Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: GRAYHIL on April 10, 2012, 08:07:51 AM
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Hi All
My machine is a lathe set up with a quick remove vertical slide so I can use it as a 3 axis mill.
My question is:-
Is it possible to use Mach 3 some how with the motors disconnected and use conventional mechanical feeds and speeds and yet maintain the DRO display.
This occurs when I have to screw cut part way thro a job as I do not have a pulse generator.
Alternative to this where can I find a laymans description of conversion to cnc screwcutting with a list of parts.
Graham
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Hi Graham,
This may be a good place to start http://cnccookbook.com/
Tweakie.
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it would be easier to ge a pulse signal and get mach to do the threading
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Alternative to this where can I find a laymans description of conversion to cnc screwcutting with a list of parts
Would seem rather dificult to provide any type of specific list of parts for a machine which we know nothing about.
That said and think what your are meaning is what is required to convert a lathe to cnc.
There are a few threads on lathe conversions worth having a look at on the site.
You basicaly need to provide a screw which is rotated using a stepper or servo motor for the Z and X axis along with the appropriate controller.
RICH
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Hi Rich
My Colchester master lathe is already converted to cnc but as a 4 axis mill i.e x,y,z,a using a vertical slide as y.
What I wanted was a simple explanation and possible parts to graft onto my BOB 6560 to make it more flexible and multipurpose.
Graham
PS I ask because I am not an electronic expert having bought a bob, power supply, and motors off ebay.
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I think what you want is a rotary encoder to take the place of a stepper or servo keeping track of your conventionally turned screws on the DRO, much like any manual machine. The question is how do you feed that back to Mach as an input elctrically? Am I undestanding you here? That brings up the question other than a pulse generator is there an interface/input to make the DRO work based on position that is not tied to a motor but the axis turning. That could be an interesting feature for Mach if you wanted to kick into conventional mode for certain jobs.
Robert
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ALLSTAR1
Yes thats what I was asking.
At the moment I disconnect the x axis stepper and have a prog that adds the correct amount to the side feed for a given cut and work the x axis manually.
Thats why I want to fit a pulse generator as well.
All part of the never ending story.
Graham
PS Just fitting new ballscrews to eliminate backlash had up to .015" on the old ones.
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Gray
When I started with Mach, one of the first thoughts that popped into my head was how could I use it as a low cost DRO without having to turn/power the stepper motors. I guess when your trasitioning from conventional to CNC a part of your machining background keeps you thinking traditional. There may be an easy way to implement this concept, but like you I am no electronic/computer whiz however I like your thought process.
I am also working on backlash issues as well so I can relate.
Robert
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Robert
Got the z axis backlash down to less than 0.0005" which I believe is down to machine flexing. I am happy with this.
Now for the x axis which will require a lot of modification but if I get the same results I will be very happy as it is currently 0.007"
Have you any experiance with this new? software MSM from Calypso that works with Mach3?
Graham
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I am messing around with the pokeys at the moment hooked up to the encoder outputs from my servo drives. What I am planning for is to be able to update machine coordinates from encoder position when I bring Mach out of reset. It is working well so far, just need to get the zeroing of the encoder working right and it should work well.
Hood
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Hood
Hope you post the results and parts required to do it.
Graham
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I have it working quite well in testing here with a 56u PoKeys. I have the encoder output from a servo drive connected to the pokeys and can count the encoders into a DRO in Mach. I have some VB in the reset button and when I press the button it compares the machine coordinates with the encoder reading and if it is within 0.001mm it will just bring Mach out of reset. If however the encoders and machine coords differ by more than 0.001mm then a box will pop up asking if I wish to update the machine coords from the encoder values, if I click Yes then it will and then Mach will come out of reset. I have attached an image below of the box I was talking about, I also have the encoder and machine coords displayed in that message box so I can compre before I opt to update or not.
In your situation what you would need is an encoder fitted to the disabled axis and a pokeys 56U. What you would do is home the machine at start up and zero the encoder. You would then do whatever you need to do, disable the axis and use it manually then once finished press a button on screen and it would update the machine coords in relation to the encoder counts which would then update Mach as to the position of the axis after the manual motion.
Hood
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BTW I would still say CNC screwcutting is much easier and much much quicker than manual screwcutting on a lathe and if your axis are already under Mach control all that is needed is a single index pulse into Mach to give Mach the spindle speed.
Hood
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Hood
I know but being a reasonable mechanical engineer and a very poor electonic engineer I need a kit? to fit to my machine or the very least a list of parts and a wiring diagram.
Graham
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A slotted disc attached to the spindle, an Optek OPB 916B optical switch and a 220 Ohm resistor are all thats required. Take 5v from the BOB to the white wire on the opto, take the same 5v source to one end of the resistor and connect the other end to the red wire on the opto. Connect the Green and black wires of opto together and connect to 0v (Gnd) terminal on Bob. Take blue wire from opto and put to an input on the BOB. In Ports and Pins, Inputs set p the Index to the port and pin you have it connected to.
BTW Mach has to be licensed for threading just in case you are in demo and wonder why it doesnt work.
Hood
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Hood
Fully licensed, thanks for the clear instructions.
Graham
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Sorry had typo, said 716B and it should be 916B have changed it in previous post.
Hood
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Hood
A search in the internet onlyy found one UK supplier of an Optek OPB 916B optical switch and they had 4 alternatve 916B types but all out of stock!
Do you have any alternative types/suppliers
Graham
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RS seem to have OPB 917B which is the same just longer leg length.
Hood
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Ordered, you may hear from me again!
MANY THANKS FOR YOUR TIME
Graham
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Hood
Where should I connect the blue wire to on a TB6560 BOB?
Graham
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Any spare input you have.
Hood
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Hood--- Thanks
Any spare input you have? They all look the same to me except the obvious power supply and stepper motor wires, as I have said before I am no electonics expert only very basic wiring.
Graham
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Do you have a manual as I am not familiar with that board.
Hood
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Hood
Is this enough
http://www.ebay.co.uk/itm/CNC-Kit-4-Axis-TB6560-Stepper-Driver-4-Motors-Mach3-/260993824823?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item3cc471b837
Graham
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Or better still
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Ok look at the eBay auction, if thats the same one you have (there are many variations coming out of China) then you will see lower left corner it says 4 Inputs.
If you scroll further down you will see a representation of E-Stop etc connecting to these inputs. It tells you there which pin on the connector corresponds to the parallel port pin so for example pin 1 on the connector on the board connects to pin 10 in Mach, pin 2 to 11 etc. If you have a spare pin then you want to connect it into that then tell Mach which pin you have connected the index to.
Hood
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Hood
More thanks, its getting clearer by the explanation off you, soon I will be screwcutting once I have the ball screws fitted and operational.
Graham (from sunny Devon)
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No probs.
Threading on a cnc lathe is just so easy. I do a lot of threads and even if I am doing something on the manual lathe if there is a thread to be done I will pop it in the CNC and thread. I would never even consider doing a thread on the manual lathes nowadays.
Hood
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Hi Hood
Thought it was too simple.
Exactly where do you get the 5 volt supply from as there are no obvious connections for it on the BOB TB 6560?
Will I have to get a seperate power supply if so what spec?
I have been given some 200 ohm resisters will two in series be OK as you specify 220ohms?
Graham
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Not sure where you would get 5v from these boards as I have never used one. If you use a separate supply you will need to connect the 0v of that supply to the 0v(Gnd) of the board so the signal has a reference.
400 Ohms may be ok, you really need to get the specs of the LED and use one of the online LED calculators to see.
Hood
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Hi Hood
You should know me by now and electronics. Tried your suggestion and all it kept saying was I needed a bigger/more power supply.
This is the optical sensor
http://docs-europe.electrocomponents.com/webdocs/025c/0900766b8025c315.pdf
What am I doing wrong????????
Graham
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Hi all
Going to take 5 volts off a usb port, one wire (red) is this ok?
Hood, have ordered some 220 ohm resistors to save confusing the issue.
Graham
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Not sure what you are meaning by "all it kept saying was I needed a bigger/more power supply." What was saying that?
If using the USB you will likely need to also take the 0v from the USB and connect it to the Gnd terminal of the inputs plug so that the signal has a reference.
Hood
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Hi Hood
From your suggestion
"may be ok, you really need to get the specs of the LED and use one of the online LED calculators to see."
Thanks for the advice about grounding the input plug back to the usb. I will have to find out where that is on my BOB.
Graham
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One or more of the pins on the connector that has the inputs will be a Gnd pin I would imagine.
Hood
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Should have said 100 ohm resistors
Hi Hood
Thought it was too simple.
Exactly where do you get the 5 volt supply from as there are no obvious connections for it on the BOB TB 6560?
Will I have to get a seperate power supply if so what spec?
I have been given some 200 ohm resisters will two in series be OK as you specify 220ohms?
Graham
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200 ohm should be fine.
Hood
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Hood
Heres where I am with the wiring.
Pulse from photo cell is sent via serial port pin one to BOB.
GND is via serial port pin 5 and via the usb to computor.
5 volt is from usb.
In ports and pins I have set pin for pulse to 10.
The PDF for the lathe is not very clear.
Will fit 220ohm resister
My question is what do I set PORT to for pin 10???
Graham
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It will be port 1 that you set it to, assuming that is what you have the rest of the BOB connected to.
Hood
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GRAYHILL, do yourself a favor and scrap the TB6560. Remove it from your system and give it a fling out the window. That's about the only thing I've found they're good for. They were junk when I bought mine and they are still junk. If I added up the cost of material I had to scrap because of missed steps, magic smoke, etc coming from a TB6560 board, I could have bought the G540 time and time again.
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Tried some screwcutting this morning with no luck.
On the auto screen, s true, builds up revs and then drops to zero and yellow bar lights up. X axis goes in but z does not traverse.
In the diagnostics screen output 2 briefly flashes then output one lights up permanently at the beginning of screwcutting.
I have still not got my head round ports,pin,etc.
Is port the main input plug into BOB? As in my set up I am using both parallel and series as main input plugs.
Then I presume the pin is the actual connection within the plug to what??? in the BOB thats where I loose track of setting up the other parameters!!!
I have tried following through the Mach 3 PDF,s but they seem to be for the earlier version of mach. I am on version .62
Any help would be appreciated.
Graham
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Are you telling Mach the spindle has started? Do you have Mach set so that the Spindle relays option is NOT disabled?
If you want to attach your xml I will have a look and see if I can find a problem.
Regarding the ports, the connection to Mach that you have is the parallel port (25 pin) the other connections do not go to Mach but instead top your hardware.
Hood
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Hood
xml attached
Spindle relays are enabled
Graham
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Ok go to config menu , ports and pins, Inputs and scroll down until you see Index, enable it and set it to port 1 and I think you said it was pin 10 you had connected and hopefully it will work.
Hood
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Another thing, you have a mill screenset loaded, you will need to load a turn screenset or it wll not work.
If you wanted you could copy the standard mill screenset and rename it with a .lset extension and it would work but when you load a mill screenset it will set that profile as a mill profile.
Hood
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Hood
xml attached
Spindle relays are enabled
Graham
Not according to your xml Graham...
Ian
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I have two shortcuts on my screen, one to COLCHESTER LATHE and one to COLCHESTERLATHE MILL.
One loads the 2 axis lathe screen and one loads the 4 axis mill screen YET I can only find one .XML profile in C/MACH3.
Does this mean there is one common .XML file for them both?
I will try out your new pin suggestion but tomorrow I am under orders to do some decorating ???
Will report back when I am free :)
In the meantime if you think of anything else especially as regards the first pargraph please let me know.
Graham
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Doesnt make any difference what the shorcut is named but it is what the target is that is important. Right click on the correct shortcut and choose properties and then see what the profile name is in the target and that is the xml you want.
Regarding the first paragraph, well not really sure as I am not sure what you are meaning by the yellow bar, also your output flashing and the other lighting will depend on what you are using them for.
Your xml will help so when you can get it I will have a look.
Hood
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Hopefully this is the correct one.
Right clicked on shortcut and the target was to mach 3 turn. Knowing that I was able to find the correct XML. I had been looking for the wrong name SORRY FOR THAT
Attached is the right one.
Hood, the yellow bar is on the Auto turn screen under S TRUE
I will get there one day but there may be many more messages before I do.
I start my spindle through the mechanical lever (so old fasioned)
Many thanks Graham
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Will have a look at the xml in a few but when you say "I start my spindle through the mechanical lever (so old fasioned)" I presume that is outwith Mach so are you telling Mach the spindle has started by having a M3 in the code or pressing the spindle button? If not then no spindle speed will be seen and threading wont work as Mach needs to be told to look for the spindle speed.
Hood
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Ok first thing is Ports and Pins, Motor Outputs, you have Spindle set to Pin 10 for step, you cant have that as it is an input pin and I think you control the spindle on/off manually anyway so just disable spindle all together on that page if that is the case. Next on your outputs page you have Output 2 set to Pin 10, you cant have that as previously mentioned it is an input pin, just place 0 in that box instead, same goes for Outut 1, you can just enter 0 for that as well as I dont think you are using it.
See how you go with changing these settings and also remember to tell Mach the spindle has started (M3 in code or press Spindle button) and hopefully you will see a spindle speed and threading will work
Hood
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Hood
Redone ports and pins.
As you can see from my screenshot there is an m03 in the code and I have manually started the spindle The s true box shows a build up of revs and the dwell active red light is on. Then it drops to zero and the dwell active light goes off and the yellow bar appears.
The same happens with no programm and just pressing spindle start.
Latest xml attached as well.
Graham
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Config menu then General Config and over to the right at the top you will see Index Debounce, its at 100 so is unlikely to work, set it to 0 and see.
Hood
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Hood
Debounce set at zero, no change to symptons,
Graham
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Ok then it would seem your index signal is not getting to Mach. A scope would soon let you know if its working but I would imagine you dont have one. I am thinking a volt meter should work though if you have one. If you connect the meter between the input and the Gnd terminal and move the spindle so the slot is in the sensor you should see 5v I would think.
If you can do that and see and we can take it from there.
Hood
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Hood
4.98 volt at supply side to sensor cell.
4.43 volt on output side when slot is opposite cell and when it is rotated away.
Graham
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Cant see how you would get an output when its blanked but then again I am no electronics expert so maybe. Dont think I have one here to test but should have one at the workshop. Can you unhook the connector from the BOB and see if its the same on the signal pin, may be the Bob that is supplying the voltage.
Hood
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Hood
Just the same.
Will take a photo of connections etc and post later
Graham
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Ok will try and remember to look for an opto to test at the workshop tomorrow. I think I should still have one there anyway, dont use them now as I use the encoders on the spindle motors but I never throw anything away ;D
Hood
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Hood
Amateur wiring pictures as promised.
I have rechecked everything again and seem to be getting 4.95 volts on every terminal and gnd with the slot there or away. What do the resistors do as I get 4.95 volts after them and to gnd. Is there a right way round for resistors?
Graham
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Looks ok I think. I am OTT today at the workshop, always happens on a Friday ::) but will try and get a chance to look out for an opto and test it.
Hood
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Ok found an opto and tested it out and it does as I thought (5v on blue to black when open, 0V when blanked) so looks like your is faulty in some way.
Just to confirm, you tested it without it being connected to the breakout board?
Hood
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Hi Hood
In anticipation of your results I ordered another opto 917B should arrive soon possibly Monday.
I tested all the wiring with it disconnected from the BOB as you asked.
Stuck now till it arrives will keep you informed of progress.
Graham
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Hopefully all will work this time :)
Hood
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Hood
New opto came late this afternoon, fitted and all systems working. :)
Tommorrow I will run the screwcutting wizard to see what I can accomplish.
Again many thank for your patience and quick advice
Graham
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Good to hear :)
Hood
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Wondering if someone could take a look at another Opto Sensor type. It's the HOA1405-001 (http://datasheet.seekic.com/PdfFile/HOA/Honeywell_HOA1405-00108916.pdf). It doesn't require a slot because the IR LED and the Sensor are pointed at an angle to each other so all that's needed is a reflective spot.
I'm just to ignorant to make a definitive call on how the wires go together.
I'm using the cnc4pc c11 board.
My thoughts are as follows:
C - Input Pin on BOB
E & K - Wired together and put on GND of BOB
A - Place 220 Ohm resister prior to connecting to 5V on BOB.
Any advice would be appreciated before I destroy something. I don't want to fry the IR LED nor burn out the Sensor. Also want to make sure I put the Ground wire where it's supposed to go on the c11 as well.
(I'm still attempting to touch base with Arturo but haven't been able to talk to him in weeks now.)
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Talked to Arturo and got some other things sorted out, but we didn't get to work on the above post's question about wiring the opto.
Anyone got any comments?
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Hi All
What would be the best way to achieve full motor control on my Colchester Masster via Mach 3 with the attached old motor.
I am converting single phase to 3 phase via a 2 hp Motorun convertor.
I have a spindle encoder but want to introduce stop/start, forward/reverse and constant cutting speed.
Graham
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Can you elaborate on the "Motorun" a bit?
Hood
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Hi Hood
Its a very old one of these and the company have responded once with a not very helpfull reply.
http://www.motorun.co.uk/
As far as I know it just changes 1 phase to 3 phase and I might need to change it for a more modern one
Graham
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Ok its a static or rotary converter, it will likely work fine but if its a static you will need a pilot motor in parallel with the converters output and the lathes motor to enable you to make frequent stop/start/reversals.
How you will control the stop/start/reversal depends on how your lathe is currently started, can you give a bit of info on that?
Hood
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Hi Hood
This is something I drew a long time ago (originally in Autocad) hope you understand it.
All motor controls are via levers on the headstock. Stop/Start and FW/REV.
I once tried to run a suds pump off it but it did not like it one bit when the main drive was started.
How can you tell if its static or rotary the paperwork I got with it does not say??
Graham
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If its a rotary there will be a motor incorporated into it.
I think I follow the wiring ;)
I think really what you would need is a pair of suitably sized interlocked contactors, one for Fwd the other Rev. You would then need two relays to switch the contactors coils so that you could fwd/rev from Mach.
Spindle speed will not be an option for you, it will still have to be set manually via your headstock.
Hood
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Hi Hood
I do not think its rotary there is no feel/sign of another electric motor.
I understand what you mean by interlocking relays but what if I ditch the converter and fit something more modern and stay in one appropriate gear?
I have read a bit about VDF? and the even more modern VD? converters and there are some posts about them on this website. Are they worth the effort?
Graham
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You could use a pilot motor to basically make it a rotary converter.
As for a VFD, not a huge fan personally but they do work well enough as long as you realise what their limitations are. Lots of people think that you can basically set the spindle speed to whatever you want, whilst that is true the torque drops way off at low revs and on a lathe that is where you need the torque. You can of course use one gear on the headstock for high speeds and if needing low speeds then use another, you will then be able to vary speeds in these ranges, within reason.
Hood
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Hi Hood
Thanks for your replies but I think I will stay with the set up I have which is working very well. I am just getting lazy and want to press and forget!!!
Graham