Denford Software & Machines

Hi

I have a Micromill 2000 and would like to set up a 4th axis. Sherline produce 3700 CNC rotary 4" table with a controller (8700). This controller has two program options that can run a block of instructions. These instructions can stop / start via an connection port as well as sending an output.

My though was to control the 8700 via an aux in/out on the Micromill via M Codes or the other way round. Gear cutting comes to mind along with other 4th axis control.

Alternative is to invest in an upgrade? including software / Mint etc. I have the circuit diagrams, but was wondering if anyone else has had a go?

I understand this will not be true 4th axis - but I'm on a limited budget.

Any comments will help.

Kind regards

Chris

Hi Chris,

What software are you running the machine from?

Hi Martin

The software is VR Milling ver 2.31 running on a XP Pro machine. The 8700 comes with a controller that has its own software that can divide 360 by the no. i.e 12 = 30 degrees each or degrees etc. The 8700 allows blocks of instructions that also allow daisy chaining other controllers.

https://www.sherline.com/8700inst.pdf

Cut Gear: start 0 degrees on 8700
signal Micromill 2000 to start

For example: M3 (Start Motor) G01 X10 G01 X50 M5 (Stop Motor) Signal 8700 and wait for 8700 to start again.

8700 turns 30 degrees - signals Micromill again and so on.

You can do this manually but would be good if the machine can do it itself

I have not brought the 8700 yet - thats my next thing, but have jobs I need to do that requires the rotary table.

Hi Chris,

There are a couple of ways you can go with this.

1. Retro fit a aux in/out.

2. There is a header on the control card that will output step & direction signals to a 4th axis drive. you can then control it through the VRMilling version 2.

Hope this helps.

Hi Martin

Thanks for that. I have a DenStep (with the red 7 seg display). There is a header connector on the card. I looked into a upgrade to the newer version that comes with VR Milling ver 5. Does v5 have 4th axis control?

Cheers

Both version 2 & 5 will support the 4th axis.


To enable it you need to go to the "Machine Capability" section in the "Machine Setup Parameters" window. You can then enable the IV axis near the bottom of the screen.

Here is pics of controller... I noticed there are just 3 driver chips !

Also the step motor wire colour is not the same on the circuit.

Hi Chris,

After looking at your pictures & a Denstep card in our factory, it does not support the 4th axis. I have confirmed this with Technical.

Sorry for getting your hopes up.

You can still fit the Aux`s though.

The other option is to upgrade to the USB Next Step top card with VRMilling ver 5.

Regards Martin

Hi Martin

As I thought. Back to the original idea for now of an aux in/out.

Cheers for your help.

Best regards

Hi - as Martin says, you wont be able to get hold of the 4th axis step/direction signal because the top board doesn't have the IDC header which we currently use to drive a 4th stepper drive.

However, the machine is setup by default for 2 AUX inputs and 2 AUX outputs. This snippet from the Mint may help with the I/O:

M code 62 (ie M62) REM: Turn auxiliary output 12 on
X4.0=1
Mcode64 REM: Turn auxiliary output 12 off
X4.0=0
Mcode63 REM: Turn auxiliary output 13 on
X5.0=1
Mcode65 REM: Turn auxiliary output 13 on
X5.0=0
Mcode66 REM: Wait for input 10
Mcode76 REM: Wait for NOT input 10
Mcode67 REM: Wait for input 11
Mcode77 REM: Wait for NOT input 11

Note that the outputs Sync to GND