Certainty. This is the goal of every manufacturing process. Manufacturers need to have total confidence that every aspect of their production process will go according to plan. The adhesion process needs to be controlled just like any other production operation, with accuracy and on-going monitoring. Manufacturers need to know that when they apply an adhesive, coating, paint, ink or any other bonding surface that it will stick every single time.
The criterion for what a suitably prepared material surface actually is needs to be adjusted in the minds of manufacturers and Quality Assurance Managers. The new benchmark needs to be founded on a scientific understanding of what is occurring on the surface.
By removing material (e.g. abrading, media blasting, particulate washing) and by changing the chemical nature of the surface (e.g. plasma treatment, solvent cleaning, chemical etching) the uppermost molecular layers are being altered or displaced. This is a crucial principle to understand in order to fully control adhesion outcomes and it is the least understood element in manufacturing.
There are three underlying elements that need to be totally controlled for successful adhesion:
Composition of the adhesive or coating material
The adhesive or coating application and curing processes
The composition and properties of the first few molecular layers of the surface receiving the adhesive or coating: ‘Surface Preparation’
It is the surface preparation element that gets short shrift when manufacturers are planning adhesion processes or trying to solve existing adhesion failure. Without focusing on how control of this key element affects adhesion it can feel like a never-ending cycle of trial and error. Since adhesion is a function of chemical reactions occurring on the surfaces of two components bonding to each other, it needs to be approached as more than a merely mechanical operation.
When manufacturers can rely on the consistency of their surface preparation process to achieve the chemically favorable surface they require to ensure adhesion, then they can begin to build that certainty they hope for. The clearest and surest path to certainty is to quantify each of those aspects of the production process where uncertainty lurks.
There is an inevitable variation in production processes and environments but if the focus of control is on the material surface then the impact of these variations can be understood and compensated for. Implementing a quantitative measurement of surface quality at every point where there is uncertainty about the state of the top molecular layers of a material is the quickest way to seize control of the entire process.
If an adhesion process has a set, quantifiable specification for precisely what a fully-prepared surface needs to be before the adhesion step, then manufacturers are freed up to concentrate efforts on achieving this value every time. This simplifies the equation. If you know you have a surface that measures at value [A] and you require that surface to measure at value [B] to ensure proper adhesion, then you can weed out any steps and processes that do not result in value [B].
In order to place a quantifiable value at each point where the surface can be changed (we call these Critical Control Points) a surface inspection method with a numerical result is required. Equipment that will incorporate into a production process and provide this value are required to seamlessly take the necessary measurements and gain insight into how to adjust parameters and practices to get to the desired goal. This will ensure consistency. If the specification is not met, then the material does not proceed and adhesion failure is fixed before it starts.
Partnering with surface experts is necessary to fully understand how to properly optimize the parameters and practices that might need to be adjusted in order to achieve perfect adhesion. Manufacturers can find help to make these changes thoughtfully and based on data rather than hope and speculation. The data is gathered through the inspection equipment and on-going monitoring to track any changes.
The risks are really high of not re-looking at the manufacturing process through the lens of what changes are occurring to the top molecular layers of a surface. Rework that ensues once failure happens can hamper production rates and doesn’t allow personnel to focus on innovations or developing new projects. Warranty claims and recalls can be costly ways to realize there is an adhesion problem. Solving these issues up front can save companies a fortune in the long run.
To find out more about developing a surface quality specification that fits your process, download the "Manufacturer's Roadmap to Eliminating Adhesion Issues in Production" ebook. This guide gives clear insight into eliminating guesswork around adhesion so manufacturers can achieve consistent and successful results.