King Midas mill conversion

[diy-john]

It has been quiet lately, while waiting bits to arrive. Status update:

- Jonathan now has the ballscrews.
-- Screws are R 1605 -type. They are un-machined, and only roughly cut to length
--- 900 mm screw will be cut to ---> 853 mm (X-axis)
--- 600 mm screw will be cut to ---> 508 mm (Y-axis)
--- 300 mm screw will be cut to ---> 259 mm (Z-axis)

Jonathan will have a look at the screws, and lets see what can be done to them.

Motors, drivers and other bits were dispatched on Wednesday 28.03. Now they are in Germany, latest status on EXPD -site:

30/03/2012

11:43

IN TRANSIT - DEPARTURE SCAN - LANGENHAGEN, GERMANY

Meanwhile, thought time will pass more quickly, if one would do something, instead of constantly checking where the parcel is.

1) Downloaded today Ubuntu / linuxcnc from:
http://www.linuxcnc.org/docs/2.5/htm...tting_EMC.html

2) Burned on a blank CD ubuntu-10.04-linuxcnc1-i386.iso from
http://dsplabs.upt.ro/~juve/emc/

2.1) For burning used my linux laptop: (commands given on command-prompt, screen output on violet)
- though could use Windows, or whatever software you have. One just likes linux, so that it will be.
cdrecord -scanbus
scsibus1:
1,0,0 100) 'MATSHITA' 'DVD-RAM UJ890AS ' '1.00' Removable CD-ROM
1,1,0 101) *
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *
cdrecord -v dev=1,0,0 ubuntu-10.04-linuxcnc1-i386.iso

3) Found a dusty old PC, with a parallel port, it is an 800mhz pentium processor -pc
- vacuum cleaned the inside a bit (it was really dusty)


3.1) Attached an old 160Gb maxtor -drive into it (to be used for the Ubuntu-linux installation)
- there are some DIY-cabling inside this old PC. She used to have a lot of hard-drives inside it, so the extra cabling is because of that. Not needed for this project.


3.2) Going to boot the computer with this freshly burned Ubuntu (linuxcnc) -bootable CD:


3.3) Almost ready to boot now


3.4) On bootup newly added hardware shows


3.5) Installation process begins and there are some easy-to-answer questions


3.6) Installation took perhaps 30-40 minutes. Once installation is finished, installation says to remove the CD from drive, and press enter for a reboot
3.7) On starting up the Ubuntu first time, noticed there are indeed CNC -related software there, EMC2 for example



Okay this is how far we got now. Did not try the software more. Next steps would be:
- postman brings the Nema 23-motors, drivers etc.
- We buy some cable and sundries, try to connect them to the old PC.
- try to make the motors turn with the computer. (can't wait for this to happen )

[Jonathan]

Just had a look at the drawings again...

You've currently drawn the Z-ballscrew with similar end machining to the X and Y screws which will put the screw in tension. On the Z-axis putting the ballscrew in tension is surely such a large force that it will pull the quill to one side. You also can't really combine a quick release with a tensioned screw as it would take too long to setup every time.

[diy-john]

Jonathan, here is a sketch of how I have planned Z-axis::::




So there is not going to be tension on quill at all. If you think I have mis-understood how it could work, please let me know.

Thanks!

[diy-john]

Items arrived yesterday from Zappautomation.



In box were:
3 x SY60STH88-3008 Nema 23 stepper motor
3 x PM752 Microstepping Driver
1 x SPS705
3 x R1605T3-FDID-P1 Ballnut
1 x HTD3M-9MM Timing Belts
1 x HTD3M-9MM Timing Belts
1 x HTD3M-9MM Timing Belts

Ballscrews, ballnuts, pulleys will come later. Jonathan will have a look at them, in view of machining them. Though I appreciate they are going to be quite tough to machine. (hardened..)


Thought the summer was here, and one would have the motors running in no time. But it is winter back again and the motors will not turn at all.

What I have done, is wire one of the drivers like this:
1) High voltage side (in picture, the upper set of wiring)
- GND ---> goes to power supply "GND"
- +VDC ---> goes to power supply "V+"

Then Nema 23 motor wires go into:
A+ ---> BLUE and RED/WHITE
A- ---> BLUE/WHITE and RED
B+ ---> GREEN and BLACK/WHITE
B- ---> BLACK and GREEN/WHITE

Then the Signal wires:
PUL+ ---> into PC parallel port PIN 3
DIR+ ---> into PC parallel port PIN 2

The "PA settings" (SW1 ... SW8) are:
- first four (4) are "ON"
- last four (4) are "OFF"




Think the high voltage side wiring is correct. Signals not so sure about. Is two (2) wires enough, or does one need more connected?

I have sort of verified parallel port outputs some signals, by doing a similar test as here
http://www.youtube.com/watch?v=EtX3p4HFbtc

...by running this little C-program on linux:
http://eagerfish.eu/lpt-programming-...r-ubuntu-linux

Tried turning a single motor by running EMC2 (linuxcnc). But no luck.

Have tried googling, where to connect parallel port PINs on the stepper drivers. Have found some information, but not sure one has it right. Please can someone help?

Thanks for looking

[Jonathan]

With only one wire per input the circuit is incomplete, so no current can flow... so no go.
Connect a wire to join up PUL- and DIR-, i.e. the negative terminals, and connect those to one or more of the ground pins on the parallel port. If it's not marked pin 25 (among others) is ground.

If you still get nothing then check the voltage between PUL+ and PUL- (then DIR+/-) and it should be 4-5V ideally when active.

[diy-john]

WOW it runs now

- connected PUL- and DIR- to pin 25 on parallel port, like you say Jonathan.

The cables are so loose one does not dare to breath near the machine.

Going to try to buy some electrical connectors or something for the parallel port, tomorrow.
- I have tried to use an old printer cable, which I cut in half. But the wires are so small it is difficult to handle them.

Thanks so much, very happy now.

[diy-john]

Status is now that all three (3) Nema 23 -motors turn. Driving them with EMC2 (linuxcnc)

To get here, what I have done yesterday and today is:

1) Bought some sundries from a local Electrical store:


2) Parallel printer cable - test each of the small 25 different wires with a multimeter.
- try to understand which colour cable links to which PIN on the parallel port
- here is the printer cable cut, from the "printer end" of the cable
- measured with "continuity mode" in multimeter, each of these 25 small wires.
- for all of you these are probably really elementary steps. But for me it was a bit of a surprise, that one would have
to get into this level of detail.
-- Had relied on some charts I had found from internet, on colour schemes of the parallel cable wires. But they did not seem to match my cable, so had to manually check each of the wires,
to which PIN they connect in parallel port.
- Found these "alligator jaws" handy


3) Here are the parallel port PIN's, cable colours, and where I have connected them on the Leadshine M752 drivers.





4) A picture of how they are on the table now
- had bought 30 LED's for troubleshooting.
- found them helpful, though 30 is too many. I ended up using just one single


5) Now, what do you think?
- Could one now solder cables neatly in place?
- Have been thinking of using this kind of 9 PIN -cables for each stepper-driver


-- So that the cables could be quickly attached / detached.
-- Would use these for the low-voltage, parallel cable wires.
--- Parallel cable (25 wires) ---> divide to 3 smaller cables (9 PIN) ---> each stepper driver

Motors seem to work okay, though they don't "home" itself on the EMC2. Not sure why that is. Haven't got a stop-switch, limit switches yet.

Please comment on whether one can now solder things, or should one wait until have limit switches and emergency stop-button?
- actually, any and all comments welcome

Thanks!

[Jonathan]

- for all of you these are probably really elementary steps. But for me it was a bit of a surprise, that one would have
to get into this level of detail.

Most people buy a breakout board and connect the drivers to that which simplifies things as the pins are labelled. Breakout boards also add isolation, but since the drivers you are using are already optically isolated there's no point having additional isolation on the breakout board, so connecting it directly is fine. However if you connect the switches directly (with just one pullup resistor on each) clearly there is no opto-isolation, unless you DIY.

[diy-john]

Just a brief update;
- decided not to solder cabling yet, as one might still want to make changes
- today have been thinking what kind of functionalities one might want from the mill, in terms of
-- homing
-- limit switches
-- zeroing

Fiddled with EMC2 (linuxcnc), added a similar function, as here
http://www.youtube.com/watch?v=DOBxt9MIbFo

...to auto measure workpiece surface level.

Of course haven't got the mill converted yet. Just simulated the real thing, with Z-axis motor running on table, and two wires in my hands (one cable attached to parallel port PIN 13, the other ground, think it was PIN 21).

[diy-john]

Hello!

Well, it has been some 6 months since this project has been on hold.

Not much has happened since. Got screws machined - thanks to Jonathan. Then got tied up with work, had to put all hobbies aside, and let's leave it at that. Really quite embarrassed and sorry for being away for this long.

1) Plan now is to pick up the pieces, try to remember which planet we are on, and get the mill running. Not pretty. Not good, but get it running.
1.1) For that need some bearing mounts made. A local machining workshop will make some simple mounts, hope to get them in a couple of weeks
1.2) Need attach the ballscrews
1.3) Need attach the ballnuts

For 1.2) attaching the ballscrew on Z-axis, I have today started removing the Z-axis existing pinion / spring.
- For reference, discussed this Z-axis matter earlier here: http://www.mycncuk.com/forums/diy-ma...onversion.html

What I have done today is:
A) Started removing these levers


B) So far quite easy, just use a HEX -key to open screws


C) After about 5-minutes, got already most things away from right-hand-side of the mill



D) Spring mechanism was on the left-hand-side


E) Now the spring-mechanism was easy to remove, but this is as far as we got today


F) On the other (right) hand side it looks now like this:



Now, would appreciate some tips:
- please should one remove the rest of the gears?
-- Reason I would like to remove the gears,is that I am hoping to use the hole(s) for attaching a rigid structure, on either side of the quill, to mount Z-axis bearings + motor
-- Or do you think one would be happier having the hand-lever to lower the quill?
- If gear should be removed, how does it come out? Attached is a technical drawing of the mill components, if someone would take a care to give an opinion (on how to remove the stuck gear/shaft)?



Thanks for reading