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| Posted on 6/17/08 at 01:01 PM | |
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I've worked with them both. It depends upon where in the stroke of an air indexed machine you try to stop it. Electric drive servos do not have a high power rating. They have a lot or torque because they are generally geared, pullied or belted in a ratio other than 1:1. Its not that they have that much more final power than air...but they get up to speed quicker. The danger from servos is because they are up to speed through a longer portion of the total stroke with all of that mass of the ring and the palletes. With either drive its the mass and final speed that gets you. If you already have resistance on a servo driven press arm when the servo starts...you can greatly slow it down if not stop it altogether. On an air drive, since the cylinder will be at the top of the stroke with very little air volume yet operating against the small area of the piston....if you grip an arm...you can pretty much keep it from moving. But...once that air cylinder is further into its stroke and accelerating....it is moving the same mass at the same ultimate speed.....and it will snap bones to the same extent as a servo. But yes....it is much harder to stop a servo driven machine. Its quick. In the end, thats not the kind of distinction I want anyone to know. I want them out of the machine if its not safed...with either drive type. ray | ||
 
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