A SCARA (Selective Compliance Assembly Robot Arm) is a type of articulated robot arm first developed in the early ’80s for use in industrial assembly and production applications. All robotics designs have their strengths and their weaknesses, and the SCARA layout was designed to be rigid in the Z axis, while allowing for flexibility in the X and Y axes. This design lends itself well to tasks where quick and flexible horizontal movement is needed, but vertical strength and rigidity is also necessary.
This is in contrast to other designs, such as fully articulated arms (which need to rotate to reach into tight spots) and cartesian overhead-gantry types (like in a CNC mill), which require a lot of rigidity in every axis. SCARA robots are particularly useful for pick-and-place tasks, as well as a wide range of fabrication jobs that aren’t subjected to the stress of side-loading, like plasma cutting or welding. Unfortunately, industrial-quality SCARA arms aren’t exactly cheap or readily available to the hobbyist; but, that might just be changing soon with the Creo Arm. Continue reading “Creo Arm Might be the SCARA You’re Looking For”→
Recently we started a series on the components used to assemble a circuit board. The first issue was on dispensing solder paste. Moving down the assembly line, with the paste already on the board, the next step is getting the components onto the PCB. We’re just going to address SMT components in this issue, because the through hole assembly doesn’t take place until after the SMT components have gone through the process to affix them to the board.
SMT components will come in reels. These reels are paper or plastic with a clear plastic strip on top, and a reel typically has a few thousand components on it. Economies of scale really kick in with reels, especially passives. If you order SMT resistors in quantities of 1-10, they’re usually $.10 each. If you order a reel of 5000, it’s usually about $5 for the reel. It is cheaper to purchase a reel of 10 kOhm 0603 resistors and never have to order them again in your life than it is to order a few at a time. Plus the reel can be used on many pick-and-place machines, but the cut tape is often too short to use in automated processes.
In the 80s and 90s, building a professional quality PCB was an expensive proposition. Even if you could afford a few panels of your latest board, putting components on it was another expensive process. Now, we have cheap PCBs, toaster-based solder ovens, and everything else to make cheap finished boards except for pick and place machines. ProtoVoltaics’ semifinalist entry for the Hackaday Prize is the answer to this problem. They’re taking a cheap, off-the-shelf CNC machine and turning it into a pick and place machine that would be a welcome addition to any hackerspace or well-equipped garage workshop.
Instead of building their own Cartesian robot, ProtoVoltaics is building their pick and place around an X-Carve, a CNC router that can be built for about $1000 USD. To this platform, ProtoVoltaics is adding all the mechanics and intelligence to turn a few webcams and a CNC machine into a proper pick and place machine.
Among the additions to the X-Carve is a new tool head that is able to suck parts out of a reel and spit them down on a blob of solder paste. The webcams are monitored by software which includes CUDA-accelerated computer vision.
Of course a pick and place machine isn’t that useful without feeders, and for that, ProtoVoltaics built their own open source feeders. Put all of these elements together, and you have a machine that’s capable of placing up to 1000 components per hour; more than enough for any small-scale production, and enough for some fairly large runs of real products.
You can check out some of the videos for the project below.
Jigsaw puzzles are a fun and interactive way to spend an afternoon or twelve, depending on the piece count and your skill level. It’s exciting to find the pieces you need to complete a section or link two areas together, but if you have poor dexterity, excitement can turn to frustration when you move to pick them up. [thomasgruwez] had the disabled and otherwise fumble-fingered in mind when he created this pick and place jigsaw puzzle aid, which uses suction to pick up and transport puzzle pieces.
The suction comes from an aquarium pump running in reverse, a hack we’ve seen often which [thomasgruwez] explains in a separate Instructable. A large, inviting push button is wired in line to turn the pump on and off. An equally large and inviting momentary switch turns off the vacuum temporarily so the piece can be placed.
At the business end of this hack is the tiny suction-cupped tip from a cheap vacuum pen. To interface the pen head with the pump, [thomasgruwez] designed and printed a rigid straw to bridge the gap. With utility already in mind, [thomasgruwez] also designed a ring that can be bolted to the straw to house a steadying finger of your choice, like the pinkie hook on a pair of barbers’ shears.
Our favorite part of this hack has to be the optional accessory—a tiny platform for quickly flipping pieces without cutting the vacuum. Check it out after the break.
There have been quite a few DIY pick and place projects popping up recently, but most of them are limited to conceptual designs or just partially working prototypes. [Juha] wrote in to let us know about his project, LitePlacer, which is a fully functional DIY pick and place machine with working vision that can actually import BOMs and place parts as small as 0402 with pretty good accuracy.
While some other DIY pick and place setups we’ve featured use fairly exotic setups like delta bots, this machine is built around typical grooved bearings and extruded aluminum. The end effector includes a rotating vacuum tip and a camera mounted alongside the tip. The camera provides feedback for locating fiducials and for finding the position of parts. Instead of using feeders for his machine, [Juha] opted to pick parts directly from pieces of cut tape. While this might be inconvenient if you’re placing large quantities of a single part, it helps keep the design simple.
The software that runs the machine is pretty sophisticated. After a bit of configuration it’s able to import a BOM with X/Y information and start placing within seconds. It also uses the camera to calibrate the needle, measure the PCB using the fiducials, and pinpoint the location of cut tape sections.
If you want to build your own machine, [Juha] published detailed instructions that walk you through the entire assembly process. He’s also selling a kit of parts if you don’t want to source everything yourself. Check out the video after the break to see the machine import a BOM and place some parts (all the way down to 0402).
Populating a board with tiny SMT parts can be really tricky, and we’ll take all the help we can get. If you’re in the same boat, [vpapanik] has two devices you should check out.
First up is the manual pick-and-place machine. Wait, what? A manual pick-and-place? It’s essentially an un-driven 2-axis machine with a suction tip and USB inspection microscope on the stage. The picker apparatus is the “standard” needle-plus-aquarium-pump design, and the rails are made from angle aluminum and skateboard bearings.
Yeah, yeah, yeah. It’s not a robot. But sometimes the right jig or tool makes all the difference between a manual procedure being fiddly and being graceful. And we couldn’t help but laugh at the part in the video where he demonstrates the “machine” moving in a circular pattern.
One of the projects that has been on [Peter Jansen]’s build list for a long time – besides a fully functioning tricorder, of course – is a pick and place machine. It’s a project born out of necessity; each tricorder takes four days to assemble, and assembling the motherboard takes eight hours with a soldering iron and hot air gun. The pick and place machine isn’t complete yet, but one vital component – the vacuum head for picking up components – is getting there with the help of some odd components.
A few months ago, [Peter] saw a post on Hackaday about repurposing a tiny piezo micro blower for use as an extremely small vacuum pen. The original build was extremely simple – just a few pieces of foam board and a power supply, but the potential was there. A tiny electric air pump that’s able to pick up large chips and modules along with tiny resistors without having to run a hose through the mechanics of a CNC gantry is a godsend.
[Peter] got his hands on one of these micro blowers and started work on a proper tool head for a pick and place machine. A port on the micro blower was covered so it would suck instead of blow, the vacuum port was threaded through a stepper motor with a hollow shaft, and a fine tip was attached to the end.
What can this vacuum head pick up? 0604 size resistors aren’t a problem, but larger modules are simply too heavy. It looks like this micro blower would only be able to pick up small components. There are other options, though: [Grant Trebbin] has had some luck with a larger pump from Sparkfun, but this requires a vacuum line to run through a CNC gantry. There’s still some work to do before a small vacuum head shows up on the tool head of a pick and place machine, but given how long it takes [Peter] to put together a single tricorder, it’s well worth investing the time to do this right.