From 4aae1cc6e6688d032a5b822cf8c625c053552639 Mon Sep 17 00:00:00 2001 From: Frederick Yin Date: Mon, 15 May 2023 20:16:07 +0800 Subject: projects/reflow-workshop: 2023-05-14 update --- docs/projects/img/reflow-workshop/paste_best.jpg | Bin 0 -> 177957 bytes .../img/reflow-workshop/qfn32_paste_sun.jpg | Bin 0 -> 402023 bytes docs/projects/img/reflow-workshop/trash.jpg | Bin 0 -> 1219270 bytes docs/projects/reflow-workshop.md | 70 +++++++++++++++++++++ 4 files changed, 70 insertions(+) create mode 100644 docs/projects/img/reflow-workshop/paste_best.jpg create mode 100644 docs/projects/img/reflow-workshop/qfn32_paste_sun.jpg create mode 100644 docs/projects/img/reflow-workshop/trash.jpg diff --git a/docs/projects/img/reflow-workshop/paste_best.jpg b/docs/projects/img/reflow-workshop/paste_best.jpg new file mode 100644 index 0000000..75a13be Binary files /dev/null and b/docs/projects/img/reflow-workshop/paste_best.jpg differ diff --git a/docs/projects/img/reflow-workshop/qfn32_paste_sun.jpg b/docs/projects/img/reflow-workshop/qfn32_paste_sun.jpg new file mode 100644 index 0000000..75fd12f Binary files /dev/null and b/docs/projects/img/reflow-workshop/qfn32_paste_sun.jpg differ diff --git a/docs/projects/img/reflow-workshop/trash.jpg b/docs/projects/img/reflow-workshop/trash.jpg new file mode 100644 index 0000000..30087f2 Binary files /dev/null and b/docs/projects/img/reflow-workshop/trash.jpg differ diff --git a/docs/projects/reflow-workshop.md b/docs/projects/reflow-workshop.md index 7539e49..95cc211 100644 --- a/docs/projects/reflow-workshop.md +++ b/docs/projects/reflow-workshop.md @@ -605,3 +605,73 @@ Monster](img/reflow-workshop/people_who.jpg) ▲ This is honestly how I feel Later, I found my bag in another room. + +## 2023-05-14, Sunday + +OK today I put my bag in the right place. And we have more tables to sit +around. This is good because I don't have to run around all the time. +I also got to use a giant LCD screen to project slides on. Overall +a significant improvement. + +Today we have 9 people coming. That's one more than yesterday, but we're +more prepared than ever. + +One person did a perfect paste job in one go; most did 2, 3, or 4. For +some reason the people today are really into reworking. One of them +reworked a near-perfect board only to end up with the same thing. But hey, +practice makes near-perfect. + +This trend of endless reworking brought us behind schedule. We expected to +move on to pick & place at 19:30, but didn't manage until 20:something. At +least they're having fun?? + +I really should have forbade reworking once it's good enough. + +Introducing today's contenders in the QFN arena: + +![Four decent QFN32 paste jobs](img/reflow-workshop/qfn32_paste_sun.jpg) + +The first one is the one-go job. Pads 27-31 didn't seem to catch any +paste, but that's fine because we can fix that at the end. The +bottom-right is an outright expert. They somehow managed to separate +_every single pad_. + +This person's job overall is also impressive: + +![Paste job with very few defects and clean outline on every +pad](img/reflow-workshop/paste_best.jpg) + +▲ D6 and the 0402 region are _flawless_ + +Pick and place is easy. And since I have slides to help me today, it was +a piece of cake. Only one person had challenge understanding the +orientation of the RGB LED, and another misplaced the speaker by 90 +degrees. Other than that, no problem at all. + +And as always, now the job is almost done for everyone but me. We ran five +rounds on the hotplate. Twice I forgot to monitor temperature and let it +go too low, but luckily nothing went wrong. About 2 or 3 boards needed +manual fixups, like un-shorting resistor packs, but after that every +single one works. All the LEDs light up, too. + +One interesting problem: on one board the sound is intermittent. I pressed +down the MCU, which seems to solve the issue for once and for all. + +We ended at around 21:40, but then one person came back telling me their +battery holder broke. The positive contact snapped off. The only way is to +replace it, so that's what I did. + +One remarkable observation: despite the facts that + +- my uni is mostly boys +- my major is mostly boys +- TechJI is mostly boys + +this workshop has more girls. This is really nice, because I experienced +a level of diversity not present in a room of dudes. This is the future we +want. + +At the end we took out more trash than we ever imagined: + +![A box full of waste: wipes, packaging, bubble wrap, +etc](img/reflow-workshop/trash.jpg) -- cgit v1.2.3