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Goings on at the Because We Cannery

Frank's new brain! (4g Geckodrive upgrade from Shopbot)

One of the coolest things about our CNC routing table is that it's fully upgradeable and hackable. One very recent example of this is the new 'brain' we just got for it.

PRT 4g Upgrade Board

The 'brain' in this case is the controller box for the CNC table. It controls and provides the voltage to the stepper motors that move the CNC table's cutting tool around. You hook a computer up to it, via USB (I love that it's USB), and by running the Shopbot control software feed it jobs to cut. Think of it as a '3D print spooler'. Now, this 'brain' is simply mounted in a modified beige PC case. Here's a picture of the old one.

old PRT board

This is the one that came with the Shopbot originally. It worked fine, but it was kinda slow. We could only cut at about 2-4 inches per second, and 'jog' (that's when it's quickly moving to the next cut over the top of the material) at about 4-5 inches per second...

new PRT board

As you can see the new controller board is much larger. Those big black slabs are the 4 Geckodrive 202 stepper drivers. These not only supply more voltage to the stepper motors (making them go faster) it also sends that power with more 'pulses' for finer resolution. See, the old board drove the motors at a 4:1 (that's four pulses per move) and this one does 10:1. This makes it cut smoother. It also makes the stepper motors not 'groan' anymore (they made some great noises) which is a big of a shame, for that was an endearing characteristic and part of why we named the CNC table 'Frank'. This board can also take a fifth one, so when we get another axis we can drive that too.

old PRT board

It was an easy swap, no different from swapping a motherboard on a old PC. Shopbot uses a lot of off-the-shelf parts to make it easy to fix and upgrade these machines, something we really dig.

old PRT board

Here I am finishing the install...

Adjusting the voltage

The only 'hairy' thing was adjusting the voltage. See, while it's just a normal PC case, with a normal power supply in the back, there is a second power supply in the front of the case for the stepper motors. You've got to turn this up a notch to get the full effects of the upgrade.

But man, what an upgrade! We're cutting at 6 inches per second now, and jogging at about 12. That's a foot a second! Things that took 30 minutes to an hour now take 15 minutes or less. It's a big jump, we can now screw up faster than before. We've also got to hold down things more now as well, for the motors move with a lot more force, which tries to push things around more when they are cutting. But it's so great to have be able to simply double or efficiency in about 15 minutes of work...

Jeffrey McGrew