Messages

421

General Mach Discussion / Re: Centering in Mach3

« on: July 15, 2008, 03:31:53 PM »

Just to follow on from Hood - where is the 0.0.0 position in your VCarve Pro program. On a mill it is normally on the bottom left hand corner of the workpiece, with the cutter touching the workpiece.

Dont take my word for that - FIND OUT.

Then as Hood said - Ref All Home by all means, but then press the Machine Co-ordinates button so the light goes out. The DRO then displays Program Co-ordinates. Jog to where the 0.0.0 position is on your work, then zero all the DRO's.

Press Cycle start and off you go.

Just to go a move further then - if you now look at your offset table, under Config/Fixtures you will see that G54 has taken on some numbers - this is the offset from the "Ref All Home" position to your program position. You can copy this position into one of the other offsets,(say g55) and save it.

If you have a fixed position on you table for your workpiece, then to run the program on subsequent occaissions, fix in your workpiece, Ref All Home, type G55 in the MDI line (or include it at the beginning of your program) and the machine will automatically move to the correct start position.

422

General Mach Discussion / Re: General frustrations in Mach 3 setup...

« on: July 15, 2008, 03:03:25 PM »

I don't think you can blame Mach 3 if Lazy Cam does not do the buisiness. I have not used Lazy Cam, but there must be some way to set parameters before you start.

All you have said is that you have not got everything set up yet and you are running the motors on a bench or something.

Your laptop is OK, I run mine with one - dedicated (although I have a WiFi connection to my system to pass stuff about on). If you are worried about Zylotex (which I have not heard of) I would suggest that you buy a non-powered break out board, and three Gecko 201 drives. These work from the LPT1 port (25 pin printer port). The Geckos (rated at 7 amps and 70 odd volts) will power a wide range of stepper motors without difficulty.

As far as you difficulty with programs is going, you seem to be missing the first essential point of CNC. The machine must know where it is and what parameters it is working under. Specifying where 0,0,0 is is a must, and the total travel of each of the axis is a close second.
If your z axis is starting on the moon, it is because nobody has told it it can't do that.

I think you should build your machine first, and worry about what programs to use later. If you are professional or semi-professional, there are some good programs on the market that will satisfy most needs, and Mach 3 can run any GCode programs.

There is nothing wrong with writing your own GCode programs, in fact, unless you are routing a sailing ship on a choppy sea, it is nearly as quick to write your own programs. If it is for cutting shapes with your plasma cutter, then Mach 3 has controls for plasma cutters programmed in.

A good drawing program (2D) to draw your shapes, then a simple CAM program to convert that to a GCode program would suffice (there are several  you can download).

423

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

« on: July 15, 2008, 02:40:51 PM »

The last few post and your pictures do not answer your question which was " Why does the addition of one line cause a 60 thou error"
What you do not say is whether the error was due to missing steps or additional steps. We must assume that it is missing steps.

What this means is you are loosing 6 thou per cycle. I have analysed your program , and in the first program each axis changes direction twice. In the second program, each axis changes direction 4 times.

I have run this into my machine and run it several times. I am not sure but the answer might be "Constant Velocity"

The movement is made up of several sharp changes of direction - i.e. not straight lines back and forth, but sharp 10 degree, 20 degree etc angles and I noticed that with constant velocity on (my normal state), the axis stopped well short of the X-3 Y-1.5 position. It then travelled down to the X3 position and stopped bang on (a 90 degree turn follows). It was similarly short on the zig zag of the additional move entered.
Using my digital calipers I noticed that when running in CV I was 2 or 3 thou out. (measuring one axis (Y) only).
I changed to exact stop and watched the DRO's - the axis stopped at the precise distance. X0Y0 was bang on.

Now I have scratched my head, becasue, in theory, the fact that corners are "rounded off" should not affect the positional DRO's and so the final position should be the same. If you are loosing one or two steps in the sharp corners being rounded, then that well might be where your discrepancy occurs - especially if you are running at speed.

424

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

« on: July 14, 2008, 03:50:09 PM »

Hood - These run in Metric or Imperial (I hope)

Dave  - I'm sorry. For some reason the multi macro file is empty/ I have posted it again.

The lset file should be put in your Mach3 folder. You will probably see other set and lset files in there as well. Open Mach 3Turn and select View / Load screens from the top menu. This will open the Mach Folder and list - probably only the .set files. If you click "Files of type" you will see Turn Files .lset.  Click this and 1024.lset (your current set) and my Macro.lset should be shown. Select that and your screen display will change (not drastically) and on the Auto Page you will see I have juggled the Dro's around and added the User DRO set.
These User DRO's are persistant, and will remain even after switch off. So when you use them, ensure that only relevant information is in each one. If not required, enter a zero.
 
The Multi Macro file should be opened when you are in Mach3 (It should also open with Notepad - but in Mach 3 key words are different colours, which makes it easier to read)
If you open Operator/VBScript Editor you get a window. Go to File/Open and then select MultiMacro from whereever you downloaded it to.
I have just put three Macro's in this file - each one has a preamble of Rem remarks. If you either cut and paste, or better still just copy the three parts into seperate files, into the Macro folder in Mach3, each file should be M200 or similar number starting at 200 (with M prefix).
The macros have no preamble on them - they start work immediately, so you must start the spindle, coolant, etc G20 or G21 for yourself. They can either be used as stand alone macros, on the MDI line, or incorporated in GCode programs.
As I said in an earlier post, they are written with X0 on the centreline and Z0 at the end of the workpiece.

I would suggest you test them first (possibly without a cutting tool in, or without the barstock in), just to make sure they actually do what you think they will do. I offer no guarantee that they will work - they do for me (or did last time I used them - a few days ago),
and I am hoping that any last minute tweaking I did is correct - but have a go.

425

General Mach Discussion / Re: Having difficulty with torch heigth set-up

« on: July 14, 2008, 02:25:09 PM »

I have not the slightest idea - but is it that you have entered parameters in both Mach 3 and Sheetcam - and the two sets are working against each other.

I would have thought it was a bit like milling, or a lathe, either you enter all these parameters in your CAD/CAM program, which then writes the program to run the machine directly, or you write the program as you would draw it, and let Mach3 work out tool diameters and other offsets.

426

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

« on: July 14, 2008, 05:45:28 AM »

Rich -

Here is a taste of some I have put together in a single file. You will have to split them up and number then seperately m200 upwards, or something like that. Most of them designed to run metric or imperial, (despite what Hood says). There is no "preamble" to them so it is assumed that the user fill in G20 or G21, M3 in some cases, and anything else. They will run in either Gcode programs or stand alone MDI calls.

The are based on X0 being the centreline, and Z0 being the end of the workpiece.

The GetUserDRO codes are shown at the side of the labels for convenience.

427

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

« on: July 13, 2008, 04:10:39 AM »

We are firing code at Dave - but I think he needs to know how to get started - perhaps.

The most important thing is - where is your 0.0 position in your code.
The X0 position is usually down the centreline of the lathe. The Z0 position is normally on the end of the workpiece. So -

Put a piece of barstock in the machine, and jog up to it and take a facing cut across. (You can do this with the jog buttons, if you run the speed down to about 10%) Zero your Z axis.
Move your tool out, and down the barstock a little, and then, with the jog, touch the tool on the stock. This is you X position, but you need to measure the diameter (or radius) of the barstock and enter it into the X DRO. You can run the lathe in either diameter mode, or radius mode, which ever you feel more confident with. In diameter mode, you enter all X axis workings to the finished diameter you want, in radius mode, you have to half these (obviously) .

Z minus is towards the chuck, Z plus is away from it. X minus is towards the centreline, X plus is away from it. If you enter in the MDI line (not jogging becasue the jog buttons are changable) a plus move and check if the axis goes the right way. If it does not, then on your Config/Ports and Pins/Motor Outputs, change the DIR pin to "Active Low" or vica versa. This will reverse the movement of the axis. You will then need to check your jogging buttons and make sure they move the axis the same way - Config/Hotkeys

A lot of lathe work is repetative, as Hood said, and, therefore, a lot of us make use of macros for say thinning down barstock, where you might make 10 cuts to get down to where you need - all the cuts are the same, just 20 thou or so deeper.

On page one of my lathe, I have several User DROs which I can fill in with lengths, cut, feed and radius etc, and I have written several macro's to take this information, and then write the GCode - rather like the wizards - but it writes the code on the fly, whilst the machine is running. You are welcome to my lset, and macros if you would like them. They do simple work, like facing, thinning down, cutting axle ends (two different diameters), boring, and rounding off bar ends. I work in steel.

Keep at it, when the machine starts running as you want it, it gives you a nice buzz - but then you have to run round getting rid of all the shavings it makes - and it makes them faster than you can get rid of them.

428

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

« on: July 13, 2008, 03:32:19 AM »

Speaking off the top of my head - because I have no idea - but if you can control X and Y axis, why can't you change the program and control say Z and A axis.

The control for all axis are identical - therefore it is just a case of pointing then at the right axis - OK so you will need two joysticks ( or a selector switch) but you are after the extra controls anyway.

429

General Mach Discussion / Re: please help

« on: July 13, 2008, 03:22:43 AM »

Mach 3 needs to know what you want it to do at a tool change.

1. - It can ignore it
2. - It can stop and wait for you to change the tool manually
3. - It can follow some local code and run an automatic tool changer.

If you look on Config/General Config - in the top left hand corner you will see the choices. You probably have "Ignore it" ticked if nothing is happening. If you change this to "Stop and wait - " then the machine will do just that, it stops. It will change the tool number to whatever tool you have selected in M6 T? (and will select offsets for that tool if the tool table is completed) and then wait for you to click cycle start again.

You can expand this by writing your own macro to use with M6 so that the machine might move to a specific location for the tool change and then return afterwards etc. - see the Tutorials on "Scripting"

430

General Mach Discussion / Re: Problem with pulse width

« on: July 12, 2008, 03:48:08 AM »

I must assume that the original chinese drivers would go faster than 5000mm/min or you wouldn't be asking.

Try turning the kernel speed up (Config/Ports and Pins - first page, bottom left)