Originally Posted by
peteeng
Hi Mactec - I agree that VSR can crack structures. Tabs and small cantilevered areas can freely vibrate and over deflect and crack in my experience too, even with thick structures. That's one reason a modal analysis is first done to establish if there are areas of concern. With the mining equipment VSR small pieces are tacked or clamped onto ram mounts and areas of concern or experience to stop them from getting over excited at resonance.
All processes require a good understanding of how it works & its pitfalls. Horses for courses... As a note - we are not really concerned about the internal stress of a structure this is in equilibrium and will not affect the performance of a machine,. We are really concerned about making a correctly dimensioned machine. So the TSR or VSR or peening or whatever is used is a step along the way that allows the maker to get to a satisfactory dimensional result. As you have said you can fabricate stuff and hit the required dimensional spec. This can be done in a repeat environment as the people learn along the way how to get a result., The hobby maker has one shot at it so they only learn about this stuff once and correct it once... Hopefully the forum stores & transmits some useful knowledge to short circuit some grief... Peter