Messages

301

Show"N"Tell ( Your Machines) / Re: Matchmaker Revival

« on: February 17, 2013, 04:41:35 PM »

Progress has been slow due to the usual 'too many jobs/projects, not enough hours in the day' syndrome, but I have managed to get a few bits cleaned and back on. There were a couple bearings in the head, and the x-axis extension support bearing that were very rough, so they've all been renewed. The head is now just needing lifted back on, which will be a two man lift back onto the table, followed by lots of handle cranking and some brute force.

I'm opting to drive the spindle motor with a 240V VFD for now. It does mean I lose power above the base frequency (29Hz), but it means I get a working spindle for not very much money until I decide what a longer term option will be.

I've also been working on what IO is required, and how that's all going to be acheived.
I ordered a kflop and kanalog tonight, which will be dealing with all the critical stuff, and I'm looking to use modbus for all the non-critical stuff. I'm not sure if the modbus will be through the Kflop or straight into Mach, or possibly a mix of both.

302

Third party software and hardware support forums. / Re: Dynomotion slave axis problem

« on: February 15, 2013, 04:09:22 PM »

If you've not solved this, your best option is either post on cnczone in the Dynomotion board - http://www.cnczone.com/forums/dynomotion_kflop_kanalog/ or over on the Dynomotion Yahoo Group - http://tech.groups.yahoo.com/group/DynoMotion/

Tom Kerekes (the man behind the KFlop) is very active on both of those.

303

General Mach Discussion / Tapping on a non-reversible lathe

« on: February 11, 2013, 03:46:12 PM »

If I was to build a simple tap holder, that is capable of disengaging and letting the tap spin after a set distance, what G-code would you use?

I'm trying to eliminate having to move the parts to my manual lathe, just to run a tap up the centre. If I could do it on my (little) CNC with a non-reversible DC spindle, running the tap back out by hand will still be quicker than swapping lathes.
I'm thinking a tap holder that's mounted onto a round shaft, and when retracted is held stationary by a couple drive dogs/pins. Just before the required thread depth is reached, the Z-axis stops moving, and the tap holder keeps going until the the drive dogs disengage. I'd have the tap holder always slightly floating, to allow for Machs lack of rigid tapping or speed/syncronisation variations.

This isn't going to be a long term solution, as I'm already planning a bigger and better lathe, so I'm trying to spend as little money as possible.

304

Modbus / Re: Encoder for spindle true rpm via modbus

« on: February 11, 2013, 02:55:05 PM »

That could be one of many issues. I'd suggest posting in the General discussion board so more people see the post.

However, first you need to check that the BOB is actually seeing the signal from the encoder, this is done by using a multimeter to make sure the signal at the BOB switches as the spindle is slowly rotated past the index position.

However, it could be that the encoder you've used may not provide a long enough index signal to be detected by a parallel port.

305

Modbus / Re: Encoder for spindle true rpm via modbus

« on: February 10, 2013, 01:58:00 PM »

Modbus isn't the answer.

A far simpler type of encoder would of done the job, as mach only needs (can only use) a single pulse per revolution for threading, but what you've got can be made to work, as it does have an index pulse.
You need to supply voltage and a gnd to the sensor (you'll need to check the datasheet for the recommended voltage), then connect the Z wire to a spare input on whatever breakout board/interface your lathe uses. Then set that up the relevant pin in Mach to recognise the spindle index signal.

306

Show"N"Tell ( Your Machines) / Re: Matchmaker Revival

« on: January 27, 2013, 08:03:17 AM »

The autolube is now back together, and working with the exception of 1 partially blocked metering unit, but it's one of two on the same slide, so it can wait for now.
Just need to get a new bearing for the X-axis motor support/extension block so I can get all the X-axis mounts back on.

I've pretty much made a decision on the axis motors, but am currently trying to decide what to do about the spindle motor.
It's a 2.2kw (3hp) 440V only motor, and the only three phase I have is via a rotary converter, which I'd like to avoid using.

307

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: January 24, 2013, 08:08:52 AM »

Steve,

Thinking about it some more, I think a solenoid-controlled needle valve driven by a simple (even software) PWM would be the way to go.  Simple to implement, and should give very good control.

Regards,
Ray L.

Right on the money, as usual. The trick is to find something 'off the shelf'. I'm thinking there must be a computer controllable (PWM, analog, or whatever) orifice or regulator. Hopefully there are some industrial control gurus lurking around here that can provide an example.

In hydraulics, you get electrically controlled variable flow control valves, and I'd guess someone will do something similar for air.
However the usual way for controlling cylinder speed with air is by controlling how quickly air escapes from the non-powered side of the cylinder. The flow restrictors are usually plumbed in with a one way valve, so you get full flow into the cylinder, but any flow out goes through the restrictor.

308

General Mach Discussion / Re: motion controllers working with Mach3

« on: January 24, 2013, 07:12:08 AM »

All I can find about KFlop and lathe threading, is it uses the KFlop's coordinated motion functions and can handle spindle speed fluctuations (both speed up and slow down).
I can't find anything on MPGs and Mach3, but if you were to contact Dynomotion, I'm sure they'd give you a quick answer (I've yet to see a single problem go unasnwered on their yahoo list!)

309

General Mach Discussion / Re: motion controllers working with Mach3

« on: January 23, 2013, 07:29:53 PM »

CS-Lab CSMIO, and Dynomotion KFlop are two higher end controllers that work with Mach.

310

General Mach Discussion / Re: Special code for threading?

« on: January 23, 2013, 06:33:15 AM »

Could it be something to do with how the DSPMC handles threading?
It could be the DSPMC works by buffering the threading move, hence the 20% spindle increase to fool Mach into supplying a buffered feed.