Earlier this year I decided to really splurge and bought a Fireball V90. Think of it as a wedding gift to myself. It’s a very nice entry level CNC machine. I figured if I was building controllers and whatnot, it was the natural way to upgrade the hobby. Plus, it will let me build more than one copy of a project much more easily.
The machine comes as a kit – putting it together is pretty easy (especially as I lazied out and got the option with the assembled USB control box). In fact, the CNC USB controller is one of the best parts of the kit – it has tons of growth potential, and you can mod a lot with it. For the price, it’s a very nice machine. But to really get the most out of it, you need to make a couple of mods.
1. Homing switches
Most projects are best designed in pieces – first route out the pockets, then cut the holes, then cut the main parts, and so on. It’s very handy to be able to stop between these steps, and not have to worry about alignment/registration issues – and it’s even nicer to be able to change the cutting bit for different parts. In order to do this, the machine needs a known zero point. By default the V90 does not have this, but the USB controller supports it. You need to add microswitches, capacitors as spike filters, and then run a cable back to the controller board. Once they are installed, all you need to do is hit the “Go Home” button on the USB controller UI, and then machine returns to (0,0). This is a must have mod.
2. Jogging joystick
The USB controller UI has a set of jog buttons (these let you manually move the cutting head around to position it for cleaning, maintenance, etc). However, in my shop the CNC machine is quite a ways from the PC that controls it, which is inconvenient. The USB controller supports an external jog stick (some microswitches and filters again). I cut up an old TI 99/4A joystick I had lying around, installed the switches, and ran some ribbon cable back to the controller box.
3. Dust management
This is by far the biggest problem with the V90 – if you are cutting MDF (which is my most common material), then you have an incredible amount of very fine dust flying around (which cannot be good for your lungs, and it’s definitely not good for the machine’s bearings).
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To solve this problem, I first bought a Ridgid shop vac, but the MDF dust is so fine that it clogged the filter in about three minutes. This I solved by getting a Dust Deputy, which is a hobby grade cyclonic dust separator. You attach this device inline in the vacuum hose, and it forms a mini cyclone that extracts 90% of the dust before it reaches the the vacuum filter. This device is just amazing – it works exactly as advertised, and my shop vac keeps happily snorting for hours.
The second part of the equation was attaching the vacuum hose near the cutting head. I built a custom holder (the grey bit below) that bolts to the router clamp. It took quite a bit of planning to ensure you can still reach all the correct bits of the router to change cutting bits, and I made it as small as possible to keep the weight down – I wanted to add as little drag to the stepper motors as possible. Then, I built a detachable dust skirt (they brown piece below). This attaches with magnets for easy removal, because with it installed, you can’t get to the router head. The only problem was that the bottom part of the skirt is made of PET plastic, and to glue that to the MDF I had to use Household Goop (a silicone based adhesive), which is the messiest crap in the world. But it does the job – it keeps most of the dust from flying away from the vacuum head.
The final step in dust management is to reduce the amount of dust produced in the first place. In my first cuts, I used a .25″ endmill, which eats a lot of material, and therefore kicks up a lot of dust. I used the larger head so that I could increase the traverse speed of the head, but I decided that I would rather wait than create a dust cloud. By switching to a .125″ endmill and reducing the traverse speed, I reduced the amount of dust significantly.
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