MESA Cards, low cost PCIe cards for CNC Machines

[VitranAccad]

An odd topic that I am unsure if something people would be interested in here. It's techy. It allows you to interface servo motors with your computer. It makes machines come alive with potentially hundreds of IO to interface with the real world. It up-cycles old computers too. I am posting here because it seems like something Linus Tech Tips would be interested in in some sort of brief discussion, but not something to seriously look at. If someone wanted to make a VR chair, a full servo 3D printer, a robot arm, or something similar, this would be a great tool to use.

 

LinuxCNC* (http://linuxcnc.org/) is a DIY CNC program for CAD/CAM. People have used this program and equipment to rebuild CNC machines weighing tens of thousands of pounds to making their own custom 3D printer. It's capability is large and is (relatively) easy to use compared to other industrial cards and programs. I would hail it as one of the best open-source programs to come out of the community behind Blender and Inkscape. I will also say I am not an expert in the full details about LinuxCNC, but I have used it to rebuild a Hardinge Superslant CNC lathe. A true expert would be someone named AndyPugh on the LinuxCNC Forum. https://forum.linuxcnc.org/

 

The program runs on Linux, and has a ready-to-install CD running Debian. It can run on any old PC and if the computer has a parallel port it can be used to control a plotter, laser cutter, or XY gantry. If anyone has used GRBL on an Arduino, this is a massive step up.

 

However, where LinuxCNC really shines is its interface with Mesa. Mesa cards are ~$300USD and connect via a PCI or PCIe port to allow rapid communication to perform closed loop controls on servo drives. You can custom program in Ladder, C, and other methods if required. Mesa cards are made by PCW, and he is also a big member of the LinuxCNC forum.

 

My latest LinuxCNC project was a Hardinge Superlant 3 Axis. It is a production CNC lathe that I purchased for $3k, however I have seen similar CNC machines go for $1 as companies want you to pay for the rigging to get rid of it (rigging cost me $900) and the number of people capable of taking an old machine like this are rare. I learned a lot about how data and communication is performed, as well as how motion control is done in the production of this machine. I am also looking at swapping out our other machine, a Deckel FP50CC/T, with LinuxCNC as well.

 

The control case. A nightmare, I know. And yes, the computer is held in with a shoelace. 

 

My CNC used a Mesa 7i77 and a 7i64 to have enough IO to control the machine, and even then, I have 0 spare. I should have gotten more. They were from here:

http://store.mesanet.com/index.php?route=product/product&path=69_73&product_id=214

http://store.mesanet.com/index.php?route=product/product&product_id=120&search=7i77

http://store.mesanet.com/index.php?route=product/product&product_id=110&search=7i64

 

*used to be known as EMC and may be referred to as such

[ColinLTT]

Can put my 2c in here: 

 

Going from GRBL -> Mach3/4 is a big step up, and totally manageable for a day to day use machine - however, going from Mach3/4 up to LinuxCNC is a HUGE upgrade. Because everything runs at your PC's clock speed when you hit pause, it actually pauses - no waiting for the buffer of movements to finish like with Mach3

 

It's not for the faint of heart though, as configuring it is rather tedious and I spent a fair few weeks banging my head against the table when I did my (now gone) G0704 - I used a 7i76 I believe, its been a year or two so I've forgotten some. I actually ended up getting a Pathpilot disc and had the machine running with the nice PathPilot GUI and macros. 

 

What the CNC community has done as far as retrofits for old machines with LinuxCNC is amazing - fully reworked tool changers, multi spindle machines, you name it. If you have the time and the skills, you can get it to run in LinuxCNC - highly recommended if you can spend just a little more money for the cards.