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Author Topic: Making a list of things that need fixed in Turn  (Read 8062 times)

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Offline Hood

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Re: Making a list of things that need fixed in Turn
« Reply #10 on: January 04, 2011, 07:10:01 PM »
Scott heres a pic I posted a year or so ago, two done with PP and two with SS.
2mm pitch 140mm long and as you can see there is no variance in pitch as I have them reversed alternately. This was with a 17HP induction motor being driven via an electromagnetic clutched  gearbox so no VFD.

http://www.machsupport.com/forum/index.php?action=dlattach;topic=8040.0;attach=6447;image

Hood

Offline RICH

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Re: Making a list of things that need fixed in Turn
« Reply #11 on: January 04, 2011, 09:37:41 PM »
Scott,
Quote
an easy way to "Pick up" a thread
I have a how to pick up a thread in the Threading writeup. Guess one could write a macro or wizard to
guide one through the steps. Problem may be  how manny times will one ever pick up a thread.
I only had to do it probably two  times in the last 10 years. Not being negative on the request, just a comment.

Quote
Hey would you mind doing a how to use/get threading in mach3?
Something like a "quick and dirty" how to thread...not sure that would do since the big picture includes so manny things
 ( i struggled to keep the write up size to 60 pages or so ). Maybe start a new thread and post what your interested in seeing.

Quote
So, since it works for you, and works for Rich, then I am doing something wrong

You can move this reply later  to a  new thread so we don't clutter up what Hood is requesting.
 
Only set rpm manualy if VFD. The more stable your rpm the better ( Mach is reading the rpm to like 3  decimal places and is
more accurate than any device i had to read the rpm ). Make sure you have the configuration correct see the writeup.
All the testing done was mostly 2" thread lengths and had to satisfy a lead tolerance as defined in the writeup.
I did 4 and 6 inch scribes and they didn't have any lead problems. Accurately measuring  the scribed line will tell you a lot as that eliminates
say x axis influence.

More in a new thread when you start it..
RICH

Offline DaOne

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Re: Making a list of things that need fixed in Turn
« Reply #12 on: January 04, 2011, 11:02:07 PM »
Feed per rev is also broken. Has anyone talked to Brian and got any answers on fixes?

Offline Hood

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Re: Making a list of things that need fixed in Turn
« Reply #13 on: January 05, 2011, 02:19:05 AM »
Feed per rev is also broken. Has anyone talked to Brian and got any answers on fixes?

In what way? I use FPR exclusively on the lathe and it seems fine here.
Hood

Offline DaOne

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Re: Making a list of things that need fixed in Turn
« Reply #14 on: January 05, 2011, 03:23:12 AM »
Well I have had it freak out twice on me when using it. Might have been a CSS issue. I will have to try it again and see.

Offline Hood

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Re: Making a list of things that need fixed in Turn
« Reply #15 on: January 05, 2011, 03:31:31 AM »
CSS doesnt work as it should, thats for sure, it seems to keep a constant feed per min rather than a constant feed per rev. If I recall the start feed when doing CSS is based on what the FPR would be for the spindle speed at the time but the FPR doesnt stay constant as the spindle speeds or slows. This means moving out to in will take a lot longer than a feed from in to out as the former is starting and maintaining a slow feed per min and the latter a faster feed pe min. . FPR in constant spindle mode works well, for me at least, as its the only type of feed I use on the lathe and never had an issue with it.
Hood
Re: Making a list of things that need fixed in Turn
« Reply #16 on: January 05, 2011, 06:00:54 AM »
Graham pointed out the freakishly high speeds needed to maintain true CSS as X moves to Zero

So as most peeps cannot reach those speeds can it be made to work as follows

When it starts it uses the minimum speed available and when it reaches the X Zero it will have reached the maximum speed available

This assumes you are feeding towards Zero so though not true CSS it will allow everyone to get the best available speed out of their machine from starting slow to finishing fast

The same applies when turning the OD

Phil
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable

Offline Hood

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Re: Making a list of things that need fixed in Turn
« Reply #17 on: January 05, 2011, 06:10:08 AM »
What do you mean by min speed available?

Offline Hood

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Re: Making a list of things that need fixed in Turn
« Reply #18 on: January 05, 2011, 06:17:55 AM »
I am not following what you are meaning now I read again ;D
CSS is constant surface speed so you are trying to maintain a set amount of material that passes the tool in meters per min or feet per min, so just plucking figures out and saying it will start at whatever revs and finish at max if it goes to zero kind of defeats the point of it.

Max spindle speed should be observed by Mach whether  its because you specify a G48 (max) or it is  simply the max you have the spindle tuned to .
Hood
Re: Making a list of things that need fixed in Turn
« Reply #19 on: January 05, 2011, 09:22:55 AM »
OK real world scenario on my machine

VFD controlled spindle i can have a max speed of 1500 RPM the slowest is 375 RPM controlled by Mach3

I want to face a 150mm dia billet at a CSS of 70 SMM

I start at 150mm X the min speed i can run is 375 RPM (176) gives a feed rate of 176 SMM

When i get to 3mm on X i am only cutting at 14 SMM (7430) in brackets is the desired RPM to maintain 70 SMM

So i have a very small window where i am truly cutting at 70 SMM (60mm dia to 15mm dia)

I agree about still conforming to the Max speed set in G48

So at 375 RPM i would be cutting at 70 SMM at 60mm dia my target and i would stay on target to 15 mm dia when i will be running at 1500 RPM

I hope this makes more sense now as i haven't had the opportunity to use CSS as its broken but if it was working i wouldn't be able to use it as my spindle cannot reach those speeds

But doing it my suggested way, everyone could get the best out of their available spindle speed. The SMM is blended between Min and Max. It may be worth asking Brian if this is an easier way of doing it

Or am i talking gonads as usual.  ;D

Phil
The Good Thing About Mach3, Is It's very Configurable

The Bad Thing About Mach3, Is It's Too Configurable