Witek GB wrote: > I am thinking of taking the plunge and buying a VMC maybe with an ATC. > I plan on buying it for the iron and upgrading it to EMC. I have manual > machine tools already so I know what to look for when I see a manual > machine, but with CNC I really do not know much. What should I look > for? Are there any resources on the Internet that show you what to look > for when buying a used cnc? How can I determine if the ball screws are > good or bad? Servos?... I will use this machine for hobby work and > maybe some light production runs. Any help is appreciated Servo motors are pretty tough. Really old encoders had light bulbs in them. They can be retrofitted with infrared LEDs. Many older machines had resolvers instead of encoders. (I'm working on a lower-cost retrofit for those, but it may still be cheaper to install US Digital encoders where they will fit.)
Ball screws are fairly hard to evaluate in the field. You can put a dial indicator on the table and see how far you can turn the screw by hand to check backlash. The general condition of the machine can be a useful guide. If every nook and cranny is stuffed with chips, and layers of brown sludge coats everything, you know the machine was run hard in heavy production. That will take its toll. As for the ATC, the simpler it is, the easier it will be to get EMC to control it. If it is a massively complicated hydraulic monster with several changer arms, lots of position sensors, etc. then it will be more complicated. Ray Henry did manage to get the Mazak working at Roland's shop. That is a pretty complex ATC. Remember that the tooling is a major expense on these machines, a rack of NMTB 40 holders and collets is worth a LOT more than most older machines. Jon ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
