I have my Christmas present: the Mini CNC mill physical assembly done during the Christmas break and I have recently wrapped up the electronics portion (mostly) using a RaspberryPI CNC controller and 7 inch touch screen.
I started this build shortly after I finished my build of my own design which I called a Micro Mill (https://plus.google.com/u/0/+ScottLewis901/posts/3EskBsBqqcV). The MicroMill also uses a combination of OpenBuilds parts, 3D printed parts, KT70 X-Y table and a Raspberry PI, 7 Inch touch screen and Raspberry Pi CNC shield.
There are a couple of things I have questions about or noticed during the physical assembly.
Ok, well when I got all the physical assembly done then I decided I needed to have a Z-Axis manual jog knob. So I got the additional parts from Openbuilds except for the 8MM x 400 MM drive screw that I got with some other stuff from Amazon. Sorry Openbuilds, I was trying to save some shipping cash.
- Can I extend the z Axis head another 40 mm in the y-axis to use the full scale of the y-axis travel (or add spacer blocks behind the z-axis gantry)?
- The c-beam end plates have reliefs cut for the low profile 5mm screw heads. Either the screws are not all consistently sized or the end plates I got in my kit did not properly have the reliefs properly sized for the 5mm screw head in all cases. Some were to small or screw heads to large.
- Can a guy go with the 40 MM C-beam gantry plate on the bottom of the x-axis assembly to get an extra half inch of travel in the y-axis direction?
- Can I put in the stand off plate on the z-axis top motor and then also have a manual knob adjuster for the z-axis as well? (DID THAT!)
I am using a Marvel 40 for the spindle motor that came from MLCS that I had purchased years ago to run on my wood lathe and used maybe one time. I don't think they even make these anymore.
Note that I added the 67mm Spindle adapter STL file to the files section for 3D printing.
See the above picture of that which is including a nice 3D printed housing for the belt drive to keep things out of it (STL file for that can be found in the files section).
I added a side mount rail for attaching the Raspberry PI 7 Inch touch screen (case) that also holds the Raspberry PI and the CNC Hat and stepper motor drivers.
So I have everything wired ...
And its operational now (see YouTube video)...
Note that the DRV 8225 stepper drivers are running around 40 degrees C with heat sinks, during my initial tests, after I adjusted the current. With the 40mm fans they should be ok I think.
Calibration is just a bit off where I currently am seeing 47mm instead of 50mm on the calibration diamond, circle, square.
Also I am waiting on a speed controller for the spindle motor (SuperPID). I think 30000 RPM may be a bit too much for some materials.
I also still need to add a big red e-stop. If I am feet away from the computer or the PI's Touch screen (whichever is running the job) and the job goes south or the spindle starts moving in an unexpected direction then I want/need to kill the process.
Now of course - I can see I may need an even larger Mill What for you ask? I'll think of something
CNC Mini Mill Build
CNC Mini Mill build with some mods after following standard build on Youtube video.
- Build License:
- CC - Attribution - CC BY
Reason for this BuildI first build a MICRO CNC of my design, had not yet seen the Mini Mill design and wanted something bigger than my Micro Mill.
Inspired byI had created my own Micro Mill before I ever saw the Mini mill from OpenBuilds and was wanting something bigger. So when the Mini mill went on sale at Christmas I decided to get it
Qty Part Name Part Link Comments 1 Mini Mill http://openbuildspartstore.com/openbuilds-minimill-1/ Link I got mine without electronics 1 Protoneer RPi CNC Hat https://www.zyltech.com/store/p186/Raspberry_Pi_3___Proto... Link A very nice integration of Arduino and Pi with place for standard motor controller drivers and other GPIO. I also got the Pololu socket to integrate with external motor drivers if I wanted to. 1 400mm 8mm ACME Lead Screw https://www.amazon.com/gp/product/B017AR5QBS/ref=oh_aui_d... Link Needed one longer than the 290mm long one that Openbuilds had 1 Raspberry Pi 7in Touch Screen Case https://www.amazon.com/gp/product/B01HV97F64/ref=oh_aui_d... Link Nicer case than the one I 3D printed for my Micro Mill, has a place to mount a camera as well. 1 Raspberry Pi 7in Touch Screen https://www.amazon.com/gp/product/B0153R2A9I/ref=oh_aui_d... Link The display for local control 1 Raspberry Pi Motherboard Model B https://www.amazon.com/Raspberry-Pi-RASPBERRYPI3-MODB-1GB... Link Nice micro system 1 32 GB Simm Sandisk https://www.amazon.com/SanDisk-Samsung-Note-Dual-Sim/dp/9... Link used in Raspberry Pi 1 DRV 8225 Stepper drivers https://www.zyltech.com/store/p60/DRV8825_Stepper_Motor_D... Link Pak of 3 drivers - while these are maybe not as good as external drivers I thought I would give them a try for this. 3 Nema 23 Stepper motors, 3A, 1.9nm, 269oz. https://www.zyltech.com/store/p95/Nema_23_Stepper_Motor_-... Link These guys draw current right at the edge of the DRV 8225 - so we'll see how long the DRV 8225s last. 1 Stepper Driver Cooling Fans - 40 MM 12 VDC https://www.amazon.com/2packs-0-15A-Brushless-Cooling-AB4... Link Something like this - I already had some around. I wired the 2 in series for 24VDC operation. Also see the 3D printed Fan Mount STL file. 1 300mm x 20mm ALU Extrusion - used to mount RPI https://www.zyltech.com/store/p242/ZYLtech_Black_2020_Alu... Link Yes, I could have gotten this from Openbuilds, but was ordering several things from ZYLtech at the same time and figured to save on shipping. 1 Bluetooth Keyboard/mouse https://www.amazon.com/Logitech-920-007119-Wireless-Keybo... Link I like this keyboard and mouse combo for the Raspberry PI