how to measure surface profile
how to measure surface profile
(OP)
I have a microprocessor and a surface profile call out pointing to the bottom surface of one of the pins. There are 48 total pins.
I understand the theory of what surface profile is (somewhat), but I'm unsure on how to measure it.
We do have a microscope scanner that can produce 3d height map renderings of the leads.
The way I see it, it can be one of two things.
I can create a plane on each individual pin, and then create one much larger plane out of all those planes. Then, I can measure the z difference between the large plane and each individual small plane.
Or, I can measure the surface roughness (min and max height) of each individual pin bottom.
I understand the theory of what surface profile is (somewhat), but I'm unsure on how to measure it.
We do have a microscope scanner that can produce 3d height map renderings of the leads.
The way I see it, it can be one of two things.
I can create a plane on each individual pin, and then create one much larger plane out of all those planes. Then, I can measure the z difference between the large plane and each individual small plane.
Or, I can measure the surface roughness (min and max height) of each individual pin bottom.





RE: how to measure surface profile
RE: how to measure surface profile
RE: how to measure surface profile
So, no I don’t think you are looking for surface roughness (which is a different symbol) of each of the 48 pads.
And that you have the correct philosophy of first measuring the z location of each pad. Then create a plane out of the three tallest pad. These would be the three that if placed on the circuit board would be the three point definition of a plane. Then all the other points must be within 0.10 of this plane. This could be done on some of the digital 3D microscope or even a CMM by laying the part on what would be the top surface when mounted and then touching off on each pad . . .
RE: how to measure surface profile
This drawing is severely lacking. djhurayt is attempting to interpret the intent but it's all just a best GUESS as he already acknowledges.
I have a feeling this is why you haven't gotten a response from any of the heavy hitters on this forum. There's just no way to really know since the drawing is so bad.
Keep in mind that whatever you wind up doing, if your customer is satisfied, it in no way means that the drawing is sufficient. It just means you GUESSED correctly.
Good luck.
John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
SSG, U.S. Army
Taji, Iraq OIF II
RE: how to measure surface profile
Anyhow, there are a couple of ways to measure profile on curved surfaces. You could take impressions of the features and inspect them on a comparator, or you could use a CMM. It really can be a challenge to inspect curved surfaces manually regardless of the GD&T used on the print.
RE: how to measure surface profile
RE: how to measure surface profile
RE: how to measure surface profile
RE: how to measure surface profile
Is the resolution of your 3D scopes Z-direction accurate enough?
other verification options
* a granite/flat table and go-nogo feeler gauges, 0.10 goes, 0.10+ does not
* realy trick would be a series of indicators (if it is even possible to get them that close) or maybe some lazer depth gauges that you zero out with something very flat, then set the part on it, no gauge should read greater than 0.10, how much money do you have
RE: how to measure surface profile