Emco F1 Mill Upgrade

[DrDaveParticipant @drdave]

After the recent demise of the controller for my cnc mill, I decided that the time had come for an upgrade.  I hope to explain here the steps (forward and backward) that I take to get my machine working again.

Last week, the controller jammed in the fast jog mode, making it impractical to use.  I had been thinking of upgrading for some time, but this has twisted my arm.  In addition to a new controller and software, the stepper motors will be changed.  The original motors are of a 5-phase design and are not compatible with moden drivers, so they have to go, too.

<>What controller should I go for?  Linux?  I have built Linux computers before so that should be easy, shouldn’t it?  No.  After spending a couple of hours trying to “mount” a USB stick, and failing, I rejected the world of Linux.  Which leaves Mach 3 or 4.  Not quite what I want, but it seems to be popular.  Fortunately, Muzzer recently mentioned Centroid’s Acorn controller on another forum thread.  A quick check on their website and it looks like just the job.  I ordered one from Denmark & it arrived a couple of days later.

<>Another box has arrived from Cnc4you (I have no affiliation to any of these companies, I am just say what I have done in case anybody wishes to follow in my footsteps) full of stepper motors and their drivers.  It is all spread out on a table, ready for wiring up & bench testing.

<>Centroid’s website has a series of videos showing how to wire the bits, how to set up the computer & software.  Excellent.  So it is all wired up and – it is not working…  The problem, I hope, is that the stepper drivers need a 5 volt supply, which is not available from the supplied PSUs.  I am awaiting delivery of a 5/24 volt supply from RS and will continue when it has arrived.

Edited By DrDave on 14/05/2018 10:05:45

Edited By JasonB on 14/05/2018 10:40:59

[DrDaveParticipant @drdave]

Bringing my mill into the 21st century

[DrDaveParticipant @drdave]

The new power supply arrived this morning. All wired up and all three steppers wiring away happily on the bench. More importantly, Mrs Dave was out, so another parcel was smuggled into the workshop without the Domestic Authority knowing. Result!

Next, the hard part of physically fitting the steppers to the mill.

[EmgeeParticipant @emgee]

DrDave

If the new steppers are NEMA 23 type with 1/4" output shaft and you are going to retain the geared drive it should be a pretty straightforward job transferring the drive pinion to the new motor, the original plates and fixing screws can be re-used.

Can you please post a link to the Danish supplier ?

Emgee

[DrDaveParticipant @drdave]

The Danish supplier is at **LINK**.

The steppers are NEMA 23 with ¼” shafts, as you say. The shaft is slightly shorter than the Emco ones. The pulley on the stepper has a roll pin at the outer end: this will be in fresh air on the new steppers, so I am thinking of Loctite (or similar) to hold them together. Otherwise, the attachment bolts should be in the same place as the originals and the change should be simple. Or that is the theory.

Dave

[Another JohnSParticipant @anotherjohns]

Posted by DrDave on 14/05/2018 09:55:08:

<>What controller should I go for? Linux? I have built Linux computers before so that should be easy, shouldn’t it? No. After spending a couple of hours trying to “mount” a USB stick, and failing, I rejected the world of Linux.

DrDave;

What I generally do to mount a USB stick on Linux is to:

1) plug it into the computer;

2) (if not already opened) open a file viewer, and you'll see it on the left hand side.

Other than little UI differences, it's the same on my Imac, and my Win10 computer.

—

Creating a bootable ISO image on a memory stick – if you get the LinuxCNC iso image, you can push that to your USB stick; I'll often use my iMac for this, but do use Ubuntu Linux sometimes. Have not done it on Win10 yet. (google is your friend here)

—

Booting a USB stick – when your computer boots, F2, and ensure that you have USB booting enabled.

—

Something went wrong; have a cuppa and try to figure it out – it's quite simple (I tend to do a slap to my forehead and mumble "what a dummy" under my breath when I find the issue).

—

The Centroid (etc) machines are great, but for me, I like the options available in LinuxCNC, and as I have dedicated computers per machine (no touch screens, only a trackball and MPG, no keyboards) they are self contained.

I can "remote desktop" into my dedicated machines if/when I want – I think the Centroid one needs an attached Win laptop for config changes?

Whatever you do, feel free to tell us of your progress!

[SillyOldDufferModerator @sillyoldduffer]

Posted by John Alexander Stewart on 14/05/2018 15:59:39:

 

Posted by DrDave on 14/05/2018 09:55:08:

<>What controller should I go for? Linux? I have built Linux computers before so that should be easy, shouldn’t it? No. After spending a couple of hours trying to “mount” a USB stick, and failing, I rejected the world of Linux.

DrDave;

What I generally do to mount a USB stick on Linux is to:

1) plug it into the computer;

2) (if not already opened) open a file viewer, and you'll see it on the left hand side.

Other than little UI differences, it's the same on my Imac, and my Win10 computer.

…

 

I assumed DrDave had hit a lower level problem than that. John describes what a linux system does when you plug in a USB and it's recognised correctly. It can get much more complicated than that if something in the system is adrift. In getting into that detail DrDave may have become entangled with 3 different historic approaches to the problem, viz mounting a bare-bones device (circa 1995); or debugging devfsd/hotplug; or debugging a modern udev configuration. A big problem with the internet is no-one tidies up antique advice, which can lead you up the garden path good and proper!

In the good old days connecting a new device to a computer meant configuring everything manually. Usually with much weeping and wailing. These days computers are programmed to recognise standard devices like memory sticks and normally 'just work' when you plug 'em in. Nothing's ever perfect though – every so often something goes wrong, for example if you plug in an device your hardware or configuration can't handle. Then you can have loads of fun making it work. Tricky on all operating systems and might involve you in some old-fashioned device black-magic. Sometimes it's quicker to try different approach even though Linux is wonderful.

 

Edited By SillyOldDuffer on 14/05/2018 18:19:14

[DrDaveParticipant @drdave]

Thanks for the feedback on Linux. It is a couple of year since I tried to investigate LinuxCNC, so I cannot remember where I failed. I think that it was at the “mount the drive” stage. I will drag out my old Linux laptop & try again, just to have a play. But I must get the mill working first!

[Another JohnSParticipant @anotherjohns]

Posted by DrDave on 14/05/2018 18:24:09:

Thanks for the feedback on Linux. It is a couple of year since I tried to investigate LinuxCNC, so I cannot remember where I failed. I think that it was at the “mount the drive” stage. I will drag out my old Linux laptop & try again, just to have a play. But I must get the mill working first!

Don't worry – I'm behind in just about all of my projects … Finished a short "couple of hours" project I started close to a decade ago last night – feels good! Now if I can only remember what I wanted it for!

[DrDaveParticipant @drdave]

I’ve stripped out the old steppers and the new ones are a very similar size.

The drive shaft is shorter (21.2 vs. 25.4 mm) so I cannot re-use the roll pins to retain the drive pulleys. A drop of Loctite 641 and fingers crossed: I don’t think that they will come off again if they are not right. To get the location right, I set up the motors on the surface plate and touched the height gauge on their mounting face. The height gauge was lifted 25.4 mm and used as a reference for locating the pulley. The pulley fit is slightly loose, so I used a screwdriver to hold the pulley against the gauge until the Loctite had cured. The first motor was tried on the mill & appears to fit, so the rest have been done, too.

[EmgeeParticipant @emgee]

DrDave

Thanks for posting the link.
By the sounds of it you have all you need to get running, please keep us informed.

Emgee

[DrDaveParticipant @drdave]

First stepper installed. Originally, I wanted motors with a single-ended shaft but I have ended up with double-ended shafts. With hindsight, this has an advantage that I had not expected. After fitting, I turned the motor with a spanner (there is a flat machined on the shaft) the ensure that the bed moves, which it did. However, it felt a bit stiffer than I expected, so I took the motor out again. Turning the motor was a lot easier. Motor re-installed and it is now a lot easier to turn. I suspect that the drive belt was not correctly fitted to the pulley for the first installation. Without the ability to manually check the installation, I would have continued and probably damaged the belt.

I am now trying to squeeze all of the electrical gubbins into an old PC case, so fitting the other two motors will have to wait.

[DrDaveParticipant @drdave]

Major milestone reached: I can control spindle speed from the PC now. Firstly, I tried using an old Dell computer case to put all of the control gear in. It might have worked, but was very much a pig’s ear. But I finally managed to get an old Apple G5 tower computer last Saturday. It is far larger and, more importantly for me, has lots of flat areas to mount bits on.

I had one scare whilst trying to get a pair of the old cooling fans to work. There are 4 wires per fan: ground, 12v, temperature and control. I had no idea which wire was which (they are all black) so I started to try every combination to find one that works. Part way through this process, the fan glowed orange and emitted the magic smoke. “Oh dear, that’s fried it”, I said. It must have been the temperature sensor that I fried with 12v because I finally found a combination the works.

Now to get the steppers installed, wired up & working. Then some microswitches to define “home”, a major omission on the original machine.

[DrDaveParticipant @drdave]

Some more progress to report. All three axes work under their own steam and I have run some of Centroid’s sample g-code files. All seems OK: I just need to work up the confidence to start cutting metal now. The only significant mod left is to install the home switches. These are a nice-to-have, rather than a must-have, so it is my own inertia stopping me!

This is the new controller, a modified Apple mac G5 with the guts stripped out. The 5, 12 & 24 v PSUs are in the base, the old Apple PSU used to be, with a 36 v PSU on top. From left to right a re the spindle driver (KBIC), drivers for axes X, Y and Z (with room to add A if required). The Acorn controller card is under the top plate. A much neater job than the old PC case would ever have been.

The cables to the mill come out the top of the case:

And it fits in the same space that the old Dell PC sat:

The blue wire is the Ethernet cable to the Windows 10 PC that controls it via Centroid’s software. I have moved the ammeter for the spindle and the e-stop from the old controller to new homes on top of the mill:

[NigeParticipant @nige81730]

Cracking job DrDave Nice to see a project go reasonably to plan

Nige

[DrDaveParticipant @drdave]

Thanks, Nige. I was a bit worried when I started the mod. There is no way back and, if something didn’t work, it could have ended up as an expensive boat anchor…

Dave

[BitzerAgainParticipant @bitzeragain]

Hi Dr. Dave,

Despite your kind assistance with parts to get my mill running it looka as though the original boards are u/s so I am going to have to admit defeat and go down your route.

I have an Acorn controller on order but could you let me know the details of the steppers and drivers you used? There are umpteen listed on the CNC4U site and I would appreciate some guidance to make sure they are compatible.

Thanks,

Bitzer(Again)

[Rod AshtonParticipant @rodashton53132]

DrDave – Ref F1 Acorn conversion. – Could I enquire as to how you connected the spindle motor (assuming it was the original?) I see you put in a KBIC driver. Was it difficult to configure at all please. Like Blitzer I would also appreciate stepper details

Regards

Rod

[DrDaveParticipant @drdave]

Hi Rod,

The mill has the original DC motor. The wiring schematic from Centroid shows the KBIC motor controller with their SI-5 barrier terminal board. I bought one of these (sound of air being sucked through teeth), wired it in accordance with the schematic & it worked first time.

I have a 3 phase motor with VFD in my lathe. That also uses an Acorn card and, when I set the correct parameters on the VFD, the 0-10V output on the Acorn controls the spindle speed.

Bitzer: my apologies for not answering. I did not see your post come in… Digging through the paperwork showed the steppers to be 57HS82-3008B.

I trust this helps. If not, please ask and I will do my best to answer.

Dave

[Rod AshtonParticipant @rodashton53132]

Dave – Thanks for the info. If the wife is not watching, how much teeth sucking did you have to do please.

I am a Dunstable ex pat. See you are in BFDS.

Regards

Rod

[DrDaveParticipant @drdave]

Rod, I paid £102.60 for the SI-5 board from Axis Controls in May last year.

Regards

Dave

[Rod AshtonParticipant @rodashton53132]

Dave – Thanks. Just doing my costing for everything now. Better not let my wife see either.

Rod

[BitzerAgainParticipant @bitzeragain]

Hi DrDave,

I went ahead and bought some 1.8Nm NEMA23 steppers, which may be a bit light for the duty. CNC4U suggested using their CWD556 drivers as being capable of driving a 4Nm stepper if I want more oomph. Currently using a 36V power supply (with the option of 48V for 4Nm steppers), although I haven't tested it yet as I'm still wiring everything up.

I looked at trying to extract the spindle drive from the original Emco box but I think I will have to go down the KBIC route as well. It looks like the KBIC240D is the right one? The motor is 540W so, depending on which Hp standard KBIC use (metric/imperial) the resistor should be 0.035 ohm (part no. 9840). Can you confirm please?

Having done some reading about steppers and the fragility of drivers for high inductance motors. I'm a bit nervous abouth this conversion, especially as it looks like a stepper fault which blew the O/P transistors on the Emco board.

There will be a lot of teeth sucking if I let the magic smoke out of several hundred pounds worth of PCBs!

Regards,

Bitzer

[DrDaveParticipant @drdave]

Hi Bitzer,

Yes, I used the KBIC-240 (stock code BB-9428), the reciept does not say whether it is the D model… I have used the 0.05 ohm resistor, but don’t take my word that this is the correct one! I has worked so far, but the mill has not seen much use over winter since I finished the mod.

Steppers & drivers are a bit out of my comfort zone. I chose steppers that looked to be similar to Emco’s originals in terms of torque, though I never did find the specs for Emco’s steppers. I was concerned that an increase in stepper torque, without beefing up the screws & nuts, would invite serious damage at the first crash.

Regards

Dave

[EmgeeParticipant @emgee]

DrDave & Blitzer

Original Emco steppers are less than 1 Nm torque, but assisted by the gearing to the ball screws, so if driving the screws direct more than std will be needed, 1.8Nm sounds OK but advisable to fit some limits especially considering the size of the working envelope.
The PM DC 180v motor on my F1 is rated at .44kW, is your .54 a typo ?
Homann Automation in Oz do an interface to use the std Emco controller with other OS.

Emgee

[Author]

Posts