[To...] Posted September 18, 2019 Share Posted September 18, 2019 Any thoughts on the attached drawing? Is this possible with Contura Aktiv? Or, any CMM? Sorry for the poor quality image. Link to comment Share on other sites More sharing options...
[Ch...] Posted September 18, 2019 Share Posted September 18, 2019 Is this waviness on a plane? Link to comment Share on other sites More sharing options...
[Ri...] Posted September 18, 2019 Share Posted September 18, 2019 Can you afford a Rotos? Link to comment Share on other sites More sharing options...
[To...] Posted September 18, 2019 Author Share Posted September 18, 2019 Please sign in to view this quote. Customer probably can but probably won't. Are you saying this has to be done with a different piece of equipment? Link to comment Share on other sites More sharing options...
[To...] Posted September 18, 2019 Author Share Posted September 18, 2019 Please sign in to view this quote. OD Link to comment Share on other sites More sharing options...
[Ch...] Posted September 18, 2019 Share Posted September 18, 2019 Waviness on a plane with a CMM I wouldn't touch with a 10 foot pole. With enough work and information you can get an OK waviness on an OD shaft; However, IMO you will need something with a known waviness to confirm your measurement strategy/parameters. I spent a lot of time trying to do waviness on a CMM a couple years ago. The moral of our story is that we ended up spending the money of a proper waviness analyzer and do not report any waviness measurements from the CMM. Link to comment Share on other sites More sharing options...
[Br...] Posted September 18, 2019 Share Posted September 18, 2019 Typically this is a job for a profilometer. It's a type of surface texture that has more of the high frequency wavelengths filtered out compared to roughness which has the low frequency wavelengths filtered out. But why do you think this is a waviness requirement? Those symbols don't mention any waviness parameters. I'm confused about what they want here? Typically where you see the "8", if a number is placed here, that indicates the Ra value.(this was changed in the 2018 standard. now everything goes inside the symbol where this has a note placed.) Then you put notes on top, and any other parameter such as Rz or Wt(waviness), would be placed inside the symbol. 8 seems like a really big number. maybe that's supposed to be the cutoff? IDK hopefully you got some clarification. Even if you did try and scan the surface with some tiny stylus, you would still have to calculate the data based on the parameter stated. Maybe you could do this with PCM but I don't really know how you could achieve this. edit: Ok I found a really old version of ANSI B46.1-1978 that states waviness can be placed on top of the tail there. Link to comment Share on other sites More sharing options...
[To...] Posted September 18, 2019 Author Share Posted September 18, 2019 Please sign in to view this quote. Brett, with my limited expertise, I've always considered waviness to fall into the mid-band wavelengths which exposes problems with equipment, i.e. harmonic vibrations from cutters, defects with machine ball screws, etc. I have only seen waviness called out 2 or 3 times in my 40 years of mfg. experience, so if anyone has something to add, I'm all ears. Link to comment Share on other sites More sharing options...
[Br...] Posted September 18, 2019 Share Posted September 18, 2019 Please sign in to view this quote. I would agree with that. It's basically somewhere in between form and roughness. But I've never heard of anyone trying to do that with a CMM. Your CMM's uncertainty is probably not good enough to merit this type of evaluation. You have a Wt of .00003". That 8 Ra is going to have to be inspected with some type of profilometer anyway. Link to comment Share on other sites More sharing options...
[Ch...] Posted September 18, 2019 Share Posted September 18, 2019 The way it was explained to me is to think of waviness and roughness like grassy hills. The grass is the roughness and the hills are the waviness. Link to comment Share on other sites More sharing options...
[To...] Posted September 18, 2019 Author Share Posted September 18, 2019 Thanks to all Link to comment Share on other sites More sharing options...
[Kl...] Posted September 19, 2019 Share Posted September 19, 2019 Evaluate waviness by CMMs is possible starting at UMESS UX. It was first used for crank shaft bearings and later gear shafts. The function is/was qualified by waviness normals which calibrated by a National Standard Labaratory. Actual waviness at ball drives (nut and shaft) and brake disks is a standard job for CMMs. Yesterday I had to qualify a noisy cam shaft Important questions - We do not check the waviness of a roughness, we looking for characteristic periodical form deviations on profiles. - The equitment (CMM) has an influence on the result! 1-dimensional (Flatness) If a slope on thread (10mm) is analysed axial and the adjustment on the scales isn't well you will find a signal at 250 harmonic Standard CCM scale pitch = 40µm => 10mm/0.040 = 250 Ultra CMM scale pitch = 8µm => 10mm/0.005 = 1250 2-dimensional (Circular) Overlay of the two scale effects. Check of CMM is necessary - Air beared rotary tables do not show the behaviour of the ball bearings harmonics - The circumstance and conditions do not allow to get the true value. But if "good" and noisy parts are measured, it's possible to find the characterisic harmonics. - Normally the harmonics of the acustic measurement is compared with the mechanic results to define the critical harmonics and the tolerance for the amplitudes. Standard output 1 revolution at thread shaft At 25, 50 and 75 typical "significant" Peaks, effect of part holder inside grindig machine or vibrations??? Link to comment Share on other sites More sharing options...
[Ch...] Posted September 19, 2019 Share Posted September 19, 2019 I have an Air Bearing Rotary Table. Sweet Link to comment Share on other sites More sharing options...
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