If you work with surface mount components, you might want an air pickup tool (sometimes called air or vacuum tweezers). You can find inexpensive ones that use a bulb or spring mechanism (like a solder sucker). While these are cheap, they don’t work very well. [Natsfr] had one of these cheap tools and decided to add a proper pump to make it work like a much more expensive tool.
This is a fascinating take on building your own pick and place machine. It does an amazing job of automating the hardest parts of hand assembly, while relying on human dexterity to achieve the hardest parts of automation. It’s a semiautomatic pick and place machine driven by an Arduino and controlled by an Android tablet.
The machine is built in two parts. The portion in the upper left feeds components from reels and is fully automated. The portion on the lower right consists of a padded arm-rest which slides smoothly along two axes. A mechanical arm with multiple articulations is attached to the end, culminating in a tip connector for some vacuum tweezers. Right handers are the only ones who will find this convenient, but oh well. The clip after the break shows it in action. The assembly technician first selects the component from an icon on the Android tablet. The reel machine then dispenses that part, which is picked up by the vacuum tweezers using the left hand to switch the vacuum on and off again. If the part orientation needs to be rotated it can done using the jog wheel on the Android app. It smooth, quick, and best of all, clever!
Everything you need to build a vacuum tweezers is laid out in this image. The parts should run you about $20 and when you’re done you’ll have the perfect tool for placing very small surface mount parts for reflow soldering.
This project uses the same concept as other fish pump tweezers projects but builds upon them with some interesting additions. The first step in the conversion process is to tear down the aquarium pump to reverse its flow. There are several steps but all-in-all it’s not very difficult. With the source of vacuum established [Technically Artistic] begins work on the business end of the tool. This is where the array of different pens see some action. The large blue one is the outer assembly, with the others combining to help connect it to the plastic tubing. The business end is made from a needle adapter for an air compressor, with an alligator clip cleverly modified to serve as a valve to release the parts from the tip.
We try to stick to the 0805 parts because they’re still big enough to solder by hand. But [Scott] shows us that it doesn’t take too many special tools to reflow fine-pitch components at home. In this case he’s using 0402 resistors, a footprint that we consider functionally impossible to solder using an iron.
The two parts of the equation that he spent some money on are professionally produced PCBs and a solder stencil. The stencil is laser-cut from Kapton, which is heat-resistant so it doesn’t warp during the cutting process. An acrylic frame holds the PCB in place, and he just tapes the stencil over it and uses a chunk of acrylic as a squeegee to evenly apply the solder paste. Splurging on the PCB and stencil means you’ll achieve tolerances which lead to success.
The next issue is placing the components. [Scott] shows off some vacuum tweezers he built using an aquarium pump. Watch the video after the break to see how small those 0402 parts are when he extracts one of the resistors from the tape packaging. With the board manually populated (check everything twice!) he moves the board to a completely unaltered toaster oven for reflow. We have seen a lot of projects which add controllers to these ovens, but he really makes the case that you don’t need it. Instead, he uses a thermocoupler read by a multimeter just to let him know what’s going on with the temperature. He uses a smart phone as a timer, and switches the oven on and off to match the solder’s heat profile. Continue reading “Fine-pitch SMD soldering with minimal tools”
[Ken] found that using traditional tweezers is a good way to lose tiny surface mount parts and so set out to make his own vacuum tweezers (PDF). He already had a small aquarium pump that he used as a bubbler for etching circuit boards. After opening up the case he found it was possible to connect tubing to the input of the pump to use as the source for the vacuum. The business end of the device is a syringe which he already had for applying oil in tight spaces. A file took off the sharp tip, and a small hole lined with a bit of soft tubing serves as a valve. Put the needle tip in place and plug the hole with your finger to pick it up. Works like a charm and will go well with our next feature, building your own reflow skillet.
We like [Ken’s] work. We just looked in on his copper clad enclosures yesterday.