>>> Igor Chudov wrote: >>> >>> Thanks to all for some clarifications that encouraged me to take some >>> ginger first steps towards this (read, bought a servo motor on ebay). >>> >>> Guys, do you think that this servo motor will "do" to motorize the >>> knee of my Bridgeport Interact: >>> >>> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390233108125 >>> >>> This is an "Italiano servomotori", with a 15:1 gearbox and a tach. I >>> think that it can give me about 7 ft-lbs of torque on its chain drive >>> at 200 RPM. That should be enough to move the knee with air assist. >>> With 1:1 transmission, it would amount to 40 IPM, probably a bit less >>> in real life. >>> >> Jon Elson wrote: >> >> Is this just a power elevator or a real servo axis? If servo, what will >> you use to measure >> W position? Probably not good to put an encoder on the motor, between >> the worm gear on the motor, >> the bevel gear in the knee and the Acme screw, the backlash will be large. >> >Igor Chudov wrote: > >Jon, good question. > >I think that the heavy knee will always sit tight on the acme screw. > >Other backlash may be at least repeatable. I will see. I am not >totally averse to just putting an encoder on the knee handle shaft. >
Igor, your Bridgeport is similar to John's Bridgeport IIa NC except his has the original Bridgeport II stepper motors (800 in-oz?). John's uses the knee for Z and runs with the quill locked, because it originally had Bridgeport's "Spindle Wizard" (trick quill-cycling thing), and John took that off. It still has a manual lever on the quill. We might add a "W" quill DRO to EMC2 at some point. John's has the 4J head (4 HP/3 KW). The motor to ballscrew ratio on X and Y is 2:1, and Z is 4:1. We can send you some photos and diagrams later. I'll be in touch off list. The point is that (unless you just want a "knee up/dn" switch) I believe you will have to get rid of that acme screw in order to have proper control of the knee axis, even with the factory air counterbalance. What John recommends is that you look for a BP2 with a ballscrew knee and motor drive (motor mount, at least) that someone is scrapping out. And if you can find one set, find two, as John's 2nd BP2 (on the list of things-to-do) has an acme knee screw as well. We'll look for two as well. All should bolt right in. Welcome to the BP2 club, and if you're in the Minneapolis area, John says plan on stopping by for a look at his. Kim ------------------------------------------------------------------------------ This SF.net Dev2Dev email is sponsored by: Show off your parallel programming skills. Enter the Intel(R) Threading Challenge 2010. http://p.sf.net/sfu/intel-thread-sfd _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
