Bend Adhesion & Tape Test


The evaluation of lamination core plate adhesion is vital in ensuring proper resistivity performance on recoated laminations. A common method for examining this adhesion is the Bend Adhesion and Tape Test, which comprises two tests evaluating coating adherence to laminations that make up motor and generator cores. Typically composed of silicon steel, laminations also feature a layer of core plate insulation applied to reduce heat loss and prevent shorting of laminations during operation. Therefore, verifying coating cohesion to metal laminations through testing plays an essential role in maintaining interlaminate resistance. 

To examine any flaws with the coating that could result in inadequate adhesion, inspectors conduct a specific type of testing procedure. The bend test requires them to wrap a coated strip of electrical steel over a steel mandrel. Using two clamps at either end, they apply pressure gradually until it reaches a curve of 90 degrees. The act of bending places stress on the electrical steel coating, which can lead to cracking, peeling or similar defects; these conditions indicate poor adhesion. The examiner then checks for any possible imperfections and documents their findings accordingly. 

If no flaws are present, the test is deemed successful. The second part involves utilizing a strip of 3M tape and fastening it onto the bent bar's surface before rapidly removing it to ensure that both the tape and part's coating maintain proper adhesion. As an industry standard, the tape used for this test is often a standard 3M Scotch tape that can be easily obtained. 

When applying the tape onto the coating, it must be precisely pressed down before being removed at a swift 180-degree angle. The adhesive found on the surface of the tape applies additional stress to the coating, which permits any faults missed during the bend test to become apparent. 

If both surfaces or bars adhere firmly and remain intact after completing this step, then it passes as an acceptable result. In various industries, the quality and durability of laminations & coatings are essential, and the Bend Adhesion and Tape Test plays a crucial role in determining them. By identifying any defects or flaws in the coatings, this test limits the possibility of loss of adhesion over time that may lead to energy inefficiency or shorts. 

The electric motor industry is one such sector where laminations form an integral part of the core. Additionally, aerospace and automobile sectors use lamination & coating applications for diverse purposes. Laminations and coatings are significant components in aerospace and automotive industries. 

The Bend Adhesion and Tape Test is a cost-effective method that can be utilized to evaluate the robustness and durability of these components. Whether it is conducted in the laboratory or on-site, the test can provide valuable insights concerning product quality. 

It enables manufacturers to identify defects in their products quickly and take necessary corrective measures. The Bend Adhesion and Tape Test serve as a critical tool in assessing the adhesion of coatings commonly used in various industrial processes. Its application helps identify any potential weaknesses or defects that may compromise the product's durability over time, leading to decreased efficiency and increased downtime. 

With its relative ease of administration and affordability, it is an invaluable tool for manufacturers seeking to improve product quality.