Proto full assy cost, ideal board dims, and a single thru hole component. - Page 1
Forum section: electronics / general

author: viper
author_rank: Regular Contributor
timestamp: October 08, 2025, 06:27:13 pm
content: A few questions. As I shape up a design, it's looking like due to component sizes these days, the board will shrink quite a bit. The question here is how hard should we be pushing to shrink it as it relates to PCB mfg costs? Right now, it's looking like a 1.5x2.5" board will work, or let's say 3.75sqin as I can scoot things around. Ideally I'd like to nest multiple boards/sheet. We can break them apart here if needed. I realize about testing but I doubt that will be cost effective. I think we are best to do that in house so we can both do a quick function test, then move right to programming in the same fixture.As this relates, i'm curious if there are any standard or most common sheet sizes to consider if nesting a full sheet? Is there a preferred method for breaking apart? I've seen types of scoring and/or routing. This does not need to be aesthetic, just functional.i have realized that due to the size of the ICs we are using, DIY is mostly out. I need to start the process of understanding proto costs to see if we need to just budget for that, even if we have to go through a few iterations. In short, it might be best to just design and build like it will work.We also have one power resistor that is designed to bleed off about 1/2W of power at times. It will get hot. I might prefer an axial lead for this to both keep it up off the board, and better allow for any expansion from heating. Not sure if a single thru hole component during mfg is a big issue? If so, we have no problem taking care of that one as we might need to make small value adjustments anyway.Thanks!

author: Matt-Brown
author_rank: Regular Contributor
timestamp: October 08, 2025, 06:40:54 pm
content: When you say multiple boards per sheet. I assume you mean same board assembly but many on a panel?raw pcb mfg usually goes like an 18x22 inch sheet (dont quote me, but I am close). Most smt machines wont handle that though, so I would stick to circa 8.5x11 (sheet of paper). So you would get 10 or 12 per sheet which is good.If board is rectangular (no curved edges or indents and also no overhanging parts I would go for v-score and route. add rails all around of 0.3 inches for machines to grab and fids on each board and on rails (all corner edges).1 t/hole part and off the board does add cost as you now have more processes (wave or hand soldering and lead forming). I also assume assembly is one sided (one sided smt is the cheapest labor wise).PCB standard fr4 with 2 or 4 layers and 0.062 inch thick is kind of standardso lets say 12 part types and 50 placements you would be circa in the $3 range for pcb and assembly depending on volume and the parts on it

author: viper
author_rank: Regular Contributor
timestamp: October 08, 2025, 07:03:27 pm
content: Quote from: Matt-Brown on October 08, 2025, 06:40:54 pmAppreciate. I should have added more info. yes, all the same board, 2 sided, components only on one side. Certainly will have some vias but nothing crazy. Overall simple board. 50 components/board is probably very close. If you est $3 at what I assume is per board with a single nested sheet of say 10 boards? I break apart and test? Still probably a good proto direction for us. If we need to make adjustments, we do have a microscope and hot air.

author: viper
author_rank: Regular Contributor
timestamp: October 09, 2025, 07:38:09 pm
content: Rather than another thread, figured I'd ask another question. Components. I have noticed places like JLC have serious inventory but I don't know how to navigate their parts vs ours. Some of the ICs are pretty specific and likely not stocked. How is that handled? Do we send them parts? What about more simple passives or what we have is polyfuses? Do they recommend what they stock and we need to then eval if those are acceptable substitutes?

author: thm_w
author_rank: Super Contributor
timestamp: October 09, 2025, 08:43:12 pm
content: Quote from: viper on October 09, 2025, 07:38:09 pmhttps://www.eevblog.com/forum/manufacture/deciding-on-generic-parts/https://www.eevblog.com/forum/manufacture/finding-parts-on-jlcpcb/You can find threads here.If they don't stock the part you can send it to them.https://jlcpcb.com/help/article/How-to-consign-parts-to-JLCPCBhttps://www.reddit.com/r/AskElectronics/comments/1cwq6tf/consign_parts_on_jlcpcb_purchased_from/

author: viper
author_rank: Regular Contributor
timestamp: October 09, 2025, 09:17:37 pm
content: Really appreciate. I will soak that up but I did a little price comparing on the parts I need. Digi vs JLC. The price is SO much different, it can't be believed! JLC is like 1/10th of the price! Are these guys running legit chips or is all that fake goods?Another issue I have is we are looking at one TI chip that is apparently newer and just can't even get them! Digi, JLC, no one has them, but JLC shows a good price.

author: thm_w
author_rank: Super Contributor
timestamp: October 09, 2025, 09:31:17 pm
content: Quote from: viper on October 09, 2025, 09:17:37 pmJLC parts are genuineDigikey has huge markups for various reasons (free shipping, labor costs, etc).

author: viper
author_rank: Regular Contributor
timestamp: October 09, 2025, 09:39:43 pm
content: Honestly, the numbers are game changing for our budget and component selections! May I ask if there are many with this sort of "one stop shop" and good web interface? I've been away from this too long to even know the players. PCBway keeps coming up. Rather stick with someone all the way through production qty.

author: free_electron
author_rank: Super Contributor
timestamp: October 09, 2025, 11:09:41 pm
content: JLCpcb is good.- standard panels are 18x24 or 18x12. but usable size is like 16 x 22 and 16 x 10. they need tooling rails- when selecting parts : make sure to select as much as possible from the "BASIC" poolwww.jlcpcb.com/parts. Anything not in that pool incurs a 3$ fee to load the reel.- design your board to be able to depanelize using v-scoring but only in one direction. Use gap milling in the other direction. You can create arrays on their web interface. Select a gap between stripes. Typical gap is 2mm as that is the standard routing bit size. anything else costs money- if you are using v-scoring : there are rules.-- No components can cross the score line ( no connectors that hang over an edge or end up in an adjacent board. it is ok for those to land in the contour. essentially you have two opposing sides where nothing can stick out, and two sides where it can.)-- you need a distance for copper to edge of board of no less than 0.8MM-- when using SMD parts : no ceramics close to the scored line. If you must : short side towards scoring line. The board is under stress when depanelizing, you don't want resistors and caps to crack.

author: viper
author_rank: Regular Contributor
timestamp: October 09, 2025, 11:32:45 pm
content: Quote from: free_electron on October 09, 2025, 11:09:41 pmThank you! really great post. I'm curious since I have not walked through all their stuff yet, is it pretty intuitive on seeing value in complete panel population? IE, buying qty based on a loaded panel? Also, do they usually do the depanelizing there?Oh, and you mentioned about the 'basic pool'. So if a component is needed, but not on that list, the entire batch, whether 1-20 board, is hit with a $3 fee per component that is not on the list? Ha, I can't even imagine most of mine would be. But I understand the R&D and proto path. Just amazed how far things have come since we last did an electronics product.

author: viper
author_rank: Regular Contributor
timestamp: October 10, 2025, 12:01:52 am
content: OK, confused. I was looking up parts at m.jlcpcb.com. Then at jlcpcb.com/parts. Radically different pricing! can someone tell me the difference?

author: free_electron
author_rank: Super Contributor
timestamp: October 10, 2025, 03:12:26 am
content: Quote from: viper on October 10, 2025, 12:01:52 amthat pricing includes the tooling cost to load the parts. The 3$ is per reel they need to load. So if you are building something that requires 6000 of a resistor you will be hit with 6$ . A reel holds only 3000 or 5000 so you need 2 reels loading.If you use parts from their "basic" collection there is no load fee as those parts are by default on their machines. they are often used commodity snot like 100nf , 1k 10k and many other resistors/caps. they have a select number of transistors/diodes as well.If you are cost-sensitive it is worth swapping out parts. I did a board last week where i swapped stuff to their basic as much as possible. knocked my assembly price for 5 pieces from 270$ to 80$ ! The bulk of the cost was in reel loading.

author: viper
author_rank: Regular Contributor
timestamp: October 10, 2025, 03:51:26 am
content: Quote from: free_electron on October 10, 2025, 03:12:26 amThanks. I'm still trying to find something on their site that explains this, but as for some of the sample parts pricing, I am running things out to 500qty, so if there is a $3 fee to load a reel, that would be covered in a couple parts. As an example, ESP32-S3. the M.JLCP page is like $0.56 in qty, but JCP parts is like $4.00. Just trying to understand it. I haven't really found any place to get the ESP at dirty prices, and not willing to use a sort of knock off.And whatever "extended" means, that's pretty much ALL of my parts...lol I really can't substitute on ICs.