Messages

351

General Mach Discussion / Re: A-axis rotary lathe question for Mach 3

« on: November 13, 2017, 07:53:29 PM »

Bob,
Glad you got it fixed and on the first try.

#4
The 4th axis or rotary defined in degrees is used for indexing.
If verticaly mounted you could move way from the center of the rotary to some location drill a hole , index some angle and drill another hole. When mounted horizontaly you are still indexing.

The rotation of movement + or minus , cw/ccw, is defined by mathematical standards and the Right Hand Rule is good way to remember it. Direction of spindle rotation is the same as the mill, namely, one views from the spindle towards to the chuck in the direction of the axis.

Say you wanted to drill the holes in the quitar bridge, relative to the top of the bridge without removing  it  from the holder. Index 90 degrees and while in that position  run the code for drilling the holes.

Do the following commands using the MDI in the order shown. BUT
On a piece of paper write down what you think the motion will be and what  the dro
will show for position. And if you want to take this a step further do the same for  Machine Coordinates and  also Work Coordinates along with G90 and G91.

G54
G94
G90
G0 A0
G0 A10
G0 A-10
G0 A0
G91
G0 A0
G0 A10
G0 A-10
G0 A0
G0 A360
G0 A720
G90
G0 A1.5
G0 A0
G91
G0 A1.5
G0 A-1.5

The way the rotary rotates to get to a position and what is also shown in the DRO
can be affected by "Rotational"  settings. Config>General Logic Configuration has three Rotational settings you can use.

Rot 360 rollover – if checked the A axis DRO will display from 0 to 360 degrees and then start over at 0. If not checked the A axis DRO will be additive such that 2 revolutions will display as 720 degrees. The rollover only works for G91.

Ang Short Rot on G0 – The axis will move in the shortest possible move to a new position. So if at 0 degrees, and you jogged  to 359 deg then it would just rotate  -1 degree.

Rotational Soft Limits – if checked will apply software limit switches to the rotary axis.

You don't have any of these settings selected and suggest you try some commands
with the Rot 360 rollover and Avg Short Rot on G0 selected.

To be continued,

RICH

352

General Mach Discussion / Re: Alright fellow campers...a frankenstein moment!!

« on: November 13, 2017, 07:23:06 AM »

Simply, and I mean very simply stated, your problem us that you have a transmitter creating interference and something that acts as receiver of the interference.

There may be no single simple solution but what Gerry said is a start.
Most folks just don't understand interference and there are many books written on the subject. Hopefully the electrical and  instrumentation folks will give you specifics on what to do.

Will not go into any detail, but, resolution of the problem is something like this:
- Identify the source of the problem
- Eliminate, isolate, reduce, contain the  source of interference
- Provide protection from interference to any device

I have good grounding all the way back to the main panel of the building

That may be true from a purely electrical code point of view.

For interference, ( term used very loosely for the sake of simplicity) one
may want to provide a seperate ground system.

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

Simple things to do and  try:

- Make sure your wires are all shielded
- Provide a ground system for the shielding
- Move the electrical plug of the VFD to different outlet  that is not part of the circuit
  used for the PC or electrical supply to the router.
- Move the VFD as far away from the router as possible
- Keep wires to and from the vfd away from other wires
- Any control boards etc for the vfd should be enclosed

Only do one change at a time and see if it solves the problem
RICH

353

General Mach Discussion / Re: A-axis rotary lathe question for Mach 3

« on: November 12, 2017, 08:08:38 PM »

Bob,

Still addressing the 4th axis defined as being angular.
For motor tuning you calculated the steps per value, and then used the calibration feature.

Now lets go back to motor tuning again. Be aware of what the grahics is showing in the motor tuning window.
The graph shows how the stepper will ramp up in time ( accelerate), run at at some velocity, then ramp down. Change the velocity or acceleration and be aware of what the graphics is telling you. With a 25k Kernal speed the graph will only change so far ie; you can only get so manny pulses to drive the motor.

At some velocity, acceleration, or combination of both the motor will skip.
Practicaly speaking you can't go from a standstill and accel instantantly. For a stepper as the motor rpm increases the torque decreases, so,  you need to limit the max velocity so there is adequate torque for machining. Speed can come once reliability is assured. Depending on what you are machining will determine how "you" limit the velocity.

You should know what your max velocity and accel is.
At a combination of max velocity and accel you can check the rpm. The rpm at any lower velocity value can be found  quickly by just succesively dividing  the max velocity  found ( ie; find rpm using a stop watch for one revolution ( 360 degrees)  at max velocity).  Max rpm/2 is rpm of the lower velocity if it was cut in half. Note that the total time to rotate 360 degrees is influenced by the acceleration. Looking at the graphics can show time required for the ramps.

You can do a lot of hand calcs, but, there is an easier way:

STEPS PER UNIT CALCULATOR - members docs
http://www.machsupport.com/forum/index.php/topic,16315.msg110286.html#msg110286

This spread sheet will calculate the required steps per unit for linear and rotary stepper motors.
Imperial and metric calculation are provided for. Pulses per second  are also calculated based on miscellaneous inputs.
 
StepperCalc_ALENZ_rev1.xls

Play with the calculator for different values.

------------------------------------------------------------------------------------------------------------------------------
Before we do some gcode commands for the rotary you need to be aware of the current state of the machine.
Different gcodes are shown in the upper right corner of the screen and they will change depending on an
an entered gcode command.

SO
 
Print the Gcode Reference which can be found in Using Mach3 Mill  Manual  - Page 10-12 Figure10.4
There are few others commands not listed but the list will serve you well.

Then compare the codes listed on the screen to the list. After a while you'll know what to look for.

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

To be continued,

RICH

354

General Mach Discussion / Re: A-axis rotary lathe question for Mach 3

« on: November 11, 2017, 06:50:13 PM »

Relative to xml files as we progress:
Original xml file posted was reply #3:  bobmill
Lesson one I asked you to copy and rename the original and use:  4thbobmill

I want at different stages of this thread for you to use different xml's.
That way not only you, but I /we can also have a look, at what you did if necessary.

I guess the following may be a progression:
- mill w/ 4th defined as angular
- mill w/ 4th defined as linear
- 4th used as a lathe only
- 4th used as a lathe with live tooling or some goofy variation

Not sure of the above but it can  get rather confusing .............
Will let you know when to use a new xml.

BTW,
Just found some of my old notes ...... been almost 7 to 10 years since I was fooling around. Good grief forgot more than I once knew.

No....... haven't put the keys in the refrig yet! 

RICH

355

General Mach Discussion / Re: A-axis rotary lathe question for Mach 3

« on: November 11, 2017, 06:24:49 PM »

Let me add that if you had a lot of "stuff" in an old version and wanted to also keep it for later use.
THEN
Remame the Mach3 to ZMach3. That puts the old one down the directory list and avoids a possibility that the first file found in the drive will be used. 

Any version installed after will be put into the Mach3 directory.

RICH

RICH

356

General Mach Discussion / Re: A-axis rotary lathe question for Mach 3

« on: November 11, 2017, 06:18:07 PM »

Bob,

First save your xml file and your license to a safe place.

I suggest that you just uninstall mach3 v066 and then install 062. Don't think you will ever use 066 again.
After new installation is complete place your saved XML file and license in the Mach3 directory.

Per Dude it does overwrite but guess I am old fashion and want to make sure it is gone.

Your choice on what to do...........


RICH

357

General Mach Discussion / Re: Machine coordinates reference home question

« on: November 11, 2017, 10:56:57 AM »

John,

I would suggest you purchase CNC Programming Handbook by Peter Smid.
Read and study it since it's a single source of info that you will refer to for
professional advice / information.

RICH

358

General Mach Discussion / Re: This is just plain... WRONG

« on: November 11, 2017, 10:46:42 AM »

Just tell him that you if did it for him he would be quilty of plagiarism and can be thrown out of college for that. I am dated, so maybe the schools  don't do that anymore.

That's why in some cases you get educated / degreed  folks that are total incompetent.
Fortunately not to often.

Once I got stuck with a person that I had to mentor who had a associate degree in engineering but had an arithmetic level of a 6th grader.  What a PITA assignment that was for the sake of political correctness and diversity. In a way it was interesting, but, still a PITA with the all the reports. Then something good happened, the person quit and moved to the other side of the earth!

This a quote from that person that I never forgot:
" I was told that as long as I came to class I would be given a passing grade"
I had to deal with that college because of  the matter and what BS they gave.

What an injustice our educational  system did to that person!

RICH

359

General Mach Discussion / Re: Machine coordinates reference home question

« on: November 11, 2017, 10:14:23 AM »

john,

Please read 10.7.17 in the mill manual about the G53 command.

Machine Coordinates are absolute coordinates from some 0,0,0 defined datum point.
The defined datum point of 0,0,0 is where some physical point ( controlled point would be a better word) is on the machine. Mach is the controlling software and has an internal 0,0,0 point to work from. Until the machine is referenced it does not know / can't relate the software 0,0,0 to some defined physical location of 0,0,0. Only you can say where the physical point is. So the controller provides  a way to do that since it can't hear, see, what ever, and provides for using switches to electronically and automatically relate the software 0,0,0 to the physical 0,0,0. When that is done it can keep track of the axis coordinates for the current session.

RICH  

360

General Mach Discussion / Re: Machine coordinates reference home question

« on: November 10, 2017, 09:34:06 PM »

John,
Something could happen when the machine is turned off that would mechanically move the axes. Mach needs to be told where the physical location of the axes are. Referenced, referencing, home, setting home are play on words used over time. Using switches does it automatically per your configuration. If you don't use switches you need to do it manually.
So yes reference the machine each time you start.

G53 is a command to move in Machine Coordinates which are absolute.

There are some options  in general configuration to save current position on exit.

BTW, I don't use switches, need to many of them and just think they are a PITA. But you know what they say about opinions....................,

RICH