Messages

181

General Mach Discussion / Re: Steps/Inch on Lathe = 75,000; Seems a Tad High

« on: September 02, 2014, 11:32:31 AM »

Ha, I did wonder if there really had been a surge in lathe kflop mach users 

A couple things that stand out are the missing code to tell the kflop a kstep is attached, and your velocity, acceleration and jerk are low.
Try using the basic kstep example file supplied with kmotion, and editting it to suit, as it contains settings that are pretty good to start with, and the required code to implement all the kstep features.

Should be a case of just editting the DefineCoordMotion statement so only 2 axis are activated.

182

General Mach Discussion / Re: Steps/Inch on Lathe = 75,000; Seems a Tad High

« on: September 02, 2014, 05:32:44 AM »

Ignore backlash until you get the units set correctly.
The Mach backlash setting will have no effect on an external motion controller anyway, as the backlash is handled internally by the controller.

Probably best if you have a read through this post I made last week over on the HSM forum - http://bbs.homeshopmachinist.net/threads/63822-Help-Choosing-Electronics-for-CNC-Lathe-Conversion?p=933822#post933822 as it covers the basic process of setting things up.

Something does seem a bit strange with your Z-axis steps. Any chance you could attach your kflop init file, or even just copy and paste your channel configuration settings from it?

183

Show"N"Tell ( Your Machines) / Re: A Wee Prober

« on: September 01, 2014, 07:27:17 PM »

After a bit longer than planned, the extra additions are now installed and working.


X Glass Scale by mc_mtb, on Flickr


Y Glass Scale by mc_mtb, on Flickr

As I mentioned in the previous post, accuracy wasn't quite as good as I had hoped relying solely on open loop stepper control, so I needed to close the loop. Now one of the other reasons I opted for a KFlop, is it's flexibility, and the ability to easily close the loop by adding suitable encoders or scale, so a couple micron accuracy glass scales were purchased. The main reason for the scales, is the fact they directly measure the axis position, whereas an encoder only measures the motor position so is still affected by any backlash in the system.

Using the cable from my previous post, it was a simple case of wiring the cable in, a not quite so simple case of mounting the scales, plugging the scales in, changing a couple settings within the KFlop initialisation so it knew there were now encoders fitted and to run in closed loop stepper mode, then finally a quick change to the kflop probe notification program so the actual position was returned from the scales and not the commanded stepper position.

After that, the probing accuracy has greatly improved, and I now just need to iron out the kinks in my workflow from probed sample to machined copy.

184

General Mach Discussion / Re: atc setup 101

« on: September 01, 2014, 08:09:00 AM »

A 5/2 valve, is a changeover valve designed for reversing double acting actuators.
A quick google has thrown up this page - http://www.angelfire.com/ia3/jrtdogbone/pneumatic.htm
If you scroll down a bit, it's got a good diagram/animation/explanation.

It would help if we knew what ATC you're looking at, as it saves guessing about how it should be setup.

185

General Mach Discussion / Re: Steps/Inch on Lathe = 75,000; Seems a Tad High

« on: September 01, 2014, 06:04:27 AM »

KStep microstepping is fixed at 16, but Mach doesn't know the difference. All Mach is interested in is how many steps it takes to move a known distance.

The amplitude setting that gets grayed out is of no interest in the KMotion Config&Flash screen. In StepDir mode, all you are interested in is the output channel (should be 8-11 for a single KStep), and the output gain if you need to swap axis direction. Remember that any changes you do on the Config&Flash screen will get wiped out by the settings in yout init.c file whenever you hit reset in Mach.

Anyway, using your figures-
Z-axis = 8tpi x 200 x 16 = 25600 steps per inch
X-axis = 25tpi x 200 x 16 = 80000

You're 6475 is only about a quarter of what it should theoretically be. You've not changed the output gain from 1 to 4 on that channel by any chance?
You can use output gain in open loop to increase the number of pulses, however it has no benefit and usually makes things more confusing when you come to setting up the axis or want to change something later.

186

General Mach Discussion / Re: atc setup 101

« on: September 01, 2014, 05:48:32 AM »

It all depends on the tool changer.
If the ATC requires critical timing, then you'll need to use some form of external controller to act as an interface between Mach3 and the ATC, as Mach3 macros only have a 10hz update rate so critical timing points can easily be missed.
If it doesn't require critical timing, then it's just a case of connecting up the inputs and outputs.

Regardless of how it's connected, you need to write/modify a suitable toolchange macro to handle the required toolchange sequence, via whatever inputs/outputs are being used.

187

General Mach Discussion / Re: X Axis Goes Backward in Mach3 Turn

« on: September 01, 2014, 05:38:29 AM »

To change direction on an axis using a KFlop, in your init.c file, you need to invert the OutputGain setting i.e. if it's currently 1, swap it to -1.

Obviously swap init.c for whatever the name of your configuration C file is, which you can check by going to the Dynomotion plugin config page in Mach.

188

General Mach Discussion / Re: New PlugIn just about done..

« on: August 22, 2014, 07:21:01 AM »

Officially M4 and the PP plugin are still in testing, so I'd guess the website won't change until M4 is officially released.

189

Show"N"Tell ( Your Machines) / Re: A Wee Prober

« on: August 22, 2014, 07:16:43 AM »

Now I'm back after a week enjoying some french mountains, I'm back to getting this working how I'd like it to.

Initial attempts at probing were not ideal for the level of detail I'm looking for, so after a bit fettling with the mechanics, the only major issue I came across were the 698 bearings which are used as thrust bearings for the ballscrews, were absolutely rubbish. Using standard bearings for thrust bearings is pretty poor practise, but given the loads of this machine, some good quality ones have solved the roughness issues.
However accuracy still hasn't been that great, despite minimal measurable backlash.

So this package turned up yesterday -

More Bits by mc_mtb, on Flickr

And I've just finished doing some soldering-

More Wiring by mc_mtb, on Flickr

I've got to head of just now, but I'll hopefully get everything mounted later tonight, and post up the details.

190

Show"N"Tell ( Your Machines) / Re: A Wee Prober

« on: August 05, 2014, 07:24:15 PM »

First job today was finishing of the dummy spindle/probe holder -

Touch Prove Mount by mc_mtb, on Flickr

Nothing fancy, just a lump of round aluminium bar reduced to slightly smaller than the original spindle motor. Removing the motor took more force than what I'd expected, so the slightly smaller diameter means only the use of a single screwdrive to open up the clamp was needed along with hand pressure to get slide it in.

Then it was a case of installing the probe, along with the additional boards, connecting up the remaining wiring, and testing it out-

Calibration by mc_mtb, on Flickr

The only issue I had, was I forgot to change the allocated pin in the KFlop notify program, so despite the probe input showing as active in Mach, it never stopped movement during probing moves. However a quick edit of the code fixed that, and things worked as planned.
Initial attempts at probing aren't that good for fine details, but I still need to measure and set the backlash for the axis, so that will be tomorrows job.