non-monotonous alarm

[9wleadfoot]

Hi new to this forum and to a tl-2. I get these non-monotonous alarms when its in a g71 cycle need a simple explaination i can understand of whats wrong an how to change it any help is appreciated

[ckirchen]

Here's a good description straight from Haas: www.haascnc.com/CNCMag/PDF/v11i38.pdf (page 48)

[BlueChip]

Well, first non-monotonous ... meaning that either the X or Z axis does not consistently grow in the same direction. Take for instance a shaft with three OD diameters ... say .500, .750 and 1.00 respectively ... the X axis is always growing from the centerline in the same direction ... now say that the diameters are .750, .500 and 1.000 respectively ... this is non-monotonous because the X goes from .750 down to .500 then up to 1.000 ... the diameters don't grow in the same direction ... similarly, the Z axis works the same way.

There is a Type I and Type II canned cycle for G71 and others ... Type II is an option. You can invoke the Type II ... or get an alarm ... by incorporating an X and Z move in your first move within the P and Q sequence numbers. Sometimes just a U0 or W0 will do the trick.

For example :

Type I :
N1111 G00 X1.000;

Type II :
N1111 G00 X1.000 W0;

You will get a different alarm if the Type II option isn't there ... in which case you can't use the G71 to make your non-monotonous part.

Hope this helps ...

Real World Machine Shop Software at
www.KentechInc.com

[Geof]

Post the code that is giving you a problem.

The Haas manual does not explain non-monotonous very well but if you get that alarm you have selected type I but as bluechip mentions you can select type II by having both X and Z moves on the P line.

On a TL2 type II is available

[9wleadfoot]

so you would use type 2 to do an coke bottle shape is this correct?

[Geof]

Originally Posted by 9wleadfoot so you would use type 2 to do an coke bottle shape is this correct?

That is correct.

Your start point ahead of the G71 line has to be a larger diameter than the largest diameter in the shape and then on the P line put in both X and Z moves.

If you are doing arcs, G02 or G03 using R and get them mixed up, or have a wrong R value you may cause a non-monotonous alarm because the arc is trying to go outside the diameter limit set by your starting point. This can be confusing because the error is in the arc command and is not immediately obvious.