The Curiously Low-tech Side of High-tech Manufacturing
In this article, engineers discuss seemingly primitive parts of the manufacturing process and the feasibility of replacing those processes with automation.
Electrical engineers create some of the most sophisticated technology in the world. And yet, while electronic components are becoming smaller, more powerful, and more energy-efficient, some of the processes employed in manufacturing these components remain rather primitive.
Many of our readers have emphasized the need to revolutionize in-house PCB assembly and other low-tech processes in electronics manufacturing.
We collected the perspectives of a few experts in the field to discuss whether these processes could actually be automated and why some of them are likely to remain as they are. We hope to shed some light on why some EE manual practices have been around for so long, while also touching on the possibility of greater automation in the future.
Hands-on Processes: Outdated or Essential?
Engineers typically assemble prototypes manually, despite the time and energy required for manual assembly, to negate the cost of outsourcing for a small batch. On a larger scale, however, it's practical for government and private agencies to send their designs out to be manufactured and assembled by third-party companies.
Paper Travelers vs. Digital Traceability
When most people consider what goes on in an automation factory, they might imagine, well, automation. But Ryan Saul, VP of manufacturing at Tempo Automation, explains that this isn't always the case.
Tempo Automation, an electronics manufacturer based in San Francisco, is trying to address some of the low-tech pain points of manufacturing by using software automation to speed up the time required to fabricate prototypes.
Automation machinery at Tempo Automation. Screenshot used courtesy of Tempo Automation
In a discussion on cyber resilience in industrial control systems, Saul emphasized how some manufacturing facilities still, for instance, use paper travelers.
"I would say that electronics manufacturing is in many ways impressive and state-of-the-art. I would also say that it is archaic and unaltered by modern software in many facilities,” Saul said.
“You might go to the facility that's making a medical device or wearable and find that—even though that part will be running in the most advanced hospitals and healthcare plans—in order to manufacture it, they're still using paper travelers.”
Paper travelers are essentially sheets of paper where engineers write down information about a given product or prototype to keep track of its manufacturing progress and outline the steps required to complete the PCB.
At Tempo Automation, Saul and his colleagues have introduced a new strategy that removes the need for paper travelers. Engineers can instead use software to track how far along a product is in the manufacturing process. This new strategy is based on digital traceability and controls both incoming materials and in-process manufacturing.
Tempo Automation uses a software system that tracks every step of the manufacturing process. Image used courtesy of Tempo Automation
“Once we begin, each of our boards is controlled by a serial number and is tracked individually through each operation," Saul explains.
"So, I can bring up right now the status of all of the jobs we're running today and it will tell me how many of them have been through SMT—and by that, I mean not by job, but by serial number."
Gerber Files and Their Replacements
Another established process employed in electronics manufacturing is the use of Gerber files. The standard coordinates in Gerber files were first introduced toward the end of the Apollo spacecraft era and since then, they have only been updated a few times.
Mark Hughes, a researcher and content writer for the PCB assembly company Advanced Assembly (and also a regular contributor for All About Circuits), feels that there is a reason why Gerber files have been around for so long.
“There are only so many ways that you can create a computer file that says 'this board is 2" wide and 3" long', or 'this copper pad is a rectangle 20 mils by 40 mils', so the Gerber file format has survived the decades,” Hughes explains.
Gerber files in the Autodesk EAGLE Control Panel. Image used courtesy of Autodesk
“However, it has evolved over time. In the late 1990s the extended Gerber format superseded the original format and then extended Gerber was superseded by Gerber X1 and X2. These file formats contain the same numeric information of the original, but add additional information.”
Over a decade ago, a few alternative standards were introduced, including OBD++ and the IPC-DPMX (IPC-2581). Both of these generic standards are used to transmit information between a PCB designer and a manufacturing or PCB assembly facility.
The industry trend is currently toward the IPC-DPMX (IPC-2581) standard, which was first introduced in 2004.
Is Fully-automated Assembly Feasible?
While achieving full automation in electronics manufacturing sounds like a desirable end-goal, for the time being, it seems a rather unlikely possibility. A few engineers commented on why they feel full automation in the manufacturing process is feasible in some cases and unrealistic in others.
PCB Printers: the Next Big Thing or the "Easy-bake Oven of Manufacturing"?
From time to time, people discuss the possibility of PCB printers eventually substituting current manufacturing processes. Hughes does not see this happening any time soon.
“Desktop machines are currently the easy-bake ovens of the manufacturing industry,” he said.
“There are certain high-quality desktop PCB printers (limited to two-layer PCBs) and desktop pick-and-place machines. However, these machines are hundreds of thousands of dollars and produce relatively low-quality boards.”
Ordering a pre-fabricated and assembled PCB from a third-party manufacturing facility is currently far cheaper, faster, and easier than buying a PCB printer. Some PCB assembly companies, including Advanced Assembly, can deliver boards at fairly affordable prices—sometimes within a day.
The Merit of Machines
While full automation of EE manufacturing processes doesn't seem to be a possibility in the near future, there are still a number of processes in which machines are essential.
One example of this is lamination, which refers to the manual process of sandwiching and aligning copper, cores, and prepreg together. These PCB layers are then placed in a heated hydraulic press, in which tons of pressure squeeze them together permanently.
Advanced Assembly facility in Aurora, CO. Screenshot used courtesy of Advanced Assembly
“There are processes that machines do well and processes that humans do well,” Hughes commented.
“Oftentimes, it is very difficult to come up with an accurate, reliable, low-tech solution to a high tech process. For example, the pick and place process, solder-paste printing, and drilling and routing. There is no way a human could ever hope to come close to machine-performance in either speed or quality.”
Prototypes and Attention-to-Detail
Engineers working at PCB assembly companies, where many processes are now automated, still do some things manually. For instance, they inspect PCBs for flaws that computer vision models are unable to detect, determine the importance of specific errors identified by machines, and repair these errors manually.
Sebastian Weber, who collaborates with Hughes at Advanced Assembly, believes that some processes are difficult to automate on a large scale, particularly those that involve precise manual work.
“Everything in the low-volume, quick-turn, and specifically, the prototype industry is somewhat difficult to automate,” Weber said.
“This is simply because of the amount of change that can often occur during these early phases. We have often seen customers requiring extensive rework (jumpers, wires, dead bug, cut traces, etc) that need to happen on low-volume builds typically because boards were bought in bulk initially before a design issue was discovered. These processes are very manual and would be very difficult to replicate/automate on a large scale.”
Traditional assembly process (top) vs. Advanced Assembly's first article PCB manufacturing process (bottom). Image used courtesy of Advanced Assembly
According to Weber, some manual processes involve too many scopes and variables, thus accounting for these factors using logic or computational analyses. While theoretically, one could map out all the variables involved and subsequently devise techniques to complete these processes, this is typically too expensive and time-consuming.
“At that point someone needs to objectively identify if the cost is worth it, as often machine setup time takes longer than the actual process, which doesn’t provide any real ROI,” Weber added.
“Don’t get me wrong; Advanced Assembly has been using custom software to help automate the flow of digital data throughout the assembly process to reduce setup time while still maintaining quality for 14+ years. In doing so, however, we have found that some processes do not necessarily benefit from full automation. Moderation is key, as it is in most things.”
The Future of Automated Manufacturing
While new computational tools for automating manual tasks are being developed every day, the full-automation of EE manufacturing processes still appears to be a distant possibility.
Even if automating some of these low-tech processes is technically feasible, they might require expensive equipment and significant effort, ultimately making them inconvenient or impracticable. However, this could change in the future, particularly if highly-performing computational tools and PCB printers become more affordable.