mpfan, rotary,axis substitution,feed problem

[Eric S.]

Hi, I hope i can explain this good enough.

I have to cut out a rectangular filleted corner contour. And it has to be rotated about the y-axis.

So in my matercam parameters, I put on the, rotary axis, axis substitution, substitute y axis, and my rotary diameter is 4.0in. I have it set to feed at 40in/min. Backplot is fine, it does exactly what i want.

When i post it with Mpfan the first line of movement it has the 40in/min., but then theres a whole bunch of lines of small A. movements, which give me a different feed for everyline. The feed seems to accelerate from 664.in/min to 999.in/min. The different A. movements are fine, but the crazy high feed acceleration, i don't need, and know how to get rid of.

I've tried looking at the post using 'Fastmode', but whatever I try to change in the post, doesn't work.

 

Please, is there anyone that can help!

[Glenn Bouman]

What you are seeing on the angular moves is degrees/min

Machine cannot output wrapped arc moves so the post breaks them into linear segments.

[Eric S.]

Oh I see that it inverses the time feed mode, with G94, and G93.

Thanks.

[Eric S.]

no tongue was intended on that reply.

[Eric S.]

Okay, so now that I've looked through a dry run of the program on the machine, I'm going to have to change up a comment I made on my orignal problem.

The different A. movements (segments) are not fine, the change in Feed/min to deg/min is fine. Is there anyway for the post to follow the contour smoothly, with out the linear segment movements?

Your help is so appreciated!!

[Glenn Bouman]

What machine are you using? Fadal and Haas have their own wrapping function which will support arcs. Otherwise tighten up the vtol variable in the post.

[MasterNick]

Hi, I work with Eric and he uses a Haas VF3 and VF2. We only have level one, of Mastercam 8.1.1 if this matters.

[cadcam]

Masternick, I have to try and dig my post for the haas that I have made these change to all ready. I ran into this all ready and changed the post to over come this thought.

 

I know it did not like the inverse time for sure when I was doing this.

 

I will try and put up the post tommorrow.

[Allan]

For the Haas I would switch the post to the mighty Mpmaster post right away, It has all the switches in the post for what you want to do. (Thanks be to Dave ) But as Glenn said with the Haas you can get the controller to do the math, much easier.

 

Allan

[MasterNick]

The Mpmaster post is much better , although it calls up an outragous feed (1228.64in/min) while it does the A. movements. Is there a way of getting rid of the feed in the A. movement?

 

Nick

[MasterNick]

Oh yeah, and it doesn't call up a inverse time g code for that feed either.

[McRae]

Masternick - Thee feed rate you are seeing with the "A" motions are in degrees per minute. I have the same condition on the Integrex. Abandon all hope and think Polar...

[Allan Brown]

If you don't want to use the calculated deg/min rotary feeds or combined linear/rotary 'tangential feeds' that are calculated in the post, set the 'rot_feed' switch to 0:

 

rot_feed : 0 #Use calculated rotary feed values, (0 = no, 1 = yes)

 

I believe you will need to input an approximate rotary diameter on the control.

 

[ 06-20-2002, 09:32 AM: Message edited by: Dave Thomson ]

[Eric S.]

Alright, so I'm definitely getting somewhere , it works just the way I want it too now , but , it only works for the first tool. Now for the rest of the tools it goes back to giving me line segments. Is there some line I can change in the mpmaster post?

This is really progressing greatly....I really like the mpmaster post. Hopefully this little problem can be fixed. Thanks for al your help so far.

Nick

[MasterNick]

Actually looking it over, it doesn't seem to be a toolchange problem.

It just worked out that the first tool was my roughing cutter, and it didn't have to follow the radius corners on the rectangle. My finishing cutter, and corner rounders do however. So when it gets to cutting the corner radiuses of rectangle, it goes back to cutting them in line segments, with small X. and A.-axis movements. I guess the mpmaster isn't able to adjust for wrapped corner radiuses?

 

nick

[McRae]

Think about what you are asking. There is no mathematical solution to express the X and A movements as an arc (your g02 is only active in orthogonal planes - g17-18-19)

[MasterNick]

Hey, I just wanted to give the people that helped us last week a BIG thanks. It all worked out, but it was a lot less of a headache with you guys. I'm sorry if some of my questions might not of been fully thought through. Mastercam/programming is still a learning experience for us.

 

Thanks

Nick and Eric

J.S. Foster Corp.

[McRae]

Nick -

 

Glad to hear you are meeting with success. We are all learning everyday.