multiple repetitive threading cycle

[nabil_elbadri]

hi gents
i need to understand very good the value P for G76 in the first line, as you know P letter contains 6 digits each 2 digits represent function, i need to understand the second digits which are responsible for the retract value , how to calculate this value , i tried to understand it from the lathe operator's manual but it didn't work in my head, so if any one could help me and explain in details and support the explanation with an example with dimension i will be really apreciate it.

controller is fanuc 21i TB & GE FANUC AlphaX
thnx in advance for any help

[chucker]

This file should help I can not take credit for wrighting it I downloaded it for somewhere may have been here

[nabil_elbadri]

thank u for ur reply chucker, the file u sent me explained the same way as the manual that i have, i didn't understand the part of explanation
(- second 2 digits is % of the lead or pullout exiting the thread- 00
00 = almost no angle at pullout and 99 = 9.9 leads away start out ),
if i have 4 mm lead and i want to pull out in 45 deg, and thread lenght is 50mm , how much valu i put in second 2 digits???
thank u for ur reply again , and i am waiting for an answer
rgs

[dcoupar]

Originally Posted by nabil_elbadri thank u for ur reply chucker, the file u sent me explained the same way as the manual that i have, i didn't understand the part of explanation (- second 2 digits is % of the lead or pullout exiting the thread- 00 00 = almost no angle at pullout and 99 = 9.9 leads away start out ), if i have 4 mm lead and i want to pull out in 45 deg, and thread lenght is 50mm , how much valu i put in second 2 digits??? thank u for ur reply again , and i am waiting for an answer rgs

I would put 00 if your thread ends in a thread relief groove or need to obtain maximum full thread up to a shoulder, and 10 if not. I don't think you can calculate an exact distance that will give you a 45 degree lead out. Does your part drawing call for exactly 45 degree lead out?

[sinha_nsit]

Ex.: P031560

03 = number of finishing passes (01 to 99 allowed)
15 = chamfer amount (00 to 99 allowed)
60 = angle of thread (80, 60, 55, 30, 29 or 0 can be selected)

Chamfer distance = chamfer amount / 10 * lead of thread
So, in this example, chamfer distance is 1.5 times lead.
The chamfer distance is the distance covered along Z-axis during angled retraction.
The angle is always 45 degree only, irrespective of chamfer distance.
If you do not want the end of the thread to get spoiled, use minimum 05 as chamfer amount.
Too large a value would skip last few threads (so, you would need to specify a larger thread length, in order to obtain the desired threaded length).

Sinha

Edit: I am not sure, but I concluded from an earlier discussion on this forum that if you specify a value smaller than 05, the control would use 05 only. Actually, smaller than 05 is not logically correct, unless there is a groove at the thread end.

[nabil_elbadri]

now i understand it very good
thank u very much sinha and thanks for all ppl who replied to me.
lets have some