I had a 3d printer for some time now and it was put together via a DIY kit and it has thought me alot in terms of how CNC machines operate and communicate with software that prints your CAD design. Although 3d printing is additive manufacturing vs milling that is substractive manufacturing, but the basic concepts of the machine design are very similar.
I started thinking if I should CNC my existing SX2P mill and SC2 lathe. Although the platform is rigid enough, I just did not want to make swiss cheese out of my machines by drilling holes and tapping them. I decided that it was best i left these machines for manual operations as it is not always practical to go onto CAD and CAM simply to drill a few holes or a pocket.
I saw several people posting on the internet about building CNC routers using MDF board and a dremel like tool. They seem to show good success but mostly in softer materials.
I wanted something a bit more rigid and yet not to go bankrupt over it.
Shopping online on Aliexpress, I noticed several CNC engravers on sale in the US$ 1k-2k range. Although the frames were rigid enough, these machines lacked powerful spindles or steppers and were using very old and cheap grade electronics.
So I thought if I do buy a ready machine, I am going to spend alot of money modifying the machine for my liking.
The good news is that that manufacturers of these machines are also selling the frame kits without any motors or electronics. This gave me a starting point.
I didnt want a router that was too huge and thus I settled on the 3020 size of cnc.
Since then I have been purchasing lots of bits and pieces for my CNC router and I am now complete in terms of putting my CNC machine together. The waiting and collecting parts period is well over a few months as this included reasearching, budgeting funds, ordering and waiting for parts to be shipped.
The following is a big list of all the small parts I have had to collect to put together the CNC machine (prices do not include shipping):
3020Z DIY Frame Kit (ball screw design) US$ 350
4 axis 100khz Mach3 compatible USB Breakout Board - US$ 40
3 sets Nema23 287oz.in dual shaft Bipolar Stepper Motors (57BYGH603B) with matching Stepper drivers (DQ542MA) - US$ 150
1.5kw Air Cooled Spindle - US$ 90
1.5kw VFD - US$ 88
400w 36v 11a switching power supply - US$ 32
60w 12v 5a switching power supply- US$ 7
Laser cut acrylic electronics enclosure - US$ 25
Shielded electrical cabling - US$ 65
Limit switches (10pcs) - US$ 3
E-Stop switch - US$ 2
23 Nema Aluminum stepper motor mounts - US$ 19
6.35mm to 8mm motor shaft couplings - US$ 4
6.35mm ID aluminum knurled handwheels (3pcs) - US$ 10
Power switches (3pcs) - US$ 2
Panel mount power outlets (2pcs) - US$ 3
Panel mount usb type B 50cm extension - US$ 2
AC EMI power filter- US$ 11
GX16 4 pin connectors (5 pcs) - US$ 5
GX16 2 pin connectors (4 pcs) - US$ 4
AC cooling fan 90mm - US$ 9
DC cooling fan 40mm (2 pcs) - US$ 3
18x25mm cable drag chain (1m) - US$ 7
18x25mm cable drag chain ends - US$ 2
Z Axis touch plate tool - US$ 5
10 position common grounding terminal - US$ 1
Miscellaneous bits & pieces (wiring terminals & connectors, heat shrink tube, fan grills, screws and nuts, adhesive cable holders, etc) - US$ 20
The rough total cost is under US$ 1000 for sourcing the various components. Please note the pricing is excluding shipping costs as this will depend on your location and your final source for the various parts.
The next challenge will be putting these parts together as all my tools are still packed up in storage. The wiring is my biggest concern as without my soldering station and magnification clamps using a cheap soldering iron is not going to be very clean. Then after a new dilema to tune the machine for use with Mach3.
Will it all work in the end, I cant be too certain till i have it all hooked up and tuned in but I am sure I will be able to retrofit everything.
For me the catch is a much powerful air cooled spindle(i wanted to avoid the hassle of a water cooled spindle), bigger stepper motors with independent drivers, accurate ball screws, thick and rigid frame, USB connectivity as most cheap CNC machines rely on obselete parallel port computers, higher quality insulated electrical cabling and other bits to control electrical noise.
I hope this info to someone who is thinking of buying an off the shelf CNC machine bs building one yourself.
