Messages

931

General Mach Discussion / Re: CNC Lathe conversion with threading

« on: April 24, 2016, 07:05:49 PM »

Cheryl,

PP is  Parallel Port.

You only use one slot. Can make a disc from a CD disc...cut slot...paint it black.

Not up on the latest greatest breakout boards. I have no need for one here.
Others will chime in for sure and make suggestions.

No, DO NOT use any turn diagnostics plugs in's as they were used for testing a long time ago.

RICH

932

General Mach Discussion / Re: CNC Lathe conversion with threading

« on: April 23, 2016, 02:02:51 PM »

Cheryl,

Have a look at the write up called "Threading On The Lathe- MACH3 Turn".
Don't know if it's still included in a MAch3 software download but you will find the latest in Memeber's Doc's. It cover's a lot about threading.

I am currently using V.062 along with a PP and all seems to work well so far,BUT,
must use at least a version greater than 3.043.33 and probably 3.042.38 would be  better.

I use a Hall's Affect sensor, but an index wheel will work fine for the index for PP.

Note if your lathe has a "wimpy" motor then your threading may be limited in size
even when using some of the other cutting methods. The ability to do good threading will only
be as good as your total lathe "system" which also includes physical setup. Your pc should provide a good pulse, not much variation from Kernal speed ( the closer and more consistant the better ) as actual DRO rpm should not vary by much...say 1-2 rpm. The threading cycle provides for motor slowdown, but frankly, it's not the way to go.

If you don't use a PP then an external motion controller is need that supports threading.
Not up and the latest greatest so research before you buy. Post back for suggested boards.

Now since your just starting your project, strongly suggest, that the heart of your lathe,
namely the axis screws should not be junk and do it so there is no backlash.

Threading is not hit or miss if you do it right the first time and know before you go!

Seems someone has told me that before,
And I never listened
Slow learners we Lithvac's 


RICH
   

933

General Mach Discussion / Re: Hot Stepper motors

« on: April 23, 2016, 07:10:02 AM »

FWIW,

140 deg F is considered a temperature at which protection against burning should be done. So if you can briefly and lightly hold / touch
the stepper but can't maintain touching it your at or above  140F. Depending on how the stepper is wired can change it's
performance and operating temperature, BUT, again it depends on the particular stepper.  The heating comes from resistance to the
applied current or said differently, no heat not working hard. As long as you stay below the rated temperature of the stepper, and recommend being conservative, you are doing no harm.
The Gecko site provides  a lot of info and worth studying.

RICH

934

General Mach Discussion / Re: Need some advice!

« on: April 23, 2016, 06:50:20 AM »

FWIW,

You will find rather standard / similar charts and info as a that posted  in reply #2 for metal and the basis is from research done
many years ago. The info is a good reference point to start from. I have never found research based info for wood cutting. Wood and plywood have what I would call "non- standard" characteristics as the machinability can vary a lot even for a specific wood.

Burning comes from heat caused by friction. Adjust the way you machine the wood ( which includes the cutter ) and you can greatly reduce the condition.

So no use rambling on.......... test and adjust accordingly for what you are doing.

RICH

935

General Mach Discussion / Re: Backlash correction not working?

« on: April 22, 2016, 05:52:32 AM »

As noted BC must be enabled  and also look at the following:

http://www.machsupport.com/forum/index.php/topic,29149.msg204717.html#msg204717

RICH

936

General Mach Discussion / Re: Constant pulse generation?

« on: April 22, 2016, 05:47:57 AM »

Note that a stepper is not a good choice for driving the index to mimic a spindle.
The gear ratio of the index is usually high and stepper torque drops off as the motor rpm increases.
Also if rpm indication is wanted, you will find that it is not linear over the range.
Just something to be aware of. Depends on range of desired index rpm.

FWIW,

RICH

937

General Mach Discussion / Re: How to calibrate a axis

« on: April 20, 2016, 08:38:12 AM »

the a axis turns the x axis moves -0026 for no reason do you have any ideas why.

Something is sending an impulse to the X axis, could be noise.
If you command only an A axis move the X axis should not move.

For rotary the setup is in degrees and also not the following configurations :

Rotational:
Rot 360 rollover, if checked, will measure a rotary axis modulo 360 (0 to 360 then restart
at 0). Otherwise, it will keep counting up (for example, two revolutions would be 720).

Avg Short Rot, on G0, if checked, makes any rotary axis treat the position given as an angle modul.360 degrees. Moves will be by the shortest route to that position. For example, if the axis were at 0
degrees and a request was made to rotate to 359 degrees, it would rotate –1 instead of +359.

Rotational Soft Limits, if checked, applies software limit switches to rotary axes.

RICH

938

General Mach Discussion / Re: Z Acceleration

« on: April 20, 2016, 08:29:13 AM »

As said, I don't know much about the details of plasma. You can thank "Dan" for
the macro.
 
This macro probes the TOM using G31 to set torch height. Used with a floating head such that
a switch mounted on the Z provides an input to Mach post probing. Consider creating a
user DRO on the screen for inputing a torch height based on material thickness and use that
value for the Z offset value in this macro as that provides for cleaner cuts.

Code generated by LC provides an M3 before / after each cut. Since the plate TOM may not be
flat due to mounting, the plate itself , or warping the macro takes care of that problem. Your offset of
the torch ( piece height ) will be based on your experience of cutting different material and
thickness. You will need to adjust the macro depending on machine setup and generated code.

Call SetOEMDRO(802, 0) 'Set Z DRO = 0.00
Code "G31 Z-8.0 F60" 'probe surface and z needs to be > actual TOM lcoation so it touches off
While IsMoving()
Wend
Code "G4 P.5" 'wait
ZprobePos = GetVar(2002) 'get Z contact point
Code "G0 Z" &ZprobePos 'return to point to remove overshoot See note below
While IsMoving()
Wend
Call SetOEMDRO(802, 0) 'Set Z DRO = 0.00 This is TOM
While IsMoving()
Wend
Code "G4 P.5" 'wait
Code "G0 Z.480 F30" 'remove floating head travel Adjust for your travel
While IsMoving()
Wend
Code "G4 P.0" 'wait
Call SetOEMDRO(802,.100) 'Set Z DRO = 0.00 See comment on pierce heght above for Z offset value
While IsMoving()
Wend
ActivateSignal(Output2) ' Modify for your inputs and outputs Fires torch

NOTE: One can calculate touch off overtravel. There are different thoughts about feedrate and
how best to do it,but,for my lathe tool touch off the axis rapids close to material and then a
slow feedrate is used for the touch off ( touch off is repeatable to around 0.0002"). So it's
like a single axis move and no adjustment is needed.Don't think that the overtravel distance
will have that great of an infuence on the pierce height, but, depends on yout switch
characteristics and feedraqte used. You calculate to see what the timimg influence is. I just
mention this  since maybe there is no need for the overshoot adjustment in the macro.

RICH

939

General Mach Discussion / Re: How to calibrate a axis

« on: April 19, 2016, 09:13:37 PM »

Have you looked at the Manual?

RICH

940

General Mach Discussion / Re: How to calibrate a axis

« on: April 19, 2016, 06:01:29 PM »

Go to members docs and you will find info on how to do it and also a spread sheet that will calc it for you.
Also have a look in the Mach Manual.

RICH