Small batch, large pcb, white soldermask suggestions - Page 1
Forum section: electronics / general

author: yeah_indeed
author_rank: Contributor
timestamp: February 14, 2016, 12:11:18 pm
content: Hi everyone,I hope I'm in the right subforum for this, if not let me know and I'll delete this post.For a project I need to manufacture some large PCB's (12x48 cm / 4.72"x18.9"). The size is not because of components, but they are for an LED cube which has this size.Now, we want the solder mask to be white, and we have small single unit sockets which fit the copper wire from which the cube is constructed. The mounting holes for these sockets need to be in between 1.96mm and 1.91mm.At first we were going with PCBWay but I read they don't deliver reliable quality, especially with white silkscreen.Does anyone have a recommendation on the service we can use?

author: DerekG
author_rank: Frequent Contributor
timestamp: February 14, 2016, 01:10:46 pm
content: Quote from: yeah_indeed on February 14, 2016, 12:11:18 pmWe have had about 1500 boards (over 4 designs) manufactured by PCBWAY & all have been fine.

author: yeah_indeed
author_rank: Contributor
timestamp: February 14, 2016, 01:18:19 pm
content: Quote from: DerekG on February 14, 2016, 01:10:46 pmGood to hear, and they were white solder mask as well?

author: DerekG
author_rank: Frequent Contributor
timestamp: February 15, 2016, 12:05:45 am
content: Quote from: yeah_indeed on February 14, 2016, 01:18:19 pmI think you mean white silkscreen?We have boards with white silkscreen from PCBWAY with a line thickness of 1.5mm. We have sent away 1.2mm line thickness, but they adjust that to 1.5mm unless you want to pay extra.We have had the usual green solder mask plus red as well. The green is better for optical inspection due to the lower reflection.The last batch of boards I have ordered with blue solder mask, so we will see how that compares to the green during optical inspection (different solder mask colours cost no extra).The only problem we have had was the solder paste screen (stencil) was one up instead of two up (to match the panel). I took a photo & sent it to PCBWAY & it was replaced within 7 days via courier to Australia, all at no cost to us.

author: printedcircuit
author_rank: Contributor
timestamp: February 15, 2016, 01:03:03 am
content: do you mean the silkscreen quality from PCBWay is unreliable? as i know, the quality of the board is decent. there are few reported unclear silkscreen before. it is mainly due to unskilled worker as the silkscreen is made manually. i think that issue happen more than half year ago. the quality of PCBs from PCBWay is better now.

author: yeah_indeed
author_rank: Contributor
timestamp: February 15, 2016, 12:40:04 pm
content: Quote from: DerekG on February 15, 2016, 12:05:45 amI actually mean that the whole board is white, with black text. That's white solder mask, right?Quote from: printedcircuit on February 15, 2016, 01:03:03 amYeah, I read it herehttps://www.eevblog.com/forum/reviews/pcbway-mini-review/Also, to add, I see you are from PCBWay yourself, so I cannot trust that statement unfortunately. It is also hard to rely on reviews when you offer in store credit for positive reviews. Not the best representation for a manufacturer.

author: DerekG
author_rank: Frequent Contributor
timestamp: February 15, 2016, 04:37:55 pm
content: Quote from: yeah_indeed on February 15, 2016, 12:40:04 pmNow I understand. You did not mention above that you wanted black text.White does not cover the darker circuit board so well as it is more translucent. If you want a "good white" for your cube & not a "dirty white" you will need to ask that it be solder mask twice with the first layer allowed to dry before the second application.Make sure you get a prototype first, otherwise the answer from many/most/all Chinese manufacturers will be "yes, we can do that" ............. but they will apply the white mask only once.

author: yeah_indeed
author_rank: Contributor
timestamp: February 15, 2016, 11:28:36 pm
content: Quote from: DerekG on February 15, 2016, 04:37:55 pmThanks for your reply. It doesn't have to be perfectly colored, so I think once is OK, it's just nice to not have a green board in this application, but the color doesn't need to be perfect. Thanks again, I think we'll check PCBway out again.

author: Wilksey
author_rank: Super Contributor
timestamp: February 16, 2016, 04:42:31 pm
content: I had a white board with black text from Smart-Prototyping, and the white came out perfectly, with no issues with see through etc, mine was 10 x 10cm, that's the only time I have had a white board so can't comment on other manufacturers.P.S. Not affiliated with any PCB house etc, just sharing my experience.

author: yeah_indeed
author_rank: Contributor
timestamp: February 16, 2016, 06:43:32 pm
content: Quote from: Wilksey on February 16, 2016, 04:42:31 pmThanks for your response, never heard of them. Unfortunately they have a 40cm limit I see. But thanks!

author: Wilksey
author_rank: Super Contributor
timestamp: February 16, 2016, 10:31:08 pm
content: Never hurts to email them, they might be able to accommodate, you never know!

author: DerekG
author_rank: Frequent Contributor
timestamp: February 17, 2016, 01:43:09 am
content: Quote from: Wilksey on February 16, 2016, 04:42:31 pmNormally solder mask is somewhat opaque so that you can still see the tracks underneath for visual inspection etc.

author: Wilksey
author_rank: Super Contributor
timestamp: February 17, 2016, 09:09:01 pm
content: You can "see" the tracks, i.e. they are raised as per normal, but there was no I.S. visible through the mask as far as I remember.