Starmill PC - Mach3 conversion and Tooling

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Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Wed 02 Feb , 2011 20:27 pm

Hello, I have recently purchased a Starmill PC with a despatch date of February 1994. Unfortunately, the machine came without a manual, software, or any tooling. I do have a little experience of using Mach3 on a CNC lathe, so I would like to convert the mill over to this. I have read recent postings, and it sounds like it should be quite straightforward. I am hoping to re-use most of the existing electronics (power supply, stepper drivers, and spindle driver).

The wiring is very neatly laid out in this machine, so it is relatively straightforward to identify where most of it goes. The problem is, I don’t know the wiring details to the stepper driver inputs. It looks like these should be accessible via the micro-controller board pcb plugs on the top of the driver board. (The controller in my machine is a smart step /3 board with a MINT /3.28 EPROM v 1.05f/s). Does anyone have a circuit diagram that they could scan for me please? Am I correct in thinking that the only hardware I will need for the conversion is a suitable breakout board and an isolated analogue board for the spindle driver input; such as the V3 range from diycnc. (The spindle driver board on my machine is the Fenner 522A3700.)

My other problem is tooling. The machine has an Easychange tool holder but no adapters. I have done a quick search, but could not find a supplier of easychange tools. I was wondering if it might be better to change over to some other tooling. The manual for the earlier (BBC) Starmill shows a BT35 tooling option; would this be suitable for the Starmill PC? or should it be R8? I guess another problem here might be finding a suitable draw bar / pull stud arrangement.

Apologies for all the questions; but I would hope to post a wiring diagram for the basic Mach3 conversion for a Starmill PC when I have finished so that others can share it (if it doesn’t already exist).

Many thanks, Peter.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by angel-tech » Wed 02 Feb , 2011 21:34 pm

This is the first place to start.

viewtopic.php?f=54&t=2264

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Re: Starmill PC - Mach3 conversion and Tooling

Post by angel-tech » Wed 02 Feb , 2011 21:38 pm

Mscj&l do the toolholders, they're called Coventry toolholders.

http://www.mscjlindustrial.co.uk/CGI/IN ... ord+Search

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Re: Starmill PC - Mach3 conversion and Tooling

Post by Denford Admin » Thu 03 Feb , 2011 10:39 am

I've posted all I currently have in the way of none BBC, Baldor starmill drawings: viewtopic.php?f=45&t=3185

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Thu 03 Feb , 2011 21:50 pm

Many thanks for the pointers to the wiring and tooling links; it looks really helpful. I will take a closer look at it all over the weekend.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Sun 06 Feb , 2011 17:19 pm

RE: My 1994 Starmill PC Mach3 upgrade. I attach a few wiring diagrams that I made over the weekend, as you can see, there are some differences to the Baldor Rack circuits. On close inspection, it looks like I should be able to re-use the existing spindle-motor driver interface board (Optimised Control D401 issue 2) with just a few minor modifications. This board already has a fully isolated pulse to dc converter –so I should be able to interface it safely to a diycnc PCPPS V3 breakout board. I will post details of the mods when I get the breakout board and test it out.

Anyone know the spindle size for the 1994 Starmill PC ? I would like to look at alternative tooling to Easychange.
Attachments
Driver-board.GIF
Driver-board.GIF (16.01 KiB) Viewed 24019 times
Relay-connections.GIF
Relay-connections.GIF (15.34 KiB) Viewed 24019 times
Main-power.GIF
Main-power.GIF (18.1 KiB) Viewed 24019 times

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Re: Starmill PC - Mach3 conversion and Tooling

Post by angel-tech » Sun 06 Feb , 2011 17:22 pm

R8 spindle

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Sun 06 Feb , 2011 21:22 pm

Many thanks angel-tech.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by angel-tech » Sun 06 Feb , 2011 21:27 pm

if you're thinking of getting a cnc lathe with autochanger, you may want to consider an R8 sidelock holder the same bore as the bore of the autochanger tool position. You can then make several holders for tools to go into the sidelock holder, that would be useable in both machines

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Mon 07 Feb , 2011 19:09 pm

Excellent idea. Just had a quick look on e_Bay and seen a number of R8 Bridgeport Sidelock holders with 7/16" UNF drawbolt. At the moment I'm struggling to remove the existing Easychange holder, is there any advise you can give me about how to go about this? Is there a recommended drawbar torque setting when fitting a new holder? Many thanks, Peter.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by angel-tech » Tue 08 Feb , 2011 13:51 pm

to remove the existing toolholder you loosen the drawbolt a turn and tap it with a soft hammer. This releases the toolholder from the spindle, then unscrew the bolt and pull out the toolholder. Check the thread on the bolt as it may be metric.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Tue 08 Feb , 2011 19:57 pm

Thanks again angel-tech. Came out easily with a gentle tap. The 'drawbar' is just a 1 1/2" long 7/16 UNF bolt.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Sun 27 Feb , 2011 18:58 pm

Just to say thanks again for all the help. After a short half term break, I now have my Starmill PC fully converted to Mach 3. I was able to reuse the existing spindle-motor interface board after making a few modifications (I attach the circuit diagram and a photo of the modified board). I had to replace C16 -which had gone leaky; removed the two ICs in sockets (ULN2803 and PAL16L8); connected 5V to pins 14 and 20 and 0V to pin 6 of the PAL16L8 socket. (Putting 5V on pin 14 disables the chip-select lines of the two IC’s closest to the 50-way connector as these are no longer used.) The Mach 3 PWM spindle-speed signal was fed to the board via a screened cable to pin 13 and grounded at pin 8 of the ULN2803 socket. I re-used the ULN2803 as a buffer for the PWM signal and as relay drivers for the Spindle Go Relay and the Spindle Reversing Relay. I fitted this IC on a small Euro-card with a 92-pin DIN 41612 socket for making all connections to the existing stepper driver board. I also fitted an R8 6mm sidelock end mill tool holder as suggested – great idea thank you. I bought this and a matching set of FC3 milling cutters from Gloster Tooling. Everything seems to be working OK, just need to tweak the motor settings. The Y-axis stepper seems a bit noisy when moving -probably needs a good clean out. If anyone needs more details of the conversion of a 1994 Starmill PC to Mach 3 I would be happy to help. (With hindsight, it is probably simpler to buy a new spindle driver board than modify the existing one – I have one on order to use on my lathe.)
Attachments
PWM_board_photo.JPG
PWM_board_photo.JPG (148.66 KiB) Viewed 23957 times
PWM_board.gif
PWM_board.gif (182.13 KiB) Viewed 23957 times

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Re: Starmill PC - Mach3 conversion and Tooling

Post by Andycnc » Mon 18 Apr , 2011 21:43 pm

I'm just converting mine- haven't actually wired the thing up completely yet. Am I correct in thinking that the BOOST inputs control full/halfstep drive to the motors?
If so, which way did you end up tying them? (I guess they're probably pulled one way on the base board anyway).

Half step=better resolution but less tourqe...

Anyone know what the original control used?

Thanks
Andy
25 years as Electronics design Engineer, cnc machines used for manufacture of prototypes. Have Boxford 240tcl and 260vmc, Denford starmill, used to have an Orac. All converted to run Mach3. Happy to try to help with any tech issues.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by Denford Admin » Tue 19 Apr , 2011 8:36 am

Boost is to do with dropping the holding voltage (so the motors aren't sat 'burning up' with full voltage when idle)
I'm not sure about your machine but all Baldors since about the 1990's use half-step - 400 steps / rev

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Re: Starmill PC - Mach3 conversion and Tooling

Post by peter.healey » Tue 19 Apr , 2011 17:44 pm

I connected the boost inputs to the parallel port so that I could controll them via Mach 3. Haven't had chance to try them yet as I have been diverted on a bathroom project!

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Re: Starmill PC - Mach3 conversion and Tooling

Post by paul hunt » Mon 29 Aug , 2011 10:33 am

Hi Some great info here, Can any one help please. I am just making an interface board for mach 3 and just wondering
if the connections on the 96 way conector for the X Y Z step and Dir for X y Z need to be pulled to GND to operate
or do they need a +5v signal to operate? as i don't have the whole machine here to test it is making it a bit
difficult to determin, i have looked at the wiring and i think that the pins 14 a , b c, are floating and need pulling to GND to
function. but not entirly sure, for the direction it will obliviousl be high or low for CW CCW. i have seen on another post the
96 way plug and i think it is the female to plug into the lower board, again i am not sure?


Like wise to operate the SSr and SGR relays they need to be pulled to GND to activate. does anyone know if this is correct?

On the same board i am going to incoporate the spindle speed control, (isolated) my intial thought was to
use a LM2907 freq to voltage converter for the 0 to 10v output for the fenner drive. once i have finished the PCB i will post up the
etch file for the PCB to share.

Many thanks to every one in advance
Paul

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Re: Starmill PC - Mach3 conversion and Tooling

Post by Andycnc » Mon 29 Aug , 2011 12:22 pm

yep, they need pulling low. I think there's a pullup on the board but it wouldn't hurt to provide this on your board. Pay attention to the isolation on the spindle drive as the input could be floating up at mains potential.
25 years as Electronics design Engineer, cnc machines used for manufacture of prototypes. Have Boxford 240tcl and 260vmc, Denford starmill, used to have an Orac. All converted to run Mach3. Happy to try to help with any tech issues.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by angel-tech » Mon 29 Aug , 2011 13:05 pm

Definately need an isolated 0-10v board for the spindle speed, and do watch your fingers.

Radio control servo leads are quite handy for connecting to the 96 way header for step and direction feeds.

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Re: Starmill PC - Mach3 conversion and Tooling

Post by paul hunt » Mon 29 Aug , 2011 17:44 pm

Thanks for the info good idea on the radio control leads...

definatly be isolated from the spindle drive as it bites!! :shock:

thanks again
Paul

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