Mill power feed & controller

[John HaineParticipant @johnhaine32865]

Here are a few photos of the power feed and controller on my VMB mill.

The electronics from the mains input end.

Arduino UNO + CNC shield with one stepper driver on top (space for 4 if needed). Bluetooth module at left.

Enclosure with lid on.

Power feed attached to the end of the table. The drive pin is parked in a hole through the top cover…

Slipped through the handwheel disc to engage with the pulley. Next time I have the lathe fired up I'll make a nice little brass knob to replace the inside of a bit of choc block for something to hold on to!

Control interface is through the "GRBL Controller" jogging screen on my phone.

This isn't customised as shown – I have jogging step sizes and feeds at more convenient values and so have set up two "soft keys" for "canned" power feeds. GRBL is set up to that the movements shown on the controller screen correspond to the DRO and it seems very accurate.

[John HaineParticipant @johnhaine32865]

[BazyleParticipant @bazyle]

The pin instead of dog clutch or other joint seems a good idea. Perhaps a pull and twist lock like some back gears would save it getting mislaid anytime. Do you have an emergency stop – what happens if the bluetooth gets interference?

Edited By Bazyle on 19/07/2020 10:54:47

[John HaineParticipant @johnhaine32865]

Idea is to pull it out and park it in the hole!

Good question about the estop. Biggest problem with bluetooth is going out of range I think, by nature of its operation it should be fairly interference resistant. As an experiment I tried disconnecting the link in the middle of a feed and it just carried on which was a bit scary. I think an external reset button would be a good idea. Or just turn the supply switch off.

[duncan webster 1Participant @duncanwebster1]

I've belatedly invested in an emergency stop button which will be in the feed to everything to do with the machine. Hit that everything stops

[Mark Davison 1Participant @markdavison1]

What is the controller, is it something like an Arduino? How does the phone app interface, via Bluetooth. I'm after something like that to tide me over until I get linuxCNC running on a raspberry pi.

[John HaineParticipant @johnhaine32865]

Mark, the controller is GRBL v1.1f running on an Arduino Uno, with a Protoneer CNC shield carrying Polulu DRV8825 stepper drivers. Controller on my phone is GRBL Controller through Bluetooth to an HC06 BT module on the Arduino. All SW is open source. Note that GRBL will also run on the Pi and there are several other front-ends that will feed g-code commands to GRBL. The main lack as far as I can see is one with Wizards, but even Linux CNC doesn't seem to have a big selection of those. Currently I'm a Mach 3 user but I am seriously considering switching to GRBL. Have a browse….

GRBL

**LINK**

**LINK**

**LINK**

I hope this is useful.

[Mark Davison 1Participant @markdavison1]

Thanks, I will do. I have several arduinos and Teensy 3.2s, so i think ill be giving this a go. I need to ouyput to much bigger stepper drives/ NEMA 34 motors, but I assume I can do that (5v or 3.3v pulse/dir signals will drive them)?

[John HaineParticipant @johnhaine32865]

Yes, the shield has step & direction outputs, 5v levels

[John HaineParticipant @johnhaine32865]

If you are looking at LinuxCNC I'd be interested to know what you think of GRBL – given that you need a front-end to drive it. But there are several of those to choose from as described in the Wiki.

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