Quality Control in Manufacturing: Ensuring Reliability in Consumer Electronics
From material analysis to in-process inspection, manufacturers must take every step to ensure their parts meet the stringent standards set by the consumer electronics industry
From medical devices to car parts to consumer electronics, production of components is subject to various types of quality control. This is a process or set of processes designed to ensure quality at every stage of production, often with several stages of inspection to closely analyze the conformity of the parts.
In consumer electronics, manufacturers must detect discrepancies and defects before production, during production, and before shipment. There are many reasons why a manufacturer must do this: to prevent product recall, financial loss, reputational damage, and consumer harm, for example, which all relate to maintaining quality standards.. The scale of consumer electronics products makes quality control especially important from an economic perspective; while most consumer electronics are not safety-critical like aerospace or turbine components, many can have high retail prices, so recalling a batch of thousands could be catastrophic.
Quality control takes place throughout a product’s development—not just at the end of the production line. Pre-production quality control can involve processes like material inspection and design verification. During production, experts may monitor assembly processes, perform functional testing, and use monitoring equipment to identify defects that can subsequently be repaired. Pre-shipment quality control steps may involve random sample inspection and performance testing, assuring customers that the batch is of an acceptable quality.
This article focuses on elements of quality control during the microscale printing of electronics components. Because of the intricacy of such processes, quality control must be stringent, but challenges can arise due to the microscopic scale of printed features.
Material Analysis
An important part of quality control for consumer electronics is material analysis during the pre-production stage. A consumer electronics product may comprise a variety of materials, such as thermoplastic buttons, an anodized aluminum housing, and nanomaterials printed onto its PCB. Testing of nanomaterials presents a unique challenge due to the size of the nanoparticles within.
One important method for material testing is Transmission Electron Microscopy (TEM). In this process, an electron gun emits a beam downwards through a microscope column in a vacuum. Along the way, the electron beam is focused by a series of electromagnetic lenses onto a sample measuring less than 1 μm in thickness. The beam passes through this sample, creating an image that is magnified onto a fluorescent screen. Consumer electronics manufacturers need to use nanomaterials with precise nanoparticle sizes in order to make miniature sensors, chips, wearable displays, and other items, and TEM provides a means of accurately measuring the size and uniformity of these nanoparticles. Microscale dispensing specialist XTPL’s use of TEM reveals an average nanoparticle size of 35–50 nanometers.
High-Precision Equipment
Another aspect of quality control during pre-production is the evaluation of production capabilities. In other words, a manufacturer’s machinery, tools, and workflows must be capable of producing the specific electronics parts being made. XTPL’s Ultra-Precise Dispensing (UPD) technology is built to offer the highest levels of precision, accuracy, and repeatability during dispensing, enabling users to achieve line widths down to 1 μm. This is only made possible through high-quality hardware with a motor movement accuracy of 2 μm and repeatability of 0.5 μm. Quality control in manufacturing demands the use of such equipment if the product has features that would be hard to consistently manufacture with less precise machinery.
High-quality manufacturing equipment can also contribute to quality control in other, more indirect ways. For example, XTPL software features an intuitive GUI that can help users reduce errors that may be more likely to occur when programming commands directly. Additionally, use of macros can ensure a high level of repeatability during at-scale production, while an emergency alert feature can prevent manufacturing errors such as nozzle collisions.
Real-Time Monitoring
Quality control process in manufacturing involves several steps that must be followed during the production stage, once all pre-production practices have been followed. In some areas of manufacturing, this can be as simple as inspecting in-progress parts with the naked eye to ensure that the manufacturing process is operating as intended and that parts are not obviously defective. In consumer electronics, optical inspection techniques can be classified as manual optical inspection, which is performed by a human, or automatic optical inspection (AOI), which is performed using an image sensor and processor.[1]
Production processes like nanomaterial dispensing for microscale parts are more difficult to monitor than macroscale processes and require specialist equipment. Microscale features cannot be critically evaluated with the naked eye, so microscopic equipment is required for process monitoring to ensure that the printing of tiny electronics components is successful. While real-time monitoring does not replace post-production inspection processes, it can contribute to a much lower manufacturing scrap rate by enabling operators to immediately identify errors and defects.
XTPL’s UPD technology is equipped with a three-camera process monitoring setup for in-process video feedback. This includes both side view process monitoring (real-time XY-axes dual microscopic cameras with 30x optical magnification) and top view monitoring (available with an ultra-high-resolution microscopic top view camera offering 5 pixels per μm resolution and a 100 x 200 μm field of view).
Defect Repair
A major aspect of quality control in manufacturing is the identification of defects—either in materials, unfinished parts, or finished parts awaiting shipment. Depending on the nature and extent of the defects, defective parts may be consigned to scrap. However, a low yield increases the overall cost of manufacturing (and also increases its environmental impact by necessitating a greater quantity of raw materials and further resource-intensive manufacturing operations).
A better outcome of defect identification is successful defect repair. In electronics, the repair or refinish of a defective PCB is known as a rework. Typically, however, a rework cannot be completed using the same mass production technology used to produce the PCB, but instead requires a specialist using manual techniques at a rework station and demands strenuous visual effort.[2] For microscale features produced during HDI PCB production, manual repair becomes less feasible, so other avenues must be explored.
One of the key abilities of XTPL’s UPD technology is its capacity for open defect repair on 2D or 3D connections. Capabilities include on-circuit via and microwell filling and the ability to dispense materials on complex technological substrates. This unparalleled ability helps consumer electronics manufacturers improve yield and reduce waste by enabling precise, non-contact repairs of defective conductive traces and microstructures. Using ultra-precise deposition, manufacturers can restore functionality to defective circuits, displays, and other components that would otherwise be scrapped.
Challenges and Innovations in Printing Technology
While XTPL’s method is transformative, scaling the production of ultra-fine conductive lines presents certain challenges. Manufacturing at such a precise level requires rigorous quality control and specialized materials, which can complicate the production process. XTPL is actively working to overcome these hurdles through innovations that streamline the process and improve material compatibility. By addressing these challenges, XTPL is positioning itself to lead future trends in printing technologies, ensuring that ultra-fine conductive lines remain feasible for large-scale production. The ongoing evolution of printing technologies in electronics indicates a promising future for methods that prioritize precision, sustainability, and efficiency.
XTPL’s ultra-precise printing method demonstrates the transformative potential of ultra-fine conductive lines in next-generation electronics. By enabling intricate designs that support miniaturization, XTPL’s technology is advancing the capabilities of modern electronic devices. As the demand for smaller and more powerful electronics grows, XTPL is positioned to play a significant role in shaping the future of electronic manufacturing, pushing the boundaries of what is possible with printing methods. With continuous innovation and a focus on sustainability, XTPL stands at the forefront of a rapidly evolving industry, driving progress in electronic fabrication and technology.
Conclusion
By reducing material losses and improving production efficiency via open defect repair, XTPL’s technology enhances cost-effectiveness and sustainability. Manufacturers benefit from higher overall device reliability and fewer defects reaching consumers, ultimately leading to better product quality and lower production costs in a competitive market.
However, this is just one of the ways that XTPL’s technology and expertise lead to quality control in manufacturing of consumer electronics. For example, the company’s expert material development team can produce custom nanomaterials with consistent nanoparticle sizes and densities, enabling a wide variety of cutting-edge microscale electronic applications, while its commitment to dispensing precision and comprehensive in-process monitoring leads to high-quality parts, a high level of repeatability for scale production, and minimization of errors and defects that results in higher yields.
Resources
[1] Abd Al Rahman M, Mousavi A. A review and analysis of automatic optical inspection and quality monitoring methods in electronics industry. Ieee Access. 2020 Oct 6;8:183192-271.
[2] Geren N. Model-Based Flexible PCBA Rework Cell Design. InComputer-Aided Design, Engineering, and Manufacturing 2019 Apr 23 (pp. 6-1). CRC Press.
