right but accel will still only be 1 g where as larges servo systems and smalll precision high speed machines are capable of several g's . accel is pretty important to a plasma table. one thing i like about the idea of a pantograph style is the lack of mass in the supporting structure . obviously the high accel machines im speaking of are not the ones we are typically building and it does look like this accel would not be a limiting factor in this machine
On Sat, Mar 30, 2013 at 3:52 PM, cogoman <[email protected]> wrote: > On 03/26/2013 01:21 AM, Gregg Eshelman wrote: > >> I am not sure you will see good acceleration. In fact, it is > >> >always > >> >going to be less than 1g. This is because for any faster > >> >acceleration > >> >the strings go slack as the weighs don't fall fast enough. > > No need to go anywhere near that fast because an oxy-acetylene torch or > plasma cutter can't cut that fast. This rig is most often used for cutting > steel 3/4" thick or thicker. > Since counter weights are often used on Z axes on servo machines, I > once decided to calculate how much of a limit the acceleration due to > gravity would be. The metric calculations are left for you folks across > the pond. > > Acceleration due to gravity = 16 feet/second/second > > After 1 second the velocity can be 16 feet per second > > times 60 = 960 feet per minute (I love spreadsheets!) > > times 12 = 11520 inches per minute > > divide that by two, so half of that force can be applied to your cable = > 5760 inches per minute > > HERE'S WHERE I AM MAKING ASSUMPTIONS THAT MAY BE OFF BY A LITTLE. > > If I recall properly 1500 inches per minute is a FAST servo system. > > 1500/5760 = .26 ( assuming linear acceleration it should only take .26 > seconds to reach 1500 IPM) > > 1500/60 = 25 inches per second > > at 25 inches per second that servo system would travel 6.5 inches at > full speed while the gravity system would be accelerating to 1500 IPM. > Of course the servo system wouldn't be able to accelerate > instantaneously, so the counter weight would only slow a 1500 IPM servo > system down a little bit. > > I thought gravity would be much more of a limit too. > > > ------------------------------------------------------------------------------ > Own the Future-Intel(R) Level Up Game Demo Contest 2013 > Rise to greatness in Intel's independent game demo contest. Compete > for recognition, cash, and the chance to get your game on Steam. > $5K grand prize plus 10 genre and skill prizes. Submit your demo > by 6/6/13. http://altfarm.mediaplex.com/ad/ck/12124-176961-30367-2 > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- jeremy youngs ------------------------------------------------------------------------------ Own the Future-Intel(R) Level Up Game Demo Contest 2013 Rise to greatness in Intel's independent game demo contest. Compete for recognition, cash, and the chance to get your game on Steam. $5K grand prize plus 10 genre and skill prizes. Submit your demo by 6/6/13. http://altfarm.mediaplex.com/ad/ck/12124-176961-30367-2 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
