Manufacturers often have a large blind spot when it comes to the causes of adhesion problems. This blind spot makes it impossible to solve these problems and generates frustration and loss rather than productivity and adhesion success. Taking the blinders off and taking on adhesion failure at its source(s) is job one for manufacturers who are determined to fix the problem.
Before making any decisions or taking any steps forward, manufacturers need to take one big step back. They need to examine and understand adhesion failure as something more systemic than what seems immediate evident. The first thing to recognize when making a serious commitment to fixing common causes of adhesion problems is to understand where the causes originate. This requires thinking outside of the usual approaches as well as looking further upstream than is typically done to address the roots of the issue.
In every manufacturing process that involves adhesion (bonding, printing, painting, coating, sealing, laminating) it is absolutely necessary to understand and control, when boiled down as minutely as possible, only involve three key elements. These three elements are:
Manufacturers have a pretty good handle on the first and third elements, but it is the one in the middle that falls into that blind spot mentioned earlier.
Historically, manufacturers have thrown the issue over the wall to adhesive manufacturers when an issue arises or when building out a new process or product. This is because the emphasis is on the first element – the adhesive. Since that is only one of three things that need to be controlled, it means the adhesive can be upgraded, re-examined or tossed out without meaningful change to the issue. Improvement might be seen in the short run but without taking a critical eye to the other elements the problem will persist.
Similarly, when the curing or finishing of the bond is over-emphasized this offers an imbalanced view. If the surface of the bond material is left out of the equation then you might be curing and finishing an imperfect product that didn’t have a chance to adhere properly due to that surface state not being prepared adequately.
That second element is every bit as important as the other two, but is commonly overlooked as a key component of solving adhesion failure. The surface of the material gets cleaned or treated, but even if failure continues, that’s where the story ends for most manufacturers. To avoid this same fate, an appreciation of what is happening at a molecular level on that surface is vital to determining the efficacy of your process. Rethinking of adhesion as a chemical process is key to taking the necessary measures to solving adhesion problems.
Here are a few steps to take to take control of your material surfaces beyond the cleaning and treatment steps already planned or in place. These are the places where rethinking of adhesion begins.
Control incoming material
Develop and maintain a way to quantitatively evaluate the state of your material surfaces when they come into your facility or into the assembly process. If you don’t have precise knowledge of the chemical properties of the materials coming from suppliers, or from other places within your company, how can you appropriately clean or treat them? Having a baseline to understand what next steps are required is critical to not have to guess downstream.
Optimize and Maintain Surface Preparation Equipment
Much like creating a quantitative way to measure the state of incoming materials, there needs to be a way to do the same to calculate the exact effect preparation steps are having on a material surface. There are always parameters that can be altered on equipment or methods that can be changed in order to produce a more desirable result in manual surface preparation processes. But if those changes are made without a way to track how much closer or farther away you are from adhesion success then all that can be said is that the bond stuck. But that isn’t really an insight because it lacks any nuance or clarity. How long will it stick? Why did those changes make it stick? Is the problem truly solved? How do we know? Without definitive answers to questions like these you’re no further along than you were when you started.
Time Takes its Toll
The bonding step should happen at the most optimal time once the preparation steps have taken place. This usually means right away. Although this is rarely possible in the real world. So, what happens to the surface during the time between the preparation step and the actual bonding, coating, printing or sealing? Work needs to be done and a spec needs to be set to know that the surface has maintained the clean or active state until the time of bonding. Without a way to verify that the surface is still within an acceptable range of that spec (because change will occur over time) when it comes time to bond it leaves success completely up to chance.
Time also has a chance to wreak havoc on surfaces when materials are on in storage. Even if a baseline is established when materials arrive from suppliers, time in storage or time exposed in the manufacturing facility can significantly degrade the surface state from that baseline. Same goes for time in between the surface treatment and the bond step. During that time the surface can drift away from the spec that was determined to be optimal for adhesion success.
Get to Know Your Critical Control Points
All of the steps just outlined have something in common. In order to get the most out of these places where a surface could chemically change or has been intentionally chemically changed, there needs to be a way to measure and evaluate the surfaces. These steps are called your Critical Control Points and when they are understood, measured and monitored they will give you a wealth of knowledge about how to find the root cause of your adhesion problems.
Watch a short video of Giles Dillingham, Founder and Chief Scientist at BTG Labs discuss the impact of time, contaminants, and the implementation of Critical Control Points in manufacturing using an example of automotive glass.
Recognizing the Critical Control Points in your process and setting up a way to ensure that everything is meeting the established requirements is the only way to move forward. It’s been said, “You can’t manage what you can’t measure” and if you can’t measure your surface throughout your process you will always be looking in the wrong places to eliminate adhesion failure.
Taking a holistic approach that defines cleanliness as a chemical state of a material surface and that understands how this chemical state changes throughout the ENTIRE process is the key to fixing common causes of adhesion problems.
Contact BTG Labs’ Process Experts about how to locate and validate the Critical Control Points in your manufacturing process. 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."