Most common trace width? - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: August 04, 2024, 02:12:07 am
content: When you design a PCB, what is the trace width setting you most often use?The reason I ask is that I run PCBShopper.com (a price comparison site for PCB manufacturing). I've set the default trace width on the quote form to 7 mils, and I think most users do not think to change it.But one American manufacturer offers much lower prices for 8 mil boards, so default PCBShopper search results exclude those deals. Another manufacturer's 2 oz copper boards require 8 mils, and their prices get excluded.Am I being overly restrictive, setting the default to 7 mils? If most people set their PCB layout defaults to 8 mils, maybe I should change my default. (I usually use 6 mils on my boards, but I might be unusual.)

author: Someone
author_rank: Super Contributor
timestamp: August 04, 2024, 02:20:53 am
content: Plenty of the volume houses are using metric as their base units and round up for wrong units. So I get finer boards at no extra cost by specifying 0.2mm

author: MarkF
author_rank: Super Contributor
timestamp: August 04, 2024, 02:37:19 am
content: I use DipTrace and its default trace width is 13 mil.I don't change it unless it's necessary.The times I have changed it have been to make it wider.Like 0.5mm or 1mm for normal traces.Why have your traces hair thin unless it's necessary?

author: exmadscientist
author_rank: Frequent Contributor
timestamp: August 04, 2024, 02:38:34 am
content: Almost always 5/5 (really 125um/125um). Manufacturers never blink at this. I could use wider copper for a lot of things, but it's not worth the increase in routing time, and my library is all set up to a 125um grid as much as possible anyway. I do use lots of fills and wide traces for power, but still on that 125um base.

author: ataradov
author_rank: Super Contributor
timestamp: August 04, 2024, 03:10:40 am
content: I default to 10 mil and drop to 6 mil when necessary.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 04, 2024, 07:55:36 am
content: There is no default. A common advice is to use tracks a little bit wider and with a bit more clearance then your PCB manufacturer's minimum specification. It's also quite common for PCB manufacturers to have different rules for different PCB's. 2-layer PCB's often have coarser rules then 4 or more layers. If your use too narrow tracks, then the quote for your PCB costs may be higher without you realizing it.But for a number. 0.25mm is pretty wide and compatible with (nearly) any PCB manufacturer. It's a good starting value for "beginners" If your PCB's get more complex or you want to route smaller PCB's, then it's easy to go narrower. With KiCad for example (only EDA suite I know) you can create a selection of tracks and then change width / clearance of the tracks, and when you make them narrower later, you can just push them aside more withe the interactive router. Going the other way is much more time consuming, as widening the tracks instantly leads to hundreds or even thousands of DRC violations because the minimum clearances are not met.And there is also current handling. A 0.25mm wide track can already handle 800mA (with 10 degree celcius temperature rise) This is plenty for all signal wires (usually <10mA DC) In principle it would also be enough for routing power to most of a PCB, but none the less, for power I tend to use at least 1.5mm, even if it's just to get power to an I2C EEPROM and does not need 3A.