Single sided PCB on metal surface - Page 1
Forum section: electronics / projects

author: electr_peter
author_rank: Unknown
timestamp: February 21, 2015, 08:57:45 am
content: In found interesting PCB on metal surface. PCB contains motor with motor driver, it is used in laser printer imaging head.As you can see from the picture, supporting material is aluminium, PCB is single sided. It has soldermask and what looks like a normal copper traces. Soldermask is green-blue colour (is suspect it is transparent green, metal surface gives slight blue tint). Soldered component are surrounded with black material.Metal thickness is 0.8mm.IC number: Panasonic AN44000A 348A318U. Maybe someone knows how to drive this motor?Have you seen such metal PCBs in other devices? How do they make it?

author: peter.mitchell
author_rank: Super Contributor
timestamp: February 21, 2015, 09:04:29 am
content: metalcore pcbs are quite common in the LED market - the provide a good way to heatsink the chips.no idea how they're made

author: Pjotr
author_rank: Frequent Contributor
timestamp: February 21, 2015, 09:11:43 am
content: Those as made as any other multilayer PCB.

author: electr_peter
author_rank: Unknown
timestamp: February 21, 2015, 10:43:17 am
content: I think topic "History of PCB construction techniques, common and not so common PCB materials" could be an interesting EEVblog episode.

author: Flenser
author_rank: Regular Contributor
timestamp: February 21, 2015, 11:27:28 am
content: 10 boards for US$60 on ebay. I saved this link from another post on this forumhttp://www.ebay.com.au/itm/Aluminium-base-PCB-manufacture-etching-low-price-fast-/290575172294?pt=LH_DefaultDomain_0&hash=item43a7a142c6

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 21, 2015, 04:33:59 pm
content: Quote from: electr_peter on February 21, 2015, 10:43:17 amHere's some historyhttp://www.vintagetek.org/tektronix-printed-circuit-boards-1969/(warning: extraordinarily loud audio)Also quite awesome if you have nostalgia for the 1960s/Space Age.Then there'shttp://history-computer.com/ModernComputer/Basis/printed_board.htmlhttp://www.google.ca/patents/US3102213

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 12:41:00 am
content: Actually those metal core PCB are extremely useful but not used that much except as mentioned earlier for LED lighting.That is to bad more people should take advantage of this type of PCB's.My latest project called Solar BMS (Battery Management System) takes advantage of this type of PCB.All the power mosfets and current shunts are mounted on this PCB that also acts as back plate for the case and it can be installed on an additional heatsink when required.There is just about 100um layer of Teflon between the copper trace and usually aluminium as metal core and this allow for a great thermal transfer and much larger currents with not that much copper.My latest design can handle simultaneous charging with 120A and discharging same 120A that will be on Kickstarter soon and you can see details about it on my webpagehttp://electrodacus.com

author: langwadt
author_rank: Super Contributor
timestamp: February 22, 2015, 01:06:14 am
content: Quote from: Flenser on February 21, 2015, 11:27:28 amyou really have to check the specifications, if it is just regular prepreg slapped on a piece of alu the performance isn't so impressive

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: February 22, 2015, 02:54:00 am
content: It is going to be hard to route everything on single side. I guess there will be lot of bridges. How do you make these bridges - with 0 ohm SMD resistors?

author: Len
author_rank: Frequent Contributor
timestamp: February 22, 2015, 03:05:29 am
content: Quote from: Alexei.Polkhanov on February 22, 2015, 02:54:00 amYes, you can see a couple of those in the photo in the OP.

author: Pjotr
author_rank: Frequent Contributor
timestamp: February 22, 2015, 10:13:18 am
content: Quote from: langwadt on February 22, 2015, 01:06:14 amI've visited a PCB factory and that was actually the way it was done. Vias and multilayer are no problem with buried vias. Performance also depends on the thickness of the layers (which can be very thin as you can see on the picture of OP). But they still prefer regular multilayer and using 2 power planes inside the board of 4 OZ copper for complex boards, because of thermal expansion balancing.Although the board making is not complex by itself, the reflow process is very critical due to the large amount of heat such boards take (and hold) during reflowing.

author: wagon
author_rank: Frequent Contributor
timestamp: February 22, 2015, 11:15:38 am
content: Quote from: Alex Eisenhut on February 21, 2015, 04:33:59 pmThank you for these links, awesome stuff!

author: langwadt
author_rank: Super Contributor
timestamp: February 22, 2015, 02:47:17 pm
content: Quote from: Pjotr on February 22, 2015, 10:13:18 ammy point is that the cheap IMS boards are probably just using regular FR4 prepreg, the real thing uses a special heat conducting prepreg that is 10 times better

author: max_torque
author_rank: Super Contributor
timestamp: February 22, 2015, 04:05:49 pm
content: IMS (Insulated Metal Substrate) pcbs are rather handy for anything that makes heat! I've done a 500A rms 3 phase mosfet inverter that only used ~100cm2 of pcb real estate! (water cooled directly on back of IMS) Seeing 500A traveling across copper traces on the pcb without melting is rather eye opening!

author: electrodacus
author_rank: Super Contributor
timestamp: February 22, 2015, 09:57:45 pm
content: Quote from: max_torque on February 22, 2015, 04:05:49 pmThat is quite something 500A. I have used this on my last project up to 80A with 1 Oz copper on a 2.5mm Aluminium substrate but the next version of Solar BMS will need 3Oz for 120AI hope more people see the benefit of this metal core PCB's.Do you have any photos of that board ?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 23, 2015, 01:33:49 am
content: Quote from: max_torque on February 22, 2015, 04:05:49 pmRC "toys" are getting there.http://www.hobbyking.com/hobbyking/store/__25608__Turnigy_Fatboy_V2_300A_ESC_4_15S_OPTO_.htmlI couldn't quite believe it at first with my first boat, but it works. For like 5 minutes at a time and needs water cooling too.

author: electrodacus
author_rank: Super Contributor
timestamp: February 23, 2015, 01:42:49 am
content: Quote from: Alex Eisenhut on February 23, 2015, 01:33:49 amThat seems the same size and weight as my Solar BMS I will like to see what they use inside. I needed to go for the lowest RDSon 60V mosfet available for 2x 120A continues(120A charging with 120A discharging at the same time). Of course total TDP on my device is 22W so no water cooling is needed just a small passive heat-sink.I will like to see how it look inside are there any photos with one of those open ?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 24, 2015, 05:32:02 pm
content: Nah, at least not mine. Typically they are built face down, the top of the controller is just the regulator, the micro, the power FETs are on the bottom coupled to the heat sink.There isn't much to see, it's a brushless controller driving 6 big FETs and a PCB with a whole lot of vias, and 200C silicone wiring that gets pretty hot.

author: electrodacus
author_rank: Super Contributor
timestamp: February 24, 2015, 05:42:45 pm
content: Quote from: Alex Eisenhut on February 24, 2015, 05:32:02 pmI was thinking that is build on a metal core PCB. Thanks for the replay.Also I think those 300A are less likely to be continues since current is based on load and not sure what voltage drop is on motor windings at this 300A but even at 2V that is a 600W almost one HP motor.What motor do you use with this controller?

author: M. András
author_rank: Super Contributor
timestamp: February 24, 2015, 06:38:49 pm
content: Quote from: electrodacus on February 24, 2015, 05:42:45 pmnitro engine replacements for fpv and big jet models, they pull a few kw from the battery during takeoff and manuvershttp://www.hobbyking.com/hobbyking/store/__25413__Turnigy_RotoMax_150cc_Size_Brushless_Outrunner_Motor.html

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 24, 2015, 07:01:25 pm
content: Quote from: electrodacus on February 24, 2015, 05:42:45 pmBoat guys use monstrous motors, but keep in mind this stuff is on the thin edge of blowing up at any time.Batteries are abused, wiring gets hot, etc. It's not meant to run more than say 10-15 minutes at a time. You can run longer with lower power stuff. Boats are lucky because they float on their heat sink. But there is no pump, you need to move for the water to get a "head" through the plumbing in the rudder.Big planes are trickier, you want to put the heat sink in the airflow for a ducted fan, but you don't want it to get too heavy.There are super light "foamies" basically made of "for sale" signs that can use free-air controllers and smaller motors.There might be metal core PCBs, it's hard to tell, this stuff changes almost monthly.Typically on boats it's not just the controller that's water-cooled, also the motor and on really big boats the shaft bearing too.Motors like thishttp://www.hobbyking.com/hobbyking/store/__31677__Turnigy_AquaStar_4084_1050KV_Water_Cooled_Brushless_Motor.htmlBasically everything gets hot, and needs to cool down. Boats take the crown for monster power.Your intuition may be wrong if you base it on industrial motors and ratings.Oh check these guys outHehehe, the scale electric boats get pretty close LOL

author: peter.mitchell
author_rank: Super Contributor
timestamp: February 25, 2015, 12:16:08 pm
content: Quote from: Alex Eisenhut on February 24, 2015, 05:32:02 pmThe very high end ESCs for RC cars are pretty nuts though, 3 H bridges, each with 10 FETs in parallel for each side of the H bridge(60+ FETs), thick copper on multilayer boards, copper busbars, via stitching out the waazoo to one side left blank and pressing down on to a thermal pad against a heatsink.This has some pics of an entry level controller for 1/5th scale - it's pretty garbage.http://www.rc-monster.com/forum/showthread.php?t=31997I can't find any teardown pics of the ones that my firends use buthttp://www.mgm-controllers.com/cars/speed-controllers-escs/tmm-25063-3-for-cars-x2-series.html?set-region=3they are much better built and will actually do their rated spec.

author: electrodacus
author_rank: Super Contributor
timestamp: February 25, 2015, 05:06:17 pm
content: Quote from: peter.mitchell on February 25, 2015, 12:16:08 pmThat is what I'm saying in this cases a metal core PCB will be a much better solution. They use so many parallel mosfets because they use the very cheap ones they find on the second hand market. A modem one can usually replace all those parallel mosfets. I use for example the IPT007N06N in my Solar BMS on metal core PCB that mosfet is expensive but not for the characteristics it has just 0.66mohm RDSon