Messages

4541

General Mach Discussion / Re: Jog VS G00 Performance

« on: June 24, 2010, 09:28:41 PM »

If i recall corrrectly you are limited by the max velocity, so when jogging at 100% or G0 (a rapid move) you can go only to max velocity.
Irrelavant, you would only continuosly jog or rapid at a rate such that you are not missing steps. With steppers anyway....

There is a feedrate can be overiden from 20 to around 300% by putting a percenatge into the DRO, maybe that's what you have and didn't realize it,
but the Led will light up warning you. Same practical comment made above would still apply.


RICH

4542

Tangent Corner / Re: eliminating taper on deep cuts

« on: June 24, 2010, 09:04:53 PM »

outer edges longer than the center)

- they all have a ground relief to the center of the end mill, when plunging down into solid stock you want a center cutting end mill

 

0.010 or I tend to break tools

- You are saying you have run out at the end of the end mill, you have what you have and that will affect the cutting, couple that to
lack of rigidty and backlash and you will break them
-So just do shallow depth of cuts and plenty of them ( what more can i say ?)

run the spindle speed as slow as I can get it to run smoothly

- good spindles with appropriate holders run just as good slow as fast, like i said you have what you have and need to fool some to gain
experience with what you have. minimize the extension of the tool from the holder.

Like i said, take a piece of round stock and machine the outside trying different depths of  cuts, feed rate / spindle speeds leaving say .010"
for finishing to some diameter. Look at results of  machining to a depth of 1/2", is it square to the face, out of round, plunge cuts coming out differently?..........experiment with finish cuts cw and cw at different finish cut depths and look at the result

If you had say a normal mill i would just give you some recommended info that you can find anywhere, but with your machine you need to experiment and see what you can do.

Can't give you any better advice than the above,

RICH

4543

General Mach Discussion / Re: Relationship of Velocity/Accel to G0...

« on: June 24, 2010, 04:25:35 PM »

 

I have even noticed a change in the motor sounds when using a usb mouse with just wiggling

- don't / quit playing  with your mouse      .......what happens when you do the driver test and move the mouse around as i would bet that
  you will see a bunch of spikes, which are interuptions to the pulsing, which when doing that will screw up the pulse stream to the drives.
  Same for changing the feedrate.

G203V current resistor is set to give 6amp/

-what are the motors rated for...a stepper can behave rather koofy when the amp rating is too high ( trust me as i have four machines, different motors and need to switch the amp selection on the dirves for them to work correctly)

motor dialog vs gcode

 
Co-ordinated Linear Motion  (Section 10.1.5 in manual)
Co-ordinated linear motion - each axis moves at constant speed and all axes move from their starting positions to their end
                                               positions at the same time, also defined as control the axes so that, at all times, each axis has completed
                                               the same fraction of its required motion as the other axes
                                            - IE; any two axes ( x,y or z ) produces motion in a straight line
                                            - the motion can be done at prevailing or rapid feedrate and may default to the slower axis feedrate
 
FEEDRATE ( unless G93 is used ) Section 10.1.6 in manual
1. X, Y, Z  + A, B, C         - without simultaneous rotation -  F =length / minute  ( along the linear path )
2. X, Y, Z  + A, B, C         - with simultaneous rotation -       F =length / minute  ( for the XYZA combination linear path ~ modified F
                                                                                                                           based on a diameter)
3. X, Y, Z  + A or B or C  - with simultaneous rotation -       F= Degrees / minute of  A or B or C
3. X, Y, Z  + A B C                                                                  F= Degrees / minute  using a blended ABC / conceptual angular motion
                                                                                                        for total time


3 Feed Rate Modes - ( Section 10.7.25 in manual )
G93        - inverse time feed rate -            F = 1/F#  minutes ( if the F number is 2.0, the move should be completed in half a
                                                                                                   Minute) 
                                                                 - if active, an F word must appear on every line which has a G1, G2, or G3 motion
                                                                 -  an F word on a line that does not have G1, G2, or G3 is ignored.
                                                                 -  does not affect G0 (rapid traverse) motions.
                                                                    It is an error if: inverse time feed rate mode is active and a line with G1, G2, or G3
                                                                    (explicitly or implicitly) does not have an F word

G94        - units per minute feed rate         F= inches / minute, mm / minute, or degrees / minute, determined by length  units are being
                                                                         used and which axis or axes are moving

G95          units per rev feed rate                F= number of inches / mm / degrees per spindle revolution, determined by what length units
                                                                         are being used and which axis or axes are moving. 

RICH

4544

General Mach Discussion / Re: lazyturn problem

« on: June 24, 2010, 04:08:44 PM »

I don't see the problem here.
I created a tool, used the same parameters for pathing, and did a rough and finish pass, one when in diameter mode and one in radius mode.
Looking at the generated code i don't see the problem. Didn't try it for numerous tools, but assume all is well.

RICH 

4545

General Mach Discussion / Re: Relationship of Velocity/Accel to G0...

« on: June 24, 2010, 10:42:43 AM »

   Stan,
I could not find a motor curve for your stepper motor. You really can't use info from some similar motor, yes maybe ball park,
but not good.  The info on kelings site usualy gives torque to PPS ( pulses per second ). Note that that you need to know at what voltage and how wired to compare.
Here are some ball parks figures:
pps    rps  rpm
2000  10   600
4000  20  1200
6000  30   1800
10000 50   3000
I wouldn't think that you can get 3000 or even 1800 rpm from that kind of motor.
Now if at 4000 pps, you are probably at almost no motor torque, so max speed / no torque ....poor power.
"In a way" you could actual find the peak rpm , you just turn the stepper, letting it generate a voltage and see at what rpm  the max voltage occurs.
 Then to drive it at that rpm, your controller would need to be able to provide a signal of adequate quality and voltage, etc , but you would have no power.
So if you can get 1377 i see no value in that rpm, and would practicaly think that  it would a lot lower since you are using 25 volts.

Kernel speed is ok at 60k ( 1377x 2546/60= 58431 ). You could set the motor tuning to whatever you want, that dosen't mean in reality you will get there.
To get the high speed you probably need a higher voltage, thus your limited.

Since you don't have info to get a rough idea on what to expect, then, you will have what you have based on testing with it hoooked up to the machine.
Then additionaly other things will come into play and that 425 is probably not even a reliable ipm to be had.

FWIW, off to the sidelines,
RICH

4546

Show"N"Tell ( What you have made with your CNC machine.) / Re: Bass Boat Dash Plates

« on: June 24, 2010, 07:22:22 AM »

Glad you having fun and keep up the good work.
RICH

4547

General Mach Discussion / Re: lazyturn problem

« on: June 24, 2010, 07:17:41 AM »

jekran,
Can you give me some more info?
Are you saying that, for the posted gcode, for one defined tool the "generated code" will be based on a diameter , and if for a similar tool ( lets say the tip radius is changed ) the generated code will be based on a radius?



RICH
  

4548

Tangent Corner / Re: eliminating taper on deep cuts

« on: June 23, 2010, 10:00:02 PM »

Bill,
- max depth of cut should be 1/2 the cutter dia say, so no more than .050" ( if you have backlash reduce it even more )
- the end mill should be one that will plunge ( cuts to the center of the end mill)
- clear out the bulk and leave say, .010 for finish cuts
- make one finish cut at .004" , .003", and finaly do a .002" at max depth
- use appropriate speeds and feeds

Now before doing the above, i would test the machine and just see what happens when you reduce, say the od of some al scrap.
This way you can fool with depth of cut, rough and finish passes, and gain some experience on what your machine will do relative to holding
the diameter and strightness along the side.

Just some rough suggestions,
RICH

4549

General Mach Discussion / Re: unrepeatable axis

« on: June 23, 2010, 11:49:48 AM »

Sounds like a mechanical problem......how much z backlash do you have?
 
RICH

4550

LazyCam (Beta) / Re: Opening LC in plasma mode

« on: June 23, 2010, 09:14:31 AM »

Mike,
I don't remember anything posted about it and plasma is not covered in the manual.
Don't have any suggestions.
RICH