Need Help!- Citizen L20

[humbertocnc2007]

Hi to all gurus of swiss machine. Could somebody help me with a problem on L25 citizen V II?
This is the problem!!. I'm running a 17 mm stainlees steel annealed 17-4 PH and its broke a lot of tapping tools (VEGA xhp-mb 10-32 threat) ann I drill it with a # 19 (.166) carbide.This is the part of the program.
M23 $2=300
T3300
G0 Z-.05 T33
G84 Z.570 R.03 F.03125 S300R1
G80
B3 ( oil pressure )
G4 X2.
B3
G99
M25
T3000
M16
M99
So, any recomendation, am I ok on feeds and rpm's? There is a better tapping tool? Thanks a lot guys.

[UK-Engineer]

"G84 Z.570 R.03 F.03125 S300R1"

Normally when working on back spindle you'd need to add D2 (spindle 2) and a comma before the R1. E.g

G84 Z.570 R.03 F.03125 S300 D2, R1

However to the best of my knowledge "rigid" tapping G84 is not possible on this age of machine. Normally I'd use a sprung collet or sprung drill chuck and G32 cycle as follows

(G32 THREAD)
G44
G99
M23 S2=400
M118
T 3300
G0 Z-0.05
G32 Z.57 F0.03 T33 (95% of pitch on entry)
G32 Z-2.0 F.03125 M24 (100 % pitch while reversing)
G4 U1.0 (Dwell for spring)
G0 Z-0.05 T0
M119

Good luck

[humbertocnc2007]

Thanks UK - Engineer
I'm sorry, I made a mistake the machie is citizen L20. Is this part of the program will work for L20 machine? and do I need B3 for those curly chips? because those chips stick on the tapping, and this is the main problem to broke the tap.

[UK-Engineer]

G84...........D2 , R1 will work on your L20

Some other things to check maybe if you think that chips is causing the problem

1 - If coming from drill turn your HP coolant line on and leave for 2 -3 secs to wash chips out of hole before tapping

2 - Use either spiral flute tap to get chips out or a roll tap which forms thread generating no CHIPS - you'd need to change drill to effective size of thread. I assume your thread is 10/32 UNF so drill size would be 4.3 mm as opposed to 3.8

3 - Peck tap in two or three stages to help evacuate chips e.g

M23 S2=300
T3300
G0 Z-.05 T33
G84 Z.3 R.03 F.03125 S300 D2, R1
Z.45
Z.57
G80
G0 Z-0.05 T00

I think you should be OK now

Good luck

[humbertocnc2007]

Thanks a lot UK- Engineer
Is very helpful your recomendations, and I'm realy appreciate it.

[elsanch]

definitely try breaking up the full thread depth to 3 or 4 increments (.150-.160 each depth)..i think its just too deep a hole to one shot it...especially if it's a blind hole.

good luck

[PoiToi]

Along with the above, I'd also consider taking out the R.03 from the

G84 Z.570 R.03 F.03125 S300R1

line of code, or starting much farther back. With that code, you are starting the tapping only .020" from the front of the part. I always like to give it twice the thread lead, to make sure the slide and spindles are caught up.

hope all this helps!!

[MikeMc]

I strongly agree that roll form taps are the best way to go. I am not sure about the tap designation, but if it is a spiral point plug tap then your problem is the HP cooling. The tap is designed to push the chips forwards, and the HP cooling keeps pushing them back into the tap.