Bridgeport DX-32 post processor drilling cycle problems

[russellmakes]

Machine is Bridgeport Torq-Cut 22 with DX-32 control.

Post processor is a modified version of the DX-32 post in the Fusion Library, and is attached. The previous mods mostly had to do with G9, and @a.laasW8M6T hooked me up with those mods here: https://forums.autodesk.com/t5/fusion-manufacture-forum/post-processor-g9-formatting-g9p-005/td-p/13...

Now I have found problems with the drilling cycles.

First problem: G83 (deep drilling) outputs only one peck depth.

In the output we get:

G0Z0.1
G83X0.Y0.Z5.1Z1.5F10.4
G80

From the machine manual:

"The format for the deep hole cycle is:

G83X_Y_Z_Z_Z_F_

Where Z_Z_Z_ is the total Z depth, the first peck increment, and subsequent peck increments."

So the output from the post is omitting the third Z value for the 'subsequent peck increments', causing the hole to be drilled in 1.5 in increments all the way down.

*Possible conflict: The pecking depth reduction setting can't be effective since the format listed in the manual allows for an initial peck increment, and then the increment for the rest of the pecks, not a series of smaller and smaller pecks.

Second problem: The feed height is set to 0.020" above the hole top, but the feed actually begins at the retract height with the output code I listed above. So if the counterbore is already done, it cuts air on its way to the hole top. This occurs on G81 (drilling - rapid out) as well. A workaround could be to set the retract height to 0.1" above the hole top instead of stock top in this case, but then if there are a series of holes, the linking moves are too low and would break the drill off in the countebore.

Any help is appreciated. Thank you!

*edited because I messed up the formatting.

[a.laasW8M6T · Accepted solution]

Hi

Ive added the subsequent peck to the cycle.

See video for context

[russellmakes]

Andrew! Coming through for me again! You're the man.

As for the second issue with the feed height:

I believe the yellow line here is representing rapid travel, but the way it ends up being written in the code is:

G0X0.Y0. <- rapid to XY location
Z0.2 <- rapid to clearance height
G0Z0.1 <- rapid to retract height
G83X0.Y0.Z5.1Z1.5Z0.1F10.4 <- (G83)Deep drilling cycle, XY location, (Z5.1)total Z depth from current position, (Z1.5) first peck depth, (Z0.1) subsequent peck depths, feedrate
G80 <- cancels drilling cycle
G0Z0.2 <- rapid to clearance plane

If I were to hand-edit the code to rapid down to the feed height (set to 0.020" above hole top), for this example I'd change the underlined:

G0X0.Y0.
Z0.2
G0Z-0.98
G83X0.Y0.Z4.02Z1.5Z0.1F10.4
G80
G0Z0.2

You got me to finally download VSC and I got the Fusion post extension installed and working. I'm still confused, so I'll have to study it a bit more. Thanks for showing me how to better solve these problems on my own as well. Much appreciated.

All that being said, switching from "false" to "true" is not a bad option either. It's an old machine and memory is sometimes an issue, but not usually for what I'm doing.

Cheers.

[a.laasW8M6T]

Hi

Sorry about the late reply

Normally drilling cycles have a G code that determines the behavior for the Retract plane(Feed height) and the initial position.

See this page for Fanuc:

https://www.helmancnc.com/fanuc-g83-peck-drilling-cycle/

G98 G99 Modes

After completing drilling depth the return is made with Rapid feed, the return height can be controlled through using G98 or G99.

G98 Drill will return to the Initial level
G99 Drill will return to R-plane.

Do you have the manual pages for your control for the G8X cycles?

[russellmakes]

Interesting. It looks like I found a limitation of the Z axis canned cycles on this control as there are no provisions for an "R" plane. Also, G98 isn't listed in the manual and G99 is for deceleration override.

I do have the manual. Here's what the page on Z axis canned cycles has to say:

"The command format for the basic Z-axis cycles is:

G81(82...)X_Y_Z_F_

G81(82...)A_Z_F_   (polar)

The Z-axis canned cycles generally comprise a sequence of the following operations:

Operation [1] Position X and Y axes

Operation [2] Feed down (-Z)

Operation [3] Operation at the hole bottom

Operation [4] Retract to initial Z position

NOTES

1. The Z depth for a canned cycle is input as an incremental unsigned value equal to the depth of the hole plus the clearance distance desired to the tool tip.

2. An X or Y coordinate word is required for the drill cycle to occur. This may be U0 if the hole is to be drilled in place.

3. Once a Z-axis canned cycle is input, it remains in effect until it is cancelled by a G0 or G80 code. In every data block that contains an X or Y word, the specified Z-axis cycle occurs.

4. To change the Z-axis depth, the entire Z-axis canned cycle format must be reentered with the new depth.

5. A rapid traverse Z move is not permitted within a fixed cycle. If required, the cycle must be terminated by a G0 move, then the cycle must be reinstated with the desired Z-axis canned cycle code."

Anyways, the peck cycle fix was my main issue. Thank you for the fix! For the feed height, I'll just have to keep in mind what I'm working with and either do the 'false' to 'true' change you recommended. Or set the retract height to the hole top instead of model or stock top while being sure there are no linking moves that cross over taller stock, and if there are, then perhaps I could do separate drill cycles for each hole to get the rapid plunge behavior I'm after.

Thanks again. Cheers.