Halogen floodlight SMT reflow

flood_reflow_01

David Sanz Kirbis built his own reflow device with an halogen floodlight, that is available on Github:

First test was to check the speed of the temperature rise inside a standard halogen floodlight. Reflow soldering temperature curves are quite demanding, and some adapted ovens can’t reach the degrees-per-second speed of the ramp-up stages of these curves.
I bought the spotlight, put an aluminium sheet covering the inside surface of the protective glass (to reduce heat loss), and measured the temperature rise with a multimeter’s thermometer…. and wow! More than 5ºC/s… and I better turned the thing off after reaching 300ºC and still rising quickly.
So the floodlight was able to fulfill the needs.
Next step was a temperature controller, that is, the device that keeps the temperature as in a specified reflow curve profile in each moment.

See the full post and more details on his blog, TheRandomLab.

Check out the video after the break.

[Dave’s] Not Just a Member of the Air Club for Tweezers

We are always surprised how much useful hacking gear is in the typical craft store. You just have to think outside the box. Need a hot air gun? Think embossing tool. A soldering iron? Check the stained glass section. Magnification gear? Sewing department.

We’ve figured out that people who deal with beads use lots of fine tools and have great storage boxes. But [Dave] found out they also use vacuum pickup tweezers. He had been shopping for a set and found that one with all the features he wanted (foot pedal, adjustable air flow, and standard tips) would run about $1000.

By picking up a pump used for bead makers and adding some components, he put together a good-looking system for about $200. You can see a video of the device, below, and there are several other videos detailing the construction.

The pickup needles use the same fitting that medical syringes use–known as a Luer lock. [Dave] provides links to all the components over on Hackaday.io. The actual build is simple enough. No Arduino, ESP8266, or Raspberry Pi. Just a foot switch and a solenoid along with a collection of tubing and fittings.

We were hoping the first video would show the finished product working, but it doesn’t. You have to skip to video 7 for that, and you can find it below. If you want to build it yourself, you’ll have to pick up the 5 videos in between.

We’ve talked about raiding craft and art stores before for lots of project help. Of course, vacuum tweezers aren’t strictly necessary. We’ve also seen cheaper builds, often based on aquarium pumps, but not always.


Filed under: tool hacks

Reflow Soldering at Another Level

We’re used to reflow soldering of our PCBs at the hacker level, for quite a few years people have been reflowing with toaster ovens, skillets, and similar pieces of domestic equipment and equipping them with temperature controllers and timers. We take one or two boards, screen print a layer of solder paste on the pads by using a stencil, and place our surface-mount components with a pair of tweezers before putting them in the oven. It’s a process that requires  care and attention, but it’s fairly straightforward once mastered and we can create small runs of high quality boards.

But what about the same process at a professional level, what do you do when your board isn’t a matchbox-sized panel from OSH Park with less than 50 or so parts but a densely-packed multilayer board  about the size of a small tablet computer and with many hundreds of parts? In theory the same process of screen print and pick and place applies, but in practice to achieve a succesful result a lot more care and planning has to go into the process.

This is being written the morning after a marathon session encompassing all of the working day and half of the night. I was hand-stuffing a row of large high-density boards with components ranging from 0402 passives to large QFPs and everything else in between. I can’t describe the board in question because it is a commercially sensitive prototype for the industrial customer of the friend I was putting in the day’s work for, but it’s worth going through the minutiae of successfully assembling a small batch of prototypes at this level. Apologies then, any pictures will be rather generic.

Would we be insane to use a pick-and-place machine for this job, or are we insane not to have used one? Peripitus [ CC BY-SA 3.0 ], via Wikimedia Commons.
Would we be insane to use a pick-and-place machine for this job, or are we insane not to have used one? Peripitus [CC BY-SA 3.0], via Wikimedia Commons.
Some of you reading this will now be asking “What on earth are you doing making this run of boards by hand, you should be doing it with a pick-and-place machine, or you should be hiring a specialist company!”. The answer to that isn’t really mine to give as the boards weren’t commissioned by me, but in reality it’s a nuanced decision based on a combination of cost, number of boards, and the eventual customer’s deadline for a trade show. Setting up a pick-and-place for a very large job is a performance in itself, and for a very small run of boards there is a hard financial decision to make over whether it is justified.

So there we were, setting out to make a batch of eight prototype PCBs. The story didn’t start on the build day, instead a few weeks ago the Bill Of Materials, or BoM, was exported from the CAD package, and the task of sourcing all the components began.

It stands to reason that the complexity of component sourcing increases with the number of individual component lines in the BoM. If your design consists entirely of generic components that every supplier has by the reel then sourcing is as simple as making the order, but sadly very few real designs are like that. So this step became an involved trawl through an array of suppliers for the elusive parts, sometimes ringing company reps to beg a few free samples.

The Great Gathering of Components

In the days running up to the build, a variety of packages arrived containing the components. There began the second major task, that of collation. It’s necessary to both ensure that everything has arrived and is the right component for the job, and to index and array them in a form such as to make the placement on the boards as easy as possible.

The hanging file box we used, a Really Useful Product.
The hanging file box we used, a Really Useful Product.

We started with a storage box of the type designed to hold hanging files. Each hanging file was labeled with a range of numbers corresponding to BoM lines, so 1 – 5, 6 -10, 11 – 15, and so on to the end of the BoM. Every line on the BoM spreadsheet was checked, that the component was present, was it compatible with the package it should be on the board, and was it present in sufficient numbers to populate the boards. Its line number from the spreadsheet was written on the label, and the spreadsheet was updated to show that it was present. The numbered bag of components was then placed in the appropriate hanging file for its line number, and the process was repeated with the next line number and so on until the whole BoM was covered.

At the end of the component collation, we had a box of hanging files containing numbered component lines, and inevitably there were a few lines which either weren’t quite right or hadn’t arrived. Some last-minute overnight ordering was in order, followed by collation steps for those parts.

It might seem like a lot of work to put in before making any boards, but this couple of days getting everything in a row will save you time when it comes to populating the boards, and will in turn result in better quality final prototypes.

On the day of the build, our components were all collated and were handed a stack of bare PCBs from the board house. We set up adjacent workstations for the two of us, and set to work.

Become a Paste Aficionado

Solder paste on a PCB, probably depositied by machineas it's much tidier than our stencil work. Ossewa [CC BY-SA 3.0], via Wikimedia Commons.
Solder paste on a PCB, probably deposited by machine as it’s much tidier than our stencil work. Ossewa [CC BY-SA 3.0], via Wikimedia Commons.
The first task when populating boards is to screen print the solder paste on the pads. We used the jig supplied by the board house for this task, with locating pegs fitted to align both board and stencil, and extra pieces of scrap PCB material taped down to support the stencil beyond the edge of the board.

Screen printing solder paste is in principle quite simple. Align the stencil with the pads, and using a scraper spread a layer of solder paste over all the holes. When you lift the stencil away the board should then be left with a uniform layer of solder paste on each pad, ready to have a component placed on it.

Describing this crucial step in those terms makes screen printing solder paste sound so easy, but of course it isn’t. The paste consistency is very important for a large board in the way it isn’t for a small one. The paste you print on the pads will spread out over time, and eventually your closely spaced tiny pads will be completely obscured by an amorphous blob of paste. If you have a small board you can get away with it, but on a large board it’s important to ensure that the spread is not too quick. You’ll then have a chance to place your components and reflow the board while the printed solder is still well-defined.

Solder paste. Just like peanut butter, except it's toxic and grey. Lady Ada AKA Limor Fried [CC BY-SA 3.0], via Wikimedia Commons.
Solder paste. Just like peanut butter, except it’s toxic and grey. Lady Ada AKA Limor Fried [CC BY-SA 3.0], via Wikimedia Commons.
It’s best to describe the optimum solder paste consistency in terms of smooth peanut butter. Think of the perfect-spreading peanut butter, it’s not the runny stuff at the top of the jar where the oil has started to separate out, neither is it the stuff at the bottom of a jar that’s stood in the fridge for six weeks and goes all clumpy as you spread it on your toast. It’s the easy-spreading middle of a new jar, keeping its consistency and just about right for your knife. And so it is with solder paste, for a large board you need to very carefully ensure that your paste is well-mixed, and not dried out. Too runny and it will quickly spread out, while too thick and it may clump in the stencil and not stick to your pads. It’s something you gain a feel for with a bit of experience.

With the jig, stencil, scraper, and boards ready, and the correct consistency of paste to hand, there is one more step before spreading. Clean everything with IPA solvent; every single PCB, stencil, board, jig, the entire lot. It seems tedious, but it will make the difference between good and poor results. All drying paste residues, dirt, and oils can affect the quality of the job, and you need the best possible result.

After all that effort, the paste scraping itself is very quick. Make sure you have enough paste on your scraper, draw it across the stencil in one go covering all the holes with a firm pressure. Lift the stencil away, and inspect the quality of your paste printing. Don’t be afraid to clean it off and do it again if you aren’t happy with the results, we redid a couple of our board run.

Knowing Your Place

There are 500 0402 resistors, you have to find one of them in the crowd. Where's Wally record attempt, William Murphy [CC BY-SA 2.0], via Wikimedia Commons.
There are 500 0402 resistors on the board, you have to find one of them in the crowd. Where’s Wally record attempt, William Murphy [CC BY-SA 2.0], via Wikimedia Commons.
Towards the end of the morning then on our build day we had a row of boards ready screen printed with solder paste. They were lined up in front of my friend at one workstation, while at the other I had the box of parts and the BoM both on the computer and as a print-out. We both had large-scale print-outs of the component layout, and my job was to supply the tape of each component line in turn with the plastic strip ready lifted at the end, while he placed the components using a vacuum pencil and a magnifier. He has better dexterity for those 0402s than I do. The task of spotting component positions was shared, a game of Where’s Wally/Waldo on paper and computer, but without the stripey jumper.

Once you have started stuffing boards you are in a race against the spread of your solder paste, so there is no letting up until the task is complete. In our case the whole process took us all day and well into the evening, working through the BoM omitting any large components that would obstruct access for smaller one, then returning to fit them in a second pass. There followed a checking step during which a few inevitable omissions were rectified, no matter how hard you try there will be a few that you miss. Through all this process all that work collating components came into its own, when asked for any line I could pick it out in very short order, and I could return to it when any omissions were detected.

Bring the Heat

Our reflow oven was a lot smaller than this one. Nelatan [CC-BY-SA-3.0], via Wikimedia Commons.
Our reflow oven was a lot smaller than this one. Nelatan [CC-BY-SA-3.0], via Wikimedia Commons.
The final step was the reflow soldering itself, in this case with a small purpose-built reflow oven. Each run became a ten-minute anxious wait watching the display as the temperature cycled through its ramp, smelling the flux smoke and finally lifting the finished board from the drawer. There is something magical about the process of reflow soldering, watching messy spreading paste going in and bright well-defined solder joints come out. We examined each board as it came out, and it is inevitable that each one will require a small amount of reworking. There will always be a few bridges between adjacent pins or even components slightly off their pads, but this is the nature of prototype assembly.

After a very long day and a lot of preparatory work before that, we had a row of prototype boards. We should be able to commission them all as working devices, and from those my friend will have more than enough to satisfy his customer’s demand. All of the above describes a very long and tedious process but there is no reason why any Hackaday reader should not also be able to do a large board with a bit of practice. If we’ve inspired you to have a go at reflowing your own boards of whatever size then share the results with us on hackaday.io, meanwhile if you have any tips to further streamline the process with larger boards we’re all ears.

If you enjoyed this story of a marathon small-run manufacturing session you will also enjoy [Bob Baddeley’s] series on the topic called Tools of the Trade. You should also take a look at the process used to create the Hackaday SuperConference badge.


Filed under: Featured, Skills

Turn cheap USB soldering irons in to tweezers

This is 2016, and almost every hacker dabbles with SMD parts now, unlike back in the day. This means investing in at least some specialized tools and equipment to make the job easier. One handy tool is the SMD soldering tweezers – useful not only for manual soldering of parts, but also for de-soldering them quickly and without causing damage to the part or the board. Often, especially when repairing stuff, using a hot air gun can get tricky if you want to remove just one tiny part.

smd_tweezer_04[adria.junyent-ferre] took a pair of cheap £5 USB soldering irons and turned them into a nifty pair of SMD soldering tweezers. The two irons are coupled together using a simple, 3D printed part. [adria]’s been through a couple of iterations, so the final version ought to work quite well. The video after the break shows him quickly de-soldering a bunch of 0805 SMD resistors in quick succession.

Earlier this year, we had posted [BigClive]’s tear down of these 8 watt USB soldering irons which turned out to be surprisingly capable and this spurred [adria] to order a couple to try them out.

The 3D printed part is modeled in SolveSpace – a parametric 2D and 3D CAD software that we blogged about a while ago.


Filed under: tool hacks
vid_20161202_175318

A DIY Vacuum Pickup Tool for $75

If you’re assembling prototypes of SMD boards on your own, placing the parts accurately can be a pain. Of course, it’d be nice to have a full pick and place machine, but those are rather expensive and time consuming to set up, especially for a small run of boards. Instead, a vacuum pickup tool can help you place the parts quickly and accurately by hand.

The folks over at Ohmnilabs have put together their own DIY pickup tool for about $75, and it’s become part of their in-house prototyping process. They grew tired of placing components with tweezers, which require you to remove parts from the tape before lifting them, and have a tendency to flip parts over at the worst time.

The build consists of a couple parts that can be bought from Amazon. An electric vacuum pump does the sucking, and the vacuum level is regulated with an adjustable buck converter. A solid foot switch keeps your hands free, and syringe tips are used to pick the parts up.

This looks like a simple afternoon build, but if you’re prototyping, it could save you tons of time. To see it in action, check out the video after the break.


Filed under: tool hacks

Hackaday Links: October 23, 2016

It’s the Hack ‘O Lantern edition! First up, Slic3r is about to get awesome. Second, Halloween is just around the corner, and that means a few Hackaday-branded pumpkins are already carved. Here’s a few of them, from [Mike] and [yeltrow]:

[Mike]'s Hack 'O Lantern [yeltrow]'s Hack 'O Lantern

The latest edition of PoC||GTFO has been released. Holds Stones From The Ivory Tower, But Only As Ballast (PDF and steganography warning). This edition has a reverse engineering of Atari’s Star Raiders, [Micah Elisabeth Scott]’s recent efforts on USB glitching and Wacom tablets, info on the LoRa PHY, and other good stuff. Thanks go to Pastor Manul Laphroaig.

Oh cool, we can be outraged about something. The Freetronics Experimenters Kit is a neat little Arduino-based ‘Getting Started In Microcontrollers’ kit. This kit was sold by Jaycar. Recently, Jaycar ripped off the kit and sold it under the Duiniotech name. The box was copied, the instruction manual was copied, and there’s a lot of IP being violated here. Can Freetronix do anything? Legally, yes, but it’s not worth it.

[Oscar] broke his phone, but it still works great as an SMD soldering camera/microscope thing.

Pobody’s Nerfect in Australia so here’s a 3D printed didgeridoo. What’s a didgeridoo? It’s an ancient instrument only slightly less annoying than bagpipes. It’s just a tube, really, and easily manufactured on any 3D printer. The real trick is the technique that requires circular breathing. That’s a little harder to master than throwing some Gcode at a printer.

[Chris Downing] is the master of mashed up, condensed, and handheld game consoles. His latest is another N64 portable, and it’s a masterpiece. It incorporates full multiplayer capability, uses an HDMI connector for charging and to connect the external breakout box/battery, and has RCA output for full-size TV gameplay. Of note is the breakout board for the custom N64 chip that puts pads for the memory card and a controller on a tiny board.


Filed under: Hackaday Columns, Hackaday links

Design and Hacking Drilldown: SuperCon Badge

One can imagine a political or business conference without an interactive badge — but not a hacker conference. Does this make the case for hackers being a special breed of people, always having something creative to show for their work? Yes, I think it does.

Following the Hackaday Belgrade conference in April of this year, we met at the Supplyframe offices to discuss the badge for the Hackaday SuperConference that will happen in Pasadena on 5+6th of November. The Belgrade conference badge (which was fully documented if you’re curious) was surprisingly popular, and I was asked to design the new one as well.

I was prepared to come up with something completely new, but [Mike Szczys] suggested keeping with the same basic concept for the project: “No reason to change anything, we have a badge that works”. To which I responded: “Well, the next one will also work”. But then I realized that “works” does not stand for “being functional”. The key is that it was embraced by visitors who played with it, coded on it, and solved a crypto challenge with it.

The World Doesn’t Have Enough LEDs

led-modules-versus-smdFast forward six months — here are the modifications made to the basic concept. First, the existing LED matrix, which was composed of two compact 8×8 blocks, was replaced by 128 discrete SMD LEDs. It was a much needed change to help scale down the dimensions and clunkiness, but also to avoid another painful experience of trying to purchase and have the matrix displays shipped, which seriously threatened the production of the previous badge.

It’s a long story which I discussed in my Belgrade talk — it turned out we did not manage to get enough common anode (CA) displays from all distributors in the whole world. We had a plan B, which also fizzled, leaving us with the plan C which actually included two “C”s: Common Cathode. We cleaned up all the supplies at five distributors, and managed to get 122 CA red, 340 CC red and 78 CA green displays (enough for only 270 badges) — the entire world supply. After that, you couldn’t get any 38 mm Kingbright’s display for months! The only problem was that there were two different versions of PCBs, one for CA and the other for CC displays, but luckily only one version of software, as it could autodetect the display type.

accelerometer-on-the-boardMotion and Expansion

So, what else was new in the concept? In the Belgrade version, the badge supported an accelerometer module and included an unpopulated footprint in case you decided to install it, but now the badge has the MEMS chip LIS3 as an integral part. There are nine pads (with five I/O ports, driven directly from the MCU) to which you can add a 9-pin expansion connector. There will be a number of these connectors at the Design Lab, so that anyone can expand their badge for their convenience, on the spot.

The Visual Design

The biggest change was in the visual design. What we came up with ended up being a fair bit smaller, lighter, with a more convenient shape, and less than half the thickness of the previous one. After we had scrapped quite a few ideas during the development process (including stylized skull, frog, etc), we were left with a couple of options which you can see on the image below. The wireframe drawing on the left hand side is the Belgrade badge, shown here for a size comparison. At this point the locale and date of the conference weren’t yet definitive, which is why you see San Francisco written on the images.

design-options-2016-supercon-badge

Design number 4 prevailed, so the PCB layout could begin. I don’t like autorouted PCBs, so I was in for quite a rough time trying to solve the routing manually having only 2 layers on the board at my disposal.

Routing a Compact LED Matrix

The LED matrix is so dense that there was virtually no room on the LED layer, so most of the tracks on the component layer had to be routed as if it was a single layer PCB. To make matters worse, the LED layer is routed as a matrix, with a bunch of horizontal and vertical tracks, otherwise a good reason to use a 4-layer PCB. To stay inside the budget, everything had to be placed on 2 layers, and that’s why the final result seems so confusing at the populated area between batteries:

led-matrix-layout-2016-supercon-badge

That pretty much covers the changes — the badge is virtually the same as the previous one in all other aspects. It includes an infrared optical port, which uses the existing UART on the MCU, so it is easy to implement in user programs. Communication range is several meters, and as long as you are in a room with white walls and ceiling, you don’t have to worry about the direction of the transmitter and receiver. Every badge has its unique serial number, and the default infrared UART routine will receive only messages which contain the matching number in the address field of the header.

Hacking the Badge

The badge was presented in a video we published last month. We plan to have a lot of fun with this hardware throughout the weekend. SuperConference visitors will be challenged to use their badges to solve the special puzzle task, which will be composed of several layers. And we want everyone to give badge hacking a try, with firmware, hardware, or both.

Here is the schematic diagram for the new badge:

schematic-2016-supercon-badge

The badge is hacking friendly, as there is a USB port and bootloader, so the programming is fast and easy, even without a separate hardware programmer. All you need is your computer and one Micro-B USB cable, and you’re all set for hacking at the SuperConference.

bothThe firmware is more or less the same as the Belgrade badge but the bootloader has been updated. Our friends at Microchip adapted their Xpress board bootloader for us so that the Hackaday SuperConference badge acts as a USB mass storage device. Simply plug in the USB cable, hold power while pressing reset, and drag your HEX file to the drive that appears on your computer.

There is a kernel in protected bootloader space which covers all BIOS functions. LED matrix scan is fully supported, so all you have to do in your software is write 0’s and 1’s to the 16-byte frame buffer in the Data RAM. All other services (keyboard scan, low power sleep ON-OFF, brightness adjust, infrared serial reception and pause screen) are also located inside the Timer Interrupt routine, so the user does not have to deal with low-level hardware if they don’t want to. Some more routines (32-bit pseudorandom number generator and Accelerometer support) are also available in kernel.

Choose Your Hacking Difficulty:

I Can Blink

Even those who have never touched a bare PCB can still easily get this badge to do their bidding. Start with the example in the C framework. Play around with which LED turns on and how to change the timing, then build your skills from there.

Bring It On

You fancy yourself a programmer? Show us what you can accomplish in one weekend. The low-level hardware servicing is completely handled for you, which means the rest is up to your creativity. Program a clever and creative user experience to claim your moment of glory.

Hurt Me Plenty

You are a wizard of embedded development. Read the schematic, grab a few datasheets, and take this to bare metal. Completely bypass the kernel in one of two ways. Start with the C framework but remove the “goto” assembly commands that send interrupts back to the kernel, giving you full hardware control. Or bring your own PIC programmer and completely blow out the bootloader and kernel. We only saw one person do this in Belgrade, but it was epic!

We have just published a C framework for badge hacking. You have your choice of installing MPLAB X and using the GitHub repo, or using the cloud IDE version called MPLAB Xpress.

Full documentation of the badge has begun. Follow along on the Hackaday.io page.

Will this be enough for a good time at Pasadena in November? That depends on you. If you plan on coming charged with some positive and creative energy, and even bringing some ideas with you — then there should be no room left for doubt in the answer!


Filed under: cons, Featured

[NE555]’s SMD Prototyping is a Work of Art

ne555_20yearsold
One of [NE555]’s boards from the 90s.
Over on twitter [NE555] has been posting beautiful SMD prototypes.

Back in the 90s when surface mount components gained widespread adoption, the quick and cheap PCB prototyping services of today were unavailable. This led many to develop their own approaches. In Japan a particularly novel and beautiful approach was, and still is, somewhat popular. [NE555]’s work is a excellent example of this technique using a fine enameled wire (you can find this on eBay as “magnet wire”), wirewrap board, and careful hand soldering. [NE555] has made a great video on the process (which you can watch below).

ne555_tips
[NE555] uses a slightly fatter, stumpier tip. This likely works well due to it’s increased heat capacity.
According to my Japanese hacker friends there are a couple of ways of stripping the enameled wire, you can either use a knife to scrap it off or use a slightly higher tip temperature with applying flux seem to help burn of the polyurethane coating too.

In [NE555]’s video a relatively large tip is used. The ICs legs are pre-tinned, and the IC is glued to the board, with Polyamide (Kapton) tape insulating the legs. [NE555] uses a self-developed wirewrap pen as an aid when connecting pins. There are some details of this process in English available. Aside from this, fairly standard tools are used. The fact that [NE555] uses quality Hozan brand wire cutters likely helps with the precision wire trimming required.

ne555_soldering
Soldering in progress

What’s quite shocking for me, is the [NE555] uses no optical aids. Most of my own SMD rework take place under an inspection microscope, but clearly [NE555]’s years of experience allow the process to be completed by eye. A microscope however is used for final inspection. While techniques like these maybe slowly replaced I can’t help but admire the craftsmanship and tenacity required to construct these beautiful prototypes. For more examples of these wonderful boards, check out the pictures and video below (and follow NE555 on twitter!)

ne555_x
Another beautifully constructed board.

 


Filed under: classic hacks