Incorrect rotational direction in 4axis

[John @ High Tech Machine]

Trying to post a 3d contour, using axis substitution for Y-axis. I have done it before and made a similar part successfully, but with the one I am doing now I keep getting negative rotation when I need positive (cutting a slot, and it is wrapping around the part the wrong way). I seem to be having a mental block trying to get the rotation to change to positive.

 

I have tried the post I had done the other part with as well as a generic 4axis mill post, both give me the same rotational output, so I am thinking it must be in the MMD that I need to make the change. Any thoughts would be helpful.

[Guest]

You say you're using axis-sub, do you have the direction on that set for CCW?    That fixes many issues with  directional output when using axis - sub

[John @ High Tech Machine]

Just went in and checked; with direction under axis control tab set to CCW or CW, I get the same rotational output in the posted code.

 

Attached screenshot has the output code, the file shown on the left used CW and the file on right was with CCW

 

[Guest]

John,

 

try this, open your machine def

 

 

and try changing your direction in there

 

 

If that doesn't do it, you might have to consider the "vintage" of your post and it may need to addressed in there

 

Also, this is a VMC with a rotation about A, correct?

[John @ High Tech Machine]

I will take a look in the MD. It certainly could be an old post that needs to be looked at. We have posts that originate back in the early 80's for some of the older equipment, using update post from version to version along the way.

 

Yes it is a knee mill with rotation about the A with an older Anilam 1400 control. 4th is mounted on right end of table

[John @ High Tech Machine]

So, I checked in the MD, and tried it a couple of different changes in the settings there... I did get positive numbers with some of the changes, but the rotation was still going the wrong way for what it should be on the part.

 

For now, I went back to the original file and changed the signs of all rotational moves to get through this part. I will have to work on getting the post corrected for the next similar job that comes along. Thanks for your help JP, I will keep working on it. We don't get a lot of this, so I will have some time to mess around with it and get the post checked over before the next ones come along.

[PcRobotic]

This may help you...

 

http://www.emastercam.com/board/topic/69919-strang-feed-rate/

 

The feed rate being output is deg/min rather than units/min. If your machine automatically performs the calculation for you, you can modify the post to output the programmed feed rate rather than performing the calculation.

Basically at the bottom of the pfclc_deg_inv you could add a feed = fr_pos$ line if that's what you need.