Has anyone ever designed and had made a MCPCB?

[RustyKnee]

If so, did you use regular pcb software that generates gerber files?

How much did the boards cost and where did you get them made.

Cheers

Stu

 

[dat2zip]

I can answer the first question. Yes, you can use standard PCB editors and generate Gerber files. The process is similar to a standard FR4 construction.

As for question 2. There are many places that will do the job and the prices vary dramatically. Local manufacturing in the states will cost your 2X-4X the cost you can get overseas. But, overseas is hard to deal with communications, time zone, shipping.

Wayne

 

[RustyKnee]

I can answer the first question. Yes, you can use standard PCB editors and generate Gerber files. The process is similar to a standard FR4 construction.

As for question 2. There are many places that will do the job and the prices vary dramatically. Local manufacturing in the states will cost your 2X-4X the cost you can get overseas. But, overseas is hard to deal with communications, time zone, shipping.

Wayne

Cheers for the reply. I forgot I posted this and you must have replied when the notifactions were down.

Any idea what the aproximate cost in the US is? I am in the UK, but its still easier to communicate to the US if prices are reasonable.

There is a place over here i need to ask. i think they are a uk agent for a far east factory.

My problem is going to be the numbers. I am looking at prototype figurea.

Stu

 

[dat2zip]

I think you will find NRE costs in the US ranging from $750.00 to over $1500.00 + material + machine time. I had only one US quote so I'm guessing on this.

But, it seems more like high end tight tolerance FR4 PCB houses NREs start in the $750.00 range and go up from there.

Some of the precision 2 layer boards I've made requiring tight tolerances like board diameter I have paid through the nose for some stupid tight tolerances.

I once made a board that had three holes and was approximately 0.6" in diameter and had no copper on either side. I believe I ended up paying $1500.00 for 20 pieces.

Shopping around if possible will probably help scope the range of pricing.

Wayne

 

[RustyKnee]

I think you will find NRE costs in the US ranging from $750.00 to over $1500.00 + material + machine time. I had only one US quote so I'm guessing on this.

But, it seems more like high end tight tolerance FR4 PCB houses NREs start in the $750.00 range and go up from there.

Some of the precision 2 layer boards I've made requiring tight tolerances like board diameter I have paid through the nose for some stupid tight tolerances.

I once made a board that had three holes and was approximately 0.6" in diameter and had no copper on either side. I believe I ended up paying $1500.00 for 20 pieces.

Shopping around if possible will probably help scope the range of pricing.

Wayne

:green: hehe bit pricey then. I think I will try regular pcb first using the via thermal method and or using cutouts to provide precise led locating.

I can get 8 or so made for about 50 quid.

I got my last order from you the other day .

Cheers Wayne.

Stu

 

[frenzee]

Software, design and printing method are basically the same. One difference is that if you go with copper core, copper is a particularly difficult material to drill and machine in higher thicknesses. It basically gums up the drill bit, saw blade or CNC tool bit as the case may be, so be prepared of lots of broker drill bits.

If you're talking about limited quantities, you can make your own MCPCBs, if you have the equipment, materials and patience. You'll need 12 or 18 guage copper (or aluminum) to use as the core, Arcric Silver epoxy as the dielectric and copper foil for the circuit layer. For materails you can try one of these sources:

http://www.amazon.com/b/103-3270522-3479044?ie=UTF8&me=A1DJZA8PZBRKWH
http://store.electrical-insulators-and-copper-ground-bars.com/
http://www.smallparts.com/?020
http://www.nbmmetals.com/products.html
http://www.metalliferous.com/
http://www.thompsonenamel.com/products/metals/copperflatsheetrectangles.htm

Arcric Silver is available everywhere. so I won't list it here. If you need mass production, I came across this link in the past (but I have not used them myself):

http://www.bergquistcompany.com

Best of luck.

 

[OddOne]

MCPCBs are often dubious in terms of thermal transfer anyway because there's frequently an insulator in the way - the pad for the thermal junction is often insualted from the base metal so as to maintain electrical isolation, and electrical insulation is often thermally insulative as well. What makes MCPCBs worth consideration is generally the mounting and interconnection ease, not the thermal characteristics.

I've had great success with double-sided boards whose under-device vias were filled with silver solder. (Silver conducts heat better than copper, and unloads it faster than aluminum.) I use a reflow rig to solder the LED onto the board, then flip it and use a manual iron to backfill the vias by hand. Finally I float a thin layer of silver solder over the whole contact surface and lap it flat to remove irregularities. Thermal transfer efficiency is VERY good when one uses this procedure, and can approach diect-to-heatsink mounting if you're careful in your implementation.

Where I needed electrical insulation for a filled-via board, I use a very thin piece of Kapton MT film, which is a strong electrical insulator but is thermally conductive. That combo has actually worked out better than MCPCBs for some applications.

oO

 

[dat2zip]

MCPCBs are often dubious in terms of thermal transfer anyway because there's frequently an insulator in the way - the pad for the thermal junction is often insualted from the base metal so as to maintain electrical isolation, and electrical insulation is often thermally insulative as well. What makes MCPCBs worth consideration is generally the mounting and interconnection ease, not the thermal characteristics.

I've had great success with double-sided boards whose under-device vias were filled with silver solder. (Silver conducts heat better than copper, and unloads it faster than aluminum.) I use a reflow rig to solder the LED onto the board, then flip it and use a manual iron to backfill the vias by hand. Finally I float a thin layer of silver solder over the whole contact surface and lap it flat to remove irregularities. Thermal transfer efficiency is VERY good when one uses this procedure, and can approach diect-to-heatsink mounting if you're careful in your implementation.

Where I needed electrical insulation for a filled-via board, I use a very thin piece of Kapton MT film, which is a strong electrical insulator but is thermally conductive. That combo has actually worked out better than MCPCBs for some applications.

oO

LEDs like the Cree XRE and Lumileds Rebel that have a dedicated isolated thermal pad are ideal for making thin PCBs that IMHO are superior to MCPCBs in thermal transfer. The vias under the thermal pad need to be 4 or so to do a good job and do not necessarily need to be filled. Filling the vias with solder is defintiely a large plus and you can make the backside a large copper plane that is totally isolated from any electrical connections yet thermally bonded to the thermal pad of the LED topside.

You really can't do better than this and the results are impressive.

Bummer, there are not many good proto PCB houses to get thin PCBs in small quantities.

Wayne

 

[redbaron4321]

Will regular solder bond (proper wetting) of an LED to aluminum material. I ask, because I know the lead free solder doesn't work too well on copper, and wonder if it is even worse on aluminum.

Another question: Any ideas on how to solder an XP-G package to an aluminum heatsink without the risk of shorting the power leads to said heat sink?

Thanks in advance.
-Rick

 

[Mr Happy]

Will regular solder bond (proper wetting) of an LED to aluminum material. I ask, because I know the lead free solder doesn't work too well on copper, and wonder if it is even worse on aluminum.

Another question: Any ideas on how to solder an XP-G package to an aluminum heatsink without the risk of shorting the power leads to said heat sink?

Thanks in advance.
-Rick

You basically "can't" solder to aluminum, either with lead-tin or lead free solder. For regular purposes aluminum is unsolderable.