BTG Labs boasts relationships with some of the world’s top automotive manufacturers and tier 1 suppliers. The Surface Analyst™, a fast, easy, accurate, and non-destructive surface cleanliness gauge, quantifies how prepared a surface is for bonding, coating, sealing, painting, printing, or cleaning from the lab to the manufacturing floor. Therefore, it can be implemented in a variety of applications. This non-subjective, user-friendly system allows users of all training levels to measure surface cleanliness levels in either a pass/fail mode or exact contact angle degree in under 2 seconds.
Typical Surface Analyst Applications for the Automotive Industry
- Verify readiness of high performance specifications composite surfaces for bonding
- Reveal contaminants (such as mold releases) on machined parts
- Verify cleanliness of sealing surfaces in aluminum castings prior to bonding
- Verify a polymer’s readiness to be painted or bonded
- Validate high cleanliness levels required for FIPG (formed-in place gaskets)
- Guarantee proper finishing of automotive interiors
- Validate clean surfaces on engine block for RTV sealing
- Monitor and optimize the wash process for machined parts
- Measure brake and rotor contamination and coatings
- Verify appropriate flame treatment of TPO used in bumper facias, door panels, etc.
- Monitor bonding strength of composite materials
- Measure surface preparation prior to coating glass
BTG Labs has implemented the Surface Analyst in many different automotive applications. This specific case follows an automotive manufacturer’s efforts to replace heavy and expensive traditional gaskets with lighter and easier to install RTV sealing.
As RTV sealing is increasingly replacing traditional gaskets, a reexamination of surface preparation processes must follow: this includes knowing and monitoring the cleanliness of the surface to ensure a successful bond. Moreover, RTV silicone requires a high energy, or very clean surface in order to form a strong bond.
So, when an automotive company was experiencing engine leaks in the field, they were forced to reexamine their sealing processes. BTG Labs came in with the Surface Analyst and measured contact angles on dozens of parts. The results revealed huge variability. The variability in these measurements showed ranges of low surface energy resulting from a number of different contamination elements: heavy residual oils on the surface left over from the diecasting process; washing systems designed to remove machining chips were not removing the detrimental residual contaminants; and, lastly, rust preventative—as a low energy coating—being used did not interact appropriately with RTV silicone.
With the new process of RTV sealing came the necessity to change several other processes. An appropriate surface treatment and washing process was needed to increase surface energy by properly removing contaminants. And, rust preventatives must be higher energy coatings. Furthermore, the manufacturers implemented the Surface Analyst on the factory floor as an in-place method of monitoring surface cleanliness levels.
How It Works
The Surface Analyst™ deposits a tiny liquid drop (2μl or less) onto a surface and determines the contact angle formed by the drop and the surface. This contact angle provides an immediate, quantitative measure of the state of the surface: it is sensitive to less than a single molecular layer of contamination. The measurements are fast, taking under 2 seconds.
Unlike other contact angle measuring devices which deposit a fully-formed drop onto the surface, the Surface Analyst™ uses BTG’s patented Ballistic Deposition to construct a drop on the surface from a pulsed stream of nanoliter-sized droplets. This is a mechanically robust approach that imparts kinetic energy to the growing drop, allowing it to spread to its true equilibrium shape regardless of the presence of surface roughness or imperfections. Thus, this offers a contact angle measurement that is a better indication of the true surface than angles obtained from traditional contact angle goniometers.