Fireball v90 CNC Machine
A CNC machine is a very useful tool to have around. It will not produce brackets quickly. It won't do much quickly at all. Everything takes time, but the results should be much better and more accurate than if done by hand. I purchased the Fireball v90 CNC machine from Probotix with all options fully maxed. I bought the best steppers offered, the large enclousure and that fit within my budget.
A CNC machine is expensive. The Probotix machine is on the low end around $1200 shipped, fully loaded. On top of the CNC machine you will need a spindle (Dremel) ~$50, end mills (the bits) $15-???, software Free-$2xxx, possibly a parallel to usb interface $75-170, and a computer.
You can spend a few hours reading about endmills from various places online and still feel you don't know enough to being purchasing them. Their are many types, features, shapes, etc. End Mills are expensive drill bits that are designed to cut sideways. The best site I found to order end mills from was precisebits.com.
- 2 Flute bits eject chips faster than 3 flute bits. In theory you can run 2 flute bits a little bit faster , while 3 flute bits will provide a smoother edge.
- Shank diameter should fit your spindle (Dremel is 1/4 inch).
- Depth of cut is a measurment of how deep your end mill can go. You don't want to exceed the depth of cut of a bit.
- Ball nose end mills will produces a nice, smooth finish but can leave burn marks if they drag on the material.
- Fish tail end mills will leave a rough cut. They will not leave burn marks on the material if they drag.
- Purchase bits with depth rings installed. This will allow you to set the dept the same for every bit without trouble.
- Upcut bits eject the material upward, downcut eject downward. To start purchase upcut end mills
- Use a straight cut end mill for nicely cutting acrylic.
- Use Non-ferrous metal bits for thin aluminum.
- Use engraving end mills for etching plastic, metal, wood or pcb circuit boards.
- You will break end mills, buy extra.
The Dremel is an excellent spindle to start with. The FireBall CNC v90 comes with a mount for a Dremel. Dremels tend to wear out over time and at some point will stop rotating circular. You will want to upgrade at some point. Probotix sells mounts for different spindle types. I suggest purchasing a Wolfgang spindle if you intend to cut PCB's it is very accurate. They can be found on Ebay and Probotix sells a mount or you can cut your own.
Most of the experienced CNC users will tell you just to buy an old pc and use that as it has a parrallel port. I personally hate maintaining multiple machines, so I ignored that advice. I do not do anything else on my PC while I'm milling so this is generally OK. The computer you use to control the machine should be free of actively running software that can hog the busses or processor as you mill.
Keep in mind that newer PCs do not have parrallel ports. Most CNC software requires you to have a parrallel port. If you run a 64bit version of Windows you are out of luck at present. 32 bit users of Windows can purchase specific PCI cards that will add a parrallel port and work. Those without a parallel port or a 64bit version of Windows should consider purchasing a SmoothStepper. The SmoothStepper controls the CNC machine via USB. It only presently works with Mach CNC software though. Users of Linux with a parrallel port should be okay if you plan on using EMC as your software.
Don't be fooled by thinking that you will not have a cost of software. A full free toolchain does exist but it may not do everything that you need.
Modeling: I use blender 3d (free) to do all my modeling. It has a bit of a learning curve. I found that spending 3-4 hours watching tutorials online was enough to get me up to speed. I also keep a keyboard shortcut list handy. Learn about booleans, extruding, filling, selecting and moving points, vertices and faces specifically. Lots of commercial solutions exist but I also use this software for my MakerBot, so I was comfortable with it. AutoCad is supposedly an excellent choice as well.
CAM: This software is used for creating tool paths that the machine will use to cut your piece. The code that is produced by the CAM software is called G code. If you want to make designs larger than your CNC machine can handle, you should invest in something that slices up your model and creates G code for each layer. I highly recommend Vectrix Cut3D for this. It only runs on Windows. I purchased V-Carve which has a very nice interface for creating signs and etching 2d items in a budle with Cut3D. I didn't look into free software for this step as Vectrix came highly recommended even from Probotix.
CNC Control: Many CNC sites will try to tell you this is free and you can use EMC on Linux. This is possible if you have a pc with Linux and a parallel port around. If you were forced to purchase a SmoothStepper for this part you will need to purchase Mach3 to use it. After many hours spent reading the CNC forums their is an emerging trend of users switching to Mach3 from EMC2 over time. I've never used EMC as I bought a SmoothStepper so I can't speak to why this is. Mach3 is fairly easy to use and a demo is available.
One of the most overlooked parts of a CNC machine is what you will use to hold down the part you are cutting. I've looked at several solutions and decided I would create a pattern for hold down holes in VCarve and have the CNC Machine drill them for me into the spoil board. I am then using a set of hold downs purchased from Harbor freight to screw into the holes.
A CNC machine when running will spew lots of dust and bits of material everywhere. A Shop Vac will come in handy to keep the work area clean. The addition of a Cyclone connected to the ShopVac will filter out all large bits into a convient bucket.
Shipment of my Fireball kit was very fast. In total, it arrived a week after I ordered. The packing was very well done, but one piece was still chipped on arrival. This was clearly the fault of the mail service and not Probotix. The box was badly beaten up when it arrived. The chip is shown in the pictures below and it does not hinder the machines functionality. I fixed this with a bit of touch up paint and I was good to go.
Assembly of the Fireball was very straight forward. Some of my parts came pre-assembled and I was able to skip steps of the posted instructions because of this.
The small pipes go on top, the large on the bottom.
It appears that most people struggle with getting the tension rods through the pipes blindly, just keep trying. It took me 3-4 tries, but it is possible. If you have this on a flat surface like Probotix recommends it makes it much easier.
Remember to tighten bolts as the instructions don't always remind you to do that.
Try to keep as much slop out of the drive screws mounts as possible. This will create a more accurate machine.
Anti backlash Acme nut's for the Fireball may be a good investment if you are having issues when the machine changes direction. Mach3 and EMC can compensate a little for this in software
Problems with my kit & resolutions:
After my first posting of this page, Probotix reached out to me to make sure I was satisfied with my purchase and offered to resolve any outstanding issues I might have. This was well above my expectations as none of the problems I had were major. Even before they contacted me, I was already a happy owner and would definitely make the purchase again along with recommending it to others.
- Missing 1/4-20 nuts (7/16 OD). I needed to track down three of these. They are very common and I had some in the garage, so no big deal.
- Sticker on back of large enclosure is installed upside down and none of the drivers match up as wired. Originally I labeled these with a Sharpie, but Probotix is making sure this issue is taken care of properly. Thanks!
- Front face of large enclosure was popping out on arrival. The heat sink behind this was simply out of alignment, I took out the screws holding it, realigned heat sink and washer and replaced the screws. The front now fits properly.
My first test was to wrap a marker in tape, place it in the spindle holder and draw a square. I measured each side of the square to make sure it was the desired length and once I was satisfied began using a Dremel as the spindle.