At the dawn of SMT components and creating automated electronic assemblies entirely from SMT parts, many predicted the downfall of THT (through-hole technology) in the assembly of future PCBAs. However, the vision has not become a reality. To this day, a variety of components are hand-placed, soldered, inspected, and packed by CEMs and OEMs alike across the globe.
As all these manufacturers will tell you, THT processes require highly skilled operators trained to the appropriate IPC standard to complete this function. Although typically a high-cost process, THT assembly is usually the bottleneck to fully assembling a PCB product. Let’s think about the process. Typically, PCBs go through the entire SMT process and are delivered to post-SMT in magazine racks and panels, or perhaps even broken into individual PCBs depending on how the post-SMT process is designed.
In a common scenario, a row of operators would complete the many processes required for the final assembly of a product. This can include hand-placement and solder, visual inspection, and test all the way until final assembly, labelling, and packaging. The key benefit of the manual production line is its flexibility and reactiveness. The downfalls are that they are operated by humans, which means that even if operators are highly trained, there is still a high chance of error. They have a broad window of repeatability in terms of time and quality and are not optimised for profit.
Since there are key issues when using a manual process, why aren’t people automating? Many companies are investing because of the huge advancement in recent technology. The most problematic area of automation during THT assembly has always been the placement of parts. This is the area that the market has seen drastic improvements in capabilities. Odd-form placement by its name alone is odd. Parts weren’t traditionally placed this way because they are incredibly difficult to position accurately and repeatably by robots. Early odd-form systems did not necessarily have the level of robotics or software required to justify a huge spend for an unstable platform.
Unless the process is constant, accurate, repeatable, quick, and offers a significant boost to production metrics, why would people change? We are at the stage where odd-form placement solutions are becoming the area that manufacturers can look to make significant improvements in product profitability. This is because the system’s capabilities are now far beyond the level that a human operator could ever be!
So why look at odd-form? The main arguments a credible salesperson will use include, “You can increase volumes, improve quality, and achieve significant savings with clever automation solutions.” This pitch is not just sales talk. Today’s systems are highly flexible and easy to changeover for high mix, low volume.
Odd-form process automation is an efficient way to improve profitability significantly by increasing throughput and assembly quality. For example, let’s look at a popular solution from a market-leading brand—Cencorp Automation.
Speed and precision are critical elements for an assembly line. The 1000-OF odd-form placement platform can place through a variety of feeders including axial, radial, tube, bowl, and tray. They can undertake polarity, lead checks in the feeders, and design bespoke servo grippers, accurately picking any component that requires placement quickly and precisely. More than that, they have force detection sensors in the grippers and clinchers to ensure accurate placement and can position any component in approximately two seconds. This takes place consistently over a whole shift, which is why companies tend to find a two- or even three-fold increase in production output.
Most people are now familiar with wave, selective, and robotic soldering for THT to replace manual soldering—all of which come with significant benefits over the manual method. Fewer people will be familiar with in-line physical test solutions and THT AOI that can inspect both the top and bottom of a board with 3D capabilities at once. This is another solution to labour-intensive methods and a growing part of the assembly process.
Another significant bottleneck in post-SMT where the options are less clear is during the final assembly. Final assembly is a phrase used to describe a very broad range of activities required to pass a final product. For example, your customer may require an individual PCB to be assembled and placed into a blister pack. This may then need to be labelled, placed into packaging, and boxed to ship. Some manufacturers hire a couple of operators to complete this task; however, this approach is the best way to drive down profitability and is not the future proofing production.
Does hiring a new person each time you increase production numbers offer you the best return on investment? The answer is clearly no, but many people aren’t aware of the alternative solutions. One of the key areas is a final assembly cell, broadly named because of the variety of processes that can be custom designed to suit any application. These cells are equipped with robots that can be customized for labelling, box building, blister pack dispensing, sealing, or whatever your application process might require. It may sound too good to be true, but robots are best utilised in a process that is repetitive and can be broken down into steps.
I would imagine that now you are thinking about the price tag that comes with a robot or line that can fully automate your production. The question should not be about the price of the line, but the speed of the ROI. These capabilities typically replace the most manual and costly processes of PCB assembly. Imagine having one operator on an entire line, producing double the output of a variety of through-hole products. Aside from the time-saving benefits, you now have a completely consistent process producing the same product to the same quality every time with quality guaranteed. Automate to increase quality, capacity, and continuous improvement.
Assembly solutions and the accompanying technology are consistently improving, allowing manufacturers to get the best from their manufacturing processes. Automation is becoming the norm for electronic SMT assembly, and there are now methods to help in the trend of being fully automated across an entire PCB product. The vision of creating automated electronic assemblies entirely from SMT parts without touching a board is there, which is not only helping to obtain high quality and repeatability but also improving the bottom line.
Joe Booth is business development and marketing manager at Altus Group Ltd. To read past columns or contact Altus Group, click here.