Hello,
I am having two problems with cutting a Buttress thread lathe tool out of a 3/8”x3/8”x3” HSS tool blank on a Mitsubishi FA-S wire machine using the 4th axis. The front and side relief angles are 7 degrees each and I am shooting for about five and a half threads per inch.
3 axis cutting works great for me on the Mitsubishi, but when I try to do a 4th axis taper cut, I have two odd problems that have stumped me:
(1) The actual cut lengths on the top and bottom of the tool stock are magnified about 2.5 times longer than in the CADCAM model (that I have triple checked/simulates properly).
(2) I ran 6 cuts on a couple HSS blanks and had a wire breakage each time.
I have experimented with reducing the feed rate (base feed set to 0.05 down to the greatest reduction allowed by the monitor slider). Also I experimented with epack varied from 951 to 1250 with the same results.) Wire alignment test showed good to one tenth and I am getting no U/V axis errors.
Z-taper parameters:
Z1 – Program Dimensions Held at top cut profile = 0.714": (Top of tool blank stock above the table)
Z2 – Level where feed rate is monitored = 0.357”
Z3 – Table to top diamond pivot = 1.224”
Z4 – Table down to lower diamond pivot = 0.100”
Upper Profile Cut level in the CAM package = 1.224”
Lower Profile Cut level in the CAM package = -0.814"
A top view thumb with a 0.010" grid is attached.
A clue from during cutting is that at certain times during every run, the arc audibly stops and starts intermittently instead of running continuously. Also I have noticed the XY and UV positions backing off and retrying multiple times. The stock is rigidly mounted and not moving and in each case the cut never got close to the end where a cutoff section could become loose and impair the wire movement.
This is my first attempt at doing a taper cut with the Mitsubishi and it is very likely that I am missing something in the setup due to inexperience.
Any thoughts or suggestions as to what I could be doing wrong or other things to try would be greatly appreciated!
Thank You!
Best regards,
Bruce
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GCODE
%BTTEST3;
N10M80;
N15M82;
N20M84;
N25G90G92X-0.1Y0.;
N30G01X0.0008Y-0.0004U0.V0.;
N35Y0.0196;
N40X-0.1171Y-0.0982U0.2482V0.2482;
N45X-0.1513Y-0.1325U0.3203V0.3203;
N50X-0.1057U0.3132;
N55Y-0.0004V0.;
N60X0.2043Y-0.2104;
N65X0.6Y-0.21U0.;
N70M83;
N75M85;
N80M81;
N85M30;
%
Starting XY for both top and bottom cuts (-0.100, 0)
Ending XY for both top and bottom cuts (0.600,-0.210)
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