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
Build in 'X/Y Table Style CNC Mill' published by Lindsey Lewis, Jan 17, 2018.
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