Largest practical and cost effective PCB size  - Page 1
Forum section: electronics / projects

author: raptor1956
author_rank: Frequent Contributor
timestamp: November 17, 2017, 05:44:00 am
content: If you were making a product that consisted of a PCB that was, say, 400mm x 10mm and wanted to mass produce in the most economical way I'd think making a PCB with, say, 25 of the smaller units as a single PCB that is then cut into 25 strips making the fabricated PCB about 400mm x 250mm. Now the 400mm dimension seems, perhaps, a bit large but I don't know that to be the case -- what is the maximum practical size, L x W, of a PCB that can be made using the most economical methods? Secondly, after fabricating the PCB it would then need to be cut and I wonder what methods are typically used and what the thickness of cut (waste) is. The project idea I'm thinking about would require the long dimension of the cut piece to be about 400mm or perhaps a bit more whereas the other dimension could be as little as about 8mm. That being the case and if I assume a cut width of, say, 2mm, then a 400mm x 250mm PCD would yield 25 pieces of 400mm x 8mm.So, in summary:1. What are the max practical dimension (L x W) of a PCB?2. What methods are typically used to cut a larger PCB into smaller ones?3. What is the cut width?Brian

author: Rerouter
author_rank: Super Contributor
timestamp: November 17, 2017, 06:20:03 am
content: It varies greatly with board houses. As a comparison i recently ordered a batch of 25 boards that where 300x15mm, single board routed, and left panelising to them.Cost $1.07 per pcb

author: glentek
author_rank: Regular Contributor
timestamp: November 17, 2017, 06:55:16 am
content: Some years ago the company I worked for was making reed switch level probes up to 4m long. I designed a panel of 300mm x 10mm boards routed with breakaway tabs, I think about 30 per panel. Not a lot of waste and easily hand loaded and soldered before breaking off and end joining them.

author: Ice-Tea
author_rank: Super Contributor
timestamp: November 17, 2017, 07:34:44 am
content: For separating PCBs, there are a few methods:https://www.cab.de/en/electronics/pcb-separators/These are used with V-cuts. Advantage is simple:no PCB waste, fast handling time. Disadvantage: mechanical stress along the score. This means, per example, you need to stay clear with ceramics, large components etc. This can be an issue small PCBs such as yours.Another is the use of 'mouse bites'.http://www.pcbuniverse.com/articles/Mousebites.pngAdvantage is that you can choose where you'll have your mechanical stress. Disadvantage is you loose the width of a routing bit (2mm perstandard) of PCB and separting the PCBs takes a bit more work.Obviously, you can mix and match different methodologies (routing,scoring, mousebites) but in general you need to check with the folks stuffing and producing your board...

author: HwAoRrDk
author_rank: Super Contributor
timestamp: November 17, 2017, 04:47:23 pm
content: I seem to recall mikeselectricstuff talking in one of his videos of PCBs he had made that were 1m long, with the limitation simply being the physical constraints of the board manufacturer's process.

author: phil from seattle
author_rank: Super Contributor
timestamp: November 17, 2017, 05:32:21 pm
content: For something like this you need to work with the specific PCB fab. They know what works and doesn't for their process.

author: iainwhite
author_rank: Unknown
timestamp: November 17, 2017, 06:40:12 pm
content: Quote from: HwAoRrDk on November 17, 2017, 04:47:23 pm