Tag Archives: Adhesive bonding
As the wind energy industry grows—by 2020 it is expected to provide 10% of the nation’s electricity— wind turbine manufacturers must strive for the most reliable and efficient product that operates reliably and seamlessly. Adhesion failures in the field, are unacceptable and even dangerous, but still occur.
Wind turbine manufacturers are making it a priority to overcome adhesion failures in the field and implement ways to ensure repairs only need to be done once. Currently, wind turbine repair is extremely expensive: in most cases, the part must be shipped back to the manufacturing plant for repair. And most importantly, turbine failure could be damaging and dangerous to what could be in the vicinity.
Adhesion failures most often happen due to improper surface treatment prior to adhesion. Optimizing adhesion processes and gaining control of the bond surface guarantees a reliable bond and prevents failures in the field.
As a result, wind turbine manufacturers are turning to the best in surface cleanliness gauges: The Surface Analyst.
Last month, Elon Musk announced the availability of Tesla’s new solar roof. These solar roofs are made to masquerade as tasteful, modern shingles; their attractive panels offer roofs from sleek modern to French slate. The solar panels are hidden in a pane of glass which contains a hydrographic coloring–a process that uses water to apply printed designs– to provide texture.
But, these shingles must not only look good, like all solar panels, they must be tough enough to withstand elemental threats.
Wind, rain, snow, sun, extreme temperatures–these are all stresses to any structure, especially solar panels. Because solar panels serve as an energy source, there is no room for failure in the field. The bonds that keep them together such as bonds between dissimilar materials, bonds on low energy polymers, coatings, laminates, and seals, must withstand the stresses as well. That’s why solar panel manufacturers turn to the Surface Analyst.
Manufacturers often encounter a similar puzzle, when cleaning invisible contaminants from a surface, how do you know when the surface is clean; how clean is clean enough? This is a common question that manufacturers ask when preparing their surfaces for bonding, coating, sealing, printing or painting. Until now, there hasn’t been an objective and reliable way to answer this question. Successfully cleaning a surface directly correlates to the adhesive ability of the surface. In order to get something to stick reliably the surface must be clean. How we define that parameter is different for a variety of materials.
For example, you clean your car differently than you clean your dishes. Why? Because a car rides on the road through rain, smog, dirt, maybe mud, and the other is a vehicle for your food.
At BTG Labs, our answer to the “clean enough” question is, “Depends on what you’re doing.” There are dozens of critical surface preparation processes that exist for a number of different applications. A handful include:
- Flame treatment on polypropylene bumpers prior to painting
- Plasma treatment on PET catheters prior to coating
- Hand sanding and solvent wiping on aircraft nut plates before adhesively bonding to composite
- Grit-blasting titanium golf clubs in preparation of bonding to composite
- Corona treatment on film for packaging prior to metallization, lamination, or coating
Improving Composite Bonds in Aircraft
The Surface Analyst™ technology has many of its roots in the CAI (Composites Affordability Initiative) program from the mid to late 1990’s. This industry/government partnership comprised of a team charged with addressing the perceived risks and barriers to a more widespread use of composite materials in aircraft design. The collaboration included members from the Air Force Materials Laboratory, the Office of Naval Research, Bell Helicopter Textron, The Boeing Company, Lockheed Martin Corporation, and Northrop Grumman Corporation.
Solvent wiping and sanding procedures can greatly affect the surface energy of a substrate. To investigate the surface energy differences following different preparation procedures of an epoxy composite laminate, researchers created several different surface conditions utilizing different cleaning techniques. For this experiment, a BTG Labs Surface Analyst™ obtained measurements.
The Surface Analyst is a fast, easy, accurate and nondestructive instrument that measures the contact angle of water applied to the surface in a precise, controlled manner. This contact angle is determined by how strongly the surface energy of the substrate and the liquid deposited interact. The relationship between this contact angle and surface energy is complex, but well understood. More importantly, this relationship correlates with the adhesive strength of a paint, coating, print or adhesive to the substrate.
Adhesion and Surface Processes
Dr. Giles Dillingham, President and Chief Scientist of BTG Labs, will be teaching two short courses at the annual meeting of the Adhesion Society in San Antonio, TX on Friday and Saturday, February 19 and 20, 2016.
The courses, titled “Surface Energetics and Adhesion” and “Surface Modification and Surface Analysis,” are comprehensive introductions to the science and technology of adhesive bonding, adhesive chemistry and formulation, and design of adhesively bonded structures. …Read More