On Fri, 2010-03-05 at 13:23 +0000, Andy Pugh wrote: ... snip > I am unsatisfied with the results of my attempts at gear-milling. I > think this stems partly from me not knowing which of the three cutters > I have is for what tooth count, or what the addendum and dedendum is > meant to be for each cutter. > I have decided that as a set of milling cutters comprises about 6 > cutters at £10-£20 each, a hobbing cutter which will make any size of > gear seems like a good plan.
I haven't cut any gears yet, but my plan is to use the rack form gear cutter to cut all gear sizes for a particular pitch. https://www.travers.com/Default.asp (Click on Keyword Search box, click Guest, search for "involute", their search and descriptions are pretty weak) or http://www1.mscdirect.com/cgi/nnsrhm (search "involute", or "invoute 14-1/2" for 14 1/2 degree pressure angle) (Other links welcomed, Number 1 cutters seem to be the rack form) The hobbing motion can be replicated, except you only cut one section of tooth width, one tooth at a time (actually the slot between two teeth). The gear blank is mounted to a rotary axis. The gear cutter is mounted in the spindle. The coordinated motion of the rotary and cross feed will mimic the motion of a rack tooth engaging the gear as it rotates for the entry an exit of one tooth slot. The process would need to be repeated to cut the width of the gear, then repeated for each slot. The problems with trying to replicate hobbing with CNC rotary axes are, the rotary encoders would need to be very high resolution, feedback and command control very tight, and data throughput high enough to keep up. I think it has been stated before that current systems aren't up to the task. I think it would be great to have someone try, but I think the odds are against any success. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
