How to use G12 on Haas?

[rpeterson8735]

Hi there! I'm a student and teaching myself G-Code, but I can't seem to get this one to work. Help please?

So I am trying to write a series of circular pockets, but when I run my program it alarms out and says "invalid I J or K in G12 or G13".
I'm cutting this with a 0.1875" endmill.

Here is how it looks right now (this is just a segment, not the whole program):

G00 X0.74 Y-1.45
Z0.1
G01
G12 I0.15 K0.1563 Q0.005 F30.0 Z-0.25

Any help is appreciated, thank you!

-Rachel

[KenFoulks]

Do you want to rough the pocket first? If not, K and Q are not necessary. Try using a D value on the G12 line. D0 for centerline or D1 for tool 1 cutter comp. You can also try updating Q to .0063

[glovebox20]

Here's how I would do it.

T1 M6
G0 G54 G90 X0.74 Y-1.45 S#### M3
G43 H1 D1 Z1.5 M8

X0.74 Y-1.45
Z0.1
G12 I0.15 K0.1563 Q0.005 Z-0.25 F30.0
G0 Z1.5 (Important!! see note)

M09
(NEXT TOOL)

I Like to put the D## in the tool change sequence, but other people do not.

The tool will rapid to Z0.1 and feed to the Z value in the G12/G13 line at the same feed rate as the X/Y move.

Note: Just remember to lift the tool out of the hole before moving X/Y or you will snap the tool off and or gouge the part when it rapids to the next location.

You can also put the D value in the G12/G13 line like this:
G12 D1 I0.15 K0.1563 Q0.005 Z-.25 F30.0

Address order is not critical within the block but it best to practice a standard order to make reading/ modifying programs easier.

G12 or G13 automatically turns Cutter Comp on for that block and off again when its finish.
If you do not want Cutter Comp active, put D0 in the G12/G13 line.

If you are using Cutter Comp. your cutter radius must be SMALLER than the I value in that line or a "invalid I J or K in G12 or G13" or "cutter to big" may be given.

I agree with KenFoulks. You will probably want to predrill/rough the pocket out first before milling to size. It saves a lot of headaches in the long run, Although you can getaway with it pretty easy in soft material like plastics.

Good Luck

glovebox20

[Ydna]

The Haas mill manual has a good sample program for both roughing and finishing using G13/G12. In essence you can rough the pocket using multiple passes in incremental mode, then use a single non-roughing pass at the bottom depth for finishing.