7.3 Critical Factors when Selecting Adhesives

As discussed in Section 4, the following factors need to be considered when selecting an adhesive/sealant for an application. Understanding these factors is also extremely useful when examining failure modes and systematically troubleshooting the root cause of a failure.

The above guide is a starting point; conducting a comprehensive review of failure modes would require an entire book. When performing a failure mode analysis, it is always best to keep an open mind as the little details are often the most important.

Once the problem is identified, rectifying the issue may involve some of the following: altering the specification of the adhesive, modifying the surface preparation techniques, altering the application processes, changing the substrates or further training of applicators.

7.4 Containment and Complaint Detective Work

As part of the investigation process, several questions, such as those listed below, should be asked. An adhesives engineer may be particularly helpful in this process. Having this information prepared beforehand is important for quick resolution of the issue.

• What is the item and batch number of the adhesive?
• Has another batch product (adhesive) been tested or tried? Do both batches have the same issues? If yes, the adhesives manufacturer should be contacted immediately.
• Has the batch been quarantined? If no, quarantine the batch immediately.
• How long has it been occurring or when was it first noticed?
• Has this application/assembly ever been successful?
• How many bottles have the problem? All bottles of that batch or only a few?
• What is the failure rate: the number of parts failed vs the number of parts produced?
• How is the product stored?
• Was this bought from a distributor or direct? How is the product stored prior to order fulfilment?
• How long has this product been in use? Is this a new product or process?