help with work offsets

I just got a mini mill and I have been trying to set my work and tool offsets so I can make a test part. I will apologize in advance as this is probably a common issue. I have looked online and I cant find an answer.

I started by touching off all my tools on a pre setter (no probe). All the numbers were negative and seemed accurate relative to one another.

I then set my G54 work offset on a 123 block so I could test my offset numbers. As per Haas' video I ran the following in MDI:
G54 G00 G90 X0 Y0
G43 H05 Z0.1
M30

I got error 316 (over travel range)this error was for the z axis. the first line runs fine and the table travels to G54 x0 y0 properly.

The z command is when the error happens.

I tried placing a tool well above the table and setting the tool length. The machine coordinate was -6.6600. I did the same for the z value of G54 and the value was also -6.6600.

When I run the MDI program I still get this error even if I set the z value to zero. Also, my distance to go screen is confusing me. when the tool ang G54 are in the same place I have a G54 distance to go of 1.74". I would assume it should be zero if the two values are set without moving any axis.

I feel there must be something simple I am missing about the overall process. I have watched all the Haas videos I can find and I am not sure what I am doing wrong.

Any help is greatly appreciated.

I tried clearing out all the offsets and recreating the problem. I used a 4 inch tool setter to set a face mill tool offset. I then stacked up 2 123 blocks to be 6 inches high and used that surface to set my G54. At this time my G54 distance to go was 0 as expected. The 2 machine coordinates were 2 inches apart. I jogged all the axis and ran the same MDI program with Z set to zero. I got the same error. When I jogged back above the 123 blocks my distance to go was no longer 0. It was now about 6.7 inches which happened to be my machine coordinates for z when I set the tool 1 height offset. I am not sure if this is a coincidence or not. It seems like my G54 Z0 is moving after I run the MDI program.

Sounds like you have negative and positive numbers mixed up. When I am at work Monday I will see... I think ours are positive in the tool offset (gageline to tool tip) and negative in the G54 Z.... but can't say for sure without looking.


Would be an easy check though, change for G54 opposite what it is now, minus to positive, vs verca....
Use single block and distance to go and a SLOW feedrate to check...

Mike1974 said:

Sounds like you have negative and positive numbers mixed up. When I am at work Monday I will see... I think ours are positive in the tool offset (gageline to tool tip) and negative in the G54 Z.... but can't say for sure without looking.


Would be an easy check though, change for G54 opposite what it is now, minus to positive, vs verca....
Use single block and distance to go and a SLOW feedrate to check...

Click to expand...

Thanks,

It would seem the offsets were fine as is. I was misunderstanding the process. In order to get this to work I measured the difference between where I touched off my tools and my G54 z0. If the G54 z is higher than the tool touch off height I enter the number as a positive value into the G54 z column. After this everything was good. I did not subtract anything from my tool heights to account for the tool setter.

Your G54 Z work offset should be the difference between the 4" plane that you set your tools to and the Z0 of your workpiece. So, if you set your G54 Z=0 and tell the tool to go to Z0, it will stop 4" above the table. If you were trying to set your G54 at the top of your 6" stack, the G54 Z offset would be Z2.000. If your workpiece Z0 is 3" above the table (and therefore 1" below your 4" plane), then G54 Z is at Z-1.000.

Here's what I do.

Set zero all of your tools against your tool setter.

Pick a tool. Touch off on your workpiece and zero the g54 z axis.
Minus the tool offset from the work z offset. If your workpiece is taller than the point of your tool setter, make sure it comes to a positive number!

Now commanding a z zero in your program will bring all tools to the top of your part.

Play carful, don't forge 5% rapids and e stop!