Is it hard to reach basic PROFICIENCY in 0.6 x 0.3mm RC and 0.5mm leadless chip - Page 1
Forum section: electronics / projects

author: Wilson__
author_rank: Frequent Contributor
timestamp: August 11, 2024, 01:40:43 pm
content: New to SMD but done through hole for long.How doable is 0201(0.6 x 0.3mm) RC and 0.5mm leadless chip if we buy propertoolsand play withsolder-practiceboards? If it is too difficult, we can forget it and pay PCBassembly factoryto do it? Board has relatively small number of components.Had watched some youtube videos on 0201 (0.6 x 0.3mm). Do you need to be 'gifted' with steady hands or anyone can do it, with proper practice and tools? I meant, it is perfectly doable in factory where they select the better percentage of people to this task and other people doing works that are less demanding on steady hands.Many thanks.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 11, 2024, 02:55:14 pm
content: Entirely possible. I have done many hundreds of leadless 0.5mm pitch packages (inertial measurement units, sensors etc.) and every time I'm surprised how well it works out. My hands are a bit shaky and I'm never able to position them correctly on the pads. As long as solder paste print quality and paste alignment is OK (so concentrate on your stencil technique!), even gross misalignment of square-ish LGA packages seems to work out, 99% of the time.Now 0201 is a bit hard to grab with tweezers, and when you place small parts like that you inevitably touch the paste with tweezers, so wipe them clean after each placement. All entirely possible, but if you have to do hundreds, it's going to suck.Tools: I tape or glue a few spare boards (of exact same thickness, this is important, so preferably same design or something of same stack-up from same manufacturer)) on a melamine board, so that the PCB to be produced snugly slides between and stops at a repeatable spot. Then I just tape the frameless stencil from one edge so I can lift it. Then I use an expired credit card or similar as a squeegee to spread the solder paste. I have made batches of up to 30-40 boards with consistent enough print alignment and quality like this. Can't get cheaper than this.It's worth quickly checking paste print quality with a microscope or a loupe as you can clean and repaste in a minute, but if you commit to carefully placing 100 components on a poor quality paste print, you lose a lot of time.I used to have a simple DIY vacuum pick up pen, but really, tweezers are fine. If you do large batches, you should be just using a contract manufacturer anyway. The point is to get a few prototypes donequickly.

author: ebastler
author_rank: Super Contributor
timestamp: August 11, 2024, 04:00:28 pm
content: I agree with what Siwastaja seems to imply: ICs with 0.5 mm pitch are actually easier to handle than the 0201 passives. The challenge is not so much in the placement, but in grabbing those small 0201 parts with tweezers.+1 for the solder paste stencil too. It's the way to go, I would say; more reproducible dosing and faster than a handheld dispenser.Also, do use a stereo microscope to see what you are doing! I prefer optical over camera-based, for a lag-free stereo view. I use a rather cheap one, which has a slightly narrow field of view (due to its 10x fixed magnification) but a comfortably long working distance which gives me plenty of room to maneuver. See the picture below -- sold under the SWIFT brand here, but other brands as well. I actually prefer the two gooseneck lights over a ring light, since I can adjust the illumination angle to give me good contrast and e.g. read IC markings better.Do you really need to use 0201?? I'd say you need to have a compelling reason to bother with these (for hand placement); and even 0402 I only use when I have to. At 0603, things start to become comfortable for me, and I don't shoot parts across the room any more as they escape my tweezers...

author: Wilson__
author_rank: Frequent Contributor
timestamp: August 11, 2024, 06:41:09 pm
content: Huge thanks for inputs from the community. Just tried iron-solder 0603 (imperial) that I have on hand and it works using through hole tools! Well 0201 is 10 times smaller. On youtube, hot air is easier than solder iron. Place part on atop solder paste and surface tension will right it.Good tips on sitting position, hand support, etc. are becoming critical for SMD when they were not much effect on through hole.

author: bson
author_rank: Unknown
timestamp: August 12, 2024, 04:51:35 am
content: I use both hands, bracing and leaning against the table. If you use both hands they tend to cancel out, especially if one rests on the other.It helps to have a PCB holder of some kind, even a very simple springloaded one. It keeps it steady above the desk surface and level under the microscope as you move it around. I have a cheap AliEx something or other for small boards; for larger boards I use PCBites grippers (https://sensepeek.com/). I really do want their probe grippers...

author: ArdWar
author_rank: Frequent Contributor
timestamp: August 12, 2024, 06:03:15 am
content: You don't even need steady hand that much for soldering/reworking fine pitch ICs. If the IC pads and PCB footprints are designed properly (balanced solder area, meniscus, and all) you can leave the fine alignment to solder surface tension/cohesion. Just need enough flux and decent enough initial alignment.Common problem for soldering QFN and the like at hobbyist level is that it often sit in the drawer long enough that the surface start to oxidize. You may need to "refresh" the surface first by running a fresh solder blob thru all the pins before you reflow it into a PCB.0201 passives however... I swear flux outgassing alone is enough to fling one across the room, let alone hot airflow...

author: Phil1977
author_rank: Frequent Contributor
timestamp: August 12, 2024, 07:17:41 am
content: I can't live without a little hot plate for these activities. Either for a complete reflow, or just for preheating so that everything with the iron can be done more slowly.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 12, 2024, 07:29:53 am
content: In absence of oven, combination of hot plate and hot air is simple and flexible. A regular hot air station does not blow widely enough and is fine only for very small PCBs. Especially if you have multi-layer PCB with large planes, it takes a lot of effort to push that heat from top side using air alone. Hot plate, even something which isn't capable of doing the work alone (say, 150-160degC) is super helpful, then the role of hot air is to heat thecomponentsand just push the PCB temperature over the edge.

author: Phil1977
author_rank: Frequent Contributor
timestamp: August 12, 2024, 07:44:18 am
content: Yes - even if you just set the hotplate to a temperature like 120-150°C that should not be dangerous to the components then all hot-air and also hand soldering gets much easier.Not exactly on topic but anyhow worth mentioning: Soldering on highly thermal conductive metal core PCBs: It´s practically impossible for larger components without preheating.