Kirk Wallace wrote: > I did my first rigid tap on my lathe. It worked well the first time. > (Thank you, developers) There is one minor problem. There seems to be a > burr left behind about 1.3mm (.050") into the 4-40UNC hole. I shifted Z > in my g-code to see if it would move , and it didn't, so I think it is > independent of EMC2. I have to run a tap through by hand to clear it, so > I suppose if I run g33.1 twice, that should fix it. I would rather not > do that, so has anyone had this problem and fixed it? Thanks. >
I just did some tests with G33.1 at the CNC Workshop. The key seems to be running the trajectory planner at the servo rate. In my univpwm_load.hal file, it has a line at the top : loadrt [EMCMOT]EMCMOT base_period_nsec=[EMCMOT]BASE_PERIOD servo_period_nsec=[EMCMOT]SERVO_PERIOD traj_period_nsec=[EMCMOT]TRAJ_PERIOD key=[EMCMOT]SHMEM_KEY and I changed that to have traj period set to the SERVO_PERIOD parameter : traj_period_nsec=[EMCMOT]SERVO_PERIOD and it made a huge improvement in the thread quality. I think Chris Radek or Jeff Eppler found this to work on Roland's Mazak. They also turned the servo rate up to 2 KHz, but I didn't find that to be needed on my mili-mill. I am not clear as to what is going on here, but I think the filtering for the axis following the spindle was too sluggish to settle, and also had a lag behind the rotation. This lag would be in opposite directions when the spindle reverses, so it affects a rigid tapping operation, but not a single-point threading one. I had a very similar mauling of 4-40 threads I was putting into 1/8" aluminum sheet with the minimill. It wasn't a burr, just a ripping out of the first thread, or a severe narrowing of the thread. The change to the traj_period fixed it as far as I can see! Jon ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
