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Two essential factors in custom membrane keypad design – reliability and cost!

Knowing a Custom Membrane Keypads design requirement at the early stages of the production process helps build in reliability and cost down price.

Membrane Keypads
28/01/2022
RH printed silver circuitry for custom membrane keypad design and membrane switches

Two essential factors in custom membrane keypad design – reliability and cost!

Reliability and cost are always prime factors when planning a new project. The construction of the user interface (HMI) needs to be functional, hardwearing, and cost-effective. The cost of a custom membrane keypad design needs to meet the overall project budget before committing to any production. This budget includes many components of cost, not just the interface. The cost of a custom membrane switch depends on its construction, materials, chosen features and manufacturing processes. It also depends on the application of the keypad, environmental considerations, and any testing the product requires to pass. Each membrane switch project is custom-made, and our Engineers consider all the design options before setting a cost. The best time to discuss the cost and keypad reliability is at the project’s concept stage. We are always proactively looking for the best solution for your product application and supply needs.

Cost and reliability are best calculated early in the project during a concept design meeting. Knowing a product’s specific requirement at the start of the process helps RH build in keypad reliability while reviewing cost-down opportunities. At the end of this initial meeting, everyone knows the goals and these costs before moving on. This understanding is essential when a product must have unique features like perhaps waterproofing with an IP67 rating? Are these feature benefits of the utmost importance, or do costs dictate the solution? Every scenario is a solution we can help you achieve.

Here are four things to look out for with some guidelines to consider based on our experience with previous customers.

1a. Membrane Keypad w embossing and metallic effect - close up custom membrane switches custom membrane keypads
Designing your Membrane Keypads to look amazing!

The Design of Circuitry: 

The most expensive part of a membrane keypad is the printed circuit. The number of tracks may determine the interface termination and connector type. For most simple industrial applications, we typically print a conductive silver circuit. Still, the cost of this can quickly increase with the addition of SM LEDs or even LED driven light guide film backlighting (LGF). Likewise, the addition of EMC shielding will also add cost. For other applications, we may have to consider moving to flexible copper circuits or PCBs due to track pitch or environmental and test considerations. Typically, military applications may prototype with silver printed circuits but will move to flexible copper circuits in production.

Machine and Human Costs:

It is sensible to conclude that the more complex your custom membrane keypad design is to produce, the more skilled labour time it will take to make it fit for purpose. This support may involve engineering scrutiny, prototyping, or a combination of our in-house printing capabilities. This is not an area that customers should consider cutting corners! Quality comes from care, planning and experience.

Custom Membrane Keypad Design Construction

Depending on your device’s membrane switch functionality, the number of layers used in construction may vary. Obviously, the most cost-effective option will be more straightforward in design. Membrane Keypads generally include six layers but could add additional layers to offer extra features.

These include:

  1. Graphic Overlay – The printed and durable faceplate
  2. Selective adhesive – Adhesive customised to the shape of the overlay.
  3. Tactile layer – The pressure-sensitive buttons.
  4. Spacer – A material that creates voids to hold the buttons.
  5. The Printed circuit – The layer in which electronic conductivity traces operation to different components.
  6. Mounting adhesive – A adhesive sheet placed on the back to fix the assembly.

Once you start adding unique displays, LED driven backlighting and particular functionality, the membrane keypad can quickly increase in both complexity and cost.

The Optional Features:  

Finally, your product design may include some fantastic features that go above and beyond your competition. RH can find a great solution that won’t break the budget, from embossed keys that offers a tactile response to backlighting a display for use in low light environments. Even simple additions of protective coatings or different finishes can significantly affect how the end-user perceives your product. Remember, you only get one opportunity to make a first impression.

Manufacturing is a partnership.

RH understands all the issues you experience in sourcing your membrane switches. We supplied hundreds of customers with a thousand solutions. If you are looking to keep the cost for a custom membrane switch down or need some innovation that makes your next membrane keyboard product stand out, we will find a solution to what you require. At the start of your design process, drop us a line, and we can help to start making your process streamlined with proven ideas and techniques that make a difference.