Xerox Ink Will Print Circuits

October 28, 2009 by Mike Szczys 40 Comments

Xerox has announced a breakthrough in printable circuits. They’ve developed a conductive ink called “silver bullet” that can be printed on many different types of substrate to create circuits. The key part of the new ink is its lower melting point. Plastic film substrate melts at 150 degrees Celsius but the ink is liquid when ten degrees cooler to avoid damaging the film. This begs the question: how do you then solder components to the circuit?

The benefits of printable circuitry are obvious. Aside from cheaper and easier RFID, disposable circuits like greeting cards, and fabric-based electronics, we’re hoping this will facilitate more environmentally friendly PCB fabrication. That really depends on the ink’s production process and the resilience of the resulting circuitry.

[via Gizmodo]

Double Sided Surface Mount PCB Population

October 25, 2009 by Mike Szczys 20 Comments

[youtube=http://www.youtube.com/watch?v=6M3MeADb1dE]

Above is a video detailing one method for populating a two sided surface mount PCB. We covered using a stencil to apply solder paste for a PCB a few weeks ago. In the comments there was a debate about the virtue of using stencils as well as a question about how two sided boards are populated. This was a good question because reflowing a board twice can cause components on the underside to fall off.

[Wim L’s] comment mentions that there are a couple of methods for two sided population. In the video you will see that a stencil is not being used, but instead, paste is applied by a pedal actuated syringe. The paste is applied to the underside of the board first, then a teeny dot of epoxy is added to hold the component in place. Each part is then positioned normally and baked in a reflow oven. This process both reflows the solder, and cures the epoxy. When the board is reflowed a second time, the epoxy holds the bottom components in place as the top solder reaches its melting point.

This method of applying solder paste is slower than using a stencil. But if done correctly, every component can get the amount of solder needed.

Hot Air Pencil For Under $20

October 23, 2009 by Caleb Kraft 36 Comments

hotairpencil20usd1

Here’s a project from back in 2001 that might be of interest to some of you. It is a guide on how to build your own hot air pencil for SMD soldering. He is using a super cheap 45W soldering iron from “the shack” combined with a pump type desoldering tool and an aquarium pump. He says it works pretty well, and we don’t see why it shouldn’t. This is a pretty elegant solution. There are also some more recent versions of this mod, but the idea is basically the same.

[thanks Stuart]

Dresser Tool Chest Isn’t As Ghetto As You’d Think

October 19, 2009 by Phil Burgess 43 Comments

toolchest

A dedicated rolling chest for one’s tools is among the most indulgent yet worthwhile acquisitions. Having everything mobile and organized for quick access improves efficiency and keeps the shop tidy. But holy living crap, have you priced these things? Even a mediocre setup costs more than the gross national product of some small nations!

Here’s a project that tarts up a dresser into a passable tool chest. Using casters, modern drawer pulls and a tidy paint job, they turn a nasty old dresser into something presentable. It’s nowhere near as slick as the commercial units…no ball bearing glides, not chemical resistant, and your macho grease monkey friends will just roll their eyes…but if you’d rather spend your hard-earned money on more and better tools than a pretty box to put them in, this might be just the thing. From across the room, you’d hardly know the difference.

A good tool chest will include several shallow drawers so that all the tools are visible at a glance and not buried in a jumble. If searching for a piece of furniture to re-use, look for something with multiple slim drawers rather than just a few deep ones; a large jewelry chest might work well.

[via Craftynest]

How To Populate A Surface Mount PCB

October 13, 2009 by Mike Szczys 19 Comments

Reflow_08

Let’s face it friends, everything is moving toward surface mount components. We’ve seen quite a few features here that cover using stencils to populate boards and using ovens to reflow. [Oleg] has put together a tutorial on the process he uses to populate and reflow his own boards.

[Oleg] is the creator of the USB Isolator and therefore has a need to frequently populate the same board. He’s using an acrylic frame that fits the PCB perfectly to hold it in place so that paste and be applied right up to the edges of the board. He ordered a laser cut Kapton stencil for applying the solder. The paste is squeegeed into the stencil holes, the stencil is removed, and parts are placed with tweezers and a steady hand. For the final step, the boards go into an old toaster oven for reflow.

[Oleg] uses temperature marker on his boards to monitor the progress of the reflow. This marker is basically a crayon that begins to melt at a specific temperature. When the board has cooled, the melted mark can be scraped away or removed with alcohol.

Of course this is only really useful if you have a bunch of high-quality boards to populate. But with the relatively low cost of getting professionally made boards we think the need for this type of assembly process is on the rise.

A Stirring Hack

October 8, 2009 by Devlin Thyne 29 Comments

Stirring Flask

[Oleg] of Circuits@Home and maker of the USB Isolation Board and the USB Host Shield has a new, two-part hack for his chemistry set. In Part 1 of this hack, [Oleg] discusses the method he uses to make a stir bar spin and what types of stir bars work the best. Part 2 discusses the motor control code and circuit. Given the ample amount of capability leftover in the Arduino he used, we would like to see this stirrer paired with a heating element to have a complete hotplate/stirrer. What do you think you could do with or to improve this device?

A Modular Halloween With Grid Beam

October 8, 2009 by Phil Burgess 3 Comments

gridbeam

The fantastic Creatrope blog has a great article on quickly assembling animatronic Halloween gags using salvaged electric motors, pvc pipe, and “grid beam” construction.

Grid beam is a prototyping and building medium that’s like a giant hippie Erector set. You can’t buy grid beam, but with a drill press, a jig, and some square stock you can create your own unlimited supply. It’s ideal for “sketching” and temporary constructions like these Halloween props. After use, everything can be dismantled, stored flat, and later reused for the next [Herbie Hancock] music video creative project. Looks like fun!

The article wraps up with some valuable pointers on getting started with grid beam and where to acquire parts.