A freshly reballed BGA chip next to a clean PCB footprint

Working With BGAs: Soldering, Reballing, And Rework

March 23, 2023 by Robin Kearey 27 Comments

In our previous article on Ball Grid Arrays (BGAs), we explored how to design circuit boards and how to route the signals coming out of a BGA package. But designing a board is one thing – soldering those chips onto the board is quite another. If you’ve got some experience with SMD soldering, you’ll find that any SOIC, TQFP or even QFN package can be soldered with a fine-tipped iron and a bit of practice. Not so for BGAs: we’ll need to bring out some specialized tools to solder them correctly. Today, we’ll explore how to get those chips on our board, and how to take them off again, without spending a fortune on equipment.

Tools of the Trade

For large-scale production, whether for BGA-based designs or any other kind of SMD work, reflow ovens are the tool of choice. While you can buy reflow ovens small enough to place in your workshop (or even build them yourself), they will always take up quite a bit of space. Reflow ovens are great for small-scale series production, but not so much for repairs or rework. Continue reading “Working With BGAs: Soldering, Reballing, And Rework” →

Throwback: USB Hotplate Used 30 Whole Ports

December 1, 2022 by Lewin Day 22 Comments

Once upon a time, USB was still hip, cool, and easy to understand. You could get up to 500 mA out of a port, which wasn’t much, but some companies produced USB cup warmers anyway which were a bit of a joke. However, one enterprising hacker took things further back in 2004, whipping up a potent USB hot plate powered by a cavalcade of ports.

The project was spawned after a USB cup warmer sadly failed to cook a decent fried egg. To rectify this, a souped-up version was built. The cup warmer was stripped of its original hardware, and fitted with six 2-ohm resistors instead. At 5 volts, each would draw 2.5 amps and the total power draw would be on the order of 75 watts. Each resistor would thus need five USB ports to power it to stay under the 500 mA limit, for a total of 30 USB ports in total. Six PCI-to-USB cards were installed in a motherboard for this purpose, providing the requisite ports. A 500 watt power supply meant the computer had plenty of juice to run the hot plate.

Cooking proved successful, generating a decent amount of heat to brown up some beef. Served with some white rice, it proved an adequate meal, though apparently with a noted taste of electronic components.

This wouldn’t be such a challenge today. USB-C is capable of delivering 100 watts through a single port at 20 volts and 5 amps. However, there’s something joyous and charming about cooking on a ridiculous hotplate running off 30 USB 1.1 ports. The ingenuity is to be applauded, and it is truly a project of its time.

Reflow Hotplate Teardown Uncovers The Bare Minimum

March 10, 2022 by Al Williams 13 Comments

[EEforEveryone] is trying to find a good hot plate for reflow soldering. After trying one cheap unit, he got another one. He was a bit underwhelmed. The grounding was suspect and the bed wasn’t totally flat. He tore it apart and was surprised that there was very little inside. While the construction wasn’t perfect, it was better than the previous unit. You can see a video of the teardown and review below.

Before powering it up, the first order of business was to rewire the ground system. After that, it was time to try it. However, by confusing Fahrenheit and Centigrade, he set the temperature much higher than necessary which creating a little smoke. Fixing the temperature helped, but there was still a bit of a smoky smell that eventually subsided.

The verdict? The hot plate worked well enough, but you probably do want to check the ground wiring before using it. That’s often a good idea where cheap equipment is concerned, anyway. But the real takeaway is that it looks like you could homebrew something equivalent without much trouble. The controller is an off-the-shelf module. A switch and a plug aren’t hard to figure out. The heating element could be a silicone heater or PCB heater meant for a 3D printer.

Of course, there are other options. You could use a wok. Or why not a waffle iron? You can also make a custom PCB.

Continue reading “Reflow Hotplate Teardown Uncovers The Bare Minimum” →

Iron Becomes SMD Hot Plate

July 4, 2021 by Al Williams 20 Comments

Few things have changed our workshops more than surface mount components. In 1980 it would have been strange to see a hobby bench with a microscope, hot air equipment, tweezers, and all the other accouterments that are a necessity today. [Electronoobs] wanted a reflow hot plate and decided that he could repurpose a consumer laundry iron for the job. You can see the results in the video below.

Opening the iron revealed surprisingly simple circuitry, so the build has some additional parts along with a controller and an LCD, of course. The power requirement for the heating element is significant — 13 amps — so the plate uses a solid state relay to turn things on and off.

Continue reading “Iron Becomes SMD Hot Plate” →

Reflow Rig Makes SMD Soldering A Wok In The Park

April 25, 2018 by Dan Maloney 13 Comments

For a DIY reflow setup, most people seem to rely on the trusty thrift store toaster oven as a platform to hack. But there’s something to be said for heating the PCB directly rather than heating the surrounding air, and for that one can cruise the yard sales looking for a hot plate to convert. But an electric wok as a reflow hotplate? Sure, why not?

At the end of the day [ThomasVDD]’s reflow wok is the same as any other reflow build. It has a heat source that can be controlled easily, temperature sensors, and a microcontroller that can run the proportional-integral-derivative (PID) control algorithm needed for precise temperature control. That the heating element he used came from an electric wok was just a happy accident. A laser-cut MDF case complete with kerf-bent joints holds the heating element, the solid-state relay, and the Arduino Nano that runs the show. A MAX6675 thermocouple amp senses the temperature and allows the Nano to cycle the temperature through different profiles for different solders. It’s compact, simple, and [ThomasVDD] now has a spare wok to use on the stove top. What’s not to like?

Reflow doesn’t just mean oven or hotplate, of course. Why not give reflow headlights, a reflow blowtorch, or even a reflow work light a try?

Hackaday Prize Entry: Reflowduino, The Open Source Reflow Oven Controller

November 7, 2017 by Dan Maloney 34 Comments

Face it — you want a reflow oven. Even the steadiest hands and best eyes only yield “meh” results with a manual iron on SMD boards, and forget about being able to scale up to production. But what controller should you use when you build your oven, and what features should it support? Don’t worry — you can have all the features with this open source reflow oven controller.

Dubbed the Reflowduino for obvious reasons, [Timothy Woo]’s Hackaday Prize entry has everything you need in a reflow oven controller, and a few things you never knew you needed. Based on an ATMega32, the Reflowduino takes care of the usual tasks of a reflow controller, namely running the PID loop needed to accurately control the oven’s temperature and control the heating profile. We thought the inclusion of a Bluetooth module was a bit strange at first, but [Timothy] explains that it’s a whole lot easier to implement the controller’s UI in software than in hardware, and it saves a bunch of IO on the microcontroller. The support for a LiPo battery is somewhat baffling, as the cases where this would be useful seem limited since the toaster oven or hot plate would still need a mains supply. But the sounder that plays Star Wars tunes when a cycle is over? That’s just for fun.

Hats off to [Timothy] for a first-rate build and excellent documentation, which delves into PID theory as well as giving detailed instructions for every step of the build. Want to try lower-end reflow? Pull out a halogen work light, or perhaps fire up that propane torch.

Ask Hackaday: How Do You Make A Hotplate?

September 28, 2016 by Brian Benchoff 119 Comments

Greetings fellow nerds. The Internet’s favorite artificial baritone chemist has a problem. His hotplates burn up too fast. He needs your help to fix this problem.

[NurdRage] is famous around these parts for his very in-depth explorations of chemistry including the best ways to etch a PCB, building a thermometer probe with no instructions, and chemical synthesis that shouldn’t be performed by anyone without years of experience in a lab. Over the past few years, he’s had a problem: hotplates suck. The heating element is usually poorly constructed, and right now he has two broken hotplates on his bench. These things aren’t cheap, either: a bare-bones hotplate with a magnetic stirrer runs about $600.

Now, [NurdRage] is asking for help. He’s contacted a few manufacturers in China to get a hundred or so of these hotplate heating elements made. Right now, the cost for a mica and metal foil hotplate is about $30 / piece, with a minimum order quantity of 100. That’s $3,000 that could be better spent on something a bit more interesting than a heating element, and this is where you come in: how do you build the heating element for a hotplate, and do it cheaply?

If you buy a hotplate from the usual lab equipment supplier, you’ll get a few pieces of mica and a thin trace of metal foil. Eventually, the metal foil will oxidize, and the entire hotplate will stop working. Repairs can be done with copper tape, but by the time that repair is needed, the heating element is already on its way out.

The requirements for this heating element include a maximum temperature of around 350 ºC. That’s a fair bit hotter than any PCB-based heat bed from a 3D printer gets, so consider that line of reasoning a dead end. This temperature is also above what most resins, thermoplastics, and composites can handle, which is why these hotplates use mica as an insulator.

Right now, [NurdRage] will probably end up spending $3,000 for a group buy of these heating elements. That’s really not that bad – for the price of five hotplates, he’ll have enough heating elements to last through the rest of his YouTube career. There must be a better way, though, so if you have an idea of how to make a high-temperature heating element the DIY way, leave a note in the comments.