Industry 4.0, digital manufacturing, agile manufacturing! Regardless of the term, the goals are speed, efficiency, and flexibility. Many technologies, old and new, are coming together to enable these transformations. Hot melt flows perfectly into agile manufacturing. It can enable production speeds exceeding 1,200 products per minute. It is ideally suited to robotic and automated applications. In fact, the first 3D FDM printers were based on hot melt application equipment. Like many digital technologies, optimum results depend on learning and sharing among an ecosystem. This includes the adhesive supplier, application equipment supplier, automation integrator, part designer, process designer, and production operations.
Robotics is the most obvious area where this ecosystem comes into play. The ability of a robotic work cell to rapidly adapt over multiple product generations enabled rapid improvements in important industries. Hot melt bonding in robotic work cells enables modern bezel-less device designs. Robotic hot melt bonding and sealing is essential for the assembly of the 7,104 cells in a common electric car. High-quality bonds help to achieve the many recharge cycles expected over the vehicle’s life. Non-contact jetting of discrete dots of adhesive simplifies the robot’s program and enhances its cycle speed and accuracy. Modern hot melt applicators are available that can cycle up to 1,600 times per second, or 1.6 kHz to support such advanced production. Modern robotic work cells integrate multiple subsystems, including advanced part handling systems, vision, and adhesive processing equipment.
This integration is only possible with excellent M2M communication. Ethernet communication enables an operator to track and control a complex process from a simple, central HMI. Reusable code blocks reduce the cost for automation integrators and control designers. These may be available as ‘starter kits’ for a variety of OT protocols. Strong user-interface design helps operators meet the goals of speed, efficiency, and flexibility.
Modern products are expected to have beautiful designs that are strong and work in many environments. This can require specialized hot melts, including foamed and reactive hot melts. These products share the nearly instantaneous bond formed when hot melt spreads between the joined components and cools, but take the performance to the next level. Reactive hot melts utilize the moisture in the air to react and continue to build strength and performance after the initial bond is formed. Once fully cured, they can offer strength, flexibility, and heat resistance that other fast setting, process friendly adhesives cannot. Foamed hot melts offer a soft, compliant material with excellent sealing properties. These can be used as a gasket in a design intended to be opened and re-closed or for sealing and bonding a permanent assembly.
The product designer is a key member of the ecosystem to create a beautiful, strong design. Instead of simply replacing fasteners, optimal adhesive designs follow these three rules:
1. Design structural joints so that all the bonded area equally shares the load.
2. Design joint configuration so that the basic stress is primarily shear, tensile, or compressive with cleavage and peels minimized.
3. Consider robotic access to the bondline and processing steps.
Skilled designers seek support from ecosystem members. Partners can offer a clear understanding of the adhesive and process capabilities. They can offer proven sample designs to help achieve a robust part in an efficient and flexible production process.
This becomes even more essential when sustainability is a key goal of the design. Consider the entire life cycle of the product to ensure sustainability. Adhesives can contribute to sustainability in many ways, including:
• Reducing stress, so the product consumes less materials in its production
• Enabling designs that utilize recycled or bio-based components
• Choosing processes that minimize energy in production
• Adhesives that are bio-based, compostable, or recyclable • Designs that can be de-bonded for repair (reuse) and recyclability
Often the improvement in one of these areas is a trade-off with another. For example, a recycled material that is not strong requires more material. Creative design with a good knowledge of these trade-offs can result in winning products that support a circular economy.
When these concepts are integrated into an agile manufacturing approach, designs can quickly evolve to meet rising customer expectations and stay ahead of the competition, while using fast, efficient processes to keep costs under control. While this vision of Industry 4.0 has existed for some time, it long seemed to be in some far future. However, we are seeing examples that this vision is becoming a reality faster than many imagined was possible as the pace of digitization accelerates.