The visual comparison method is the "old school" way machine shops would do it.
As an example: https://www.gardco.com/pages/surface_pro/roughness_comparison.cfm
Ed Popielarski
Engineering Manager
970 NE 21st Ct.
Oak Harbor, Wa. 98277
Ph: 360-675-1322
Fx: 206-624-0695
Cl: 949-581-6601
"It's one kind of victory to slay a beast, move a mountain, and cross a chasm, but it's another kind altogether to realize that the beast, the mountain, and the chasm were of your own design."
https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
Sent: Monday, November 16, 2015 12:41 AM
To: [log in to unmask]
Subject: Re: [TN] Surface Roughness Sample Length
Even less my area, but I had a fleeting need to understand it some years ago on a project.
I recall only two main things now
1)that there are a lot of different ways to quantify surface roughness none of which have much to do with the others. So a number in one scale is fine surface, but coarse in another.
In other words the units of measurement peak to trough, profile of peaks and troughs and frequency are all specified in different ways.
2) sort of resolved it by having multi processed sample with different roughness on and just matched the requirement by looking at it, bit like using a colour chart to match paint. Got the sample from an engineering company up the road. [I just walked in, told 'em I was next door but two and asked them to help me out.]
So the moral of the story -if there is one - is sort out your units and check out your neighbours to find someone better than me to ask!
--
Regards
Mike
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Saturday, November 14, 2015 2:33 AM
To: [log in to unmask]
Subject: Re: [TN] Surface Roughness Sample Length
Richard,
Not really my area of expertise, but couldn't one have a smooth surface with a chemical coating that gave a surface energy of X and a rougher surface with no coating or a different coating and still have the same surface energy X? I don't see how you can equate surface energy necessarily to roughness if you have not characterized the surface. Maybe I'm totally ignorant. If so, please educate me.
Eddie,
We have both types of systems Richard talks about if you want something tested - before Nov 27th.
You may want to check out:
ASTM
-D7127
-F2791
-F1048
-A 480/A 480M
-D4417
Regards,
Bev
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: November 13, 2015 8:23 AM
To: [log in to unmask]
Subject: Re: [TN] Surface Roughness Sample Length
Or if you need a cheaper but effective method, you can purchase Dyne pens.
A set of Dyne pens can be used to measure the approximate surface energy to determine appropriateness for direct dispensing of conformal coatings, adhesives, paint, epoxies, etc.
If the surface energy as measured by the Dyne pens is too low, you may then have to treat the surface prior to coating to provide a suitable surface to bond to.
Dyne pens are relatively inexpensive, ranging from around $65-$125 for a set. Here is one I use http://www.accudynetest.com/adtpen.html
I have not tried any others, so I cannot say this is the best or the worst.
Others may recommend other Dyne Pen sets.
My esteemed colleague and friend Dr. Pauls is someone whom I would heed a suggestion from, as to a reputable source. I have copied him directly. He may be quite busy at the moment writing something about half-rational elements from the planet Boron or something like that, however.
dean
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bhanu Sood
Sent: Friday, November 13, 2015 7:09 AM
To: [log in to unmask]
Subject: Re: [TN] Surface Roughness Sample Length
One can measure surface roughness either by using a contact or non-contact method. Some other optical microscope-based methods may be more qualitative.
Contact methods include using atomic force microscopy or surface profilometry. Essentially, run a stylus on the surface and track the rise and fall that corresponds with changes in the surface roughness. The measurement would give you the heights of the valleys and the depths of troughs. You can also calculate a root mean square roughness or RMS roughness.
Examples of non-contact methods include interferometry that uses white light or discrete wavelengths.
The length of the scan essentially depends on the planarity of the sample surface. At some point the global curvature of the sample is going to start influencing the measurements.
I hope this helps.
Bhanu
> On Nov 13, 2015, at 7:52 AM, Eddie Hofer
> <[log in to unmask]>
wrote:
>
> Wondering if anyone has more experience in the measurement of surface
> roughness. I am hoping to better understand the specifications
> relating to surface roughness and specifically the nuances behind
> determining sample length.
>
> Appreciate any input you can provide.
> Thanks!
> Eddie Hofer
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or
> [log in to unmask]
> ______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
|
