SCREEN printing
Let Your Factory Speak for Itself
Getting machines to talk to each other enhances output and yields.
IT’S COMMON SENSE, really, and probably one of the most familiar sayings of mankind: Communication is key. Good communication is central to productive relationships, effective business strategy … just about everything, honestly. It’s not just communication, however, but communication quality and transparency that result in informed decision-making. This is especially true in the manufacturing setting and is the basis for Industry 4.0. Machines have been cranking out data for decades, but applying them in a meaningful way is, at the core, what Industry 4.0 is all about. Until recently, however, data exchange was largely supplier-specific; proprietary equipment system software could manage tasks rather seamlessly, but communication among disparate equipment brands in relation to PCB movement and traceability was challenging. The IPC-SMEMA-9851 standard provides a solid foundation and is still successfully employed, yet enhancements are required to progress toward a nimbler, automation-friendly solution that permits open and uniform machine-to-machine communication.

How it started. While several stencil printer platforms and everything within their respective ecosystems – board handling equipment, SPI and closed-loop feedback tools – are data rich, self-correcting and optimized for the printing operation, the data generated by printers relating to the PCB characteristics must be passed down the line. That, of course, means the data must be vendor-neutral. Moving beyond simple board recognition from one system to the next, true traceability is required for smart factory effectiveness. Consequently, the Hermes Standard Initiative (IPC-HERMES-9852) was born as the result of more than a dozen equipment vendors unifying behind the cause for an improved open communication protocol, which speaks volumes for the requirement and the customer desire for such a solution. By simplifying the transfer of PCB data between machines regardless of supplier, efficiency and productivity improvement are a given. And, with scalability options, board data can be customized so that when the PCB is passed from, say, the printer to the placement machine, each machine is compelled to recognize the data set, potentially add to it, and transfer that record through the assembly line, making for a more holistic view of the PCB. In fact, these data represent the digital twin of the physical PCB, and Hermes transports the PCB and its digital twin consistently down the SMT line. Integrating Hermes with IPC’s Connected Factory Exchange (CFX) standard broadens this line efficiency and communication transparency to the factory, while other MES systems can extend that to the global enterprise.

“Analyzing the data stream in real time allows full, closed-loop process control within the demanding process of stencil printing.
For the printing operation, the potential efficiency benefits of Hermes are immense. In manufacturing sites that require multiple changeovers per day, for example, the ability to seamlessly reconfigure the printer through automatic conveyor system adjustments, corresponding program-loading and verification of proper material sets (solder paste, stencils, etc.) saves time, the potential for human error and the related costs of mistakes. Optimized board flow management enabled by Hermes raises line efficiency, with board location in-process aiding adjustments upstream or downstream to facilitate a continuous pace. Within the print optimization loop, CFX allows the SPI platform to feed its data stream into a process analysis system, transforming the data into information and then into knowledge, spurring small but continuous process corrections to the printing process. As this column frequently illuminates, the printing operation is affected by many factors. Having the data stream analyzed in real time allows full, closed-loop process control within this demanding process. Other data streams that can be transformed into knowledge using the CFX framework include material/logistics/quality of raw materials, work in process (WIP) and finished product. Equipment utilization and predictive maintenance data can also be captured.

How it’s going. To be fair, the industry is only at the start and has a long way to go, but the standards are now established. As of last November, 58 suppliers have signed on as members, and factories worldwide are increasingly embracing Hermes, as well as other higher-level powerful communications for factory and enterprise Industry 4.0 manufacturing. For early adopters, such as a North American customer that installed a Hermes and CFX-equipped line in early 2020, immediate improvements have been noted. That assembler commented the cutting-edge connectivity led to significantly reduced setup times and nearly eliminated process variation for extreme productivity. Indeed, the ability to carry out full product changeovers for the entire line with less operator intervention is one example of how this technology can reduce the resources required for low-value routine tasks. Other practical examples are seen at manufacturers of high-end industrial assemblies. These customers have small (<300 units) runs; therefore, many changeovers are performed every shift. Hermes capability saves them considerable time, enabling more productive resource allocation and eliminating potentially expensive errors.

The core of communication is transparency, comprehensiveness and analysis; this is the heart of Industry 4.0. With the Hermes and CFX standards in place and industry adoption on the rise, the lines of communication are open. Welcome to the smart factory.

Clive Ashmore headshot
Clive Ashmore
is global applied process engineering manager at ASM Assembly Systems, Printing Solutions Division (asmpt.com); clive.ashmore@asmpt.com. His column appears bimonthly.