Messages

4171

G-Code, CAD, and CAM discussions / Re: I want to learn turning program. Please help

« on: October 24, 2010, 09:55:16 AM »

I am new to this macro editing using vb script

The macro's don't need editing. Operations tab>v script editor> then open the file to have a look at the file contents.

alternative codes to use

The bulk of Gcodes available for Mach Turn are listed in the manual, but the manual was written a long time ago, so there are
 some canned cycles / macros done by users and the ones i posted are a good example. You may find some lathe canned Gcodes
 for  other controllers but they were specific for say a Fanuc controller and are not supported by Mach.

The Mach Turn Wizards provide for manny of the common single tasks to be done on the lathe. Lazyturn and LazyCam can give you code for turning a profile.

how to write repetitive program

Hm......not sure what you mean by repetitive
Do you just want to use the program generated g code for a single task, have the code available to be reused  another time, be able to use the code
at different locations along the profile, want the code to to do some machine moves prior and after the program to your liking......
or maybe use inputs on the screen and Mach will run the code........etc

I just listed the above to give you a flavor of "repetitive" use to enlighten the learning experience . Each one will require a different level of
knowledge and programming techniques.

SO here is what i am suggesting:
1.Get a good reference book on programming......Peter Smid - CNC Programming Handbook
2.Try each of the lathe wizards and look at the generated code. ( there is one to turn down a diameter) Much can be gained from reviewing
   the code.

 RICH

4172

General Mach Discussion / Re: Finally, Mach turn profile roughing, finishing cycle!

« on: October 23, 2010, 08:01:22 PM »

Guess i can't qoute you any more Fastest1.......        

Rich

4173

General Mach Discussion / Re: Huge Threading Problem Help

« on: October 23, 2010, 07:57:34 PM »

Sounds like your on a roll......
Have fun,

BTW, i will probably move this thread over to the problems threading on the lathe thread.
Will keep it here until your happy all is going well.

RICH

4174

General Mach Discussion / Re: Huge Threading Problem Help

« on: October 23, 2010, 06:54:53 PM »

SPINDLE SPEED AVERAGING
Mach3 can keep a running average of the last  8 revolutions. At the start of any pass it either uses the
 average OR the last measured time.  Every thread starts with an unloaded spindle, the 8 rev average is
 typically unloaded average. ( unless your turning very slowly on the spindle and very unlikely it's less
than 8 turns in the air prior to a thread pass)
 
 So the correction code  is all that controls speed during the cut to take  into account the spindle slowdown
 caused by hitting a hard spot or an average  slowdown due to harder material.

The averaging is discounted for correction, it cares only about the real  last index to index time,
 and it compares that to the locked in average or  locked in last rev just prior to the  thread pass starting.

Rule of thumb is  3 to 5 diameters times total thread depth for unloaded spindle travel of the Z axis.  

I use and would recommend you use spindle speed averaging.  It helps if there is a "out of rage / fluke / high" rpm
included in the averaging.  You then get a more refined feedrate. One  "fluke"  may not  influence as much as you
would think.

Some of my words but mostly Art's,

RICH

4175

General Mach Discussion / Re: Huge Threading Problem Help

« on: October 23, 2010, 06:21:34 PM »

Cartierisum,
Thanks for the info in reply #6. I'll comment a little more later. One to two years have passed since threading was addressed and i wanted to review some of my notes rather than relying on memory. I only have 500 pages of notes.......

Using Version 3.042.020

Upgrade to at least version 3.042.32 ( there are numerous problems that were fixed from .020 on and you are experiencing some of them )

Using CV

Use exact stop as CV will affect how the pullout from the thread is accomplished.
See the note at the top of page 34 in Threading on The Lathe write-up.

Can't really tell about how much RPM loss but looks like about 30 RPM

If you watched the rpm DRO you would have a better feel for the drop, 30/1000=.03 or 3%,
So threading compensation shouldn't be a problem. 10 to 25% could be
Even 3% will affect the thread pitch though.

Using VFD

I don't use a VFD and if memory is correct you should manualy set it to a fixed rpm. If the VFD is changing the RPM, Mach is planning the next pass,
they  could be fighting each other, thus  screwing up the compensation ( based on rpn reading) which will affect feedrate, which affect the thread.

Single Index

Good ........timing not longer works and should not be enabled.
 
more when i return in a little bit,

RICH


 

4176

General Mach Discussion / Re: Huge Threading Problem Help

« on: October 23, 2010, 11:31:30 AM »

Cartierusm,
Simple question ......maybe be a long winded reply......the answer is not simple and threading is complex.  
First just a few question's for my understanding:
-What version of 3.024. is it .032 or .033?
-Using exact stop and not CV?
-How much of a change in your rpm?
-Using a VFD?
-Using a single index?
-Spindle speed averaging checked / being used?
- Describe what you mean by taper.  
  Is the taper cutting over the complete threading cycle or are we talking about when the spindle slowed down?
  How much of a taper?
  What end is smaller the beginning of the thread or the end?

It is difficult to watch what is really happening when threading at say 60 ipm. I will comment that one needs to
isolate each controller reaction to a slowed down rpm in the threading cycle. There is the overall threading "picture"
and the individual parts that make up the picture. So as i continue in my reply keep that in mind as there is a lot going on.

When the rpm's drop below what mach thinks is acceptable WHY does it start to cut a taper?

Apparently a taper ( carefull as to what you mean by taper)  will be cut if say the rpm's drop, lets say 30%, and then rpm goes
back up during that cycle. As a result of the slow down, the machine must cut a varing thread pitch, not a taper over that time period.  
The "relative" thread root for that cycle would ideally remain the same since the X  axis location by code is the same / never changed
 code wise or manipulated by Mach. Because  the chip curl changed, that would create a tapered cut  and you can add cutter /  machine
 deflection to that cut taper.  Just one part of the picture.........

Mach monitors the rpm and changes the NEXT thread cycle based on how much the rpm changed. All the sampled rpm's over the cycle time
 period will provide an adjusted rpm on which to base the next feedrate. That feedrate or other feedrates over all the
thread  cycles should  provide an a properly cut thread cut. The big picture.......

Hope this simplified reply is an appropriate  answer to your question,

RICH

4177

General Mach Discussion / Re: Huge Threading Problem Help

« on: October 22, 2010, 09:57:00 PM »

What version of Mach are you using?
I will remark that if is not 3.042.032 and above then you need to upgrade.

I would suggest you have a look at the Threading on The Lathe write-up as it will give you insight into how the threading accounts for slowing of the spindle RPM........ the range it may adjust for, what you can and cannot expect from the threading cycle. Also a whole lot of other threading related stuff.

Your threading will only be as good as your Lathe "System". I may also suggest that you just do a rough HP requirement based on the insert and
 the cut depths, the inserts, rpm, etc. I suggest you also explore using the different methods of threading. Also do some of the tests.
I don't know what type axis motors your using, in my case they are steppers, so i always have the wizard check / calculate  the number of passes which
will also display the IPM feedarate. I adjust the spindle rpm  accordingly so i am at the max power level for the steppers ( ie; below the max  axis velocity as it relates
to their torque ).
 

SS will work harder and what was easy at the first or second pass may require 2 or 3x the power to do the work hardened cut. You may be dropping below what Mach can do in recovering from a problem thread cycle ........( I have actually made the spindle briefly come to a stop and was able to recover).

BTW, on my 6" x 24" Atlas / 1/2 hp motor / 53 RPM / single 60 deg insert / modified 15 deg flank ( i think) i was able to cut a 3 1/2" x 8 x 2" long thread in steel. ( I will remark that towards the end of the threading  i thought i was going to break the carriage or tool post and made 2 or 3 spring passes)

I will say this, the threading cycle is solid if the machines system is appropriate for the task.

RICH

4178

G-Code, CAD, and CAM discussions / Re: I want to learn turning program. Please help

« on: October 21, 2010, 11:28:24 PM »

While I'm at it.....
There is another macro in the lathe Macro's folder, namely, M1083 for lathe drilling. I don't use it and prefer the lathe
peck drilling macro in the following link.

http://www.machsupport.com/forum/index.php/topic,15205.msg101682.html#msg101682

RICH

4179

G-Code, CAD, and CAM discussions / Re: I want to learn turning program. Please help

« on: October 21, 2010, 11:04:24 PM »

Here is a link on  the use of a G77 / G78  in Mach.
 
http://www.machsupport.com/forum/index.php/topic,4297.msg30870.html#msg30870

Note also in the above link there is another Macro M1077 posted by Andy.
Read Andy's comment on putting the settings in Config> Ports & Pins>Turn Options of Mach3 Turn.

I remember trying out the M1077 and the M1078 a long time ago. They can be found Macro folder for the lathe.
Open them up with the V Script Editor to confirm which one is which ( M1077 is G77 and M1078 is G78 if i recall).


NOTE that some of the settings in Turn Options are relative to threading, thus be carefull, and see The Threading on The Lathe Manual
page 44 for an explaination.

RICH

4180

Macros / MOVED: LATHE & MILL DRILLING MACROS m830 and m831

« on: October 21, 2010, 10:29:23 PM »

This topic has been moved to the Mach Tool Box.

http://www.machsupport.com/forum/index.php?topic=15205.0