It's as simple as ABC or XYZ

[Vixen]

I have just completed a rebuild and modernisation of an EMCO VMC 100 mill. The VMC 100 is similar in size to my other EMCO F1 mills and was intended as an industrial machine rather than as a training machine. The VMC 100 was not a success for EMCO. It was considered to be too small, only 8" x 4" x 8" of travel. The electronics controller proved to be very unreliable and the electro/ pneumatic tool changer was both slow and clunky and unreliable.

My machine was returned to EMCO by a dissatisfied customer, it had only a few hours on the clock; allmost unused. Those parts of the electronics that still worked were stripped off and sold for spares and the mill was also robbed for spares. EMCO sold me the carcase of the mechanicals some years ago and I have been slowly rebuilding and modernising since.

My first job was to remove the rather strange EMCO, five phase, stepper motors (I had no electronic drivers for them). I replaced the stepper motors on all three axis with 4.2Nm Nema 23 steppers, driven by DM542,  4.2A 50VDC Digital Microstepping Motor Drivers. They all came on the 'slow boat from China'. Very reliable and relatively inexpensive. I built a special 50 volt power supply module to power the new stepper motors and controllers. All the existing cabling was removed to make way for a clean, new wiring installation.

Next, I removed what was left of the auto tool changer. It was always slow and unreliable and was operated by a mixture of electronics and pneumatics. I did not want to be forced to run a compressor to operate the machine and besides, I did not have any of the special tool holders for the carousel, which were unique to this machine. I replaced the EMCO tool changer and carouselle with a manual tool change mechanism of my own design so that I could use standard BT 30 taper tool holders with ER25 collets. Yet another shipment on the 'slow boat from China'. By the way, order heavy items like tool holders one at a time, otherwise the Customs and Excise get very excited about heavy packages and investigate, then charge import duty.

The VMC 100 had a very nice built-in slideway lubrication system which I retained and converted to manual control. One press of a button during start-up, pumps a shot of oil to each of the sideways.

I am a long time convert to LinuxCNC, so that was the control system I used again for this upgrade. I added a racking system to the side of the mill enclosure to provide a dedicated location for the monitor, control computer and mouse. The mouse play area is carefully positioned under the PC to be sheltered from flying chips and swarf.

The original VMC 100 spindle was powered by a large 0.75 HP,  200 volt DC motor. I could not find a suitable replacement controller to power the original motor, so made the bold step to replace the DC motor with a 0.75 HP, 2 pole, 3 phase AC motor and a Variable Frequency Inverter Drive. I needed to devise a different motor mount, off to one side, as the 3 phase motor was fatter than it's predecessor. The installation was straightforward, the programming of the Inverter somewhat tenuous but eventually I managed to get it to run from 100 to 6000 RPM under manual control. Next, I altered the Inverters programming to run under the remote control of the g-code program and LinuxCNC. I used a BOB (Break out Board) intended for a Mach 3 installation, This BOB had the necessary D to A converter to give the 0 to 10 volt signal used to control the speed of the spindle motor. At first, I was troubled with EMC noise, which made the 3 phase motor run unevenly at times. I eventually found some more parameters in the Inverter which acted as noise filters (averaged the 0 to 10 volt control input voltage over 0.5 seconds). After many hours of frustration, it now runs smoothly and sweetly and under full remote control of the g-code program or manual command.

While I was at it, I added a fourth Microstepping Motor Driver for the A axis. I can plug in my digital rotary table or my 4 axis stage as and when they are required.

To complete the new box of tricks, I added a digital edge finder probe which also serves as a digitising probe. I downloaded and installed a Probe Control Screen for LinuxCNC which automates the edge and centre finding. The new Digital Probe is incredible accurate but fragile, I have already damaged one stylus while learning how to use the probe.

Photos to follow shortly

Mike

[b.lindsey]

Quite a project Mike. Sounds like you will have a very satisfactory mill though in the end. Looking forward to the pucs.

Bill

[Vixen]

That' the idea Bill. A almost unused mill, should last me forever.

Here is a photo of the completed EMCO VMC 100 modernisation exercise. It's nice after all there years to have a milling machine with a conservative silver grey paint job, rather than the garish 1970's orange/yellow that EMCO seem to love so much.





Here is the control screen for the new digital edge/ centre finder. As you can see, by pressing the appropriate button, LinuxCNC automatically finds the selected inside or outside edge, corner or hole center and then moves to and resets the home position to zero.






To give the new machine an interesting and prolonged test, I made some miniature name plates for the ABC Scorpion engine for my friend Mike Cole. He will be adding these name plates to his casting list. The name plate is very small, just 15 mm in diameter. I used a flat bottomed engraving point with a tiny 8 thou (0.008") end flat. The engraving point was held in an ER25 collet and rotated at my maximum spindle speed of 6,000 RPM. The occasional spray of WD40 was used to cool and lube the cut.







Mike Cole provided me with a JPG image of the name plate. I imported the image into AutoCAD and traced the outline of the letters. The AutoCAD drawing was transferred as a DXF file to the DesKAM toolpath generating program and then onto the LinuxCNC mill controller. You can see from the next photo that there were 441 lines of code which will take 20.4 minutes to machine in a single pass, at a feed rate of 2.5 inches per minute, at a depth of 15 thou.






'
This photo shows one of the completed name plates, wow isn't it tiny. The screen shows the toolpath being followed as the second name pate is being machined.






Finally a photo of the completed ABC name plate, all new and shiny.







Everything went to plan, the new mill ran faultlessly at a spindle speed of 6000 RPM and engraved the name plate using the smallest diameter tool (just 8 thou wide) I have ever used. Mike Cole gets a master pattern for his name plate casting and my modernised EMCO VMC 100 gets a full workout.

It's as easy as ABC. just like the title of this topic.

Mike









 

[zeeprogrammer]

Very neat! 

[mikecole7]

   That's brilliant Mike, you are a master at detail. I wish I could make something as small but my chisels are too large.
  It will be interesting to see how the castings come out.   

    Mike

[Vixen]

Hello Mike

If you PM me your home address, I can get them in the post to you.

Cheers

Mike

[fumopuc]

Hi Mike, interesting report of your efforts to get a new, additional CNC mill.

[Vixen]

Hello Achim,

Thanks for calling by.

Do you think there would be more interest if I said the new mill could be used to make STEAM ENGINES?

Mike

[Johnmcc69]

Beautiful machine Mike & a fantastic job!

 How long did it take to put it all together?

 John

[Jo]

I think a bit of quality assessment is needed of the finished article best send me one Mike to check out  So you are a dab hand at AutoCAD as well 

Jo

[Stuart]

Hello Achim,

Thanks for calling by.

Do you think there would be more interest if I said the new mill could be used to make STEAM ENGINES?

Mike

Mike that what I use my re-electroniced kx1 for the mill was ok but the electronics were very poor with its hit and miss ‘leaf boy ‘ controller card so it was re engineered with all new electronics ( the transformer ,drivers and steppers were ok but the rest were not up to my electrical standard when it smashed up a probe it made me do something about it , I know you prefer Linux but I when for mach4 and ESS as I had four axis and 9 limit switch’s plus the probe to contented with

Great work on you resurrection

[Vixen]

John,        This mill has been a low priority project for many years. I took about a month to strip out and replace the old wiring loom and the five phase steppers with modern stuff. It then took a further five or six years to decide what to do about the spindle motor. I eventually decided on a 3 phase motor and variable speed inverter, which was installed ad set to work on about four weeks. Fortunately, I had two other CNC mills to make engine parts, so there was no pressure to get it running sooner.

Jo            Five samples sent to the other Mike for quality assessment. He will probably be selling (giving) cast name plates to his ABC Scorpion customers shortly. I have been using 2D AutoCAD as long as I have had a machine shop. It's the 3D stuff I will try and teach myself over the winter.

Stuart     I went for LinuxCNC and a dedicated micro computer for all my machines, just to get away from brother Bill Gates and his Windoz nonsense. I don't think any of my Linux systems have missed a beat in the last five years of use.

Mike

[Roger B]

That is an excellent job    One day I will have to move into CNC        I do have the option to convert my Proxxon micro mill but there seems to be a lot to learn. If I learnt it I could then start to use some of the machines at work, we have just taken delivery of a very nice DMG Mori mill 

[Vixen]

Roger,    Teaching yourself CNC has a steep learning curve, I forced myself to make the leap by removing all the handwheels on all my machines, I then had to go digital, no option.

To make the transition to CNC easier, you need to be the master of 2D drawing (to quickly extract tool path info) and you also need a good CAM program like DesKAM or CamBam to generate the G-code which drives the axes of your CNC lathe or mill.

That DMG Mori mill is an incredibly sophisticated machining centre, I don't think they will let you near it for a quite some time. Set your sights on a converted Proxxon or one of the lesser machines at work.

Mike

[Stuart]

Mike

Yes it to dislike windoze with a passion all the rest of the computers here are Apple

I had a look at Linux CNC but at the time I could not find a way to get all the io that I needed , go on tell me it would have been possible ( no don’t  go enough cash in the project )

But what I have runs fine now I have removed all the phone home , cortina , auto updates and gave it insomnia it runs ok , and removed the WiFi