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Author Topic: Dynamic feed rate - is it possible  (Read 2703 times)

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Dynamic feed rate - is it possible
« on: October 20, 2014, 05:45:51 AM »
Hi fellow Mach 3 users. I´ve been using the software for just a few weeks and still learning the basic features. I´m trying to optimize the milling time by finding the optimal feed rate. But, I notice the feed rate seems to be pretty constant, even when the mill is not touching the material. Wouldn´t it be much smarter to have a rapid motion when the mill is over the material, then a slower, second speed for the milling itself? Is there such a feature?
Re: Dynamic feed rate - is it possible
« Reply #1 on: October 29, 2014, 06:08:21 PM »
That is normally controlled in your CAM software or by yourself if you are writing your own G Code.  How did you get your G Code?
Re: Dynamic feed rate - is it possible
« Reply #2 on: October 29, 2014, 08:34:25 PM »
So how exactly does Mach 3 know where the material is?  Leaving the material and moving faster is one thing, but how about if it were moving fast?  How far ahead would you have to make the speed transition?  This kind of thing can be done by high end Cam software where the program starts from a 3D model of the stock material and a 3D model of the part, plus a 3D model of the tool and a kinematic description of the machine so that it can calculate everything.  Not to mention you need data on the material, how it is fixtured, how rigid the cutter is etc.

CNC programming is always a tradeoff.  How many parts are you going to cut, and which costs more, cutting or programming. If you do lots of one-offs you will likely cut lots of air.  If you are doing lots of parts you will spend more time programming and less time cutting air. Get yourself a CAM program, even an inexpensive one like CamBam.  Then you can program a larger number of small operations that will result in less air cutting.  If you are programming by manually writing G-Code you are likely to cut lots of air as it takes a long time and as the complexity grows so do the errors.  This results in doing air cuts to test your program, losing most of what you might have gained.
Re: Dynamic feed rate - is it possible
« Reply #3 on: November 03, 2014, 07:17:27 AM »
I´m currently using CUT2D for generating the code. At first I didn´t even have the tool change active, but now it´s moving rapidly above the material which is a great step forward. I´m currently prototyping but as I am selling these airframes in my net shop soon, (mass) production time is definitely something to look at and optimise. And that´s where airtime(just learned a new word!), feed rate and other efficiency parameters definitely makes a big difference. Thanks for the advise on cambam, will check it out!
Re: Dynamic feed rate - is it possible
« Reply #4 on: November 06, 2014, 09:12:14 AM »
CamBam has a 40 use trial for free.  Join the newsgroup, its excellent like this one.  You'll learn a lot even if you go with something else.

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Re: Dynamic feed rate - is it possible
« Reply #5 on: November 07, 2014, 02:48:08 AM »
you can also look for EstlCam,
i am using this, it's realy easy.

anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.