Messages

1141

General Mach Discussion / Re: Cut Circle in metric

« on: August 25, 2007, 03:37:51 PM »

I don't know exactley which wizard you are referring to. - BUT in the tutorials it says that we can switch between metric and imperial.
The only trouble is, I haven't found how to do t  yet.

1142

General Mach Discussion / Re: Vacuum on Flooding

« on: August 25, 2007, 03:35:18 PM »

Well - yes it is.  If you look at the video tutorials it shows you how to hook up inputs and outputs.
You could also run a script on a G code or M code to do just this.

Look at the tutorials.

The other way, of course is to do it manually when you see a problem.

1143

General Mach Discussion / Re: Problem with arcs in Mach3 Turn

« on: August 25, 2007, 05:14:09 AM »

As another point - have you tried the G2 Xpos Zpos R - being the radius. I find this a lot easier to compute (provided you get the correct + or - on the radius.)

1144

General Mach Discussion / Re: Problem with arcs in Mach3 Turn

« on: August 25, 2007, 05:12:04 AM »

Looking at your script, there is no Z co-ordinate move before the first G2 move, so I do not see how the machine can compute the move (I couldn't do it on paper since I didn't know where to start). I do not know where it gets it from ( other than one might presume it gets it from the DRO's ). This you would think would be fine, but it may be for moves like this it takes it from some other register which is updated on every X or Z move.

Try on the line above, putting in a Z position on the G0 move and see if this solves the problem.

1145

General Mach Discussion / Re: Quick conversion of code from linear to angular movement

« on: August 24, 2007, 04:16:44 AM »

The answer is, of course, a computer program to read the code and convert it - which you could easily do if you had the necessary program - say one of the Basics in you machine.

I may be way off the mark here, but looking at the tutorials and writing script, could you do something similar here and write one of your own  M codes which has a script underlying it.

The equation for your A move is  A=360 M / Pi D, where M is the move to make and D is the diameter of your piece.

Instead of calling G1, call  M *** whatever. The script takes in the code to move M*** X0 Y10 Z0 and rewrites this as G1 X0 A??? Z0. You have no other input because the script takes values from what is already in Mach3. You would need to go through your code to alter the necessary lines from G1 to M*** but other than that you do not have to do anything.

You can also write in little checks such as what happens if the diamemetr is too small to accomodate the move.

Once the script is posted, it should do for anything else you want to write.

1146

General Mach Discussion / Re: Edge finding?

« on: August 24, 2007, 03:21:45 AM »

You cannot determine the position of your workpiece with the measurements you have made. There are not enough. I assume on each touch you have an X and Y co-ordinate. To determine the angle, you would have to know at least one other point. If for instance you know where the bottom left hand corner of the piece is, then you can work out the rotation and the adjustment to put it straight.

If you wish to lay the piece on the table in any position, and have the mathmatics work out the bottom left position, then you would need to make one more touch, to determine the angle of the left hand, or bottom side of the piece, From there (if the piece in square and the included angle is 90 o, the you can work out the rest.

Perhaps the easiest way, since you have written the macro, is to run it twice with a different radius. You would then get two points on each side, and the intersection of the two is the place you are looking for.

Jim

1147

General Mach Discussion / Re: Joging an axes with inputs

« on: August 21, 2007, 02:31:41 PM »

I do not understand the question. The parallel printer port is connected to your stepper motor driver boards, perhaps via a breakout board. On my stepper driver boards there are two inputs for each axis. One is for direction, the other makes the motor take a step each time a Negative pulse is applied to the board from the appropriate pin on the parallel port ( as per your pin outs). There is no other drive to the motor. Jogging is just a longer , faster series of pulses applied to the same input as any other G0 G1 G2 etc movement.

If you are asking why you cannot Jog when on some of the program pages, I understand Art cut it off on those pages for safety, and so that you could not inadvertantly interfere with the positioning of the machine, whilst it was running a program.

1148

General Mach Discussion / Re: Accurate homing

« on: August 21, 2007, 02:19:30 PM »

I  wasn't infering that Mach3 was a cheap controller - it has all the features of the professional systems I have seen - Fanuc being the leader. What I was saying is that the machines I have seen are way in advance of mine. They have feedback, proper limit switch systems etc etc. I saw one the other day with two chucks, that could pass the work from chuck to chuck. I haven't got that because I don't want to pay for it.

As far as I can see, the DRO's have no feedback (certainly using steppers). Logically they must therefore take their position from the pulses put out to the motor (try running the program without the miller connected - the DRO's still register) - they know how many pusles move the axis how far. BUT if the computer puts out a pulse which the motor misses - for what ever reason, then the DRO IS NO LONGER ACCURATE. As an alternative - if you press E-Stop - and the computer instantly ceases putting out pulses - yet the momentum of your system carries the motor over a few steps (4.8 to the thousanth of an inch on mine) then the DRO (which registers to 1/10th of a thousanth) can no longer be accurate. I suppose in theory if you belt the E-Stop at one end of travel, then belt the E-Stop at the other, the two could cancel each other out.

If you set up a key on your keyboard to stop travel - (I was going to suggest the space bar but this might not be feasable) - then that is quicker and easier to get to the trying to click a mouse on a screen icon. That would take care of E-Stop and cut out a lot of problems. If you set up your soft limits that should take up another problem (because you shouldn't bang your limit switches anyway).

The other question about homing - have you set up your homing as per the tutorials - and seen if it works. You can use your limit switches - because when homing the limit switch function is cut off - until the homing is complete - and then it resumes.

I think you have to do all you can before adding other bits and pieces to try to fix a problem that may not be there.
To my mind , keep it simple.

1149

General Mach Discussion / Re: Losing track of the Z height - gouging table

« on: August 21, 2007, 01:39:51 PM »

I have no idea what the cause might be, as you clearly realise odd happenings are difficult to trace.

The reason for the post if to ask Art if we might have a "black box" in later editions of Mach3 - say something that recorded the last 5 secs of output from Mach 3. We should then be able to see which axis are moving and in what direction, and with a little interpolation, we could even get the speed. This would make trouble shooting so much easier.

In this case - is it Mach3? is the z stepper wire picking up stray signals? or is the driver card doing its own thing. To be able to eliminate one possibliity would make it so much simpler.

1150

General Mach Discussion / Re: Accurate homing

« on: August 21, 2007, 04:46:49 AM »

I have read the post, but , I think, most are loosing the idea of Mach3 in the first place - Convert your PC to a CNC controller for $***.
I am quite sure that the idea was just that - your PC becomes a CNC controller with the addition of a few, cheap bits and pieces - in the same way that my other computer is now performing like a Wurlitzer theatre organ - with the addition of jOrgan software.

The jOrgan cost me £600 against a price of several thousand in the shops. Mach 3 CNC has cost me about £200 against £4000 - £5000 for a professional machine.

In return I have a CNC controlled Lathe/Mill. I have just run off 16 handrails stanchions, and cut 11 window openings in the side of a miniature railway locomotive, and the results were acceptable. I won't say perfect, but I put that down to my expertise, which will improve. I keep the speeds of the machine down to within the tolerances I know my machine will accept, and I find it accurate.

I will agree with those on the forum who say that your limit switches (or soft limits) should never be hit, because that implies some error.
(Since I have never hit them (because I don't have any), I don't know the answer - but presumably when Mach 3 reads the G Code, it will not start up if any position is outside the limits set)

On the lathe, the example given, in the tutorials, on how to position a workpiece is simple and accurate. My method is similar in that I tell the tool to go to a set position, and set the workpiece to touch it which amounts to the same thing and is perfectly accurate.

With the mill, then the start place is somewhat up in the air. If you are milling a blank sheet of material, where you start seems not to matter all that much. If you are milling one pattern on another then the important thing is that the mill is in the correct position in relation to the work, not the machine - so I would have though it essential that some location device on the workpiece would be accurate. If I drill a hole in the workpiece - and the cutter tool will locate in that hole, then I know the cutter is accurately aligned with the work.

YES - it would be fine to have a perfect machine that always knew exactly where it was, in relation to all the other things around it and all you had to do was to throw material at it, which would align perfectly first time, and then the machine would cut it at the speed of light.
ALL FOR $200 - I think not.

Mach 3 is a fine program and I thank Artsoft for bringing me the pleasure of having a CNC contolled machine. I have no doubt that there are limitations, although with my little experience I haven't found it yet. If you need all these gadgets attaching to your machine, go out and spend the money, but I am quite sure that you will be able to work round them, with acceptable results.

I must admit I have though long and hard about putting an accurate homing device on my machine - but then I have to make sure the work is in exactly the right position to benefit from that. I might as well put the tool in such a position that I line the work up to the tool - it comes out the same in the end.