Problem

[JaneGao]

How to resolve the lost rate in 5aixs maching

[cadcam]

Janegao, are we talking about the cost rate as at first I was thinking you were speaking of the Feed rate changes between 3axis and 5axis that uses inverse time to align the axes?

[JaneGao]

Originally Posted by cadcam What should he be asking his dealer, curuse what you want him or her to ask.

I have been asking my dealer in Bei Jing , but he do not know how to reslove this problem, because only in the case of " Y" and "A" have change . I will use "G93" in my program . thanks a lot.

[cadcam]

Janegao, What type of 5 axis are you using and what version of MC if I may ask.

thanks Cadcam

[Rick Linnabary]

As far as G93 (Inverse time feed rate) I understand that it is 1/(Actual move distance / Desired feed rate). So if you have a move that is 1" long and a desired feed rate of F30., that is what you should see on that line movement.
But I am not staying on C/L of the 4th axis and do not any longer have the source (.nci) file for Mastercam (was done in Version 6) and I am now running V9.1 and the new Mastercam XMR2. The part is convex shaped on the top and is about 10" long x 6" wide with a full radius on each end and I am cutting a slot around the profile. The convex radius on top is very large (about 20+ inches) and only 2.25" from C/L of the 4th axis.
I want to increase the feed rate of the tools that cut this shallow dovetail groove around the profile and was wondering about 2 things; can I simply scale the feed rate larger by a percentage (I do not think that this is a problem) but on the new software for the Fadal VMC's what is the maximum Feed rate (F999.999)? If you can tell me what the limit is and it is more than F999.999 (for some reason I thought this was the maximum when I wrote the post) this will help me know if I can simply scale the feed rate. If F999.999 is the limit, I will not be increasing the feed in the area's around the ends where there is alot of small moves to generate the full radius. But if I can exceed the F999.999 that is my program currnetly there will be no problems (that I can think of).... but if this is not the case and I am only rotating back and forth 2-3 degree's maximum can you give me an idea on how to easily convert the Feed rate to degree's per minute instead of using inverse feed (G93) use the control default is degree's per minute (G94).
What is everyone else do in a situation like this when you are not staying on C/L or the A axis and the "Diameter" is not constant.
I could really use some good resources with formula's to calculate the proper feed rate when using a 4th axis for do "True 4th Axis Cutting" instead of just using it as an indexer like I have seen in so many shops.
I may also mention that the end mills that I am using for forming the top and bottom radii of the part (1/2" end mill with .0625 radius) and cutting like a pocket routine to generate the top, bottom and profile of the part work fine by just using 1 large feed rate at the start of the tool works fine, but the very small moves in the dovetail slot are tighter tolerane so the tool path will not simply go faster with a larger feed rate, causes it to not go the same feed (very noticably) all of the way around the part.

Any idea's, suggestions or resources of info would be greatly appriciated. I am self taught and do not use inverse feed very often so I have a lack of experiance in this area. Mastercam X MR2 solves this probelm for me alot easier and so this is more for my learning and solving the problem of the one job, but I want to be able to really understand what is going on.

p.s.
I there a way to use Macro / parametric programming (with the right formula) to calculate the feed rate's required when using a 4th axis on the fly by giving one of the given varibles a desired feed rate in the program that can be altered and use the Macro program to calculate the feed rate in (G93 - Inverse Time) or (G94 - Feed in degree's per minute)?????
Macro & Parametric programming of CNC machines is something that I have always wanted to learn how to use... lack of time..... but alot of desire to learn how at home using my Mastercam V9.1 license that I OWN.... just can't afford to upgrade to Mastercam X MR2 yet and add solids, lathe and some other goodies (like a better more capable NC Program editor) instead of having to use 2-3 differant editors depending on what I want to do.... this I would be willing to pay for now even though I can't afford the $9,000+ upgrade cost for MastercamX MR2 along with maitance every year.... So I guess I get to learn MastercamX MR2 after hours at work and since I am on salary, why should my boss/owner have to pay to send me to school when he knows that I can figure it out on my own (some training books would not hurt) since I have been teaching myself every version of Mastercam since V3.1 back around late 1989..... Any suggestions on a good on-line study coarse or training manuals...... is the cost of the ones that I have seen in Mastercam's Newsletter worth the cost? Or keep using the trail and error method?
Thanks to everyone that takes the time to read this in advance.
mrcnc1@cox.net