Recent content by Doc

I've already decided to make the clips as big as I am able to. This was more of a parallel exercise to learn about the process of optimization, something I will likely be able to apply to other engineering tasks down the road. I thought that optimization may be a way to solve this as I wanted to...

The clip size has a limit due to a clear aperture requirement. I appreciate the thought here, but this has been covered in specification of the preload force which I have not covered here. Yes, but there is a clear aperture requirement meaning that the clips have a size limit. No, these...

The stress will decrease as either w or d, or both are made larger: that's correct. Three clips are equispaced around the glass, and the rounded part of the clips presses against the face of the glass. There's actually a second stress, that I left out on purpose, that needs to be minimised...

Hi all, (Please move to general or mechanical engineering sub-forum if more appropriate over there. I put this here as it is essentially a mathematics problem.) Broken into sections: - problem categorization (what type of problem I think I have), - the question, - specifics (description of the...

Yes the software does decompose the interferogram into Zernikes. Am I, in effect, taking signal out of my data by removing the tilt and consequently making noise more prominent? Yes! I have that very book on my desk and have been reading through it this week. Like you say I have found it...

Thanks that all makes sense. Unfortunately the mentor has left the country for work, I have his email but I just didn't want to pester him too much regarding stuff like this. Thanks again for the response!

Hi all, I'm a mechanical engineer who has been dumped into optical metrology at work without anybody much more knowledgeable than myself to help me out. A previous mentor who left recently (who was our optical expert) always told me when measuring wavefront error of optics to "tilt-out the...

I attached photographed hand-written calculations in post #1. I calculated the angular acceleration and converted to a tangential acceleration for a point on the edge of the mirror's major diameter. This calculation yielded about 200 g's.

What you say does sound reasonable. I've done the calculations on the amount of glue that I need and it seems reasonable given the large accelerations. Any insight on why there is a factor of ten difference between the calculations?

Hi kuruman, It will likely do both, whichever calculation yields the larger g-force is the value I will use to specify the glue amount. With respect to moving back and forth in linear motion with amplitude A (2mm) I get something like 1970g: I'm not sure that that seems reasonable?

Hi all, I need to bond the back surface of an elliptical mirror (75mm major diameter and 37.5mm minor diameter) onto a voice-coil actuated mirror mount that is going to be operating at 500 Hz and has an adjustment range of +-1.5 degrees. I need to determine the g-force likely to be acting on...

Can anybody comment on the apparent contradiction of my tolerances?

1. Without being able to adjust the pointing of the laser bracket, I would initially quantify the pointing error of the laser with respect to the package: this error would then need to be accounted for in the positional requirement which would of course flow down to the manufacturing tolerances...

I'm a very new engineer so I am more than happy to hear criticism on mechanical design if you're willing to give it. Thanks, Doc

Revised drawing attached. I'd like to check my understanding with the perpendicularity tolerance I've applied here: if the part is manufactured to a tolerated thickness of 20.1mm and the hole axis can deviate from the theoretically perfect orientation by 0.1mm, the maximum angular offset I can...