Calculate Mass of PCB - Page 1
Forum section: electronics / general

author: Apn15
author_rank: Contributor
timestamp: June 28, 2021, 03:55:51 pm
content: I need to calculate the mass of a PCB I designed in Altium, and I have no idea where to start.Does Altium have a feature for the mass of a PCB?

author: Apn15
author_rank: Contributor
timestamp: June 28, 2021, 04:17:29 pm
content: Understood. Thanks for the information.The MCAD plugin may be the best approach to this problem, however I can see there will be difficulty when wanting to add in the components.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 28, 2021, 06:26:37 pm
content: The next best tool might be pouring a polygon on an unused layer (mechanical say?); check that it's clearing around keep-outs (holes, cutouts, etc.). Then measure its area.Which, uh, still isn't that easy to do, hmm; check the forums, I recall a thread about measuring polygon area. Maybe it can't be done directly, or in any convenient (even relatively roundabout) way.If nothing else, I think the area can be indirectly measured by doing a binary search on "remove islands less than X". By that I mean, editing the field, repouring, and repeating until the whole thing (assuming it's contiguous) just disappears at one value. This is, not all that roundabout really, but it sure isn't convenient...Tim

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: June 28, 2021, 11:15:21 pm
content: Silly question, why not just build 5 or so pcs and get the average weight from that?

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: July 15, 2021, 04:06:47 pm
content: Just to shed some light - the MCAD plugin isn't particularly useful here - it's JUST a connector for rapid back and forth MCAD integration.If I were in your shoes, I'd export the board from altium as a .STEP, import that into Fusion 360 (my MCAD of choice), assign physical materials with appropriate density to each component and to the PCB, and then calculate the mass parameters of the board using that in MCAD (not actually sure how to get a mass roll-up like that in F360 but I can't imagine it's too hard)Pain points will be 1) being accurate about component "density," since components are a mix of materials in inconsistent quantity. A larger QFP with a leadframe and/or leads will be denser than a DIP that's mostly plastic, and a WLCSP, while light, will be much denser than anything with plastic, etc. 2) being accurate about copper. I don't think Altium's STEP export includes copper geometry, and I know that the MCAD connector plugin CAN do that, but you have to pay extra for Altium 365 Premium to get it (probably because they know you only care about copper geometry if you're trying to do really accurate massing or thermal simulations in an external tool probably more expensive than Altium itself).If all you need is total system weight, you're probably best off putting together a spreadsheet of best guesses and summing that up, then fabricating to see how close you got. Something like:* copper (assume the weight of unbroken foil on each layer, which'll be close if you use ground pours)* FR4 (you know the area of the board, the thicknesses of the layers and can look up density)* Solder (multiply the solder mask layer area times a reasonable thickness for the paste stencil, and ballpark the density of the paste)* Components (probably have to measure each manually)