Messages

391

General Mach Discussion / Re: What controls the main spindle drive

« on: February 19, 2022, 05:25:17 PM »

The main thing Mach3 can do is output a pulse train with a variable mark/space ratio at a selectable frequency, typically 25hz.  This can be smoothed with a simple RC circuit to produce an analogue voltage to control the speed.  An important question is what drive board you are going to use?  Are you currently controlling the speed of the Denford from Mach3?  The reason for asking is that at least some Denford machines had a speed controller that was not isolated from the mains so some form of isolator is needed to keep mains voltages away from the CNC controller itself. 

For more details on this see here...
http://www.mycncuk.com/threads/7992-Denford-Novamill-Mach3-conversion/page2?highlight=Denford+Novamill+Mach3+Conversion

392

General Mach Discussion / Re: Getting started

« on: February 14, 2022, 05:17:19 AM »

There are a few references to this fault arising both here and in other places on the web, but no fix I'm afraid!  I can't see anywhere in the Mach 3 folder structure where the interpreter would be, but I know that it's there and works in Win10 as macros work on my lathe and mill both using Win10 over USB.  All I can suggest is that you reinstall Mach 3 again, getting a fresh copy from the NFS download page, and try again.

393

General Mach Discussion / Re: Bit depth zeroing tool help

« on: February 12, 2022, 10:49:39 AM »

Mach 3 has an auto too zero button on the program run screen.  If you click on the "Operator" menu, then select "Edit Button Script" from the dropdown list, some of the buttons on the screen will start flashing, including this one.  Click on it - a little editor window will open up with code in it.  If it's like my copy was it will say Message( "Not Yet Implemented" ) which means the routine to do the autozero hasn't been loaded.  Whatever you see, report back here.  Close the window, and if it asks you to save click no.

If there isn't a script there fear not, there are several scripts around to do the job.  Could you describe the "z axis tool depth zeroing tool " that came with the machine?  Even post a photo?

394

General Mach Discussion / Re: Mach 3 newbie setting axis limits and other questions

« on: February 12, 2022, 10:40:19 AM »

"The machine Co ordinates of my X axis where it meets the 1220mm end of the sheet is reading 1230mm
And the y axis upper machine Co ordinates where it meets the top of the sheet at 2440mm reads 2514mm"

So it thinks X has moved 1230 mm but has actually moved 1220 mm, and Y has moved 2440 but reads 2514.  Since it goes back to zero correctly it hasn't hit the end stops.  Mach 3 works in steps per unit, so many steps per mm in your case.  So if you asked X to move 1.23 mm it would actually move 1.22mm.  Therefore you needs to increase the number of steps/mm it's set to by 1.23/1.22 = 1.0082.  Similarly the Y number by 2.514/2.44 = 1.03033

To do this you need to open Mach3 and click on the "Config" menu, then select "Motor Tuning" from the list that drops down.  You will get a window with a blue graph on a black background with various things you can change.  At the top it will say X AXIS MOTOR MOVEMENT PROFILE, and at the bottom left is a white box with "Steps per" above it.  Look at the number in it, with a calculator multiply it by 1.0082, then type the result back into the box and press return.  When you do this the SAVE AXIS SETTINGS button text will go black - press the button which saves your change and greys out the text again. 

Now click the Y AXIS button near the top right, and repeat with the Y axis factor.  Save again.  The Z axis probably needs correcting too, just repeat the same process clicking Z Axis.  Then clock OK at bottom right to exit the menu.  It's probably wise to close and restart Mach 3.

I think my arithmetic is right, but you may have to divide by those factors rather than multiply.

Also ideally you would accurately measure the actual movement of the cutter relative to the table over a shorter distance, say 50 or 100mm, to get the factors.  This is covered in the manual in section 5.5.1, and there is also an automatic procedure described in 5.5.2.3 - though you still have to measure the distance moved.

Does your machine have leadscrews to move the axes, or toothed belt, or what?  Axes with leadscrews are probably best set up by calculation as long as you know the screw pitch.

395

General Mach Discussion / Re: Mach 3 newbie setting axis limits and other questions

« on: February 11, 2022, 03:37:23 PM »

Do you have the Mach 3 Mill manual?  It describes exactly how to set this parameter, either by calculation (for which you need to know your leadscrew pitch, any gear or pulley ratio between the stepper (or servo) motor), and the microstep setting of the driver; or by measurement.  You can download the manual from
https://www.machsupport.com/help-learning/product-manuals/

396

Mach4 General Discussion / Re: Mach4 Lathe Tool Probing (Help)

« on: February 11, 2022, 03:31:56 PM »

OK, well here is the main script which is attached to a button - see what you make of it.  As I said, this is written in visual Basic so I don't know how easy it might be to change it to Lua.  But if you can see roughly what it's doing and how it might convert, then I could provide more bits and pieces.  But I think there could be a major difference in approach as you seem to want to use an existing probe, so I'd not sure the concept works quite the same way.

Enjoy!

397

General Mach Discussion / Re: Mach 3 newbie setting axis limits and other questions

« on: February 11, 2022, 03:04:11 PM »

Sounds like your steps per unit settings are slightly wrong in the motor tuning config menu.

398

Mach4 General Discussion / Re: Mach4 Lathe Tool Probing (Help)

« on: February 11, 2022, 11:49:43 AM »

I have a system for doing exactly this but unfortunately in Mach 3!  Since M4 uses a different macro language it wouldn't be usable directly.  Anyway, it depends on three things.

First, an X axis home switch that gives me a machine coordinate zero on switch on.  This means that you don't have to reference the tools to T1, and T1 can be a real tool.

Second, a system to detect contact between any tool and a workpiece in the chuck/spindle. 

Third, a tool setter with a short MT4 taper to fit the headstock, with accurately measured OD and IDs machined on it concentric.

Then I have an extra Offsets screen with macros behind it that populates a row in the tool table with X and Z offsets.  Basically you set the tool "N" close to the setter, both in diameter and near a reference shoulder, enter the tool number, then click a button, it takes 3 readings of the contact position and calculates the tool offsets from the average.

Also on the Manual screen I have an extra 3 buttons, Touch OD, Touch ID, and Touch Z.  These can be used for more accurate setting to turn a final diameter (with OD and ID), and to find the end of the stock and set Z to zero on it.  So if I rough turn a piece to say 12.1mm with a target of getting 12mm after the finish cut, and the actual diameter after rough turning is 12.07 measured with a mike, I can do a "Touch OD" which should say 12.1, type in 12.07 which is the actual diameter, and put on the finish cut.

Happy to provide more details if this is of interest.  The macros might be a clue though they are in the wrong language, and the general workflow might be useful.

399

General Mach Discussion / Re: Drill chuck reference on lathe table!!!

« on: February 11, 2022, 05:17:23 AM »

These photos show the homing contact and pin.  The pin is a long socket-head screw with the end rounded, held in a little bracket from the cross-slide end-plate.  The first picture shows this with a previous version of the contact pad.  The second phto is the most recent iteration of the pad, a small block of Corian with a plate of beryllium copper shim glued on to it.  A short screw into a threaded hole in the plate and block connects the wire from the switch input to the pad via a crimped tag.  There's enough movement in the pin so that the slide gets stopped before the spring compresses solid.  The block is super-glued to the front of the lathe apron.

When I switch on the lathe I select machine coordinates and jog the X axis until the pin is a mm or so off the pad.  Then click the Set Home X button on the Manual screen, which causes a slow -ve move of Z until the pad grounds.  Then I click Zero World X which zeroes the X DRO.  Actually having done this if the system is restarted and you go through the process again the DRO reading is very close to zero, I think it would be zero except that the steppers don't come back in the same position if powered off and on again. I home Z manually around the centre of the bed as the actual Z position of the stock in the chuck is variable.

400

General Mach Discussion / Re: Drill chuck reference on lathe table!!!

« on: February 11, 2022, 03:44:33 AM »

It's a myth that probing doesn't work in Mach 3 Turn!  It just isn't documented.  I use it constantly with a touch sensor that detects when the tool tip touches the stock. Happy to post details if there is interest.

I don't have limit switches on my lathe but I do have a hard contact on the saddle with a sprung earthed pin on the cross slide.  The contact is connected to an input and used in the inbuilt homing routine.  At the start of every session I home the x axis to this, and I could then have a stored tool offset for a drill chuck mounted on the cross slide.