Soldering station for Weller RTP/RTM/RTU tips

Description

I want to use Weller RTP/RTM/RTU series of tips without paying for the WX station along with three different handles for the three series of tips, which would cost over 1000USD in total. I want a station with a single handle that would effortlessly work across the series, and I want a user interface that makes sense and is intuitive to use, which is rare in the professional soldering market (I am looking at you, Hakko).

Already owning the Hakko fx-950 (yes it exist, and the UI is a single analog knob instead of the fx-951 80's alarm clock UI) and the the Goot RX-802 (yes, that also exist, and is better performing than the fx-951 with a less stupid UI), I want this project to be significantly better in performance and UI than what I already have. From the prototype, it seems like this is very much possible.

Details

I started this project wishing to build the station around a pen form factor with USB PD as the power source. However, as I started using the perfboard prototype built around the USB PD idea, I realized the RT series of tips really are best used for stationary soldering and a traditional table top station form factor makes a lot more sense, let me explain. The RT pico line of tips are toothpick-thin and are great for micro soldering under a microscope, and I don't see myself ever doing that kind of work "in the field". The RT Micro line are great for general soldering, but the TS80P already exists and the type of tips available for the TS80P is growing steadily. The RT Ultra line might be good for soldering copper pipes in the field, but that seems like a pretty niche application.

The table-top soldering station form factor is not without merits, for example effortless ESD safety, possible use of high quality silicone handle cable, rotary encoder for temperature setting, easier ergonomic handle design etc.

Going forward, I'll design the PCB of this soldering station around a traditional desktop form factor, and if I ever change my mind and want to build a pen sized RT soldering station, I'll just redesign the PCB for a compact size, and most of the heating control code should be reusable anyways.

Project Logs

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Side project: Soldering iron stand
Alex Wong • 09/24/2020 at 11:27 • 0 comments

As I was going to design the station housing, iron handle etc. I thought I might as well design a proper stand for the tips as well.
The result is a soldering iron stand that works with RTP, RTM and RTU tips. To my surprise, the stand works very well with the TS80 and TS100 too! I am sure the later two in the compatibility list would make this design appeal to a large audience, so I decided to publish the design on thingiverse as well, which is my first time.
The iron rest can be tilted within a 25 degree range, and is printed in PPS, a wonderful FDM material that is wayyyyy underrated. I believe this is the highest temperature resistant plastic that can still be printed with an open-frame FDM printer, unlike filaments like PEI and PEEK. You could print PPS on a stock Prusa i3 MK3 and the resulting part would work in temperatures upwards of 200 deg C. Perhaps I'll share the print settings if there are interest in the material. Oh and did I also mention PPS is reasonably priced at 27USD per kg? I love PPS.
Link to the thingiverse thing here: https://www.thingiverse.com/thing:4605456
(It might take 24 hours from the time of publishing of this article before you can access the thing, I am a new thingiverse user)
Perfboard prototype
Alex Wong • 09/01/2020 at 15:26 • 0 comments

As I've mentioned in the project description, I started the project with a pen form factor controller in mind. So when I started to build the perfboard prototype, I decided to construct the prototype with exactly the same components as I would in a compact pen-sized PCB. This resulted in tiny components glued into a perfboard and soldered dead-bug style. Some of the more extreme circuit sections included the DC-DC buck converter and the power switch for the iron. The DC-DC converter was constructed to minimize the AC loop, and the resulting size of the converter circuit would not be much smaller on a proper PCB layout.

The soldering iron tip power switch was a p-ch and n-ch dual fet squeezed in to a 3x3mm dfn-8 package, and as you can imagine, it was a pain to solder. At this point you may wonder how bad would reworking this circuit construction be, and the answer would be surprise you. I once accidentally revered the power input and fried the DC-DC converter chip, and rework only involved cutting off the IC pins, and resoldering the chip in the same position. The process was not that much worse than working on a proper PCB.

After testing the perfboard prototype I decided to go for a desktop station form factor, where using larger parts would not be an issue, so this self-inflicted microsoldering hell is a bit moot.