What manufacturers know about the crucial role a successful adhesion process plays in a high-quality production operation and what manufacturers do about this fact can be widely divergent. Every manufacturer who bonds, seals, coats, paints or prints knows that in order to proclaim that a production process is successful, a perfect adhesion process must be a major contributor to the overall success. However, the most critical steps to ensure perfect adhesion is truly achieved are often not understood or are left out of the picture altogether.
The reasons for this disconnect come down to choices:
Manufacturers have a lot to wrap their heads around. Every production line is a complex network of interdependent steps and if something goes wrong at any of these steps, the whole operation is compromised. What’s more, when the constituent parts that form the manufacturing process are neither quantitatively regulated nor fundamentally understood at a granular level, this leaves the entire system vulnerable to unforeseen contamination and, ultimately, to adhesion failure. And that adhesion failure is directly linked to costly rework, scrap and recalls. Not to mention potential damage to a company’s reputation and credibility if bonds fail while the product is being used by a customer.
Choices about specs
The control and understanding necessary to have a reliable, quality manufacturing process begins at the research and development level. Critical choices that are difficult to alter later are made at this time of planning, so it is imperative that all the elements which make up a successful adhesion process are in place. This is when standards are defined and they need to be based on empirical, repeatable science so that the specifications based on these standards are truly the right ones for the manufacturing operation at hand. Once these specifications are determined it can be a very arduous process to change them or implement new ones.
Specifications in a manufacturing adhesion process should start at the surface. The material surface is one of three basic elements to control in an adhesion process; the other two are the adhesive or coating and the curing or finishing step. Basing a spec on the chemical state of the material surface gives manufacturers reliable clarity on whether the bond is going to stick or not. Adhesion is a chemical reaction between the top few molecular layers of a surface, the adhesive and the curing process. If this reality is not fully appreciated then the specs put in place will never fully control and give reliable data on whether the adhesion will be successful. There needs to be a verifiable measurement of the surface state set up as the standard to be achieved throughout the manufacturing process.
Choices about materials
It is usually well understood that the correct materials need to be used for any given application. Certain industries rely heavily on polymers, while others more often utilize metals or composites and other advanced materials. What is not so well understood is how these materials interact with adhesives or each other, or what preparation steps are most appropriate when adhesion is involved in the assembly process.
The most crucial aspects of the interaction between materials occurs at the molecular layer. Different materials have innately different chemical properties and respond very differently to treatment and cleaning. Understanding these molecular characteristics and being able to inspect these surfaces so preparation steps are able to truly create a bondable surface is paramount.
Choices about monitoring
There are always inspections and analysis done throughout manufacturing processes but what are these checks qualifying? Process verification is extremely important in order to ensure quality output but is everything that ought to be monitored truly being investigated?
Often times manufacturers will make tweaks to process parameters but do not validate these changes with a quantitative verification step. The parameters being checked and modified might include changes to a plasma treatment step, a new abrading method, new solvents or longer exposure to a cleaning step. On their face these seem like good choices to make when adhesion is failing and something needs to be changed. However, if the material surface quality is not measured how can the progress of these parameter changes been determined? Monitoring and enumerating the surface state gives manufacturers the freedom to make informed choices about what parameters to change and how much to change.
Choose to watch the surface
A reliable, quality adhesion process ties together the right materials, specifications based on the chemical state of the material surface and monitoring changes to that chemical state through the process. Properly planning and managing these things ensures high quality products and development as well as lower costs because guesswork is eliminated. The key aspect shared among all these choices is to pay attention to what is occurring on the material surface every step of the way.
Contact BTG Labs’ Process Experts to learn why a production adhesion process is essential to quality. A free Production Line Process Walk is available to start the gaining insight into where adhesion failure is originating. You don’t need to tackle the problem alone. To learn more about eliminating adhesion issues, please download the free eBook titled "Manufacturer's Roadmap to Eliminating Adhesion Issues in Production."