directly, but when everything is already worked out, I save a G code file on the SD card and the controller reads the code off the SD card and no computer is needed.
I tried building this kind of controller, but I really could not find any information on how to build a device that is visible to a PC as an external memory, in the file explorer.
I envision this controller to be like a digital camera, so it can work when it is attached to the machine and on its own, except instead of saving information to the SD card, it will read the G code off the SD card.
Not something I could build using PIC18 microcontrollers and my limited knowledge of USB.
You are welcome to build your own devices that work on this principle if you like my idea.
If it works out, send me a circuit, please. If you commercially succeed at building a controller like this, please send me one.
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Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
What benefits would this idea have over the computer?
Well it can store a lot more information than a mem card ie you'd have to have a bunch of mem cards and swopping and changing.Well. The benefits are that computer is really an overkill to run a CNC machine.
Too much processing power.
And how would you select a certain file to machine from the card? and mem cards are not that reliable.Plus you have a hard drive, a communication line. More things can go wrong in process of manufacturing.
It will never catch on,people like to take control of their machines rather than slip a card in and away yer go ie its the joy of routing a piece of work and the end result gets us with a big smile.Awesome project.
It takes a huge amount of processing power to contour at high speed. All the big players went to 64 bit long before pc's ever did.
You will still have to plug the card into a computer to transfer the data over for the job piece,,,,so rather defeats the object doesn't it.
The developer dropped the ball on it. I believe that anyone who wanted could purchase one.
They are used in the Shark routers that Rockler sells in standalone mode with SD cards, I believe.
And mach3 has a plugin to use it with the PC, but the plugin was never fully completed due to an apparent lack of help from the developer of the NcPOD. If the developer would have worked to get a fully functioning Mach3 plugin, they would have sold thousands of them. Instead, everyone who purchased them eventually moved on to different hardware.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Simple, they don't use PC's. They make there own hardware and software. Hell, Okuma way back, like 1982 was running twin 16 bit controllers, then in very early 90's twin 32 bit.
Here is an article worth reading, but notice the date-1999. Now we have AI nano smoothing, super nurbs, among lots of other capabilities.
Understanding NURBS Interpolation : Modern Machine Shop
I got the idea of this NURBS interpolation. Sounds like a human-friendly way to compress a bulk of discrete data. From a mathematical point of view, there is really no difference between interpolation and data compression. Unless you have all the mathematical formulas punched into the controller to "restore" a curve that an engineer had in mind when the part was drafted. But there is an easier approach, I think: allow mathematical functions in G code.
So I am not sure whats wrong with sending data to the machine dot-by-dot. The bit is still following a path, determined by discrete data sets.
You need to keep in mind, it's 1000+ blocks a second to the servo controls, but it's way more data back from the servo controls to hold position and contour. It's not just sending data, it still has to compute servo error, slow down/ramp up speeds for cornering, spindle and z axis positioning for taping/threading, all the rest of the machine signals I/O for tool changer, lube system, machine errors, timers, etc. I can remember old 286 computers on some very low end equipment that would totally bomb out and run an axis to its limits. I'm not saying its not possible to build something new, just not real easy. And how would you do tool offsets/fixture offsets? Those are all machine specific.