Denford Triac conversion

[sncf141r]

Me again! With regards to real time control - linuxCNC uses two approaches, first, it uses real time extensions (http://wiki.linuxcnc.org/cgi-bin/wiki.pl?RealTime) and secondly, you can dedicate one of the cores in a multi-core machine to handling the real-time bits, meaning that it really is as close to real time as one can get.

I think that's one of the reasons that it works so reliably.

(as my larger mill runs along downstairs without supervision - but I can hear what it's doing...)

John.

[Roger]

This is all true, but having Windows on your machine control and being able to do all the other Windows type functions wins the day for me. It's so much more than just a CNC control, it's the nerve centre for my workshop. Linux just can't do that for me however good a control system it provides. The addition of motion controllers to Mach makes a huge difference. Once Mach4 is out of the box, I think it will be better than these other offerings and still maintain the advantage of running Windows.

[sncf141r]

Roger - one of the beauties of the "X Window System" that Microsoft has been slow to copy is the ability to have windows on your display that run on different computers.

Look at sourceforge.net/projects/xming/

so you can (easily) have one computer dedicated to your mill, but without a display. The display is actually on your desktop windows box.

The X windows system, (that actually pre-dates Microsoft Windows), was designed to separate the display and the computer system.

In my office, I can control (should I wish) all 3 of my workshop CNC machines, all on one computer screen in my office.

I do sometimes control one computer (when adjusting the configuration files, for instance) from my office - much nicer than sitting beside the machine on a hard swarf-proof stool.

If you run your 3D printer with the Machinekit fork of LinuxCNC, you can have your little (and inexpensive) Beaglebone computer running your 3D printer, and you can control it from your main computer.

I think there's some kind of understanding missing; whether you use an external motion controller, or an even less expensive computer, you are using "remote computing". At least having a dedicated low cost, low energy consuming computer for your machines means that they run reliably, without having the worry of having your main computer "bogging down" and thus interrupting your machining.

Anyway, I do understand that I'm (as usual) off in left field, and that my ideas may be unpalatable for many, but I mention the above simply to indicate that there is, as always, more than one valid approach to solving a problem.

Thanks as always for your always-instructive, and always-positive and helpful posts!

(added as a last minute thought, if you go to the Xylotex web site, you can get the Beaglebone computer with power supply and "parallel port board" all configured for something like $80.00 US. I keep thinking that I should give this a try for my CNC'd Unimat lathe, rather than carting around a big computing tower. No experience yet, though) (seemingly, the Beaglebone has real time clock chip on it (the "PRU") so it has real real-time hardware support built on-board)

It's all fun stuff -

JohnS.

[Roger]

Hi John,
That sounds a little like Bruce Chaffin's kind of approach he's working on for the CNC Brain project that's currently stalled. That too aims to split the machine control element from the display and that's achieved through internet connections and web page based machine control windows. Those can be on the same computer or on the other side of the world. I can certainly see that advantages of what you're doing although I'd have to say that I'm not familiar with the things you're using.
I guess we all solve our problems using the things we are familiar with and tools we understand. I'm happy enough with the Windows based 'all on one PC' approach so long as it delivers the stability of the machine tool element. I'd need to be a lot less happy to go the extra mile and do the sort of thing you do, I don't think the effort would reap enough of a reward. It's certainly interesting though, and it's good to see more 'connected' machines. Most solutions seem determined to make the machine totally stand on its own and be just an isolated machine tool. I think we ought to expect an awful lot more of our devices in this decade, but things are still lagging behind.
Thanks for your kind comments John, I try to look at things from every angle. There are so many talented, clever and educated individuals here, it would be a grave mistake not to listen and take everything in a positive way.

[Rob]

Nov 23, 2014 17:17:44 GMT sncf141r said:

Roger - one of the beauties of the "X Window System" that Microsoft has been slow to copy is the ability to have windows on your display that run on different computers.

Look at sourceforge.net/projects/xming/

so you can (easily) have one computer dedicated to your mill, but without a display. The display is actually on your desktop windows box.

The X windows system, (that actually pre-dates Microsoft Windows), was designed to separate the display and the computer system.

In my office, I can control (should I wish) all 3 of my workshop CNC machines, all on one computer screen in my office.

I do sometimes control one computer (when adjusting the configuration files, for instance) from my office - much nicer than sitting beside the machine on a hard swarf-proof stool.

If you run your 3D printer with the Machinekit fork of LinuxCNC, you can have your little (and inexpensive) Beaglebone computer running your 3D printer, and you can control it from your main computer.

I think there's some kind of understanding missing; whether you use an external motion controller, or an even less expensive computer, you are using "remote computing". At least having a dedicated low cost, low energy consuming computer for your machines means that they run reliably, without having the worry of having your main computer "bogging down" and thus interrupting your machining.

Anyway, I do understand that I'm (as usual) off in left field, and that my ideas may be unpalatable for many, but I mention the above simply to indicate that there is, as always, more than one valid approach to solving a problem.

Thanks as always for your always-instructive, and always-positive and helpful posts!

(added as a last minute thought, if you go to the Xylotex web site, you can get the Beaglebone computer with power supply and "parallel port board" all configured for something like $80.00 US. I keep thinking that I should give this a try for my CNC'd Unimat lathe, rather than carting around a big computing tower. No experience yet, though) (seemingly, the Beaglebone has real time clock chip on it (the "PRU") so it has real real-time hardware support built on-board)

It's all fun stuff -

JohnS.

I'm a little late to this thread but I thought I'd add my point - You can also do this natively with Windows using RDP for the best part of the last 20 years, or alternatively VNC, unless I've misinterpreted what you mean!



Of course, this does mean you need Windows on all of your boxes where something Linux based would be a lot cheaper.

I have a mixture of boxes on my network, two Linux boxes for my NVR and NAS, and a bunch of Windows boxes of various flavours. Best of both worlds

[muzzer]

"Of course, this does mean you need Windows on all of your boxes where something Linux based would be a lot cheaper.
"

You can run VNC clients in Linux, eg tightVNCserver. So you can control Linux systems from a remote Windows machine or any other OS running a VNC viewer. I've been doing that to control a Raspberry Pi remotely and wirelessly over the network (no need for keyboard or display) and plan to do so for my LinuxCNC machine when that is finally working. There are even viewers available for iOS etc, so you could monitor (control?!) your machine from your smartphone. VNC was designed to work across OS's.

Muzzer

[Rob]

I meant using Windows instead of Linux requires a copy of Windows on all your boxes, not that you need Windows for VNC .

The point of my post was that Windows is also capable of what John S. was describing.

[andyhigham]

This project got kicked to the back of the workshop after I bought Mach4 and its licence, there were issues with plug ins etc.
8 years on I guessed that Mach4 and its plug ins would be mature and stable, so I exhumed the machine, downloaded the latest Mach4 and ESS plug ins and....
....It doesn't work with Windows XP any more. Bugger!
A trip to www.cfultd.com/index.php?route=common/home in Bolton got me a small form Lenovo with Windows 10 and a solid state drive for £109. Yesterday evening I installed the Mach4 and plug ins. The next job is assigning all the inputs and outputs again
I have revived this thread (obviously) to report progress

[andyhigham]

This afternoon I assigned the inputs and outputs of the break out board to the drives and sensors.
So far I can jog all three axes and the limit switches stop the motion.
When I press the "Home all" button, the Z axis and X axis both home, the Y axis doesn't
When I enable the spindle there is no rotation, maybe I am not getting the 0-10v signal to the VFD.
The contactor for the coolant pump energises. I just need the pump now.
One thing I have noticed that will need attention, the USB slots in the front of the PC are low down and obscured by the angled front of the chassis, I will have to fit a slot on an extension lead from the slots at the rear as I need a USB slot to load programs

[andyhigham]

Ok I have solved the issues I found yesterday.
I have a question about homing. The home position sensors position the table just before the limit sensors with the table at the left and towards the operator with the head away from the table.
The software then sets the indexes to zero. This will make all Z axis operations negative.
Should I put an offset into the Z axis? I have set my soft limit for Z at -138, the hard limit is -142 so would I be right suggesting 138 for the offset? This would pot the Z zero 4mm above the limit switch

[uuu]

I wouldn't bother. When you set up to do a job you will reset the axes to zero to suit the datum of the job you're doing. Most of your G codes will reference this modified zero point. But the underlying system will still know the homing zeros, so you can insert a special code if you need it, to use those. I only do this when changing tools - I can put in a G code to lift the head close to absolute Z zero, to give me lots of room - then drop down using the work-related z zero to begin cutting again.

Wilf

And - re-reading your post - yes, you can set soft limits at the other (negative) end of the travel, and just in from the positive end. I have Mach3, and it gets a bit difficult if you get into to the area beyond the soft limit, as the system prevents you from moving away.

[Roger]

Oct 23, 2022 18:30:07 GMT andyhigham said:

Ok I have solved the issues I found yesterday.
I have a question about homing. The home position sensors position the table just before the limit sensors with the table at the left and towards the operator with the head away from the table.
The software then sets the indexes to zero. This will make all Z axis operations negative.
Should I put an offset into the Z axis? I have set my soft limit for Z at -138, the hard limit is -142 so would I be right suggesting 138 for the offset? This would pot the Z zero 4mm above the limit switch

The position and value of your axis system is entirely for your preference. It doesn't impact on the way you use the machine. Every job you do will have its own zero relative to the stock, you probably won't be using the absolute machine coordinate values for anything.



Obviously if you have automatic toolchange or tool depth sensors, those will need to be defined relative to whatever you choose for your coordinate system.



Homing switches aren't normally repeatable enough to return the machine to a position with enough accuracy to continue from a previous session, so the absolute position isn't guaranteed anyway.

Incidentally, that's not the case with my system, because I use the marker positions from the Linear scales to overcome this issue.



Choosing the most convenient point to use as zero for the job is a whole new conversation that we should have.

[andyhigham]

After work I put the code in that I used earlier in this thread and set the machine running "cutting air"
The spindle motor seemed noisy so I removed the toothed belt, The motor is quiet bit the spindle felt a little gritty. I have pulled out the spindle and bearings so I can give them a swim in paraffin, the grease looks clean but a clean, check and re grease won't go amiss.
If the bearings are fubar new ones are only £27.19 each simplybearings.co.uk/shop/p45552/7208B-Single-Row-Angular-Contact-Ball-Bearing-40x80x18mm/product_info.html?backstep=1

[Roger]

That sounds promising then. I don't know how fast the spindle turns, so I can't really comment on the type of bearing it needs. The ones I deal with have much more expensive Angular Contact bearings of ABEC7 quality. Those are lubricated with a special grease, applied in only small amounts with a syringe between each ball. Those are very gently increased in speed, taking several days before full speed is reached.

My High Speed Spindle runs up to 24,000RPM with 17mm ID bearings like that, with a Medium Solid preload. It can take me 3 days to work up to top speed. If you push it too quickly, the grease melts or the balls hydroplane, chatter and destroy the bearing. The fasted we ever did with grease was 80,000RPM with a 10mm ID, and those were a nightmare. It could take a week to get them up to speed. Disaster awaits at every increase in speed. Hopefully your spindle is a slow one and you won't have to worry about any of these things.

[andyhigham]

The maximum spindle speed is only 2500 RPM.
I gave the bearings a good clean with paraffin and then a spray of brake cleaner between the cage and races, they spin smoothly and silently now.
The only thing I have with RPM in those ranges is the supercharger on my Kawasaki Ninja H2. It rotates at 9.2 x engine speed which at the 14,500 RPM max equates to 133,400 RPM

[uuu]

Even at these lower speeds, your spindle might have a procedure for setting up. My EMCO CNC mill has a five-phase schedule, with three runs of 15 minutes within in each phase at different speeds, allowed to cool down between each phase. So it would end up taking a whole day.

Wilf

[andyhigham]

I will check the manual I have with the machine

[Roger]

It's vital not to have too much grease, that doesn't end well. A fully run in High Speed Spindle that runs with greased bearings feels like it has no grease in it. It runs as if it was lightly oiled, and that's essentially what it is. The soapy part of the grease is just the reservoir for the oil which wicks out into the ball tracks. The soapy part should never touch the balls themselves else it will get pulled into the bearing and cause disaster. The running in process gradually works the grease out clear of the ball tracks, and that takes a long time. As soon as you do something that disturbs the grease, you have to run it in from scratch again.

This was one type of spindle that our company repaired for around ten years. We saw every variation of greased spindle you can imagine, with single and double row bearings at each end and countless methods for controlling the preload. It's a tough business to be in, and hard to consistently get right and make money from, especially when customers claim warranty even though it's obvious that they've done something horrible to the spindle.

[andyhigham]

I have put the bearings back in, there was nothing in the manual about preload so I just nipped up the locknut. I have just put a bead of grease in each bearing but there is a grease nipple to fill the cavity between the bearings with grease.
I have run the spindle at 200 RPM for about 15 mins and all seems quiet

[Roger]

Oct 25, 2022 20:06:39 GMT andyhigham said:

I have put the bearings back in, there was nothing in the manual about preload so I just nipped up the locknut. I have just put a bead of grease in each bearing but there is a grease nipple to fill the cavity between the bearings with grease.
I have run the spindle at 200 RPM for about 15 mins and all seems quiet

Sounds good. It's quite rare to have no preload spring, that usually comes in the form of a wavy washer behind the bearing on a cheap spindle. On more expensive ones, the rear bearing is usually in a housing which is sprung. There are exceptions though, and it's possible to control the preload with a precision assembly. My High Speed Spindle has two sleeves that separate the two bearings, and those are ground to the same length. The preload is set in the bearing itself, you can buy them with different amounts to suit the application. It may be that your assembly has been carefully measured and shims added to make up the right amount of preload if necessary.
In any case, it's probably worth running the spindle up gradually, increasing the speed slightly each hour over the course of a day just to make sure it doesn't run into trouble. You can feel the body temperature, and that will reduce as it runs in.