Messages

1481

Tangent Corner / Re: Mach users in your area

« on: December 21, 2014, 07:38:10 PM »

post an ad on Kijiji about learning Mandarin and as a result I am engaged to be married

Good for you my friend, is she Polish by any chance?

RICH

1482

G-Code, CAD, and CAM discussions / Re: Zero CAD to CAM

« on: December 19, 2014, 06:36:12 PM »

Merry Christmas...........

RICH

1483

G-Code, CAD, and CAM discussions / Re: Zero CAD to CAM

« on: December 19, 2014, 06:51:39 AM »

Geoff,
Tick the box next to "As Drawn" located in the Setup Tab / Loading Option.

RICH

1484

General Mach Discussion / Re: acceleration values question

« on: December 16, 2014, 04:28:04 PM »

However, I didn't know if I set the accel too low, or if you have high velocity with low accel, if it could lose steps

Velocity is constant movement of the axis, and as long as the stepper can maintain the required torque to deliver
 the force necessary to keep the axis movement at that speed it will not skip. Now the stepper looses torque the faster it
rotates.

Acceleration is the change in the velocity from a higher to lower or lower to a higher value in some time.
The stepper must have adequate torque to provide that acceleration to the axis. One of the factors is the mass
which it is trying to speed up or slow down. You know F=MA

So if you are trying to increase the axis velocity and it is at max velocity / unreliable you may not have the torque available to do it
and the stepper will skip. Also you may want to move the axis a small amount  in a very short time such that you need  adequate
torque to provide that move. IE; say the Z must move 0.0003" in a fraction of a second if can't do it it will skip.

So try all axis at say velocity = 100 and accel =10, then just double the velocity values until it skips, then reduce the
velocity 30%. Then double the acceleration values until it skips. Now reduce the accel value by say 30%.
You do the above  in a linear move with the axis from a dead start to rapid stop for both a long and short move.
You will quickly find approx velocity and acceleration values for your machine and you should use the values of
the weaker axis.  The 30% provides some headroom for different materials when cutting and you may find from experience that
you want to additional reduction of values. IE; what happens when you hit a knot in the wood?

Rapiding forward.........   you want power from the motors which is function of speed times torque.

Since you modified the machine as compared to what it was designed to do ....whatever that was  .......you need to
change some values to account for the modifications.

Do the above before getting into other possible system contributing factors and quit quessing what is wrong!

RICH

1485

General Mach Discussion / Re: acceleration values question

« on: December 15, 2014, 07:16:38 PM »

Like the velocity value, best way is to by trial and error. Once a reliable velocity is found, say 30% below where it skipped, then just increase the accel
in steps. Over time one finds something that is reliable. Yes there are programs which will evaluate motor requirements  for  given
conditions, but frankly, it gets you approx numbers to be verified through use of the machine.  

Counter balancing, as suggested, assists in reducing the required motor torque. You can also consider a different stepper motor.

If you change accel values in motor tuning make sure you click Config> Save Settings in the Tab. There is no need to reboot the computer.


RICH

1486

General Mach Discussion / Re: why my lazycam create cam file with hight z?

« on: December 14, 2014, 01:11:27 PM »

Add  a G28  or G28.1 code to the gcode file. See the Mach manual for definitions and have a look at the text below.
LazyCam dosen't provide for a G28.

RICH

SOME INFO ON GETTING HOME

Machine Home (zero)
 Can be set by switches,
OR REhome Button if you have no switches,
OR is set by mach when you OPEN it to the current position
OR can be zeroed to a postion via CB
OR rumored to be settable via #vars 5161-5166 (untested as yet)

Moves to get to machine home,

G53 X0 Y0 Z0 ------- Makes a straight traverse run to Machine Zero

With G30 ALL axis go home
G30 --------------------- Makes a straight traverse move to machine zero
G30 Z0 ------------------Makes a single Z move to Zero THEN all AXIS make a straight traverse move to Machine zero
G30 Z0 X0--------------Makes a Straight traverse move to Z0 X0 then all axis makes a straight traverse move to machine zero
ETC,ETC

Local Home(G28), Is an offset from Machine ZERO.  With G28 without defined axis all axis goes home in the order of Z then all the rest. USED with a defined axis ONLY the defined axis goes home via the intermediate point.

It can be the same as Machine zero or different as defined

Moves to get to Local Home

G28 ----------------- Raises Z first then makes straight traverse moves in XY to Local Home(LH)
G28 Z-1 ------------ Single axis move to intermediate point(-1.000) and then goes to Z0. Z axis ONLY goes to LH
G28 Z0 X0 --------  ONLY the defined AXIS will go to LH UNDEFINED axis remain as is . Makes a straight traverse move in ZX to 0 then ZXmoves in a   straight traverse move to LH.
ETC,ETC

Part HOME ( Part Origin, X0Y0 Z0)

G0 Z0 X0Y0 ----------------- Makes a straight traverse RAPID move to Z0 X0Y0
G1 Z0 X0 Y0 ---------------- Makes a straight traverse FEERATE move to Z0 X0 Y0

Fixture Home   

G55 G0 Z0 X0 Y0  -------- Swithes the Fixture offset then goes to X0 Y0 Z0 as straight traverse move at rapid speed
G56 G1 Z0 X0 Y0 F100 --------- Swithes the fixture offset then goes to X0 Y0 Z0 as straight traverse move at feedrate speed



*************************************************

You will note that the G28/30 in MACH3 is backwards to FANUC . In the fanuc world the G30 local Homes can be set in the parameters AND there can be MANY etc;  G30 G30.1 G30.2 G30.3 etc,etc

Also the Axis calls in G28/30 are different from each other. In g28 you can call a single axis to home, in G30 ALL axis go home reguardless

Just a thought, (;-)TP

1487

Show"N"Tell ( Your Machines) / Re: Z-axis opto probe for me Orac.

« on: December 14, 2014, 01:00:21 PM »

Hey Hey..... at least you can read / spell ......I can only write!    CLOBAL

Graham was supposed to do a full write-up on it sometime for Mach4.

I think you will only find the "Global Shift" term used once in Smid's books and it is not defined.

Have a look at the Mach4 lathe manual for definition of G52 and you can also see page 14 of 21 Appendix "F" in the LazyTurn Manual
for a partial use of G52.

Other than that, it's a DAH     on my end also.

RICH

1488

General Mach Discussion / Re: why my lazycam create cam file with hight z?

« on: December 14, 2014, 12:36:12 PM »

One must define to the software what will be machined and how they want to machine something for each machining
step. Basicaly there are no defaults other than those on importing of the dxf file.

Please read the manual.

RICH

1489

General Mach Discussion / Re: why my lazycam create cam file with hight z?

« on: December 14, 2014, 09:10:10 AM »

Have a look in the LazyCam Manual. You can change the origin and you can set the Z ( Tutorial #6) .

RICH

1490

Show"N"Tell ( Your Machines) / Re: Z-axis opto probe for me Orac.

« on: December 14, 2014, 09:00:53 AM »

Would be nice if you had a tool tab as shown below and suggested for Mach4 lathe.

RICH