Hi Guys, I have been interested in getting a small "desktop" sized CNC for a while now but costs for most kits were prohibitive. The C-Beam kit in the store comes in at a fair price (with steppers under £500), obviously still need a router and a controller. The issue with that kit is the moving base, so the Sphinx caught my eye. But a couple questions: 1. What is the cutting surface size of the Sphinx in the stock plans? I only between 250x250mm and 300x300mm (larger is nice, but I don't have the space). I do know you can make the size what you want but wondering around the plans. 2. Is this capable of milling Carbon Fiber, I will be looking to cut everything between 2 and 5mm Carbon? With point 2, I assume the defining factors are speed of cut, router and quality of bits? The reason for the Sphix over the C-beam kit, is the stationary base, as when cutting carbon the dust is crazy, and toxic. As such I need to use water. So either a bath or a jet (TBD). Next is around the quality of cut, again I assume this is down to the same defining factors as above, but I take it with a DIY build it is possible to get a production quality finish? If I don't have to spend time sanding every edge it would be great. Right now, I am having to buy products in and the finish is amazing. But there is at least 4 weeks lead time and the shipping costs are crazy. EDIT: Is the Arduino the cheapest entry point for controllers? The xPRO looks awesome, but want to keep the costs down on the initial build. Sorry to ask the same questions that have been asked a thousand times. Chris
I started with the C-beam and am slowly moving to the sphinx design. You can build the sphinx with 3 500mm c-beams and you're cut should be around 300x300 give or take a little. The plates and parts should be the same, want to grow later? just replace one axis with a 100 or 1500 axis. As far a which type of controller is best that's up to you and what you want for the long haul. Quality of cut will depend on what type of router / spindle you use. if you're going to plow through steel you want more power than if you intend to cut patterns out of MDF. my $.02
Alex from Ronin posted a build that he uses to cut carbon fiber, there may be some good info for you here: TACIT RONIN CNC - Flood Coolant Enabled C-Beam
Thanks Jim. At the moment, cost is everything. I have a way to get the plates cut out of Aluminum really cheaply which is handy. But its the electronics that to me look like a "forgotten cost"... Everything else seams to be in kits. But the electronics are always an after thought. Thanks for the link SugarJ, will have a deeper look at it. The standard c-beam makes using water a little bit more challenging than a fixed base. The other thing I like about the fixed base is that as long as something fits the width, its possible to use a smaller machine. Also would like to be able to put the machine ontop of something larger... a later project I think
The cheapest entry point for electronics I can think of is a Chinese cloned Arduino (you may get what you pay for) and a CNC shield on which you mount DRV8825 drivers. You need to glue on the heat sinks with special paste and they need a fan blowing on the while cutting or they will over heat and you will lose steps. Here is a very cheap set-up. Disclaimer: I have no experience with this brand. Amazon.com: Mercurry CNC V3 Shield + UNO R3 Arduino Compatible Board + 4 PCS TI DRV8825 StepStick Stepper Drivers: Industrial & Scientific Personally I would avoid the cheaper boards that include the A4988 drivers. They do not have the amperage needed IMHO. I personally have learned the lesson that the "genuine" Arduino boards seem to be better for not much more. I have not had one fail. I have had Chinese clone boards fail. I have not tried Spark Fun's or Adafruit's boards. Of course then there is the Ardiuino.org vs Arduino.cc feud... This is what I currently use, but others may have better success with cheap clones. Amazon.com: Arduino Uno R3 Microcontroller A000066: Computers & Accessories
Hi Craig, I agree 100% on the cloned Arduino. For the price of an Adruino its not worth it really. I believe in supporting the guys who made it. I assume that using the Arduino runs over USB, and I dont need some stupid printer connector for it?
So a genuine Arduino with a with a CNC shield, DRV8825 drivers and the NEMA 23 motors. Throw that together with a frame, bucket loads of time and I can start cutting. Looking at the Sphinx, the BOM is coming in at a LOT more than the C-Beam, so think I will need to go for the C-beam kit and upgrade down the line. I am thinking a water bath, where the carbon just fits and the water is a few mm above the surface of the carbon will be fine. Its just there to stop dust. And I cant imagine the CNC will resonate just right to cause a wake in the water. This will also weigh less than a similar sized piece of aluminum. Other wise I will have to look at pumps, drains and splash shields.
So I found the correct BOM for the Sphinx and sadly, this is coming in at a lot more for me. Around the £1,300 mark before electronics. The C-Beam kit is a steal at under £500. This will require more messing about to make it work for what I need but I am sure I can get there in the end.
