PM 1340GT Lathe (Next-Step) VFD Control System with Proximity Stop Update

[Kamloopsendo]

Mark: The compliments are both sincere and warranted Mark. By the way I have ordered a 22mm pot as per below - does that change the specs for the face plate. Do you want the dimension (exact) of my existing cover plate?
Alex

101ECX2300-5K
Potentiometer, 5k ohm, 22mm, black. Legend plate ECX2640 purchase...
Made in ITALY HS: 8536.50EA$36.50$36.50101ECX2640
Legend plate, plastic, black field, black background, white engra...
Made in ITALY HS: 8536.50EA$3.50$3.50

 

[Rodneyk]

My previous designs for VFD control systems have been posted, and I have been building pretty much the same design for about a year. I have made iterative design changes based on the requests of other hobbyists, so each system is tweaked a bit for each individual's preferences. The latest changes included a 3 way coolant selector so one can either choose continuous or intermittent (only with spindle rotation) coolant, variations on using a coolant relay/contactor/voltage source, different braking pattern selections, use of plug and socket connects for the front control panel and proximity sensor cable, Jog Joystick, and a few other changes. The only lathe control box terminal connections are for the spindle cable and 12/24VDC power for tach, lights, etc.

It has been a while, but I added Marks' system to my lathe out of the box when I bought the lathe. He actually delivered the system which detailed instructions before the lathe arrived. I was VERY intimidated about altering the machine but since I bought a 3 phase lathe, I was kind of stuck doing it and using Marks' system was the best choice I could make.
The front panel is very professionally done, and I love the fact that the jog switch is more like a joystick than a toggle switch. It has a great tactile feel. I have not installed flood coolant, but it is ready to go it I decide to someday, for now I am just using a cheap Chinese mist type coolant that works well for everything I have built so far.
Things I could still do to improve the system really come down to tweaking the VFD to brake faster. It is pretty good now, but I am pretty sure with a little tweaking it could be better. Currently the head stops in less than a 1/4 rotation at slow speed, but at higher speeds it takes a bit longer than I'd like. This is 100% my fault for not playing with the VFD parameters.

 

[mksj]

Been a while since I posted any update on this system design, there have been quite a few installs of this lathe replacement control system and I have not heard of any issues or problems. I did recently revise the wiring design which is now very similar to what I build for the 1440GT and also larger lathes like the 1440/1640 Sunmaster models. On the smaller lathes I am still using the Hitachi WJ200 VFD which has been very solid and overall the reliability has been very good. Higher end builds I had been using the Yaskawa V1000 and GA500, but there is now a 4-6 month delay in availability, as well as significant price increases. The other change I have made for the bigger lathes is to go to a 30mm proximity sensor which increases the sense range from 12mm to 15mm, they are shielded sensors so can be flush mounted. The other addition is a chip shield over the proximity sensor as random chips flying by the sensor can trigger it.

This is a recent system for a PM-1236T lathe, I had a request to add a tachometer and a spider. The spider is 1045, I core it with an annular cutter and then bore it with a carbide poring bar. There is a clamp on bracket for the tachometer sensor.

I am currently using FMX relays, these have built in suppressor diodes to prevent the voltage spikes when the coils release. I use a WEG mini contactor for the coolant circuit, by default it is wired for a 24VDC air solenoid, but can also be wired for 120/240VAC for a pump coolant suystem. I also use a schottky diode at the 24VDC voltage input, this also provides protection if someone connects the power supply wire reversed.