hey #measuringhero , Jay here. Back in Rock 7 we introduced the SurfMax and it really made
my head explode. There's so much to think about. So I'm back here in Minneapolis and I wrangled
Stephanie to bring her down to the production floor to explain some questions I had as I was
researching this thing. Stephanie, thank you. Hey Jay, good to see you again. Good to see you again back at home.
Okay so Rock 7 we talked about the SurfMax, you were explaining that guy to me
and I did a little bit of research and I saw that there are some systems out there that do
some similar things, but they use grayscale as a defect channel. Can you explain to me what
grayscale is? Kind of the methodology behind it and what
that shows and maybe some other stuff? Sure, yeah. So conventional visual inspection very often uses
just the grayscale channel. And the grayscale channel is observing changes in white light
reflectivity on the surface of the part. So it helps us to see imperfections related to
maybe changes in color or discoloration on the surface of the part. We're going to look at an
injection molded part with what we call a dot imperfection and it can also help us observe
certain contours on the surfaces of our part. Okay, got it so if I hear that right, is what we're looking
for similar to what how I use grayscale in metrology, we're looking at changes in
lightness, right? From dark to light yeah and the highest contrast possible is what
is what we get, right? That's right, yeah. Let's take a look at the example I have here.
So this is an injection molded part and you can see on the surface here we have this little
sort of dot. You can see there's something that's sticking out there. So if we apply
our algorithm to this grayscale channel, it's going to pick up on that discoloration
Because the defect kind of shows up as a color contrast. Yeah.
Makes total sense, got it. Okey, but what if there are other defects out there that
don't show itself like that, right? It's a really good question. So I have a few examples.
Something that's really unique about SurfMax is we actually use three channels of information.
That allows us to see a lot of different types of defects. The next example I have up here is a
contamination defect. So we're looking at actually a fingerprint on the surface.
So this is our grayscale channel and you can really kind of faintly see the fingerprint on there.
There's something but it's not super contrasting it's really not popping in this channel.
So we're going to take a look at what we call the gloss channel and gloss is looking at the
way light scatters off of the surface of a part. It's going to highlight textures non-uniformities
in this case contaminations are really going to pop under this channel. Okay, so you're looking at
to get to get into a vernacular that I can understand, you're looking for
like when I go to the paint store and I can choose like a matte
paint or a gloss paint that has a totally like light bounces off that different is that what we're looking for?
That's exactly what we're talking about here. So matt versus glossy is this channel, right?
So let's take a look at the gloss channel and see what happens to that fingerprint.
Yeah, it's totally pronounced. Yeah it really really pops in this channel and that's important
especially for contaminations. You know this part could be easily rejected if you didn't
weren't able to recognize that this is just a contaminant and it can be cleaned off the surface.
Right, right. So if I apply our algorithm now to the gloss channel it's really going to pick up
on that fingerprint defect for us. So last but not least let's talk about the slope channel.
This is the third channel, that's right. So I have a third example for us up here
and to give you a little bit of background on what the slope is looking for, it's actually looking at
the angles of our surface and observing how they change. So it's really good for observing
form-related imperfections, you know certain processes like painting can cause like an
orange peel where you get like a very bumpy sort of surface. It's great at picking up on
really big scratches and dings and dents those sorts of things. So you're actually real time
then calculating the nominal flatness and then comparing other angles. Yeah, spot on and
we're doing it in real time so it's as quick as that. So in this example we're looking for what
we call a wrinkle. So this happens it could be in a coating or a painting process with something - I don't see anything here.
Yeah this is our grayscale channel you're not going to see anything here.
Let's take a look at the gloss and see if we detect anything there. I see
the exact same thing. Yeah not really, not really. So let's go take a look at the slope channel
and what you're gonna see is up in this corner you see like a really faint sort of waviness.
So that's that form error we were talking about. It's a little bit coming in here
is that what I'm looking at? Yeah you got it and if I apply our algorithm to that
our inspection is going to pick up on that defect for us. So that might be like a coding
imperfection in the curing process or something that Yep it's causing kind of this waviness
on the surface so, it's very easily detected by our slope channel. Wow, so I think I'm seeing that
it's not enough to have grayscale. So you really have to do Yeah it lets us see so many more types
of defects and to correctly classify what types of defects they are, whether it be a contaminant
or some sort of form error or a scratch on the surface. Okay, okay. Stephanie, all right my
mind is spinning right now. You showed me a defect here, that I could barely see even with the slope channel.
So how does this algorithm, that you've just turned off and on, kind of interrogate whether
that was enough to be a defect or not because man even with the help of the slope channel
Totally sensitivity is super important and our algorithms can be as sensitive
or as least sensitive as you need them to be per your production requirements and your
quality requirements which are naturally going to be different to every industry.
So let's take a look at some sample reports, that I've prepared here. So we call this is a
different example I'm pulling up and you can see we're looking at some scratches on the surface
of this demonstration piece and this is our fine stage so this is actually detecting the defect
on the surface. So we're applying that scratch algorithm, but what I can do is
I can adjust the sensitivity. So it's 20 percent. Yeah we're looking at 20% on this one and you can see
a little bit of the defects are being picked up on, but not everything is being detected
at 20%. So if I go down to our next report page here, I've adjusted the sensitivity to 50%.
As you can see, there's a little bit more yellow. So we're detecting a little bit more and again if
I adjust it even further to 80% you catch a lot more of those imperfections on the surface.
Yep, so you can kind of choose the sensitivity of what you're thresh based on what your threshold is
what you're measuring. Yeah, yeah and so taking this a step further we can also then
take this and we want to classify our segments as either okay or not okay defects, because we found
a lot of scratches on the surface here. And they may not all be bad, you know some may be acceptable.
On my final report page you can see that we're applying the sensitivity to the algorithm
and we have some greens, so those are okay segments. They're not severe enough to cause
a reject. We have some yellow which are maybe borderline, they're a little more suspect areas
and then we have red. Those defects are too severe and they cause reason for rejection on this part.
Okay, okay. All right I understand, I think I'm beginning to understand how it's important
to not only have new tools to see the defect, but you also have to have tools to kind of cut out
what is not just sensitive to, but actually even interrogate all of them. Yeah, that's right I mean every
part is going to have imperfections on the surface of the parts so we have to be able to sort out
what's an acceptable imperfection and what can we qualify as a reject a do really defective part.
That is mind-blowing because if I recall correctly we take hundreds of images per minute, right?
So we're doing this analysis and this is all going in real time as our parts are going through
it takes no time at all. So for me, I definitely have to re-watch again Rock 7
to hear more about some of the benefits of the SurfMax. But I really do appreciate taking
the time to explain, because I mean to me it's one thing to have someone list the benefits to me, but
to actually be able to wrap my arms around: this is what grayscale is and this is what sensitivity
means, really helps me kind of understand. Thank you. Yeah I'm glad we could do it.
It's great, I might have more questions can I wrangle you in again? Totally. Awesome awesome. Stephanie,
thank you for doing this. Appreciate it. Thanks Jay, good to see you. Good to see you and for you
out there hope you enjoyed my nerdy journey. Stay healthy out there and we'll see you next thursday.