Topics

61

General Mach Discussion / is restart nessessary after edit?

« on: June 19, 2015, 11:11:57 AM »

Hello chaps
probably a stupid question but here goes

while running code in the autocycle mode if I stop the program using "stop"
and then edit the code. I then resave the code and it overwrites the code in memory.

At that point is it nessessary to restart mach3 ? or can i safely just rewing and start over again?

regards

fred
 

62

General Mach Discussion / feedrate changing after spindle stop part 2

« on: June 16, 2015, 05:56:12 AM »

Hello chaps

After the earlier posting i thought i should post the code for the experts to have a look at

I have marked the line in the subroutine where it always changes the f value


Here it is
% filename is    :-   simple boresinglecut.tap
% program number:-   01001  (program number -put at start of program)   
% Program name    :-   simple boresinglecut.tap
% Program description:-   Makes a single cut in the bore according to parms set
%          SETUP STRING (INITIALIZATION)------
% make sure to home the machine first then to reference x and z positions
m05            (stop the spindle)
g18            (xz plane)
g21            (feed in mm)   
g40            (g49)
g95            (feed per rev mode set on)
%G80         (cancel motion mode)
%g96         (CSS control)
s1400         (CSS cancel and set speed to 1400)
%g61         (exact stop mode)
g64            (constant velocity mode)
f.1            (feed .1 per rev)
g028          (go to home position)
% -- setting up parms-------------------------            
#1=27.0         (bore start dia)
#2=-38         (end of z cut notice the minus !!)
#10=.5         (first diameter on bore x axis)
#11=4         (second diameter on bore x axis)
#20=4.5         (first cut length on z axis)
#21=9         (second cut length on z axis)
#22=42         (third cut on length z axis)
m04         (start spindle forwards)
m98 p1 l3      (run sub no 1 5 times)
% ---- program shutdown starts----
m09             (water off)
m5              (stop spindle)
m30             (end program and rewind m2 will also end program)
% ----------this is the end of the program --
O01   (subroutine  #1 starts)
g0z19         (start to clear front of boring bar)
g0x#1         (START cut X axis)
g0z1         (move z closer)             ********this is where it always changes the feedrate
g01 x#1 z-5         (cut in 5 mm for the location)
g01 x[#1-#10] z-9   (bore first taper)
g01 x[#1-#11] z-39   (bore second taper)
g0 x[#1-#11-1]z-38   (back off quickly)
m 05 g0z50      (stop spindle move tool out of the way for measuring)
g0x#1         (put tool back to show size on dro)
%m00          (msg,stop and measure then press cycle start)
m04            (start spindle again)
#1=[#1+2]      (add 2mm on dia parm )
m99            (this is end of sub 01)
%   LEAVE THIS % TO MARK END OF FILE

63

General Mach Discussion / feed rate changing after spindle stop

« on: June 16, 2015, 05:41:07 AM »

Hello Chaps -- please suggest a solution.
 I am using mach3 on a lathe.
At the start of the code i set the  f=0.1  (mm) as the code runs i use
a m0 to stop the spindle so i can measure the size . when i use m4 to
start the spindle the feed rate has changed to about 10% of the original
setting and the DRO shows feedrate at about .04 ??
any idea what i am doing wrong??

regards

fred in South africa

64

General Mach Discussion / s word and actual speed on lathe spindle

« on: April 13, 2015, 07:22:08 AM »

Hello Chaps
Talking about speed and ratio on lathe spindle
My Machine has a gearbox with 12 gear ratios. I am using
an Omron drive controller

I have a 1400 motor and for this query I have selected
pulley number one and manually selected gear ratio that would give
spindle speed 80 rpm

When setting pulley ratio in the pulley ratio drop box
I have entered the following in the  .
pulley number 1
minimum speed 20
maximum speed 1400
ratio 1.01

With this setting when I say S1400 M4  then the speed actual reads 140 rpm and
a tachometer check on the spindle confirms that the spindle is actually
running at 140 rpm

While running as above the s word DRO is reading 1400 which confirms the speed that the
motor is running at.

this is means that the s word is referring to the motor speed.

I would have expected the s word to refer to spindle speed??

How do i get the s word to refer to spindle speed??

Regardfs

fred
 

65

General Mach Discussion / pulley ratio

« on: April 11, 2015, 11:44:05 AM »

I am really struggling master the pulley ratio setup

I have a chinese machine with a 9 speed gearbox.
the gear ratios are from 80 rpm up to 1600 rpm
I have installed an Omron MX2 drive which does a nice job of controlling
the motor revs when I use the S word in the MDI line - So that side of it seems to work nicely

Now i am setting the pulleys and am struggling to get the spindle speed to
do what i want it to do.

I am using standard screenset (1024.lset I think it is)
On screen are two boxes one says true speed . This box correctly
displays the speed of the spindle.
the second box displays the speed  as set by the S word in the mdi line.  
I have a tachometer and both DRO's  WERE  displaying correctly before i started to
mess around with pulley settings

please help with my understanding of the terminolgy on the pulley ratio setup
box

The drop-down is entitled "pulley selection"
first box is pulley no 1
second box is minimum speed - does this refer to the minimum speed of the motor or of the spindle?
third box is maximum speed _ again does this refer to the max speed of the spindle or the max speed of the motor?
the last box says ratio . I dont know what the gear ratio is  but i do know that if a certain ratio is selected
then when the motor is turning at 1500 rpm at that speed the spindle is 1245.
Now what do i enter into that ratio ?? And please show how you get to the figure.??

Stupid question ( I am sorry) but my mind is spinning at the moment

then there is a box which says "reversed" a tick in this box doesnt seem to do anything --I still have to
use an m4 to get the motor to reverse.

thanks all
Fred

66

General Mach Discussion / Omron vfd support group

« on: April 11, 2015, 08:27:58 AM »

Hello Chaps--
I have an Omron 3g3mx2 drive driving the spindle on my lathe.
Because I am trying to get into this whole thing i am looking for support specifically
on variable frequency drives

Can anyone point me to a forum??

regards

fred

67

General Mach Discussion / anyone here from Johannesburg South africa??or south africa??

« on: April 10, 2015, 10:27:45 AM »

Hello there - please introduce yourself !!
I live in Kensington

68

General Mach Discussion / qestion on pvmbasefreq

« on: April 08, 2015, 01:27:51 PM »

Hello chaps
in the setup instructions it is recommended in ports and pins that pvmbase frequency be set
to between 5 and 10 for optimum performance.
The installer who installed my OMRON PVM set the base frequency to 500
what effect would this be having on the running of the machine??
regards

fred
 

69

General Mach Discussion / ative low or active high??

« on: April 08, 2015, 01:17:49 PM »

having now (after many months) a basic understanding of gcode,Mach3, Ports and pins etc and my machine
sort of running ok i decided to start again at page 1 of the manual and go through it step by step for about the
umpteenth time!!

This is the first of a few questions concerning some thing needing  explaining
Quite a few guys have been helping and each with his own suggestions resulting in
some unknown differences being made to the setup and settings.
 
Machine setup Page 4.7 says i must tick the active low button on in ports and pins  but i see my
setup has active low off ?? is this a serious issue?
What difference does it make?? anything i could detect when using the machine

all comments gratefully acknowledged

fred evans

70

General Mach Discussion / pulley ratio ,feedrate and motor tuning

« on: April 03, 2015, 10:48:31 AM »

Hello Chaps,
I am having a lot of trouble getting repeatable sizes on my lathe x axis.

I dont know how to tell if steps are being lost but i suspect that this may be the
cause of the problem.

If steps are being lost can it be heard or how can i tell. When I do the steploss
check ( backwards and forwards 50 times to return to a zero point) it seems to be
ok - but i do not know what happens when the machine is taking a cut.

I think I might have found a possible cause.

when I mounted the stepper motors i didnt understand the torque characteristics
of the stepper. In my wisdom I decided to gear down by means of toothed belts
by a ratio of about 1 to 3 - the smaller pulley being on the motor. In theory i thought
that the gearing would prevent overloading of the stepper.
But now it has been pointed out to me that the stepper is at its most powerful
at very low revs and there is a decided reduction in torgue as very speed increases.

Am I correct in assuming that if I reduce the gearing and bring it 1 to 1 that i will
be better utilizing the torque characteristic of the motor?
My steps per mm will be much less and the motor would then be running at lower
revs at which the motor is delivering its maximum torque?.
At low revs  is there any chance of overheating the motor?

Best regards and thank you

Fred Evans