Any clever engineers or mathematicians?

oHUTCHYo

oHUTCHYo

oHUTCHYo

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We actually manufacture this product and nobody in our business knows the answer... :rolleyes:

Long shot... :p

I have a mesh product, expanded metal to be specific, I need to calculate what the minimum open area % is when looking at the product at eye-level 90 degrees.


Please familiarise with terminology and product with this image:
7PrHgu9.jpg

The answer I need is reflective of the 54% angle shown in this image:
ABBpcnG.jpg

As a case study, let me offer the following product specification:
LWD: 199mm
SWD: 87mm
SW: 24mm
ST: 3mm
Tool Specification: 199/52.23/F12.36

Of the tool specification, I know the 199 segment refers to LWD. The remaining two segments may have the answer needed to calculate minimum open area %.

To work out maximum open area %, I use a calculation of (SW*2)/SWD-1.

However with minimum open area %, clearly I need to somehow consider the angle of the mesh product, where I hope the missing link can be found in the tooling specification.

No further specifications or information is available.
 
Holy crap and 42 :D.

I'll get me calculator out.

Actually simple answer would be to get a sample and place against a solid background colour take photo at each angle and use photoshop to calculate the percentage of background colour viewable.

Edit: or if no photoshop upload the image to this;

http://www.coolphptools.com/color_extract

Unless I've completely misunderstood what you're trying to achieve.
 
Last edited:
The reason you are probably stuggling to work this out is that the question is unclear, I'm pretty sure I can work out the answer if I had clarity on the question

For a start:
90% relative to what? Eye-level means squat all.
What do LWD, SWD etc. stand for? These might be standard terms in your industry, but as someone from a maths background they mean little to me
Tool specification? What tool? How is a tool used to create something relevant to stationary mesh?


Also, is this part of your job? Do I get monetary compensation for helping you? :p
 
Judgeneo said:
The reason you are probably stuggling to work this out is that the question is unclear, I'm pretty sure I can work out the answer if I had clarity on the question

For a start:
90% relative to what? Eye-level means squat all.
What do LWD, SWD etc. stand for? These might be standard terms in your industry, but as someone from a maths background they mean little to me
Tool specification? What tool? How is a tool used to create something relevant to stationary mesh?


Also, is this part of your job? Do I get monetary compensation for helping you? :p
Click to expand...

90 degrees, not percent. As image #2, the mesh is angular, so open area, or if you wish air flow, will be more or less depending on how it is angled.

Reference terminology, thats the reason for image #1, on the bottom right theres a little image showing relationship of LWD/SWD/SW/ST.

Tool, well thats the question mark really, I'm hoping part of the tool specification is the secret to the calculation. The actual tool specification represents, in order as shown, pitch/penetration/flat, but that only serves to add more technicalities.

I was hoping to do away with technicalities and come up with an answer purely on a mathematical level.

As for your final question, I'm a project manager, so do deal with a certain mix of commercial and technical matters, but no :D
 
Mynight said:
Holy crap and 42 :D.

I'll get me calculator out.

Actually simple answer would be to get a sample and place against a solid background colour take photo at each angle and use photoshop to calculate the percentage of background colour viewable.

Edit:or if no photoshop upload the image to this;

http://www.coolphptools.com/color_extract

Unless I've completely misunderstood what you're trying to achieve.
Click to expand...

That is damn clever Mynight! So if I take a photo of the mesh at the chosen angle with a vivid background and run it through this, I should be golden! ;)

You could consider open area % as air flow really, as tilting the mesh will offer varying degrees of resistance to air, light etc.
 
Quite, although airflow will be a lot more difficult as air would still make it through the mesh just with greater drag in certain areas. I have no clue where to begin calculating that one. I would believe you'd need access to some special kit.

Although maybe a weather vane with lcd read out and a desk fan could be accurate enough for it. It really depends on how accurate you need the figures.

Yeah as for viewing area calculation as long as the background is uniform it only has to be a different colour than the metal.

What is this product for if you don't mind me asking.
 
oHUTCHYo said:
You could consider open area % as air flow really, as tilting the mesh will offer varying degrees of resistance to air, light etc.
Click to expand...

It depends on how you model the slit.. if it's a simple plane then you can calculate the area based on it's perspective.

If you're modelling the three dimensions of a warped plane.. that's a little more interesting .. especially if it's fluid dynamics. You don't need temperature in there to make a complete pig do you? :D
 
Yes thats a fair point on air flow versus open area guys, we do purposely make the distinction when publishing open area % as technically its not air flow because of the profile of each individual mesh design and how it "channels" differently.

Thanks for the help guys, as mentioned I think specialist kit is required to do this with any great accuracy given the variables involved
 
I had wrote something, but then I looked at your calculation again for maximum open area and and I got confused, as that equation outputs a length, rather than a percentage or area.

What are you claiming that maximum and minimum open area actually is?
 
Judgeneo said:
I had wrote something, but then I looked at your calculation again for maximum open area and and I got confused, as that equation outputs a length, rather than a percentage or area.

What are you claiming that maximum and minimum open area actually is?
Click to expand...

Well, if we take:

LWD: 199mm
SWD: 87mm
SW: 24mm
ST: 3mm

We would calculate open area % as follows;

(24mm x 2) / 87 -1
Therefore: 0.448, or expressed as 45%.

As mentioned this isnt airflow, just purely a mathematical expression of amount of metal versus amount of open air. Theres another more technical calculation which I use to calculate how much raw material I need to make a mesh product, both calculations present the same answer.
 
Tuppy_Glossop said:
I think we need more measurements to calculate the percentage accurately. See the red markings:

finfo_zpsb6c0f19b.png
Click to expand...

Thats an easy one Tuppy, the measurements you are showing there equate to SW x 2 (SW = "Strand Width"). So you are correct, as that is used in the example above as part of my calculation. Cookie for you ;)
 
oHUTCHYo said:
Well, if we take:

LWD: 199mm
SWD: 87mm
SW: 24mm
ST: 3mm

We would calculate open area % as follows;

(24mm x 2) / 87 -1
Therefore: 0.448, or expressed as 45%.

As mentioned this isnt airflow, just purely a mathematical expression of amount of metal versus amount of open air. Theres another more technical calculation which I use to calculate how much raw material I need to make a mesh product, both calculations present the same answer.
Click to expand...

In SI units, that reads as [L^2]/[L] = %, when it should be [L^2]/[L] = [L]

I'm glad I'm not an engineer :p
 
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