Rigid Tapping Problems

[crazycnc]

Hi!
I'm trying to get rigid tapping to work on my Bridgeport Interact 412X. It has a Fanuc O-Mate M control. Here's my program straight from Bobcad:

%
O100 ( PROGRAM NUMBER )
( PROGRAM NAME: ADS THREADING.NC)
( POST: FANUC OM)
( DATE: THU. 06/05/2008 , TIME: 03:21PM)
( T1 DRILL , DIAMETER = .318 , LENGTH = 5.)
( T2 SPIRAL TAP , DIAMETER = .375 , LENGTH = 5.)
N01 G00 G90 G80 G20 G17
N02 G91 G28 Z0.
N03 G91 G28 X0. Y0.
(JOB 1 TAP RANDOM POINT PATTERN)
(TOOL #1 0.3180 DRILL)
N04 T1 M06
N05 S552 M03
N06 G90 G54 X2. Y.6875
N07 G43 Z.1 H1
N08 M08
N09 G81 G99 X2. Y.6875 Z-.5705 R.1 F1.6576
N10 Z.1
N11 G80
N12 M09
N13 G00 G91 G28 Z0.
(JOB 1 TAP RANDOM POINT PATTERN)
(TOOL #2 UNC 3/8-16 SPIRAL TAP)
N14 T2 M06
N15 S397 M03
N16 G90 G54 X2. Y.6875
N17 G43 Z.1 H2
N18 M08
N19 G90 M29 S397 ( RIGID TAP START )
N20 G84 G99 X2. Y.6875 Z-.625 R.1 F24.812
N21 G00 Z.1
N22 G94 M28 ( RIGID TAP END )
N23 G80
N24 M09
N25 M05
N26 G00 G91 G28 Z0.
N27 G91 G28 X0. Y0.
N28 M30

%

What's happening is that the hole drills OK, but then right at the start of the rigid tapping cycle, the spindle stops and the control gives me this message:

Operator Message No 2034
Spin Servo Rigid Tap Verify Alarm

If I hit reset now and then start again the program jumps right to the end without doing any tapping. Any help would be appreciated.

Thank-you, Lorne

[Excelmachine]

Are you sure that your machine is equipped with rigid tapping?
You can also refer this post to see if it answers your problem too. Rigid tapping help

[crazycnc]

I don't know for sure if my machine supports rigid tapping. I was trying to find that out. But why would I get the rigid tapping message if the machine wouldn't support it?

Lorne

[JDenyer232]

I don't know for sure if my machine supports rigid tapping. I was trying to find that out. But why would I get the rigid tapping message if the machine wouldn't support it?

Lorne

Sounds like the control is telling you that your spindle doesn't have an encoder, it's looking for the encoder signal and not seeing it. The control may support rigid tapping but if your spindle doesn't have an encoeder you can't rigid tap and you will get an alarm, rigid tapping is done by syncing the spindle with the z axis, thus your spindle must have and encoder for this to work. Hope this helps.

[crazycnc]

But how would the machine be able to orient the spindle for tool changes if it doesn't have an encoder?

[youngjim]

You're thinking about moving the spindle in the X & Y to line up on your ATC; an indexed/indexable spindle has an encoder to measure (or rather, quantify) the *rotation* of the spindle so it can interpolate its rotation with the Y movement into the workpiece. Does this help? Jim

[JDenyer232]

But how would the machine be able to orient the spindle for tool changes if it doesn't have an encoder?

The spindle has a crude one or two position encoder for orienting for a tool change, you need a high resolution encoder for the type of spindle control needed for rigid tapping.

[crazycnc]

Sorry about my ignorance, but what would keep me from writing out a tapping sequence manually if I match the spindle speed and the feed to the tap I'm using? Or is the spindle speed not accurate enough for this?

[JDenyer232]

Sorry about my ignorance, but what would keep me from writing out a tapping sequence manually if I match the spindle speed and the feed to the tap I'm using? Or is the spindle speed not accurate enough for this?

The spindle would not be accurate enough to prevent tap breakage, the high res encoder works together with the control to predict not only speed and feed but also other factors like acceleration and deceleration. You can use a floating tap holder and just call out a regular tapping cycle if your machine won't support rigid tapping. Rigid taping capability allows you to hold your taps with any type of rigid holder, ie collets etc. Floating tap holders are more expensive, thus the reason to use rigid tapping if your machine allows it. If it were me I would just use a floating tap holder, they give enough play so that you can machine tap without the use of a high resolution encoder.

[crazycnc]

OK thanks for all the info guys!

[timlkallam]

Dont 't expect bobcad or any cam program to spit out a canned cycle that will work with every machine without changing the post prosser .
Try this you must have a g80 after rigid tap you have a G0
move while still it rigid tapping mode this will cause an alarm.You should have to tap over the hole before staring the tapping cycle. This should work if you machie has ridgid tapping turned on.

G0 X2 Y.6875(TAP IS OVER HOLE)
M29 S397 ( RIGID TAP START )
G84 G98 Z-.625 F24.812
G80( rigid tap cancel)
N24 M09
N25 M05
N26 G00 G91 G28 Z0.
N27 G91 G28 X0. Y0.
N28 M30

[cnct56]

G99 G84.2 Z-15. R4. (S400 F500);