On Wednesday 02 December 2009, stus...@gmail.com wrote: > Tramming the spindle will tell you how perpendicular the spindle > centerline is to that particular spot on the table surface. It will not > tell you the perpendicularity of the spindle centerline (or the Z axis) to > the XY plane. The actual level of the machine is almost irrelevent. If all > the machine components are fixed at the same level values and the machine > is straight and square you will be able to machine straight and square. > Sent via BlackBerry from T-Mobile > >-----Original Message----- >From: "Florian Rist" <fr...@fs.tum.de> >Date: Wed, 02 Dec 2009 17:04:26 >To: Andy Pugh<a...@andypugh.fsnet.co.uk>; Enhanced Machine Controller > \EEMC\"<emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] How to > Correct Angular Axes Misaligment in Software? > >Hi Andy > >> I think that truing up the axes can be seen as part of the >> installation and commissioning procedure. > >Well, it should be, but in this case the machine was delivered and used >productively right away without any in-depth testing and up to now the >errors were not noticed because the mill is usually used by students to >mill simple parts for architectural model making. > >> Does the machine have a twin-drive X axis? > >No, it´s a single steeper motor on the y axis and it´s rotation is >transmitted to the two y axis lead screw by a tooth belt. > >> It sounds like it is possible that the drives are out of synch, ... >> >> If the drives are linked by a belt, then it might simply be a case of >> releasing some shaft clamps and running the axis up and down my hand, >> re-tightening and re-checking. > >I tried that, unfortunately I can only move one side by about 1 mm (about >3 mm would be required).
Sounds like its belt removal time so you can slip it a tooth or 4 on just one shaft. Or would that much actually cause a bind in the carriage? >> Z-axis alignment might also turn out to be relatively easy. A dial >> indicator mounted on the spindle such that it describes a circle on >> the machine table will give a very good measure of squareness, and >> will also indicate how your adjustments are working. > >That´s how I measured the misalignment. I also have a coordinate >measuring arm at hand; it might be useful when I deice to take apart >larger parts of the machine to cure all misalignments. > >> It is not uncommon to find jacking screws built into the >> linear rail mounting arrangement, for example (but this might >> not be relevant to your machine) > >I don´t´ see any, unfortunately. > >> Given the machine type and the reported problem, I would be >> concerned that the axes are twisted and "fighting" each other. > >It looks like the table is deformed from rectangular to a >parallelogramlike shape. The table is just a bolted aluminum construction >and it´s lacking a diagonal element to stabilize the rectangular shape. Good Grief. OTOH, TSC et all sells all-thread & pump rod couplings in case the all thread isn't long enough. How about loosening the assembly bolts and pulling it into square with a long 'pony' clamp on a suitable length of pipe, then re-tighten the assembly bolts? Or even make an x brace from 3/4" square steel tubing. Pull it square with the pony clamp, then clamp the x brace in place under the table, drill and bolt in permanently. Super glue before you drill to prevent slippage. And is there room under the frame to install the x bracing all-thread permanently? No use doing the corrections every week. :( And since its students, I think once the x bracing was verified square, I'd super glue the all-threads adjusting nuts if its left in place. In any group of 'students' there will always be one that thinks its funny to subtly screw something up. [...] -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The NRA is offering FREE Associate memberships to anyone who wants them. <https://www.nrahq.org/nrabonus/accept-membership.asp> senility, n.: The state of mind of elderly persons with whom one happens to disagree. ------------------------------------------------------------------------------ Join us December 9, 2009 for the Red Hat Virtual Experience, a free event focused on virtualization and cloud computing. Attend in-depth sessions from your desk. Your couch. Anywhere. http://p.sf.net/sfu/redhat-sfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
