Messages

11

General Mach Discussion / Saving the Tool Table Changes

« on: June 25, 2009, 03:06:27 PM »

I have integrated a tool height probe & macro into my code.  It works flawlessly.  It calculates the height of the tool, updates the tool table, and I am able to use the new tool offset when I run my next program.

HOWEVER, when I exit Mach 3, all of the changes to the tool table are erased.

I have tried hitting "save settings" before closing, but that does not work either.

Is there a way to force a write to the tool table inside my VB script?

Help!

12

General Mach Discussion / Re: Soft Limit Warning

« on: June 11, 2009, 01:39:32 PM »

Well, I am not sure what the cause is, but I did find a work around.  I modified the post processor and add the command:

G00 X0.0000 Y0.0000 Z2.0000

immediately after the G43, "Set tool length" command (Inserted between lines 440 & 450), the soft warning disappears.  I can only assume that because the Z is sitting outside the limits when the tool change is requested, and even though the SET TOOL LENGTH OFFSET command puts it back within limits, unless the next command requests a Z move, I will receive a soft limit warning.

13

General Mach Discussion / Re: Soft Limit Warning

« on: June 11, 2009, 12:06:28 PM »

As a further note, I receive the error every time I run code #2.

14

General Mach Discussion / Re: Soft Limit Warning

« on: June 11, 2009, 10:51:12 AM »

Sid,

On my machine the soft limits are set as follows:

X   Min 0   Max 103
Y   Min 0   Max 49.5
Z   Min –12   Max 0

Yes, there is an inconsistency between the comments and the G code.  The comments are in absolute values and describe the actual distance between the top of the board being cut and the bottom of the collet.  But, to use that distance with a machine that homes at 0 (full up) and travels down 12”, I have to enter a negative number.  Hence the G52 offset of Z-12.5625

As suggested, I loaded both programs into the toolpath screen and both show identical results:

X – 0 to 6
Y – 0 to 6
Z – 0 to 2.5

However, when I execute the programs, only #2 creates the soft limit error (at the start of the program).  No error is ever generated in the body of the code while it is executing - nor does the program ever exceed the -12 soft limit set by the program.

But, you questions have caused me to do some additional testing.  I changed the Z limit to –12.75.  That eliminates the warning message.   Although this isolates the problem, it does not fix the problem.   The machine can only travel to an absolute distance of –12.

The G52 command sets the offset to –12.5625 (which is over the limit), however, the G43, tool length offset, adds 1.5” to that which results in a net travel of  –11.0625.

What is interesting is that both programs display the same numbers on the toolpath screen, but only #2 creates the soft limit warning.  And along that line of thinking, the “absolute z” values are 0 to 2.5 – but 2.5 is outside of the soft limits of the Z axis.  By that logic, I would think that both programs would generate a warning.

Suggestions?

15

General Mach Discussion / Re: Soft Limit Warning

« on: June 11, 2009, 08:10:00 AM »

Ok - here it is.

#1 was generated using SheetCam Standard
#2 was generated using SheetCam TNG

The post processor for used to generate both files are virtually identical. 

Thanks

16

General Mach Discussion / Re: Soft Limit Warning

« on: June 11, 2009, 07:21:14 AM »

I am running version 3.042.020.  I believe this is the latest lockdown.

17

General Mach Discussion / Soft Limit Warning

« on: June 10, 2009, 04:23:10 PM »

I have recently upgraded my Sheetcam program from Standard to TNG.  I am using virtually the same post processor (a modified version of the standard Mach2 post processor).

I have taken an existing job and re-run it through the SheetCam TNG program and generated the GCode.

When I load the new gcode, it loads without error, however, as soon as I click Cycle Start, I receive a Soft Limit warning.

I can bypass the error message and it appears to execute correctly.  I receive no additional warnings.

I have compared the code generated from the SheetCam Standard and SheetCam TNG programs, and can find almost no difference.  The primary difference is the TNG program eliminates some of the Z moves.

For example, in SheetCam standard, you might have the following sequence of commands:
G00 Z1
x2 y4
Z0.0197
G01 z0 f90
x-0.03


On the TNG program you might see:
x2 y4
z0.0197
g01 z-.03 f90


Other than that, the code is virutally idendical

Has anyone else experienced this type of problem???

18

General Mach Discussion / Re: Synchronize X & Axis

« on: March 05, 2009, 07:28:56 PM »

Each axis consists of 2 pieces - each about 71" long.  The racks are mounted to a steel bar which in turn is mounted to the CNC frame.  I removed the mounted racks and nested them together.  They align perfectly.  So, I don't think that the racks are a probelm.  The gantry currently rides on 8 guide wheels - 4 on each side.  I am going to remove the two center wheels and see if that affects how it rides.   I am wondering if the extra wheels may be affecting the ride.  Hopefully it will make a difference.

19

General Mach Discussion / Re: Synchronize X & Axis

« on: March 05, 2009, 04:29:46 PM »

I am doing some more measuring and experimenting.  I am working on measuring the X and A axis right next to the gear rack.  A quick measurement give me a reasonably accurate reading - ie the same amount of movement on the A & X axises when asked to move 96". 

My machine has a rather long Z axis (40" total - with a travel of 0-26")  What I may be seeing is a very small variance in the flattness of the X axis - that is being amplified on the length of the Z axis.

I will do some more measuring & testing to see what I can find out.

20

General Mach Discussion / Re: Synchronize X & Axis

« on: March 05, 2009, 09:42:21 AM »

The gear rack and pinion gears are "identical" - at least they are suppose to be.

What I find when I adjust the "steps per" is that ONLY the X axis can be adjusted.  When I modify the X axis' steps per, the amount of travel does adjust.  When I modify the A axis' steps per, nothing happens.  The field changes - but there is no difference in the length of travel.  I have modified it as much as 10 steps (which on my system translates to about 1/4" over 96" - but the actual position has not changed.

I have been working on the mechanical side of the machine.

Changing the pinion gear has had no effect.
Changing the gear motors has had no effect.

I have "repeatability" - ie I can move from 0 to 96 ten times - and I always end up at exactly the same stop.  So, I do not believe that I am "losing steps".

What I am seeing is that sending 292,800 pulses to the X axis moves it 96".  The same number of pulses to the A axis moves it only 95-29/32".


Any other suggestions?