Efficiencies in Industrial Tape Application
In the fast-paced world of industrial manufacturing, efficiency is key to maintaining competitiveness and profitability. One technology that significantly boosts efficiency in tape application processes is the robotic tape head. By automating the precise placement and bonding of adhesive tapes, robotic tape heads streamline production, reduce waste, and ensure consistent quality. Read on as we delves into the workings of robotic tape heads, the importance of the wet-out process, and the advanced features that make these systems indispensable in modern manufacturing.
How Robotic Tape Heads Operate
A robotic tape head is specifically designed for materials with at least one adhesive side that is covered by a liner. The basic process consists of peeling the liner from the adhesive tape and applying the adhesive tape to the part. Some systems, such as the RoboTape system include an integrated wet-out attachment which applies a pressure or force to the tape to ensure the tape is fully wet-out on the substrate.
The Importance of Wet-Out in Adhesive Bonding
The wet-out process is not in fact referring to anything being wet, but instead the process of forcibly causing the adhesive to flow into microscopic crevices in the surface. Many adhesives are referred to as pressure sensitive adhesives or PSAs, the wet-out process greatly enhances the bond, especially on hard to bond surfaces such as plastics.
These hard to bond surfaces can be categorized by their surface energy. Low surface energy substrates are things like plastic such as vinyl, polyethylene and polycarbonate. Adhesives and bonding experts like 3M have developed acrylic foam tapes that are specially designed for the adhesive to flow and bond to the microscopic crevices. This has allowed the use of low surface energy plastics in new applications, especially prevalent in automotive manufacturing. The bond is often deemed permanent providing the surface is in good condition during assembly – free of contaminants such as oil or highly pitted and rough surfaces.
An applicator tool that can apply pressure to the tape in process reduces the additional processing time and can help to speed up production. The difficulty with this built in wet-out system can be avoiding obstacles on the part such as clip bosses, screw posts, ribs, flanges and part clamps. For particularly complex parts it may be necessary to customize the wet-out tooling for the application. Check out our detailed white paper on Wetout Procedures and Systems.
Advanced Features and Benefits of Robotic Tape Heads
After the tape is applied to the part, the liner is removed and collected by either a rewinding spool or a vacuum. There are advantages with each design, but most notably, collecting the waste via a vacuum allows the liner to travel away from the head while the applicator moves.
Other features of a robotic tape apply head include sensors and guides. Sensors can be incorporated to detect breaks in the tape and splice joints. Splice joint detection is critical as most products do not allow a spliced tape to be used in the assembly. For this reason the splice must be ejected.
Various options exist for ejecting the splice from the head. The two most common are vacuum purge and paper purge. To purge into a vacuum the tape must easily release from the liner, if it struggles to do so then a wrap-around may occur at the peel tip. Purging onto paper involves the applicator moving to a purge location and dispensing a line of tape onto a sacrificial piece of paper. This method can be ideal because it allows a series of side by side applications. The tool can be programmed to purge the minimum amount of material until the splice exits the tool.
Adhesive tape dispensing tools usually incorporate an electric motor and an encoder to drive the tape in relation to the part. The encoder data is used along side the speed of the applicator tool to dispense at the correct rate. With robots, this is referred to as TCP speed or Tool Center Point Speed. A correction factor can be added to adjust for acceleration and deceleration discrepancies.
In summary, a robotic tape head is designed for high volume tape applications that require speed and efficiency. By combining multiple processes into one applicator, maximum savings can be realized.