Invert Axis For Opposite Hand Parts

More
26 Aug 2016 15:13 #79500 by fc60
Greetings,

Many years ago (early 1980"s) when I did my time on the CNC machines, most of the machines had a switch to "Invert" an axis for an opposite hand part, very common in the aerospace business.

Is there such a feature within LinuxCNC?

Cheers,

Dave

Please Log in or Create an account to join the conversation.

More
26 Aug 2016 16:09 #79503 by Todd Zuercher
No, I don't believe there is any dedicated way to do this (simple G-code). But I think there could be ways you could work around the limitation to get something that might work for what you intend.

IMHO
In this age of CAD/CAM generated code, this sort of feature has become rather obsolete. (Usually easier and safer just to regenerate the code.)

Please Log in or Create an account to join the conversation.

More
26 Aug 2016 17:22 - 26 Aug 2016 17:23 #79505 by Todd Zuercher
Such as this, if you're a little creative with your G-code you can make a file that can be fipped simply by changing a parameter value like this.
#1 = -1 (Set #1 = -1 to mirror 1 for normal)
#2 = 0.0 (offset for X mirror axis)
#3 = 3
o100 if [#1 EQ -1]
 #3 = 2
o100 endif

(1/4" End Mill)

G0 X[#1*4.244+#2] Y5.0743
S17300
G0 Z1.
G1 Z0.75F100

G1 X[#1*3.8212+#2] Y4.8068 Z0.F200
G1 X[#1*0.8875+#2] Y3.091
G[#3] X[#1*0.8256+#2] Y2.9831 I[#1*0.0631] J-0.1079
G1 Y0.9725
G[#3] X[#1*0.9506+#2] Y0.8475 I[#1*0.125] J0.
G1 X[#1*6.818+#2]
G[#3] X[#1*6.943+#2] Y0.9725 I[#1*0.] J0.125
G1 Y6.4148
G[#3] X[#1*6.8802+#2] Y6.5232 I[#1*-0.125] J0.
G[#3] X[#1*6.7549+#2] Y6.5227 I[#1*-0.0622] J-0.1084
G1 X[#1*3.8212+#2] Y4.8068
G1 X[#1*3.7348+#2] Y4.7563
G1 X[#1*3.2944+#2] Y4.519 Z0.75
G0 Z1.
%
Last edit: 26 Aug 2016 17:23 by Todd Zuercher.
The following user(s) said Thank You: tommylight

Please Log in or Create an account to join the conversation.

More
26 Aug 2016 19:39 #79506 by eFalegname
Flipping parts is a very normal daily procedure in cabinetmaking, it's a shame that Linuxcnc lacks this feature.

Please Log in or Create an account to join the conversation.

More
27 Aug 2016 01:56 #79528 by Todd Zuercher
The problem with running code flipped is that it also reverses the milling direction. That can be a big problem with wood, where climb milling might be required to prevent corners from chipping.

Please Log in or Create an account to join the conversation.

More
27 Aug 2016 15:12 #79557 by fc60
Greetings,

Forgot to mention, Boeing had a large assortment of Left Hand cutters. So inverting the axis for the opposite hand part just meant using a left hand cutter and editing the M3 to M4.

Cheers,

Dave

Please Log in or Create an account to join the conversation.

More
27 Aug 2016 19:19 #79564 by Todd Zuercher
I forgot to mention the above code modification was done to a regular g-code file in 3 find and replace steps using Notepad++ (using regex replace commands). first step modified the X commands to multiply them by #1 and add the offset, 2nd was to multiply the I commands by #1, and 3rd was to make the G2 words variable. It could easily also be done on the fly while opening the file with a script.

I still think it is more trouble than it's worth. We have 7 or 8 machines that do have the capability, to run a mirrored files, and in over 15 years we have never once tried to use it.

Please Log in or Create an account to join the conversation.

More
28 Aug 2016 20:34 #79612 by cmorley
I could really use an inverted axis option on my lathe... it has a tool turret on both sides of the center line.
i would use it everytime the lathe was used.

Chris M

Please Log in or Create an account to join the conversation.

More
28 Aug 2016 21:15 #79616 by Todd Zuercher
I would think that something useful could possibly be done with some careful Hal trickery and some custom M-codes, But I'd have to think about it a while to iron out the details. I wonder if the problem has already been solved by someone. Some time searching the archives may prove fruitful.

Please Log in or Create an account to join the conversation.

More
28 Aug 2016 21:50 #79620 by tommylight
Just thinking out loud here,
What if .......a pyvcp button with the added python script that would get the values from gcode ( outer most values ), invert them adding "-" and then offseting all that for the values it got from gcode, so everything falls in place ????
I wonder...... but i do not have the time nor did i do actual programming in a long while.

Please Log in or Create an account to join the conversation.

Time to create page: 0.191 seconds
Powered by Kunena Forum