Three Critical Factors to Achieving a High Quality Bond for Medical Devices

Posted on 1/23/2020 8:14:10 AM By ASC

Many factors affect the strength of the bonded joints in medical devices. These include the design of the joint and the substrates involved, as well as the preparation, application and curing process. However there are only three main areas which assess their quality. These are the bondline’s location, whether it cures properly, and whether the correct amount of adhesive is used.

Fluorescence can help determine all three. It’s the blue light that shines when UV light curing adhesives which include fluorescent agents are exposed to the black light emitted by lamps which generate long-wave UV. This blue light will determine the location of the bondline, reveal any gaps and give some idea of the amount of bonding materials that have been applied. Often visible to the naked eye, the fluorescent response can also be read by a sensor. The only risk involved is that adhesives can only contain a certain amount of fluorescing agents without affecting the cure.

Making absolutely sure the cure is completed in full, Dymax’s See-Cure light-curable adhesives use color-coding to ensure complete curing. The adhesive is blue when applied, but when exposed to UV light its colour gradually fades until it reaches total transparency at full cure. According to the company, See-Cure can also be used to determine the location and thickness of the adhesive applied.

To determine whether the correct amount of adhesive has been applied, a piezoresistance fluid sensor like the Flowplus16 can be installed in the adhesive dispenser to ensure free flow, the absence of air bubbles, dead spaces and clogging. 

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