Plated Cutouts in PCB Manufacturing Process - Page 1
Forum section: electronics / projects

author: tarun172
author_rank: Regular Contributor
timestamp: October 10, 2014, 08:43:30 pm
content: All,I have a question on PCB manufacturing process. When a supplier says "Plated cutout is not available in Standard spec; we will run your design with cutouts non plated", is he talking about non-plated and plated through hole on the PCB? I am trying to understand how it is going to affect my design.- tarun172

author: Sebastian
author_rank: Regular Contributor
timestamp: October 10, 2014, 08:57:20 pm
content: They are most likely just talking about milled holes. So normal vias and round component holes should be no problem.

author: Jeroen3
author_rank: Super Contributor
timestamp: October 10, 2014, 10:02:37 pm
content: Any non-round shape will be made by the milling machine. And since a lot of pcb's only require milling at the end for some cutouts, panelizing or special shapes. I think milling before plating the holes is an extra step.

author: nctnico
author_rank: Super Contributor
timestamp: October 10, 2014, 11:47:02 pm
content: I don't see how milling is an extra step. The plated thru holes must also be drilled prios to plating & etching. The only thing needed is swapping the drill for a milling bit. Unless... the PCB house uses an old drilling machine which can't mill.

author: Christopher
author_rank: Frequent Contributor
timestamp: October 11, 2014, 09:49:51 am
content: Plated milling requires an extra step as regular milling is done right at the endPlated drilling and milling is done ffirst

author: SeanB
author_rank: Super Contributor
timestamp: October 11, 2014, 11:08:36 am
content: You will pay more, as they have to add the milling bit to the carousel just for your board and lose a position for regular drills so extra work on the operator's part. Likely drilling is done on one machine, and then milling is a final process far down the line. Your plated slots means they have to do special handling on your boards manually. That costs time and extra operator work, so they will likely only do it for an extra fee, on request only.You start with copper clad board, then drill, then mask, then etch, then soldermask, then silkscreen, then test then finally separate the boards by milling.

author: Torrentula
author_rank: Regular Contributor
timestamp: October 12, 2014, 10:36:32 am
content: I've worked at a smallish PCB manufacturer for a couple of weeks during summer and at least there the PCBs are milled right at the end after the solder mask has been applied and the final ENIG finish has been plated.This is because the PCBs are actually handled in big panels and then right at the end cut out with the router to either a smaller panel size for the customer's pick and place or even into single boards.The through hole drilling is done on a different machine than the outline routing/milling, so there's an extra step, another operator having to work another machine which will add cost to your PCBs.Added to that a through plated slot would be done right at the beginning of the process because you also need to galvanically deposit copper on the inner walls of the slot, not only Nickel/Gold (ENIG).

author: Smokey
author_rank: Super Contributor
timestamp: October 13, 2014, 02:47:37 am
content: One more thing to watch out for. Depending on the size of the thing you are trying to solder into a slot, it can be very hard to get a good solder connection on both the top and bottom of the board if the slot isn't plated. You would think it wouldn't be that hard to get the solder to flow down the lead and on to the other side of the PCB, but it really doesn't want to do that. If you have access to both sides you might be able to get it to work, but if you only have solder access to one side its really hard. If you need to solder something in a slot, pay for the plating.If you really really can't get it plated and you only need a couple boards for something non-production, I've used a row of large plated holes that just barely don't overlap and then snip the middles out with some side cutters to make a slot. It's not pretty, but what's left of the barrel of the plated holes usually lets the solder flow through. Just don't overlap the drill hits or they won't make the board.

author: sca
author_rank: Regular Contributor
timestamp: October 13, 2014, 01:01:43 pm
content: I recently designed a board to edge connect into a multi-format D connector. It therefore needed 2 large slots with edge plating to connect to the high current pins.With plenty of time to spare I prototyped it with Elecrow, and made a note to myself on the mech layer to ensure that the production boards were edge plated, reasoning that I could manage without it on the prototypes.I was very pleasantly surprised to receive the boards with the full edge plating, with no queries or extra charges.sca

author: tarun172
author_rank: Regular Contributor
timestamp: October 13, 2014, 01:56:53 pm
content: Thanks you all. I did not think milling would be an extra step like Jeroen3 pointed out. I used a connector which use a square shaped through-hole connection. They indicated that they are not going plate these square cut-outs for standard order. Fortunately, the impact on design will be minimal.- Tarun

author: Rufus
author_rank: Super Contributor
timestamp: October 13, 2014, 02:08:13 pm
content: Quote from: nctnico on October 10, 2014, 11:47:02 pmSpindle bearing requirement for high speed drilling with no side forces and much lower speed routing with side forces mean a single machine can't do both well. Some machines have dual spindles to cover both requirements.Also routed edges are not as 'clean' as drilled holes so the boards will probably be put through an additional chemical desmearing process before plating.