The Role of Hot Bar Bonding Technology in the Wearable Tech Market

In today’s world, the most popular technology is portable and usable on the go. Every year, while electronic products get smaller and smaller, it makes sense for consumers to move towards wearable technology.

In today’s world, the most popular technology is portable and usable on the go. Every year, while electronic products get smaller and smaller, it makes sense for consumers to move towards wearable technology. Forbes analysts predict the net worth of the industry will increase by $20 billion in the next four years. People want convenient technology that they can take everywhere and manufacturers have stepped up to the make this happen. In order to keep up with demand, new ideas and manufacturing techniques have been put into place. Wearable technology must be small and flexible to withstand our daily activities. Flexibility is a facet new to electronics, and it requires very specific and innovative techniques. At AMADA MIYACHI EUROPE, we are experts in Hot Bar bonding technology and use this to make wearable products possible.

The Wearable Tech Market

Wearable technology has applications in varied and overlapping fields. If a piece of technology would be as convenient to wear as a watch or as part of clothing it is a potential product in the wearable tech market. Currently, health technology is one of the most prevalent market for these kind of applications. Basic health technology might include a sensor attached to the body to monitor something as simple as a heartbeat. But as sensors get smaller, more specific, and more accurate, more complicated and nuanced bodily functions could be monitored. Miniature imaging and/or position sensors could be manufactured into wearable technology that could provide sonograms and ultrasounds to monitor an injury or condition. Doctors could use the information logged by a wearable device to get a broader picture of their patient’s day-to-day health. In the future, health professionals may even be able to receive the information directly from the device.

Health devices can be expanded to self-monitoring applications, whether out of curiosity or progress tracking in exercise and sports. Athletes can use small wearable sensors to keep track of their body as they put it through its paces. In addition, lighting technology can be placed in wristbands and footwear to make walking and running safer at night.

Besides walking and exercising in the dark, people also want lights in clothing for fashion reasons or merchandise on exhibitions “Glow in the dark” bracelets and clothes have been around for years and require chemical reactions and pre-exposure to light. But clothing with actual battery-powered, light producing designs are a different story. Whether for Halloween costumes or high fashion experiments, this technology is already in use and in demand.

Hot Bar Bonding

Hot bar bonding is a general expression used to describe many processes of controlled heating and cooling using a thermode (or Hot Bar) to create an electrical interconnection between materials in a product under a controlled force / pressure. In order to make wearable tech possible, we need to be able to create electronics that are small and flexible. This means the internal sensors, connections and monitors must also be small and flexible. Sometimes sensors are that small and parts must be positioned with such precision that traditional batteries cannot be used anymore, this enables the need for flexible printed batteries. Flexibility requires new materials and ways of connecting them. Hot bar bonding offers a solution for this need.

Processes at AMADA MIYACHI EUROPE

Hot Bar Reflow Soldering

Hot Bar Reflow Soldering is a selective soldering process where two pre-fluxed, solder coated parts are heated to a sufficient temperature to melt the solder. After this the parts are cooled below the solidification temperature to form a permanent electro-mechanical bond. This technique is the most ideal process for components requiring low production costs or high electrical conductivity. Pressure is applied during the entire cycle to prevent disconnection of the parts until solidification of the solder. Hot Bar Reflow Soldering is typically used to connect a FPC to PCB, small wires and coax cables, or very light and/or small components such as those needed in wearable technology.

ACF Bonding and Heat-Seal Bonding

Anisotropic Conductive Film (ACF) laminating, or pre-bonding, is the first step in the ACF process where adhesive material to the product is applied using the AMADA MIYACHI EUROPE newhorizon laminating systems. This technology is used when a fine-pitch is required and where selective reflow soldering cannot be applied. ACF technology is the preferred solution for small pitch connections. The interconnection is made for example between flexible and rigid circuit boards, glass panel displays and flex foils. The ACF material is supplied as a reel and consists of adhesive filled with conductive particles and a protective layer. Prior to laminating the ACF to the substrate, the tape is pre-cut at the required length from a reel of ACF. Cutting is done using the half-cut method where on the actual ACF material is cut, the cover-layer is used for tape transport. The ACF is now positioned over the bond surface, by applying temperature and pressure the ACF laminating is achieved. Once ACF laminating is completed and the flex has been aligned to match the traces on the substrate, the thermode (Hot bar) is again actuated and the parts heated to final bonding temperature under controlled pressure for the final bonding step. This process is closely monitored by our MG3 process monitor. The fine pitches and flux free process achievable with this technique are often needed in the small electronics used in wearable technology.

The Hot Bar heats the conductive adhesive until it connects the surfaces and electric current can flow between them.

Heat Staking

Heat Staking is a pulsed heat process to join two or more parts out of which one at least is made of plastic. The process is to deform the plastic material using heat and force at a set process time. The bond is made by partially deforming the plastic part in order to fix the other. Heat Staking makes it easy to bond metal to plastic and is commonly used in high volume/low cost applications like automotive, IT and consumer appliances.

Heat Skating effectively adheres plastic and metal parts with heat and acute pressure.

Using these hot bar bonding techniques, AMADA MIYACHI EUROPE has the capability of providing production and assembly services to companies looking to create wearable technology. To keep up with growing demand for tech on the go and new monitoring systems, manufacturers must be well informed in these techniques needed to make them. Hot bar bonding processes not only makes miniature and flexible products possible, but directly soldering or ACF bonding flexible circuit boards together eliminates the need for connectors making the process cheaper and easier to mass produce. By supporting the first steps in creating flexible, portable technology, hot bar bonding at AMADA MIYACHI EUROPE is pushing the wearable tech market forward.

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