mandag den 23. april 2018 kl. 18.13.21 UTC+2 skrev John Larkin:> On Mon, 23 Apr 2018 08:49:42 -0700 (PDT), Lasse Langwadt Christensen > <langwadt@fonz.dk> wrote: > > >mandag den 23. april 2018 kl. 17.19.08 UTC+2 skrev John Larkin: > >> On Mon, 23 Apr 2018 04:31:46 -0400, Phil Hobbs > >> <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> > >> >I have a customer who wants me to do an extreme shrink of our > >> >semi-custom diode laser controller board, which leads to a lot of > >> >thermal issues. The obvious approach is an aluminum-core circuit > >> >board, but I've never used one. > >> > > >> >A few questions for the cognoscenti: > >> > > >> >1. Can I get a 6- or 8-layer aluminum-core PCB? > >> > > >> >2. How much more do they cost? > >> > > >> >3. Any other constraints? > >> > > >> >Thanks > >> > > >> >Phil Hobbs > >> > >> There are also extreme copper boards, from 4 oz up to 20 oz. > >> > >> http://www.epectec.com/pcb/extreme-copper.html > >> > >> My current insane project has a 4-layer PCB bolted to a machined > >> aluminum baseplate, with gap-pad and AlN insulators between. That > >> approach might be more economical. > >> > > > >some time ago I saw this 20oz board on reddit: > >https://usercontent.irccloud-cdn.com/file/gHochdce/irccloudcapture-1320676838.jpg > > > >the guy said it cost $2250 > > > > > > > > > > Looks silly, 20 oz copper and skinny traces. >from the reddit thread, “the side that you’re looking at has -450V / 0 / +450V traces. The other side has 14V @ 150A and 24V @ 80A.” The other side being this: https://usercontent.irccloud-cdn.com/file/ZjnBND2U/irccloudcapture-236812244.jpg
Aluminum-core PCB cost?
Started by ●April 23, 2018
Reply by ●April 23, 20182018-04-23
Reply by ●April 23, 20182018-04-23
On Monday, April 23, 2018 at 12:15:18 PM UTC-6, Lasse Langwadt Christensen wrote:> mandag den 23. april 2018 kl. 18.13.21 UTC+2 skrev John Larkin: > > On Mon, 23 Apr 2018 08:49:42 -0700 (PDT), Lasse Langwadt Christensen > > <langwadt@fonz.dk> wrote: > > > > >mandag den 23. april 2018 kl. 17.19.08 UTC+2 skrev John Larkin: > > >> On Mon, 23 Apr 2018 04:31:46 -0400, Phil Hobbs > > >> <pcdhSpamMeSenseless@electrooptical.net> wrote: > > >> > > >> >I have a customer who wants me to do an extreme shrink of our > > >> >semi-custom diode laser controller board, which leads to a lot of > > >> >thermal issues. The obvious approach is an aluminum-core circuit > > >> >board, but I've never used one. > > >> > > > >> >A few questions for the cognoscenti: > > >> > > > >> >1. Can I get a 6- or 8-layer aluminum-core PCB? > > >> > > > >> >2. How much more do they cost? > > >> > > > >> >3. Any other constraints? > > >> > > > >> >Thanks > > >> > > > >> >Phil Hobbs > > >> > > >> There are also extreme copper boards, from 4 oz up to 20 oz. > > >> > > >> http://www.epectec.com/pcb/extreme-copper.html > > >> > > >> My current insane project has a 4-layer PCB bolted to a machined > > >> aluminum baseplate, with gap-pad and AlN insulators between. That > > >> approach might be more economical. > > >> > > > > > >some time ago I saw this 20oz board on reddit: > > >https://usercontent.irccloud-cdn.com/file/gHochdce/irccloudcapture-1320676838.jpg > > > > > >the guy said it cost $2250 > > > > > > > > > > > > > > > > Looks silly, 20 oz copper and skinny traces. > > > > from the reddit thread, > > “the side that you’re looking at has -450V / 0 / +450V traces. The other side has 14V @ 150A and 24V @ 80A.” The other side being this: https://usercontent.irccloud-cdn.com/file/ZjnBND2U/irccloudcapture-236812244.jpgThere is something strangely beautiful about that. Now I just need to come up with an excuse to design something like that here...
Reply by ●April 23, 20182018-04-23
On 04/23/18 14:15, Lasse Langwadt Christensen wrote:> mandag den 23. april 2018 kl. 18.13.21 UTC+2 skrev John Larkin: >> On Mon, 23 Apr 2018 08:49:42 -0700 (PDT), Lasse Langwadt Christensen >> <langwadt@fonz.dk> wrote: >> >>> mandag den 23. april 2018 kl. 17.19.08 UTC+2 skrev John Larkin: >>>> On Mon, 23 Apr 2018 04:31:46 -0400, Phil Hobbs >>>> <pcdhSpamMeSenseless@electrooptical.net> wrote: >>>> >>>>> I have a customer who wants me to do an extreme shrink of our >>>>> semi-custom diode laser controller board, which leads to a lot of >>>>> thermal issues. The obvious approach is an aluminum-core circuit >>>>> board, but I've never used one. >>>>> >>>>> A few questions for the cognoscenti: >>>>> >>>>> 1. Can I get a 6- or 8-layer aluminum-core PCB? >>>>> >>>>> 2. How much more do they cost? >>>>> >>>>> 3. Any other constraints? >>>>> >>>>> Thanks >>>>> >>>>> Phil Hobbs >>>> >>>> There are also extreme copper boards, from 4 oz up to 20 oz. >>>> >>>> http://www.epectec.com/pcb/extreme-copper.html >>>> >>>> My current insane project has a 4-layer PCB bolted to a machined >>>> aluminum baseplate, with gap-pad and AlN insulators between. That >>>> approach might be more economical. >>>> >>> >>> some time ago I saw this 20oz board on reddit: >>> https://usercontent.irccloud-cdn.com/file/gHochdce/irccloudcapture-1320676838.jpg >>> >>> the guy said it cost $2250 >>> >>> >>> >>> >> >> Looks silly, 20 oz copper and skinny traces. >> > > from the reddit thread, > > “the side that you’re looking at has -450V / 0 / +450V traces. The other side has 14V @ 150A and 24V @ 80A.” The other side being this: https://usercontent.irccloud-cdn.com/file/ZjnBND2U/irccloudcapture-236812244.jpgI'd have to go to a lot of layers to get that to work, because I need quite a lot of circuitry. It's a customer requirement, so I need to go see if it's possible and how much it would cost. I might laminate the Al on one side of the boards and use it as three sides of the box. (Yes, this probably means using two flexes to join the sides together. As I said, an *inhmmhhmm* customer requirement.) Hopefully their CM will explain that to them. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●April 23, 20182018-04-23
On 04/23/18 13:37, Marke wrote:> Sorry, what is the benefit of Al over Cu here? Cu has higher thermal conductivity, 3x the density and is the standard material for PCBs. > > Is the idea that Al will radiate heat away faster? Wouldn't a Cu PCB with Al heatsink be the better choice then? >The benefit of Al over Cu is that it doesn't trash the litho resolution. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●April 23, 20182018-04-23
mandag den 23. april 2018 kl. 22.54.39 UTC+2 skrev Phil Hobbs:> On 04/23/18 14:15, Lasse Langwadt Christensen wrote: > > mandag den 23. april 2018 kl. 18.13.21 UTC+2 skrev John Larkin: > >> On Mon, 23 Apr 2018 08:49:42 -0700 (PDT), Lasse Langwadt Christensen > >> <langwadt@fonz.dk> wrote: > >> > >>> mandag den 23. april 2018 kl. 17.19.08 UTC+2 skrev John Larkin: > >>>> On Mon, 23 Apr 2018 04:31:46 -0400, Phil Hobbs > >>>> <pcdhSpamMeSenseless@electrooptical.net> wrote: > >>>> > >>>>> I have a customer who wants me to do an extreme shrink of our > >>>>> semi-custom diode laser controller board, which leads to a lot of > >>>>> thermal issues. The obvious approach is an aluminum-core circuit > >>>>> board, but I've never used one. > >>>>> > >>>>> A few questions for the cognoscenti: > >>>>> > >>>>> 1. Can I get a 6- or 8-layer aluminum-core PCB? > >>>>> > >>>>> 2. How much more do they cost? > >>>>> > >>>>> 3. Any other constraints? > >>>>> > >>>>> Thanks > >>>>> > >>>>> Phil Hobbs > >>>> > >>>> There are also extreme copper boards, from 4 oz up to 20 oz. > >>>> > >>>> http://www.epectec.com/pcb/extreme-copper.html > >>>> > >>>> My current insane project has a 4-layer PCB bolted to a machined > >>>> aluminum baseplate, with gap-pad and AlN insulators between. That > >>>> approach might be more economical. > >>>> > >>> > >>> some time ago I saw this 20oz board on reddit: > >>> https://usercontent.irccloud-cdn.com/file/gHochdce/irccloudcapture-1320676838.jpg > >>> > >>> the guy said it cost $2250 > >>> > >>> > >>> > >>> > >> > >> Looks silly, 20 oz copper and skinny traces. > >> > > > > from the reddit thread, > > > > “the side that you’re looking at has -450V / 0 / +450V traces. The other side has 14V @ 150A and 24V @ 80A.” The other side being this: https://usercontent.irccloud-cdn.com/file/ZjnBND2U/irccloudcapture-236812244.jpg > > I'd have to go to a lot of layers to get that to work, because I need > quite a lot of circuitry. It's a customer requirement, so I need to go > see if it's possible and how much it would cost. I might laminate the > Al on one side of the boards and use it as three sides of the box. > (Yes, this probably means using two flexes to join the sides together. > As I said, an *inhmmhhmm* customer requirement.) Hopefully their CM > will explain that to them. >I don't know if fr4 bonded to alu is really that much much better a than regular pcb bolted to an alu plate
Reply by ●April 24, 20182018-04-24
"Lasse Langwadt Christensen" <langwadt@fonz.dk> wrote in message news:e7a0d049-63fe-4abd-b45c-120785cd100f@googlegroups.com...>I don't know if fr4 bonded to alu is really that much much better a than regular pcb bolted to an alu plate>Basically the same thing JL's doing right now, put a Gap Pad under it and be done. Upshot: lower thermal resistance than FR-4, Kapton or other bondings! Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: https://www.seventransistorlabs.com/
Reply by ●April 24, 20182018-04-24
On 04/24/18 00:06, Tim Williams wrote:> "Lasse Langwadt Christensen" <langwadt@fonz.dk> wrote in message > news:e7a0d049-63fe-4abd-b45c-120785cd100f@googlegroups.com... >> > I don't know if fr4 bonded to alu is really that much much better a > than regular pcb bolted to an alu plate >> > > Basically the same thing JL's doing right now, put a Gap Pad under it > and be done. > > Upshot: lower thermal resistance than FR-4, Kapton or other bondings! > > Tim >Yes, that's one approach I'm considering. The Cu-on-anodized-Al approach is an interesting one as well. I could just put the transistors and sense resistors on that, and let the low-power circuitry stay on a regular PCB. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●April 24, 20182018-04-24
Rob <nomail@example.com> wrote in news:slrnpds773.6bj.nomail@xs9.xs4all.nl:> Marke <mark.e.emerson@gmail.com> wrote: >> Sorry, what is the benefit of Al over Cu here? Cu has higher thermal >> conductivity, 3x the density and is the standard material for PCBs. > > The Al is not instead of the Cu, it is instead of (part of) the FR4. > Of course it would be even better to use an equivalent thickness of > copper, but it would be more expensive. >Then he should use an anodized Aluminum plate, which is NOT electrically conductive, and have his copper traces (or the entire PCB) bonded to that. Problem solved. Use thermal epoxy to attach an anodized Al plate to the bottom of the PCB.
Reply by ●April 24, 20182018-04-24
"Tim Williams" <tiwill@seventransistorlabs.com> wrote in news:pbmag5$eth$1@dont-email.me:> "Lasse Langwadt Christensen" <langwadt@fonz.dk> wrote in message > news:e7a0d049-63fe-4abd-b45c-120785cd100f@googlegroups.com... >> > I don't know if fr4 bonded to alu is really that much much better a > than regular pcb bolted to an alu plate >> > > Basically the same thing JL's doing right now, put a Gap Pad under it > and be done. > > Upshot: lower thermal resistance than FR-4, Kapton or other bondings! > > Tim >Screw the gap pad. Use a more themrally conductive bond.
Reply by ●April 24, 20182018-04-24
