Denford novamill electronics build log

[Toolman321]

Hello welcome to my build log!

I bought a denford novamill, it didn’t come with the control box so I decided to build my own control box and operator interface. This is my diary!


I bought 2 sheet metal enclosures, one is 600x400x300 this will house all of the power and drive components. The other is 600x400x120 and this will be for the operator interface.
I managed to source the correct connector for the machine made by harting and some industrial multi core cable and some screened cable witch I had left over from another project. http://www.mycncuk.com/threads/11102...=Emco+retrofit
Using some aviation type connectors I made up a cable to provide power to the machine and receive limit switch signals from it.



I then went eBay shopping for the rest of the components.

For the spindle drive I got a Parker 508 dc drive, it will power the dc motor with the 180v dc 8A it requires.
X y and z axis stepper motors will be powered by dm542 digital stepper drives.
I designed my own safety circuit with fuses, contactor, and mcb’s.
I made it all look tidy with some slotted trunking. I did by best to separate the control signal wires from the ac and dc power by routing them around the outside whilst routing the power trough the centre. Any crossovers are at 90 degrees and I utilised shielded cable where applicable.



For this build I will be using linuxcnc specifically the 5i25 fpga card and the 7i76 breakout board from Mesa electronics in California.



The power supply for the stepper drives will be 40 volts or thereabouts, I got a toroidal transformer and a rectifier circuit and made my own power supply.

The power supply for switching etc is a 24v 3a switching power supply.
Here’s the control box almost complete:
I’ve left a space so I can add another drive for a 4th axis later.

That’s it for the control box for now as I have some decisions to make before I finalise the design, I’m not sure if I need a spindle reverse circuit and a spindle encoder I will decide that another day.

I’ve made a start on the operator interface. For this I’ll be using a 17” touch screen monitor and a waterproof keyboard. The aperture at the bottom will house the start/feed hold buttons, a feed override pot, and a spindle load meter.

[Clive S]

Is that a 7i76 Mesa I spot in there?

[Toolman321]

Is that a 7i76 Mesa I spot in there?

Yeah

[Toolman321]

Today I temporarily plugged in the machine and configured linuxcnc. I needed to cut an i/o plate for the cabinet. Specifically the holes for ac input, cooling fan and plugs for the machine. I had previously machined the outside profile on a machining centre as it was too big to machine on my denford mill.





I’ve left a couple of locations empty, one will be for the mpg and the other for a 4th axis.

[Clive S]

Nice work, keep the pics comming.

[JohnHaine]

Enjoy the Novamill. I got one also without electronics and followed a similar route with DM542 drives etc, but using Mach 3. Have been using it now for 6 years, very pleased with it, a nice machine.

[keland_uk]

Hi, Just on the off chance, do you have any details on the transformer you used for the steeper motors, the TXR-0736P05A toroidal power transformer 300VA.

I have the spec, just not a wiring diagram.230V 50Hz input, 27.5v at 10Amps output

[Toolman321]

It was a long time ago, but I had this saved in my YouTube history, maybe you will find it useful
https://youtu.be/4OoQQg76ar4

Best of luck!

[keland_uk]

Thank you, very interesting, but different transformer competely :-)

video one is 625VA, made may 2017, one in this thread is 300VA and dated May 2018?

I have looked at your other videos.
230V 50Hz input, 27.5v at 10Amps output.

Designed and manufactured to BS EN60950 and BS EN61558.
Complete with integral 85ᵒC Thermal cutout NC, and thermistor 10kΩ for Temperature Measurement and protection.

Dimensions 115mm OD x 60mm height. Weight 2.55kg

Includes mounting hardware.

Input Connections PVC flexible leads to 7 way JST in line connector

Output Connections PVC flexible leads to 6-32UNC ring crimp

Full specification and drawing available.

http://www.toroid-tech.com/clearance...nsformer-300va