George2324
Well-Known Member
Ok great thanks. 43mm spacing and 2 holes.
M4 screws right?
M4 screws right?
Heatsink machining drawing
- Thread starter George2324
- Start date
Raging Stalk
Active Member
I used m3, not sure if 4 will fit.
With aluminum plate, you only need to drill, no need to tap threads as you can mount the cob with a bolt and screw.
With aluminum plate, you only need to drill, no need to tap threads as you can mount the cob with a bolt and screw.
mahiluana
Well-Known Member
Mechanical Dimensions Figure 22: Drawing for Vero 29 LED Array Notes for Figure 22: 1. Drawings are not to scale. 2. Drawing dimensions are in millimeters. 3. Unless otherwise specified, tolerances are ± 0.10mm. 4. Mounting holes (4X) are for M3 screws. 5. Bridgelux recommends four tapped holes for mounting screws with 43.0 ± 0.10mm center-to-center spacing. 6. Screws with flat shoulders (pan, dome, button, round, truss, mushroom) provide optimal torque control. Do NOT use flat, countersink, or raised head screws. 7. Solder pads and connector port are labeled “+” and “-“ to denote positive and negative, respectively. 8. It is not necessary to provide electrical connections to both the solder pads and the connector port. Either set may be used depending on application specific design requirements. 9. Refer to Application Notes AN30 and AN31 for product handling, mounting and heat sink recommendations. 10. The optical center of the LED Array is nominally defined by the mechanical center of the array to a tolerance of ± 0.2mm. 11. Bridgelux maintains a flatness of 0.10mm across the mounting surface of the array
page 27
http://www.bridgelux.com/sites/defa... 29 Gen 7 Array Data Sheet 20170308 Rev J.pdf
George2324
Well-Known Member
Ok I'll do m3 but will need to tap it
Johnnycannaseed1
Well-Known Member
The figure comes from Julian at Birmingham aluminium, he just so happens to design/make heatsinks for a living.
He told me there is not a huge difference between different colours... but nontheless there is a difference... And in his professional experience black is best.
Feel free to ask him yourself to confirm
http://www.bal-group.com/home
Johnnycannaseed1
Well-Known Member
I hear ya and that is exactly what I used to assume until Julian told me otherwise... Seeing as he is the expert I am not about to argue with him on this one
George2324
Well-Known Member
Wouldn't no light actually hit the heat sink since the light is sending out photons at 120 degrees away from the heat sink.
Light would have to travel backwards for the heat sink to absorb any photons?
Light would have to travel backwards for the heat sink to absorb any photons?
Johnnycannaseed1
Well-Known Member
No offence Cobby but it seems to me you are the one who is assuming and incorrectly at that.
The man knows his stuff and has tested different colours and coatings.
I am nowhere near as knowledgeable as he is when it comes to heatsinks but even I know you do not need a sphere to test the emissivity value of different coloured heatsinks, so I am not even going to question an expert who does this day in day out for a living, on what he does or doesn't know when it comes to his own subject matter.
First of all learn what Black body means, note it is an ideal emitter: https://en.wikipedia.org/wiki/Black_body
Then Learn how to test for emissivity values, here is one way of doing it, you honestly think BAL haven't got top notch sensors?
http://www.tnp-instruments.com/sitebuildercontent/sitebuilderfiles/emissivity_how_to_check.pdf
Clearly no sphere testing is needed
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Raging Stalk
Active Member
Now you guys are taking it to the extreme if you are now trying to figure out the best color for your bulky over engineered heat sinks.
Ok, I vote pink just to be different.
Ok, I vote pink just to be different.
CobKits
Well-Known Member
cool id love to see any data
ultimately umol/J is what were after, so it sure is. youre completely ignoring absorbance of photons which whould tanslate into extra heat the heatsink would need to dissipate.
even if a certain color had a significantly different emissivity, it would have to be significant enough to make a difference in efficiency to have an effect on chip efficiency.my money is on insignificant difference (just my opinion)
Danielson999
Well-Known Member
Color of anodization has no impact on radiation heat transfer.
The pores created by acidic anodizing on aluminum can easily absorb dyes. Colored dyes are often used on heat sinks for cosmetic and marketing purposes. The color of anodization has no impact on radiation heat transfer. A clear anodized surface has the same emissive characteristics as a black anodized surface. To further protect the surface of dyed anodized heat sinks from corrosion, they are usually sealed by immersion in boiling hot de-ionized water or steam [2].
Various protective benefits and aesthetically pleasing colors have extended the use of anodization to many industrial and commercial applications. For electronics cooling, however, the advantages of surface anodizing are the dielectric isolation of the cooling components from their electronics environment, and the significant increase in their surface emissivity. The increase in the emissivity coefficient on the anodized surfaces of heat exchangers, electronics cabinets and enclosures, heat sinks, etc. is typically on the order of 0.83 to 0.86 [4]. When compared to the emissivity coefficient of bare aluminum, 0.04 to 0.06 [5], the importance and significance of enhancement of radiation heat transfer would become evident.
In part 2 we’ll cover the heat sinks anodization process and different types of anodization.
References:
The pores created by acidic anodizing on aluminum can easily absorb dyes. Colored dyes are often used on heat sinks for cosmetic and marketing purposes. The color of anodization has no impact on radiation heat transfer. A clear anodized surface has the same emissive characteristics as a black anodized surface. To further protect the surface of dyed anodized heat sinks from corrosion, they are usually sealed by immersion in boiling hot de-ionized water or steam [2].
Various protective benefits and aesthetically pleasing colors have extended the use of anodization to many industrial and commercial applications. For electronics cooling, however, the advantages of surface anodizing are the dielectric isolation of the cooling components from their electronics environment, and the significant increase in their surface emissivity. The increase in the emissivity coefficient on the anodized surfaces of heat exchangers, electronics cabinets and enclosures, heat sinks, etc. is typically on the order of 0.83 to 0.86 [4]. When compared to the emissivity coefficient of bare aluminum, 0.04 to 0.06 [5], the importance and significance of enhancement of radiation heat transfer would become evident.
In part 2 we’ll cover the heat sinks anodization process and different types of anodization.
References:
- Radiation Heat Transfer and Surface Area Treatment, Qpedia Thermal eMagazine, June 2008.
- Edwards, J., Coating and Surface Treatment Systems for Metals, Finishing Publications Ltd. and ASM International, 1997.
- Aluminum Anodizer Council Web Forum.
- Gustavsen, A. and Berdahl, P. Spectral Emissivity Of Anodized Aluminum And Thermal Transmittance Of Aluminum Windows Frames, Nordic Jounnal Of Building Physics, Vol.3, 2003.
- Ozisik, N.,Heat Transfer: A Basic Approach, McGraw-Hill, 1984.
- Highly Emissive Ion Beam Textured Surfaces for Improved Cooling of Electronic Devices, Electronics Cooling Magazine, September 1997.
- Chi, T. , Ballinger, R., Olds, R., and Zecchino, M., Surface Texture Analysis Using Dektak Stylus Profilers, Veeco Instruments, Inc.
Johnnycannaseed1
Well-Known Member
Cobby are clutching at proverbial straws in order to win an argument...
In reality isn't your photon/heatsink/absorbance argument seriously negligible at best...Possibly as insignificant as you imagine colour emissivity to be?
I suggest you read my original post to see "exactly" what I said with regards to differences
Hmmm so how does black body radiation fit into the above, I guess colour temperatures, plancks law etc is all a load of nonsense
...In reality isn't your photon/heatsink/absorbance argument seriously negligible at best...Possibly as insignificant as you imagine colour emissivity to be?
I suggest you read my original post to see "exactly" what I said with regards to differences
Hmmm so how does black body radiation fit into the above, I guess colour temperatures, plancks law etc is all a load of nonsense
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Danielson999
Well-Known Member
I suggest you read my original post to see "exactly" what I said with regards to differences
What I'd suggest you do is delete your comment since it's irrelevant and based on opinion. Take another look at the list Cobkits posted on page 1. You'll notice that basically all colors are identical and in the range of .82 - .88. If you tested all those colors 1000 times each they would all come out with the identical reading. This has been tested for decades now by people 10 times as smart as your buddy on equipment far more advanced than his.
Johnnycannaseed1
Well-Known Member
Will do as soon as you get back to me on how does black body radiation fit into the above, I guess colour temperatures, plancks law etc is all a load of nonsense right?
Because the smart arse geniuses who came up with the above models, who are 15 times as smart as you buddy and use equipment far more advance than those guys you know which, by the way are the exact same models/laws the lighting industry use, well according to what you are saying buddy then Cree, Citi, Bridgelux must be using flawed data and are also incorrect right buddy???
And yeah I am taking the proverbial pee and being a sarcastic so and so... and what buddy
Btw way like I said to Cobby did you actually read my first comment, or does you head and tongue simply have a particular liking to being wedged up Cobby's ass (no offence Cobby) haha!
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Raging Stalk
Active Member
It is just banter common to the LED forum. 99% of the time people are always right in some fashion even when they have different answers to the same question. Most have pretty thick skins and it is more of a jousting match over the internet.
I default back to my last post in the thread and vote pink as the best color. Why? Because each time you go into the room you can ask yourself why you picked pink as a color.
DankaDank
Well-Known Member
What's the point in anodizing our heatsinks when the're not in contact with water (24/7). Since bare aluminium forms a natural oxide layer anyway, and the naturally formed oxide layer stops further corrosion.
I imagine silver/white anodized heatsinks would surely be better for greenhouse applications where they will absorb less sunlight/heat.
Would be interesting to get chromate conversion coated heatsinks since it would allow for low resistance grounding.
I imagine silver/white anodized heatsinks would surely be better for greenhouse applications where they will absorb less sunlight/heat.
Would be interesting to get chromate conversion coated heatsinks since it would allow for low resistance grounding.
Raging Stalk
Active Member
Danielson999
Well-Known Member
Will do as soon as you get back to me on how does black body radiation fit into the above, I guess colour temperatures, plancks law etc is all a load of nonsense right?
Because the smart arse geniuses who came up with the above models, who are 15 times as smart as you buddy and use equipment far more advance than those guys you know which, by the way are the exact same models/laws the lighting industry use, well according to what you are saying buddy then Cree, Citi, Bridgelux must be using flawed data and are also incorrect right buddy???
And yeah I am taking the proverbial pee and being a sarcastic so and so... and what buddy
Btw way like I said to Cobby did you actually read my first comment, or does you head and tongue simply have a particular liking to being wedged up Cobby's ass (no offence Cobby) haha!
You aren't understanding what black body radation even is. Don't confuse an object that is visibly black with a black body. A white colored object and a black colored object can both be black bodies.
You don't even understand what black body is to begin with. Until you do, there's no point even debating anything. If you actually did understand what black body is and the effects is has you wouldn't even be talking about it because it's a moot point with LED heatsinks.
LOL!!
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