Messages

761

General Mach Discussion / Re: Milling machine

« on: March 28, 2008, 02:44:45 PM »

I am not quite sure what you are asking. G Code controls many parts of the milling machine and all can be switched on and off by G Code.

If you are asking how you  start a program , then this must be loaded into Mach 3 and press cycle start - which will start the program

Have you got a machine - is it set up, what software are you running - what do you want to do

762

General Mach Discussion / Re: Toroidal transformers vs standard IE

« on: March 28, 2008, 02:09:50 PM »

Does that answer the question

763

General Mach Discussion / Re: Code wanders off?

« on: March 28, 2008, 01:57:11 PM »

I certainly don't want to tread on Brians toes - but I notice that the line BEFORE the line that causes trouble is a G3 move. This is followed by an instruction where ( and I know this is allowable ) only one parameter is specified.

Could it be that Mach is not identifying the second parameter correctly.

I would try inserting the missing X parameter in line 1070 and 1130 and see if that solves the problem for the time being. It certainly can't do any harm.

764

General Mach Discussion / Re: Feed Rate

« on: March 28, 2008, 01:41:37 PM »

Give me a chance - I'll get there - but not with this machine.

No -  most of my stuff is mild steel 5,6 or 8 mm to drill -  sometimes up to 12mm - as I said, I need to fit a gearbox on the 3 phase motor - it looses a lot of power at lower speeds. I'm designing one now

765

General Mach Discussion / Re: Feed Rate

« on: March 28, 2008, 05:37:21 AM »

I must admit I have never bothered with the difference between G90 and G91 - and therefore I must have assumed that the lathe would be in G90 mode all the time.

Having read Graham's explanation - yes - I must agree, a G90 at the begining would make sure of it. A G91 popping up unexpectedly could cause chaos!!

Tested my new motor yesterday on drilling - yes - it worked. A 6mm drill, spindle speed about 1300 (top speed on this motor til I fit a gearbox) and a conservative feedrate of 0.25mm and it had no problems.I'll try upping the feedrate a bit, and then I'll try some of my bigger drills.

766

General Mach Discussion / Re: Use Mach3 on two computers and one is connected to CNC machine?

« on: March 28, 2008, 04:55:31 AM »

Jeff - This is exactly what I do.

I have both computers with the same  xml files (in my case two - one for use with the lathe and the other for use when I have the milling head working.

I sit in my office (front room) where it is nice and warm to write my GCode programs and test them using the tool path window. It is easier to study and think when you are comfortable.

My computers are on a network, so when I am ready I can transfer the GCode across. I also use a USB stick if I need to, and I can't be bothered firing up the workshop computer on the wireless net.

767

General Mach Discussion / Re: X axis quits functioning after 3-5 minutes only in mach 3

« on: March 27, 2008, 08:10:46 AM »

If the other software is a CNC program, then I would check the configuration of Mach3 against the other one, and try and identify where the configurations differ - which might give some clue. If the two systems use the same driver board, then the signals they give out must be almost identical. The only one I can think of that might have any bearing on it is the pulse length on the motor tuning page. Everything else must be the same by definition.

The only other thing is active high or low on the stepper pulse - is Mach3 leaving the board turned "ON" when at rest - although I think that is a function of the driver board, not Mach3.

768

General Mach Discussion / Re: Servo axis switchable between spindle and angular position modes?

« on: March 27, 2008, 07:49:25 AM »

If you read the PDF file - Using3Mill - details of how to set up Spindle motor control are shown there - section 5.5.6.3 You connect your spindle driver to two of the normal output pins - step and dir, as you would an axis. I haven't seen anything on changing them in software.

769

General Mach Discussion / Re: X axis quits functioning after 3-5 minutes only in mach 3

« on: March 27, 2008, 05:24:12 AM »

It sounds like the kiss of death for your driver board. Something is failing when it gets warmed up or put under pressure.

There is no reason why Mach 3 should suddenly stop putting out signals - especially on just one axis.
To test it  use two other output pins (if you haven't any spare, swap the x and y, or x and z) and reconfigure Mach 3 to output on these new pins.

If the fault moves (or does not appear) then the trouble lies with the computer side. If the fault stays with the same axis, the fault lies with the driver board.

You can, of course, test this by swapping the driver boards - i.e. inputs from the computer AND outputs to your motors swapped and see if the fault moves.

If you have to replace the driver I would suggest you use a single axis driver card. The trouble with 3 or four in one, with a breakout board is that if something goes wrong you have to replace everything. You could just use a seperate single card, and leave the faulty axis on your main board disconnected. That would get you going.

 

770

General Mach Discussion / Re: Feed Rate

« on: March 26, 2008, 05:42:53 PM »

You do not need home switches or any other switch for that matter.

The simplest way to set a lathe up for CNC is

Your machine wants to be in PART CO-ORDS (BUTTON ON RIGHT HAND SIDE OF THE MANUAL PAGE)

Put the work in the chuck.
Move the tool to the end of the work and take a facing cut across it.
ZERO THE Z AXIS.
Jog the tool a little way down the work and then touch it onto the work.
Measure the thickness of the work using a caliper and PUT 1/2 THE VALUE IN THE X AXIS DRO (Full value if you are in Diameter mode)
To zero the Y axis (tailstock) you can touch the drill on the end of the workpiece and zero.

The lathe is now set and knows where it is. - i.e. X0 is down the centre of the lathe and Z0 is at the outer end of the workpiece.
Your G Code program should be written from these markers. Include in the code the following at the beginning -
G17 G20(if in inches) or G21(if in mm's) G40 G49 G94. This cancels all offsets and sets the machine so it knows what it is working in.

You can check these settings each time you put in a new piece of work - but as you grow more confident you will find that it is possible to repeat without checking everytime (although bear in mind it is still possible for a motor to miss steps from time to time - you certainly need to keep an ear open)

When finished jog the tool away from the work to a convenient position to remove it.
To do another part, do G0 X0 Z0 which puts the tool back where you started, put in a new piece of stock, pull it out to the tool, tighten the chuck and away you go.

I cannot help you with the rest other than to say -
1. Yes - you must accurately set the number of pulses per unit your computer has to put out to the motor drivers - mine for example is 48,000 per inch. You must do this for each axis.
2. You MUST NOT ramp up the speed too high, because the motors will miss steps. If you have a simple system with no feedback like mine, then this is important. My lathe will only traverse at 4 inches per minute without losing steps. (This is a mechanical thing - I am working on it)
3. You must accurately set the backlash, and enable it.
4,. On your drilling with the tailstock - is the motor powerful enough. Drilling is very heavy work (more that tool turning I think). Your motor must be powerful and the feedrate (as set by the F command - not the motor settings) must be low or you will loose steps again.
If you think about drilling manually - a drill bit takes a lot of pressure and only goes in slowly - it is important to get the spindle speed correct for the size of the drill.
(On my milling head, I put too small a motor - the thing worked very well indeed - it would go up and down - and hold the tool in the same position as I milled - but when it came to drilling - it just stopped! - I have now changed it for one at least three times the power.)

Sorry if you know a lot of this - hope it helps.

Persevere - you will get better all the time. You will not get better software than Mach3 (not without paying a great deal of money, anyway) and this is the best forum in the world.