King Midas mill conversion

[diy-john]

Updates:

1) Placed an order with Zappautomation, via the online-store.
1.1) Replaced pulleys / belts with HTD -type, as suggested by Jonathan
1.2) Plan is, screws would be going to Jonathan for machining.
- not sure if the ballnuts could be detached from the screws. They are preloaded. Will talk to Gary at Zapp(automation).

£300 on ballnuts! Are you sure you can't get the cheap RM1605 ballnuts from china to fit as they're $25 each from eBay. Surely you can at least use the cheaper ones for Z?

Good point Jonathan. Thought about that, this time key criteria came to four (4) facets
- Overseas shipping costs - located in Finland, buying from different places will hike costs up. Shipping costs add zero value to the conversion, so minimize them.
- Need for the smaller dimensions of the FDI -type -ballnuts.(X/Y-axis tight space)
- Quality ... don't know much about ballnuts, but did rollerskating / skateboarding in my youth.. what a difference bearings can make

Perhaps biggest factor I have is "risk aversion". Still must admit, not sure if one will ever complete this thread. It is a big project for me, and if there are many set backs, project gets longer and longer, you never know. Does this thread end up in classifieds -section? Need to stick to safe choices.

a toroidal transformer.

Erm, would love to try that. But my skills..not very confident, have set a soft limit of "no mains" electrical appliance -jobs for me. Think one can manage stepper motor -cabling, and drivers, because they are sort of behind the power supply (not directly mains)

Have you considered in the Z-axis screw mount how to temporarily disengage it from the spindle when changing tools so that the force from hammering on the draw-bolt to release the tool taper isn't transferred to the relatively delicate ballscrew/ballnut?

Have not yet figured out how that could be best done. Some sort of a quick-release system would be cool. But not sure about design, and whether it would introduce slack to the Z-axis
- Something like this maybe, to quick-release?

Really grateful for all comments and advice in this thread. They have been very helpful. Thanks!

[Gary]

You can remove them, but i would just leave them on the screw and screw the nut out of the way when doing the machining.

Updates:

1) Placed an order with Zappautomation, via the online-store.
1.1) Replaced pulleys / belts with HTD -type, as suggested by Jonathan
1.2) Plan is, screws would be going to Jonathan for machining.
- not sure if the ballnuts could be detached from the screws. They are preloaded. Will talk to Gary at Zapp(automation).



Good point Jonathan. Thought about that, this time key criteria came to four (4) facets
- Overseas shipping costs - located in Finland, buying from different places will hike costs up. Shipping costs add zero value to the conversion, so minimize them.
- Need for the smaller dimensions of the FDI -type -ballnuts.(X/Y-axis tight space)
- Quality ... don't know much about ballnuts, but did rollerskating / skateboarding in my youth.. what a difference bearings can make

Perhaps biggest factor I have is "risk aversion". Still must admit, not sure if one will ever complete this thread. It is a big project for me, and if there are many set backs, project gets longer and longer, you never know. Does this thread end up in classifieds -section? Need to stick to safe choices.



Erm, would love to try that. But my skills..not very confident, have set a soft limit of "no mains" electrical appliance -jobs for me. Think one can manage stepper motor -cabling, and drivers, because they are sort of behind the power supply (not directly mains)


Have not yet figured out how that could be best done. Some sort of a quick-release system would be cool. But not sure about design, and whether it would introduce slack to the Z-axis
- Something like this maybe, to quick-release?

Really grateful for all comments and advice in this thread. They have been very helpful. Thanks!

[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.