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### Author Topic: A-axis rotary lathe question for Mach 3  (Read 14665 times)

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#### halfmill

• 101
##### Re: A-axis rotary lathe question for Mach 3
« Reply #50 on: November 10, 2017, 10:48:34 AM »
For Rich,

Ok I will get started on your first lesson today. again thank you.

For Gary Lucas.  Max diameter is three inches.  However I am running rather slow and shallow cuts, less than 1/8th of an inch and in soft wood--something like 15 inches a minute.  I have run on xy plane harder wood up to 100" per minute as a test.  4 flute end mill at 24,000 rpm... it did not have a problem with it.  Finally I tried holding the "round" from turning in the chuck and it had more than enough torque...so I don't think in my case with the material I am working with that I will have an issue.  thanks for the heads-up though.

bob

#### RICH

• 7,419
##### Re: A-axis rotary lathe question for Mach 3
« Reply #51 on: November 10, 2017, 11:23:45 AM »
Bob,
Have fun after lesson1 do #2 below.
---------------------------------------------

- It would be nice to have some type of index reference on the chuck so you have a visual of the  A movement.
A number of easy ways to do that ie; marked tape or even mount a plastic circular protractor on the back of the chuck.

- We deliberately set the angular wrong before ( you know what the caculated value was ). So use the axis
calibration feature of Mach  ( read / refer to in Mach3 CNC Controller Software and Installation Configuration
Section 5.5.2.30) to calibrate the A axis. The input value is in degrees and you need to tell Mach how far it actualy moved so it can calculate the step for you.

You may need to do it more than once but it is an easy way to calibrate both an angular and linear axis.
Note that   1 / steps per    is the theoretical resolution of the rotary. Say it is 400, then 1/400=.15 degrees.

You now will have a calibrated A axis.

MODIFIED THIS REPLY: Don't do the striked text below.

- Go to the MDI screen, in the Input change current mode from  G90 to G91 by just typing G91.
To rotate the A 360 degrees input G0 A360.
You should know how fast it will rotate at max and different feedrates.
If you don't have something to measure the rpm then time it over a number of rotations ( measured is  better!).
I bought a digital tack on ebay for around \$12 and it  works great.
To rotate A for 5 revolutions at a feed rate , type in MDI Input, G1 A1800 F1. Just keep doubling the feedrate  values, note the rpm, and graph the values.

- Looks like your rotary is just driven by timing belt so no gears etc and thus basklash should not be concern.

- Would suggest that you add an index so Mach can display the rpm of the rotary.

-  Click the Mach Coord's button, notice how the DRO changes. Understand the difference between
using Machine and Work Coordinates.

- Now do some manual commands changing the rotational direction using the minus sign.

-  In both G90 and G91 modes, command  A axis moves with each of the Rotational choices
that can be selected General Logic Configuration Screen.

----------------------------------------------------------------

Summary so far:
You learned how define, A as angular, tune the angular, calibrate the A axis, get / have  feedrate info for later
use, basic gcode commands, how other settings and modes can affect the turning motion.

Now remember you simply asked can you give a gcode to..........
Don't understand the "other stuff" even a simple command like G0 A 360 is like pressing some magic buttom and not know what will happen!

To be continued,

RICH

« Last Edit: November 10, 2017, 06:23:24 PM by RICH »

#### RICH

• 7,419
##### Re: A-axis rotary lathe question for Mach 3
« Reply #52 on: November 10, 2017, 11:48:05 AM »
Gary,

Good point on cutting force. Interesting that there  is research on whats required for machining metal but I have never found anything for exotic woods.

I don't do much woodwork anymore but do machine exotic woods for gun grips, knife handles and some other stuff. Use carbide tooling to machine the stuff. Nothing sucks more than hitting stone which is in ebony. Just need to experiment what feeds, speeds,depth of cuts, tooling work well for intended work.

There is still more to the tuning of the rotary which will be addressed as we progress.

HMM.... this thread will be like,   "round and round it goes where it stops nobody knows"!

RICH

#### RICH

• 7,419
##### Re: A-axis rotary lathe question for Mach 3
« Reply #53 on: November 10, 2017, 12:42:07 PM »
Bob,

To allow for easier playing around with gcode commands suggest you turn off your switch inputs.

- Config>Ports and Pins>Input Signals  un-enable all except for your EStop.

You won't have to worry about having a work offset active and you can change Machine Coordinates to zero easily.
Allows you a simple value to work from.

IE; Jog the 4th axis, Ref All Home and the 4th axis  goes to zero value.
You can also clear a work offset.

Sorry should have mentioned this in lesson#1.

RICH

#### garyhlucas

• 660
##### Re: A-axis rotary lathe question for Mach 3
« Reply #54 on: November 10, 2017, 12:46:54 PM »
Bob,
I have never seen a 4 flute wood cutter, and 1 flute cutters are quite popular! The reason is that soft materials can be cut at such high speeds that chip packing in the cutter flutes and the cut itself is a big problem.

#### halfmill

• 101
##### Re: A-axis rotary lathe question for Mach 3
« Reply #55 on: November 10, 2017, 07:35:12 PM »
Gary I don't have this problem with rosewood--that is chip problems.  I use a carbine 4 flue downcutting endmill made for machining metals, and it works fine on rosewoods from my experience.  I do work ebony as well for the fretboards, but that machines well enough too.

For Rich.  Is there a way in Mach 3, to print the screen clearly.  I usually use snipping tool, but xp does not have that feature.  I would like to print out all of my setup screens in Mach 3 before I start changing settings around as you have asked for my learning the better way of working...bob

#### RICH

• 7,419
##### Re: A-axis rotary lathe question for Mach 3
« Reply #56 on: November 10, 2017, 09:16:01 PM »
Bob,
I have been using SnagIt forever for screen captures so nothing jogs the memory for an alternate and there are ones out there.
Your setups are contained in the xml file. That's why I asked you to copy the original / posted screen and rename it to something different like bobmill0 for original so you have a record. The xml file is saved very time you save settings and you will find them in the xmlbackup directory
under Mach3 folder.

RICH

#### halfmill

• 101
##### Re: A-axis rotary lathe question for Mach 3
« Reply #57 on: November 10, 2017, 10:45:10 PM »
ok got it

#### halfmill

• 101
##### Re: A-axis rotary lathe question for Mach 3
« Reply #58 on: November 11, 2017, 01:48:04 AM »
For
Rich...

The first thing I need to know---is how to download ver.  .062 that you want me to load... where do I go to get that etc..    bob

found a free version of snagit, so that is taken care of... thanks

#### dude1

• 1,253
##### Re: A-axis rotary lathe question for Mach 3
« Reply #59 on: November 11, 2017, 02:31:36 AM »