The speed and feed for cutting the large mirror has been an item of concern for me. I suspect that a constant rpm is being used and this is contributing to the surface roughness. We are doing more analysis on the last 4 produced to see if there is a better/worst zone to the surface condition...
I don't know about the tool stick-out, my thoughts are the more its extended the greater the likelyhood for vibration. The haze occurs when the system (assembled unit) is imaged, I believe it is "general" in nature.
Set-up is critical for sure, the mirror has potential for some vibration due to the mounting design which has characteristics to eliminate localize stress at the mounting holes (pulling distortion on the mirror's face). We are using adhesives and packing to dampen any vibration. What speed...
You are both correct in suggesting polishing to improve the quality. However my goal is to get to the "30-80 angstrom" range by machining, we're currently measuring between 130-320. I'm chasing 2 parallel paths, material and machining both of which I believe are contributing to these results...
unclesyd - thank you for clarifying the "tooling plate" material, I had in my head something like ALCA Plus tooling plate which is a cast aluminum. I've sent a RFQ to TCI for a chunk of round stock. I neglected to mention the earlier concoction was used to bore steel and tool steel with a s.p...
sreid - I'm not sure about the term "figure"? The mirror is parabolic. The requirements I'm trying to meet are specified as "surface irregularity <0.7 Lambda" (this relates to control of the form)and "surface roughness <10nm RMS" (this relates to control of the surface finish) The later is the...
unclesyd - thanks for the reply. I reviewed each of the links you supplied earlier and on this 12" mirror 30-80 angstroms would be acceptable even without the post machining polishing. I need to make every effort to improve the machining process before I can justify an additional process. I was...
We haven't used cast because of the before mentioned concerns, only 6061 T6 has been used. The thought was that alloy aluminum would provide the best surface form and finish ... is this correct? We measure surface irregularity by Lambda (wave front error).
Thank you for the quick replies! My understanding of the cast materials was that they would have an undesirable porous finish and is also susceptible to inconsistant surface quality. I'll check out all the suggestions provided ... thanks again.
- more info - Yes we use a single point for D.T...
I have an aluminum mirror that has very high surface irregularity and roughness requirements which is being diamond turned. We are trying to determine if there is an aluminum available in an 11" or 12" stock diameter that could be substituded for 6061 T6 (our current mat'l of choice) to improve...
Unclesyd - Hey another good lead!! I'm glad I started my thread here because of the excellent tips I've received. I have a call into Micro Care to investigate possible cleaning improvements. I think that finding a suitable cleaning solution will help us in our process control. Thanks again
Timelord - Yes I checked out the link and fortunately they open at 6am so I was able to phone them this morning! They sound good, I wasn't aware of the fact that they don't manufacture their own bearing.
I am stuck with the bearing size ... no options there. They said it was not a real popular...
GBor - Got ya ... both done, thanks
Unclesyd - I checked out the C-Flex bearings, I'd never heard/used them before. They look interesting and I'll keep them in mind for other applications, however the bore diameter on this project has a small assembly mounted inside it. I should say now that...
Unclesyd and Timelord,
Thanks for the great tips, I'll follow these up this morning.
Timelord you are absolutely on the money with your gimble project, it directly compares with this application. I considered and investigated hybrid bearings just as you've described but found both suppliers...
You are correct and I have been working with 2 bearing suppliers/manufacturers to see if they can benchmark the torque requirement I need ... so far no go. Its difficult to image how sensitive the application truly is, my initial response when I first became involve was "You're joking ...
Hey Magical would be good but likely equally difficult to source!
I'm not sure that magnetic bearings will work. In short the bearing goes in a sub-assembly that is essentially a mini magnetic motor. The design and assembled unit are in production and have been previously optimized to the limits...
I am tasked with resolving a bearing requirement in a low torque assembly, bearing size is 1634 (1" o.d.x .75 bore dia.). It is a thin section ball bearing .156" (4mm) thick. There is very little loading on the bearing. The assembly osilates rapidly around 7-8 Hz however preliminary assessment...
