Medical User Interface Design with Biocompatible Silicone Elastomers

06 Sep, 2022

By hqt

Silicone is a common material for silicone-based HMIs. Silicone elasticity is used in many different industries and works well. From O-rings, Elastomeric keypads, toys and even kitchenware and more. And in silicone materials, the characteristics of biocompatibility are even better.

Through custom molds, silicone materials can be customized into a wide variety of products, as a final product that meets various industry specifications (such as USP Class VI, FDA CfR 177.2600 and ISO 10993) and is biocompatible depending on usage requirements Silicone materials are especially suitable for Class I and Class II medical devices, which is why so many silicone devices are used here.

What is biocompatibility?

One of the most special benefits of biocompatible materials is that human tissue will not experience any adverse effects in contact with them. If the product is in contact with people, it will cause irritation, allergies and other adverse phenomena, which means that it is not biocompatible.

Why is biocompatibility in medical devices so important?

First of all, hospitals and doctors appear to save patients, and the medical staff swears ‘no harm first’ in the oath, which also shows that medical staff are all patient-centered in the process of treatment, but medical staff cannot understand the new Whether the medical equipment is biocompatible or not, if it is not biocompatible, it is likely to cause major medical accidents. In order to avoid accidents caused by such products, the FDA requires biocompatibility test reports for medical devices, and the same is true for silicone-type HMIs. Everything is in order to be responsible for the patient.

Medical grade silicone elastomer

In the production of medical handheld devices, instrument panels, and wearable Elastomeric keypads, designers need to choose the most suitable keyboard. First of all, medical-grade silicone elastomers have different hardnesses: 10 Shore A to 80 Shore A, and the most commonly used is 50-70 Shore A. This is because the hardness of the lower value is softer, which is not conducive to wearing at the same time. Also harder to use. If the hardness is too high, it will cause the failure to release the mold and lead to a corresponding increase in cost, and the harder tactile Feedback is not good, and the touch feeling is uncomfortable.

To start the design scheme:

Design suggestions before design: Before receiving emails from customers or design inquiries, we need to know the specific use environment and requirements of the product. In this way, the designer will recommend material selection, design options and potential risks before designing. After the customer confirms the details. Our team can do the file design.

File design: The design of the Elastomeric keypad is more complicated than that of the Membrane Switch. It needs to use 3D software to create the Step format, and use coredraw to indicate the pattern file.

Mold production: After everything is confirmed to be OK, start making hardware molds. Due to the shrinkage of the silicone material, the size of the hardware mold will be designed at the request of the engineer, which is why an experienced factory is needed to carry out this step.

Assembly of carbon particles: After the finished silicone product is formed, carbon particles or printed carbon rings can be used on the back of the silicone product to perform the step of conducting conductive particles.

Spraying: Spraying in the silicone industry includes color block implantation, surface spraying and laser engraving technology.

Inspection: Finished keyboards must be dimensionally inspected to verify that they meet all geometric features and tolerances. Measuring soft elastomers with traditional instruments such as micrometers and calipers is not sufficient because these materials move under small loads and can deform elastically. A CMM, optical comparator, or laser measurement system may be required to accurately check the dimensions of non-rigid components. At the same time, the color needs to be checked with the color card. Whether the product is damaged, etc.

Get in touch with Niceone-Keypad’s full-service manufacturing facility, from the earliest stages of development to final design, and Niceone-Keypad will give you a different experience.


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