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Unetched aluminum pcb source anyone? — Parallax Forums

Unetched aluminum pcb source anyone?

CuriousOneCuriousOne Posts: 931
edited 2013-07-01 00:29 in General Discussion
Hello.

For some applications, I need unetched aluminum PCB. I will cut traces according to my requiremens (Own 3 axis CNC), so I just need bare aluminum, copper clad pcb, which I will handle as I need. Seems like easy task, right? Seeking for more than 6 months for it. Found only one supplier in Israel (forgot the name), which makes it, but this is very specific, for RF applications and cost was around $7 per square cm! :)

I tried to contact companies who manufacture custom aluminum PCB. They said, they can do bare pcb with no traces pre-cut, but their minimum order quantity is way too much for me (Starting at 100 square meters!). So maybe anyone got luck?

Comments

  • RDL2004RDL2004 Posts: 2,554
    edited 2013-06-29 09:18
    What do you mean exactly by "aluminum PCB" ? Aluminum as the substrate instead of the usual fiberglass, or as the conductive layer, or both? What is the intended use? In other words, why won't a normal type of PCB work?
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 09:52
    Yes, aluminum as the substrate instead of the usual fiberglass. I would not refuse from copper substrate one, too.
  • RickBRickB Posts: 395
    edited 2013-06-29 10:14
    Is this for heat sinking purposes? As an experiment, you might try gluing copper foil to anodized aluminum with thermally conductive epoxy. Using .01" pcb stock glued directly you won't need the isolation of the anodizing.

    Rick
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 10:22
    Yes this is for heatsinking. Experiments completed, one of manufacturers was kind enough to send me the small sheet of super thin pcb which they glue onto aluminum.

    But, I need a factory built one, with factory class consistency, build and look.
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-06-29 10:51
    These are called IMS PCBs (insulated metal substrate). They are used for high power LEDs and power supplies. There are several companies that offer this type of pcb service. You could either have them make your board(s) or contact them to see if they would sell you pieces of unetched board. I doubt if any of the substrate manufacturers would want to sell direct in small quantities.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 10:58
    Yes, already contacted, as mentioned above, volumes too large.
  • LeonLeon Posts: 7,620
    edited 2013-06-29 11:23
    Forget about making your own board and get a PCB supplier to make it for you. It will probably work out cheaper and save a lot of hassle.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 11:29
    I'm not going to make it by myself. I need blank aluminum PCBs so I can cut my own traces.
  • LeonLeon Posts: 7,620
    edited 2013-06-29 12:07
    That amounts to making a PCB, as far as I am concerned.

    PCB-Pool can make IMS PCB prototypes:

    http://www.pcb-pool.com/ppuk/info_pcbpool_alupanel.html
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 13:23
    Yes, but I have own hardware, so I can put in copper clad fiberglass, and get out ready pcb. So, I'm prototyping by myself, don't want rely on 3rd party or wait for them.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 13:32
    protomax.jpg


    Having own PCB manufacturing capabilities, allows for rapid prototyping. For example, on the attached picture you can see a multifunction device - it connects to single lithium-ion cell, charges it from USB (with charge state indication) and outputs DC 12V 0.25A. After PCB was designed, it took less than 1 hour to have assembled device at hands. However, for certain designs, I need better thermal dissipation than that is being offered by thin copper layer on PCB. And often, vias to other side aren't feasible, so, I need blank aluminum pcbs.
    1024 x 462 - 72K
  • Too_Many_ToolsToo_Many_Tools Posts: 765
    edited 2013-06-29 14:48
    How thick does the Al substrate have to be?

    How much do you need?

    What you are looking for is a specialty item which will always be expensive and hard to source. I would expect that you would only find what you want for the price you are willing to pay on the surplus market...which is not a reliable source for ongoing production.

    Have you considered using a doubled sided copper PCB where you would remove the top copper and intermediate fiberglass layer...leaving the bottom copper layer. You could mount your devices to the remaining layer with thermally conductive paste and mount the PCB to a larger copper or aluminum heatshink again with thermally conductive paste.

    Bear in mind that the Al substrate is used in high frequency applications..and the approach I mentioned is not suitable in that application if that is your application.

    CuriousOne wrote: »
    Hello.

    For some applications, I need unetched aluminum PCB. I will cut traces according to my requiremens (Own 3 axis CNC), so I just need bare aluminum, copper clad pcb, which I will handle as I need. Seems like easy task, right? Seeking for more than 6 months for it. Found only one supplier in Israel (forgot the name), which makes it, but this is very specific, for RF applications and cost was around $7 per square cm! :)

    I tried to contact companies who manufacture custom aluminum PCB. They said, they can do bare pcb with no traces pre-cut, but their minimum order quantity is way too much for me (Starting at 100 square meters!). So maybe anyone got luck?
  • RickBRickB Posts: 395
    edited 2013-06-29 16:29
    What is the size of the proposed pc board. It might be possible to find someone to heat laminate ordinary large single sided pc board to aluminum sheets, leaving you to mill the traces and cutouts for the heat producing components. Then cut out the individual boards.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-29 23:29
    861249w.jpg

    As I have CNC, for the heat producing components, I'm cutting the square hole in the PCB, cutting the apropriate sized copper shim, fitting it under the IC, and 2nd side of it is touching the heatsink. This consumes too much time, and also introduces necessity to install additional screws, that will fix IC to the heatsink/shim assembly. Situation is even worse with LEDs - I hae large stock of luxeon rebel leds, and MCPCB for them costs aersopace-grade prices. So I have to cut individual "star" boards for them from copper. Which is also time consuming, since copper is very soft metal, it is hard to machine at high speeds - cutter gets "stuck" and broken. You can see such boards on the attached picture
    820 x 591 - 99K
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-06-30 01:41
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-30 03:31
    Wow thanks!

    When I checked it, it was not available, and only was available on ledsupply.com for $7.99 per board.

    Sure, this will help me, but in general, I still need bare MCPCB.
  • Too_Many_ToolsToo_Many_Tools Posts: 765
    edited 2013-06-30 11:35
    May I ask why?

    Rule of thumb is never build what you can buy.

    Unless you can do it cheaper (in terms of time and resoures) I would recommend buying a larger quantity to get the lowest per piece price.


    CuriousOne wrote: »
    Wow thanks!

    When I checked it, it was not available, and only was available on ledsupply.com for $7.99 per board.

    Sure, this will help me, but in general, I still need bare MCPCB.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-06-30 11:54
    Because I need to prototype/manufacture in small quantities, without time expenses associated with outsourcing the pcb manufacturing.
  • Too_Many_ToolsToo_Many_Tools Posts: 765
    edited 2013-06-30 19:02
    Understood.

    Wouldn't that goal include being able to have the PCB items mentioned on hand?...or shipped overnight?

    Unless they need significant modification, I would think the Mouser offering would be ideal.

    Now if you are prototyping or significantly changing the PCB boards, then the on site ability to CNC would be important.

    FWIW..using common and off the shelf parts is the best way to make a product especially if larger production volumes are expected.
    CuriousOne wrote: »
    Because I need to prototype/manufacture in small quantities, without time expenses associated with outsourcing the pcb manufacturing.
  • CuriousOneCuriousOne Posts: 931
    edited 2013-07-01 00:29
    Generally, I work in the following way (one of possible scenarios).

    Customer approaches - "Man, I want this light to be upgraded to leds". We discuss what output power he needs, color temperature, input voltage, etc. After all agreed, I ask him to take seat and wait or come back in 1 hour. So, customer gets finished product in very short time.

    Sure, this is the best scenario, which works only with simple orders, but 90% of orders are such simple. And thermal problems are the worst problems encountered mostly.
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