Originally Posted by
nash
Guess I was too thrilled to begin with, after finding the heat treatment shop. They want Euro 1800, that is over US$ 2300.
While awaiting another response from another place, if that too turns out to be this high, I'm going back to the drawing board and redesigning the YAG-M with epoxy and hex-screws.
Another quick question: If I drive the gantry with two servo's and two screws, how difficult will it be to maintain synchronization between the two? All those with two screw's driving the gantry, please own-up and speak-up, now is the time...
Nash, the best way isn't always the cheapest.. thats for sure.. but then.. thats why its the best way
My system of screws and epoxy has worked great, I haven't put the epoxy in yet but the rest of it worked w/out a hitch. The epoxy can be expensive so just be prepared.. I've bought $320 of the stuff and thats just enough for one rail on my machine. There is a cost to making 'subplates' for the rails to mount to as well so look at the whole picture before making a decision.
Typcially w/ long machines of a gantry style. You drive either end of the gantry [usually w/ two motors, but it can be made to work w/ one depending on the size of your machine etc..], this can be done w/ most Machine control software sets [ Mach3 for example has a 'slave' function which makes both motors move together] You'll find that the longer the axis travel length the higher the cost is going to be, ie. a ballscrew that is 10' long is going to be VERY VERY expensive. You'll have to spec it for resistance to whip more than linear movement/control. If you are going this long I would sugest you check out a rack and pinion type system over a ball screw, they may not be as accurate initially but the variances can be tuned out of the system once its up and running by adjusting it and controling it in the machine control software. [ You teach it where its out and then in the future it will adjust at those locations by taking into consideration the error's in the rack]
You'll find that everything in machine design [well any type of design] is always, ALWAYS a compromise, and usually one side of that equation is cost vs ___??
Hope that helps..
Jerry [I recommend you take this part of your design process very slowly and methodically, you'll be glad you did once you get to the build process ]
JerryFlyGuy
The more I know... the more I realize I don't
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)