[MBX5]

I ran into an issue the other day where the Z-axis of my machine "dropped" about 1/4" on its way down to the part - rapid move. It was a canned cycle drill, and it buried the drill into the material, ran the cycle, pulled up - but not all the way out of the part - and proceeded to move X to the next hole...which snapped off the drill bit and wrecked the part....

I thought it was an issue w/ my canned cycle G-code... I had seen this once before a few months ago but attributed it to a glitch because it never happened again... It had never happened during a milling cycle - until today...

I was moving down to my work, and it dropped during rapid again, this time plunged my 3/4" S-carb into a block of aluminum and proceeded to cut....luckily its a center-cutting end mill so it wasn't a total disaster, but the DOC was waaaaay more than called out....it damaged the end mill but I can still use it for roughing...

Anyone seen this before? I read a previous post about a possible loose resolver...I am going to check that....any other ideas?

My machine is a 1995 4020HT CNC88HS.

Thanks!

[MBX5]

Encoder is tight.....

Is it possible that the motor/ball screw connection could be slipping?

This happened again today....

[RalphWilson]

We have this machine , It's a Fadal right?

MAKE SURE you are using G43 for all your "H" value call outs.

M6T1
G43 H1 Z1.

The machine also gets hot in the panel, Clean your fan in the back, your Z card may be getting ready to fail.
I lost low range and was using .2 for high range for a long time before I got a new card.

Offset E30 and H90 are used for O9998 , and make sure no one changed HOME Z while you were away.

It's really good just to call the tech at fadal.

you could call G10 to check for Z height; until you find the issue.
and compare value of the Machine ABS Z against the value of the height of the top of your stock.
This would tell you if your going to crash the machine.
or if it still crashes.
Notice I said if your going to crash.

Then it's the card.

G10 has a "L" number and for the life of me I can't find it again.
please don't Quote me.

say the "L" letter is 13 , to my recollection or knowledge. :
( USAGE AS A SUB NOT GOING TO WRITE IT ALL YOU MUST ADD)
#R3=0
#R2=0
G10 L13 P0
#V1=R3
#IF H0 NE 0 THEN GOTO :CRASH
G10 L13 P1
#V2=R3
#R2=0
#IF V1 GT V2 THEN GOTO :CRASH
GOTO :START
#:CRASH
M0 ( YOUR GOING TO CRASH )
M5 M9
#:START
START

I CAN'T TELL IF THAT'S RIGHT
the fadal manual might get you started.
http://www.fadalcnc.com/Tech_files/U..._1_Summary.pdf

off to play poker on facebook.

[MBX5]

We have this machine , It's a Fadal right?

MAKE SURE you are using G43 for all your "H" value call outs.

M6T1
G43 H1 Z1.

The machine also gets hot in the panel, Clean your fan in the back, your Z card may be getting ready to fail.
I lost low range and was using .2 for high range for a long time before I got a new card.

Offset E30 and H90 are used for O9998 , and make sure no one changed HOME Z while you were away.

It's really good just to call the tech at fadal.

you could call G10 to check for Z height; until you find the issue.
and compare value of the Machine ABS Z against the value of the height of the top of your stock.
This would tell you if your going to crash the machine.
or if it still crashes.
Notice I said if your going to crash.

Then it's the card.

G10 has a "L" number and for the life of me I can't find it again.
please don't Quote me.

say the "L" letter is 13 , to my recollection or knowledge. :
( USAGE AS A SUB NOT GOING TO WRITE IT ALL YOU MUST ADD)
#R3=0
#R2=0
G10 L13 P0
#V1=R3
#IF H0 NE 0 THEN GOTO :CRASH
G10 L13 P1
#V2=R3
#R2=0
#IF V1 GT V2 THEN GOTO :CRASH
GOTO :START
#:CRASH
M0 ( YOUR GOING TO CRASH )
M5 M9
#:START
START

I CAN'T TELL IF THAT'S RIGHT
the fadal manual might get you started.
http://www.fadalcnc.com/Tech_files/U..._1_Summary.pdf

off to play poker on facebook.

Thank you for the info. I am beginning to think the problem is in my post, not with the machine....

One thing I found was that the issue I had originally thought existed in my Z dropping was actually the machine dog-legging some rapid moves based on my rapid selection in my CAM package, which caused the end mill to clip the part on some rapid moves....so I got that taken care of... Kind of a ***** for a noob like myself because the backplot did not show the machine doglegging obviously....

I will check my post to make sure G43 is incorporated into the H callouts - thanks again!

[David Ferguson]

Thank you for the info. I am beginning to think the problem is in my post, not with the machine....

One thing I found was that the issue I had originally thought existed in my Z dropping was actually the machine dog-legging some rapid moves based on my rapid selection in my CAM package, which caused the end mill to clip the part on some rapid moves....so I got that taken care of... Kind of a ***** for a noob like myself because the backplot did not show the machine doglegging obviously....

I will check my post to make sure G43 is incorporated into the H callouts - thanks again!

According to the manual G43 isn't required, all tool height offsets are done when the H word is used.

I first thought your problem sounded like a programming/post issue (ie, the R0 plane in a canned cycle wasn't specified correctly) -- but since you said this only happened sometimes, then I discarded this -- If Z motions are repeating when you run the program, then the control is likely doing "exactly what you said, and not at all what you want" -- this is a classic programming issue.

Perhaps your post isn't using the correct format for a canned cycled, why don't you look at the NC G code produced by your CAM program, and show us that line. Perhaps it's not using the correct form of "R0+Z.zzz" for the retract plane.

[RalphWilson]

According to the manual G43 isn't required, all tool height offsets are done when the H word is used.

I am using the "88" controler.

Although you are correct that it is not a requirement.

consider this :

this said " a error in user program, check the messages for details." .
.....
.....
G0 E2 X0Y0 S2000 M3 M8
H2 Z.1
G81 G98 X0Y0 Z-1.25 R0-.870 
X-1.
G80
.......
.......





this does not.

....
....
G0 E2 X0Y0 S2000 M3 M8
G43 H2 Z.1
G81 G98 X0Y0 Z-.5 R0+.1 
X-1.
G80
.....
.....

the drill cycle was "R0+.1"
i needed to put a clamp between the holes so I thought I could just raze the
Z up above the clamp and change the rapid to point to below the clamp.
using the R word.

this would also run and error out just after I drilled the holes, I was done with it so I just deleted it anyway.