Messages

411

General Mach Discussion / Re: Thc 300 Macro not working

« on: July 21, 2008, 12:55:29 PM »

The program is asking for various parameters - the GetUserDRO are the ones in question - and you must fill these DRO's in before starting, so the machine has something to work on.

You say you put in "M3" - I do not understand this, becasue the program calls an M3 (DoSpin CW) without you having to do that.

Where did you get the program from, and what is it suppose to do. Yes I now it is for plasma work, but can you explain what you expect to happen - and where it is going wrong in your opinion.

KTM has also answered this whilst I have been thinking, so perhaps he knows a little more about it. 

412

General Mach Discussion / Re: Cannot get Mach 3 to run sub progams

« on: July 21, 2008, 12:19:02 PM »

Try posting your sub-routine in the "Subroutines" folder. I cannot quite remember how it works, I will have to think about it some more, but if you post the subroutine there, you can then call it from the main program. The only problem is, I can't remember how to call it. I will go have a look on my workshop machine, there are none on this machne.

413

General Mach Discussion / Re: Spindle RPM

« on: July 19, 2008, 10:59:13 AM »

I do not think that the speed of a single phase motor is variable. You will need to change your motor to a three phase one. Once you do this you can get several makes of single phase to three phase inverters to control it. Mine is an Omron (quite old) but very servicable. I changed my motor from a 1hp single to a 1 3/4 hp three phase motor - and controlled it with the Omron manually. The Omron gives full speed and direction control. The torque of the motor falls off if you try and use it below about 50% speed (30 hz), so I will be putting in some gearbox/pulley arrangements to turn some of my larger pieces.

Unlike Hood, who uses a slot detector, I use a reflective detector - same principle - ir.led shining and reflects onto a detector - mounted 5mm from my chuck mounting plate (painted matt black). A small reflector, made from my granddaughters "sticky" bits and pieces, stuck to the edge of the mounting plate, reflects the IR back once per rev.

As I put in the original post, it works well, but seems to over read. I put this down to a 12 volt supply to the Omron instead of 10. I will work on that.
By the way - one inverter (providing it is large enough for your largest machine, can supply all your machines, you do not need an inverter for them all. (You can only use one at once, though)

414

G-Code, CAD, and CAM discussions / Re: Help with multiple passes

« on: July 17, 2008, 03:31:42 AM »

Chip - I was going to suggest a macro - but I saw your post.

Can you explain how the ; in front of a line works - you say it is repetative.

What Sage was saying - and is is a fairly common thing - is having cut a groove, and then moved the tool up to go to the start again, how do you G00 the tool back down through what you have already cut, to get to the meat again.

I have looked at your code, but I can't see how it works, and I'd love to find out, because it iwould be so useful. I would have thought GCode catered for this becasue it is a very common thing.

415

General Mach Discussion / Re: Joystick control for robot arm.

« on: July 16, 2008, 10:25:07 AM »

Looking at it, I don't think you can use analogue joysticks on Mach 3. The jog controls are not alterable for speed - they are on or off, so will only react to an on/off joystick.

You can alter jogging speed but it is a seperate function.

416

General Mach Discussion / Re: I could use a GCode file for Lathe

« on: July 16, 2008, 01:09:55 AM »

Oh - was that a joke - you dour Scot!!

417

General Mach Discussion / Re: Mach3 via COM Port

« on: July 16, 2008, 01:03:43 AM »

If you want to expand your system, and bring it right up to date, I would say get the SmoothStepper board.

This is a new board that runs from a USB port. It controls all the axis, and has enough imput and output connection for anything you want. It also controls the "stepping" for the motors, so your computer does not have to do that, and is much smoother and faster.

If you already have your machine connected to the computer, the SmoothStepper is a direct swap for the LPT1 and other outputs, but only has the one connection - a USB plug.

418

General Mach Discussion / Re: "Homing" Mach3 without using home switches

« on: July 16, 2008, 12:56:51 AM »

The Mach 3 DRO's provide two different readouts.

With the Machine Co-ordinates button pushed (the surround is lit) then the DRO's are displaying machine co-ordinates. These are the co-ordinates the machine uses to keep track of itself. If you have home switches fitted, and pressed the "Ref All Home" button. the machine would visit each switch in turn and stop there, All the DRO's would go to zero. The machine would therefore know exactly where it is.

You cannot alter machine co-ordinates, and they will only zero by pressing the RefAllHome button. It is unlikely that such a position would be any use when machining (it is usually off to one side of the machine) and is only for the machine's own reference. "Offsets" are provided in the table of "Fixtures" to move the table (or cutter) to the correct position for work - and in a prfessional machine shop, the machine would be "homed" to the switches, then the appropriate offset would be called for whatever program was being implemented.

With no home switches fitted, or activated, you will find you can press the RefAllHome button and the DRO's will zero anywhere at all.

If you press the Machine Co-ordinates button, so the light goes out, the DRO's are now displaying program co-ordinates. This is the display that you use with your program. The first thing is to find out where your program says that the 0,0,0 position is. On a mill this is normally (but not always), at the bottom left hand corner of the workpiece, with the cutter resting on the top of the piece.

If this is your 0,0,0 position, then mount your workpiece, and jog the machine until all three axis are in the correct position, then zero the three DRO's (In program co-ordinates they will zero - machine co-ordinates will not). You are now ready to start.You can move the axis anywhere you wish now, provided you do not touch the DRO's and the machine will return to that position and start the program

If you look at you Fixtures table - "Config/Fixtures" you will see figures have been entered into G54 offset. This is the offset of your work position from your machine position, and you can see that if you fit home switches, you can, just like the "pro" machine shop, have the machine zero itself, and use offsets. But then again do we need to

419

General Mach Discussion / Re: Progressive Move Error with X and Y

« on: July 16, 2008, 12:27:26 AM »

Before you start swapping all the cables about - THE ERROR LIES IN THE CONSTANT VELOCITY, and is a combination of the narrow angle, speed, and relative low number of steps per unit.

If Constant Velocity is engaged, as an axis nears the end of its travel, the computer starts to calculate the next move, and actually implements it. Running the test piece, my axis was stopping some 30 thou short of the mark, and reversing, with constant velocity engaged. On Absolute Stop it ran the full distance.

I have 60 pulses per thousanth on my machine, so it was stopping some 1,800 pulses short of the mark. At a 4 degree angle, the difference in position of two lines at the 1800 mark is 125 - or 2 thou. Let us assume my old eyes are not as quick as they were and we were only 28thou short of the mark, then the distance between two lines at 4 degree would be 1.95 thou.

I do not know the precise method of calculating the CV "offsets", but if we have the old X position advancing up one path and the new X position advancing towards it on a new path, (at a known angle) then the Y distance between them can be calculated, based on the tangent of the angle, and if it exceeds the present Y position, then that is incremented.

The crunch comes as the two positions pass each other (and this only happens for acute angles), then in my example, Y may be incremented by one thou, but is short for the next thou, therefore nearly one thou is not incremented.

Now my machine has at least 6 true steps per thou, so (depending on the CV calcs) could be incremented by 1/6 thou, but if your steps per inch ar small, you will loose out.

Now Mach 3 will gaily carry on the second line, thinking it is on the correct y position ( which again could be being continuously calculated if this is at an angle to the axis) and when X reaches 0, the Y axis says I'm here - but it is a bit short. The same scenario happens to the X axis if the angle of the lines is rotated 90 degrees since the Y axis takes the lead.

I don't really want a discussion about the maths, since I have necessarily picked figures to help my explanation, but the fundamentals work with whatever angles etc, you pick - although the narrower the angle the worse it gets.

I think if you try all your tests in Absolute Stop mode, instead of CV mode then you will get accurate results - certainly more accurate than before - bearing in mind your relatively small number of steps per unit.

If you are in Absolute Stop mode then £$%&*&%$£   

420

General Mach Discussion / Re: PC locking up with a long running 3D milling

« on: July 15, 2008, 03:38:27 PM »

The PC registers there is no activity. It does this by looking at the mouse or the keyboard. If you are running a program it sees this as a period of inactivity and tries to put the screen saver on.

Get into the "Screen" and put the screen saver time up as far as you can go. There is also a similar thing for Stand By mode. Mach 3 has a mechanism for preventing the computer from going into stand-by mode, but sometimes the two conflict. Try and turn that off as well.