[jimwjr89]

New to swiss machines. I have been working on a citizen a20. I was wondering if it is worthwhile to try and single point a thread 4.5" long. Also my max chucking on the machine is 6.5" for one chuck and my part length is 6.625 do you have to program differently to do a second chucking or just put in your part length in the machine data and it will do it automatically?

[MCImes]

Hi Jim,
To your thread question: in general, a 4.5" long thread will turn out poorly. I have done this 1 time though and it would work in a very specific situation. If you're trying to make a 1/4 thread on a 1/4 bar, you can get away with a long thread (or a 1/2 thread on a 1/2 bar ect.). I made a 3" long 1/4-20 thread for a friend. I had .2500 stock to begin with, threaded the bar first, then turned the OD down a few thou, then re threaded to knock off some burrs. It was not the prettiest thread and I wouldnt make parts like that for a customer, but as a 1 off job, it worked fine. You could maybe get an acceptable finish with some 2nd ops work, tumbling, or polishing.

As for the re-chuck question, see my response in this thread:
http://www.cnczone.com/forums/cnc-sw...45996-cnc.html

In general, the sequence goes like this:

Extend Z1 near max stroke
Z2 approaches (either with or without superimposition, your choice)
Z2 chucks on part
Z1 Chuck opens
Z1 gets more stock
Z1 Chuck closes
Z2 chuck opens

Everything except the superimposition and Z2 approach happens in $1.

Lastly, The number you enter in McData will generally be your maximum Z1 stroke, or close to maximum.
Let us know if that gets you closer.

[jimwjr89]

Thank you for your help. On the thread I was thinking of getting ground stock to the major diameter (.373) and threading it in a few sections at a time and coming in and supporting with the subspindle.

[MCImes]

Ah, yes. That is the other situation that works well; if the part doesnt have a shoulder that would interfere with the sub collet you could certainly segment it and support it with the sub.

[stizzit]

There is a process called turn-thread and it does exactly what you want. You'll turn then thread then then then thread etc. your turn length is usually your guide bush land length or less. The machine has an index point and can pickup where it left off threading. I haven't tried it but I have been told how to do it. Call citizen NJ they are super helpful and can send you the code.

[rcs60]

both of the above are good ways to thread. I have done both ways and had good results
i did a 10-32 x 1.875 long i used a 32 tpi crest forming insert and the last pass was just to clean to the major dia.
segmented threading or turn thread turn thread is as STIZZIT mentioned above i use win cnc from citizen and it creates the code for you threading using g32
I did find a macro written from another post i have not tried this one



G32 Segmenting custom macro

Here is actually the copy of my program. I belive it all makes sence and should work. Please if anyone can see any problems with it let me know. Thanks. Gary
citizen a20 funac equiped controller.......


%
O1234;
#229=4 (# OF SEGMENTS);
#209=.450 (SEGMENT LENGTH);
;
#228=1;
WHILE[#228 LT #229] D01;
#200=.050 (LEAD);
#201=.250 (MAJOR DIA);
#202=.034 (SINGLE DEPTH);
#205=.010 (1 ST PASS DEPTH);
#207=.0015(FIN PASS DEPTH);
#227=2 (# OF SPRING PASSES);
#216=10 (DECRESE % AMOUNT);
;
N1 (TURN 1ST SEGMENT LENGTH);
T500;
M03 S1=1000;
G00 X#201+.050 Z-.05 T05;
G50 S3000;
G96 S250;
G99;
G71 U.050 R.025;
G71 P110 Q120 U.020 W.005 F.008;
N110 G00 X#201-[#202*3];
G01 Z0.0 F.006;
X#201 Z[#202*3]/2;
Z#209;
N120 X#201+.050 ;
G70 P110 Q120;
G80;
G00X#201+.050 Z-.050 T0;
M09;
M05;
M01;
;
N2(THREAD SEGMENT);
T0400;
M03 S1=500;
G00 X#201+[#202*2] Z0.0 T04;
;
(MATH FOR LOOPING AND DECREASING VALUES);
#203=[#202+#202]*[29]TAN;
#204=[#202+#205]*[29]TAN;
#206=#205*[29]TAN;
#210=#202*[29]TAN;
#222=#202;
;
(APROACH POINT);
X#201+[#202*2];
W-#203+[#200*4];
;
(ROUGHING PASSES);
WHILE[#222 GT #207] D02;
#203=#203-#206;
G99;
G32 U-[#202+#205]*2 W#204 F#200;
Z[#209-[#210*2]]+#206;
U#202*2 W#210;
G00 Z-[#200*4]+#203;
;
(SUBTRACT PASS FROM SINGLE DEPTH FOR LOOPING);
#222=#222-#205
;
(CACULATE DEPTH OF CUT AND NEXT X,Z MOVES);
#215=[#216/100]*#205;
#205=#205-#215;
#206=#205*[29]TAN;
#204=[#202+#205]*[29]TAN;
END2;
;
(FINISH PASSES);
(CONSTANTS FOR FINISH CYCLES)
#231=#201;
#232=#202;
#235=#205;
#237=#207;
#230=1;
N100 G32 U-[#232+#207]*2 W#210+[#207*[29]TAN] F#200;
Z#209-#210;
U[#232+#207]*2 W#210+[#207*[29]TAN];
G00 Z-[#210+[#207*[29]TAN]+[#200*4];
#230=#230+1;
IF[#230 GT #227] GOTO200;
GOTO100;

N200 #228=#228+1;

IF[#228 GT #229]GOTO300;
G50 W-#209;
END1;

G50 W#209*#229;
N300 (END LAST SEGMENT);
GOO X#201+[#202*4] M09;
M05;
M30;
%

[rcs60]

the second question about re-chucking is is again from another post again i have not used this yet to see if it works


this Your code looks fine with 1 exception. You need something to hold the stock in place while the main collet is open. If you set your guide bushing tight enough to hold the stock in place, that may work, but I would consider that dangerous because if the bar hits a low spot and the GB is no longer tight enough to hold the stock, the bar feeder could push it out and you could whip the bar in the machine, crash the sub, or generally have length problems.

So, your code is fine, but just needs the sub to approach and chuck on the part before you open the main collet, then open it after the regrip or spindle sync it.

Here's what I would do.

M3 S1=2500
T200
G0 X[#530+0.025] Z0 T2
G1 X-.035 F.003
G0 Z-0.025
G0 X.510 Z0
G1 Z4.0 F.003
X[#530]
W0.025
G0 X[#530+0.025]
M5 (STOP MAIN SPINDLE)
G4 U.5 (DWELL)
G650 (superimpose z2 on z1)
!1!2 L650 (wait for sub to be in place)
M7 (OPEN MAIN COLLET)
G4 U.5 (DWELL)
G98 G1 W-2.0 F100.
G50 W2.00
M6 (CLOSE COLLEET)
G4 U.5 (DWELL)
M3S1=0M24S2=0 (turn spindles on at 0 rpm)
G114.1H1D-2 (Spindle sync at 0 rpm. NOTE if you have an R value on this line this WILL NOT work)
(alternately, you could just open the Sub (M16) and fire up the main spindle and not sync, but I think spindle sync from a stop is a cool trick, so I do it all the time and it works well)
G99 S1=2500
G0Z3.99 (.010 SHORT OF WHERE YOU LEFT OFF)
G1 X.510 F.003
Z5.822
X.620
Z.6.05
X[#530]
W0.025
G0 X[#530+0.025]

Then in $2:
G650 (Superimpose on)
M16 (Open sub. last part should already be ejected)
G0 Z-.3 (rapid to face)
G1 G98 Z2. F120. (feed on some amount. I chose 2" for no particular reason)
M15 (close collet)
!1!2L650 (sub is in place and ready for main to regrip)

Then right before cutoff, you'd probably want to move the sub up closer.
$1
!1!2L1000
!1!2L1001
(...cutoff)

$2
!1!2L1000
M16 (Open)
G1G98Z5.6 F120. (move up) (or z5.1 if you're using a .500" extended nose pickoff)
M15 (close)
!1!2L1001 (done)