When a membrane switch is affixed to the enclosure or housing of the end product there are essentially two options: rear pressure sensitive adhesive (PSA) or a backer plate. Many of our membrane switches require backers or support layers for rigidity and structural integrity. The design often dictates whether or not a metal backer is needed. For instance, often times the customer’s enclosure or housing design requires mechanical fastening.

The most commonly used materials are aluminum or stainless steel. Other options include G10, polycarbonate or acrylic backers. Metal backers can also be supplied with a variety of hardware installed such as PEM studs. 

If the keypad is PCB (printed circuit board) based, we can typically utilize the PCB as the backer and install hardware directly into the board.

Please provide mechanical drawings (DWG, DXF, IGES, STEP) and artwork files (AI or CDR) if available.

• Mechanical dimensions (if drawings are not available) – height and width of part, keys, etc.
• Molded rubber or polyester overlay?
• Copper flex circuit or printed silver?
• What type of environment?  Does the keypad need to be environmentally sealed?
• Artwork/Graphic Overlay if not, what Pantone colors (if artwork not available)?
• Embossed (plateau/pillow or rim)?
• Tactile feel (domes)?
• Any backlighting?  Any LEDs?
• Length of tail and tail break out location?
• What type of connection?  Female connector or prep for ZIF connection?
• Are there any windows?

KEY NOTES:

• Space between keys and around perimeter of keypad should be .100” or better.
• .100” center to center min for tail with connector.
• 1mm center to center min for ZIF type interconnect.
• Tail exit should be .25” min. from edge, keys and other components (tail cannot exit under key).
• Normal final assembly tolerances = size +/- .010”, die cut to image = +/- .010”

Flexible membrane keypads which incorporate surface mounted LED’s or tactile metal domes must be handled carefully and NOT flexed, bent or rolled prior or during the application process.  The metal domes and LED’s are susceptible to varying degrees of damage when flexed, etc.  If testing prior to assembly, the keypad MUST be placed on a flat surface so as not to overstress the domes.  Once the keypad is laminated to the mounting surface the domes and LED’s will not be damaged from normal use.

Please avoid: creasing folding the circuitry tails that exit the assembly.  A gentle radius, defined as being: no greater than if it were to be wrapped around a .100” mandrel is acceptable.  In no instance should the conductors be “hard creased” this will inevitably cause opens as it harms the circuitry.

It should be noted in advance that great care is taken to protect any clear windows from scratches and blemishes.  This care needs to be continued by the customer to ensure acceptable parts.  

STEP 1 – Check your mounting surface for “bumps” or irregularities.  Surface must be clean and flat.  A tack cloth or lint free cloth and isopropyl alcohol are the proper tools for the cleaning process.

STEP 2 – Remove any separate release liner material that may be present in the flex tail or shield tab areas and discard.  Fold back approx. 1” of the main release liner (preferably at the tail exit side of the keypad, and not underneath any LED’s or metal domes) exposing the pressure sensitive adhesive (PSA).

• Feed the tail through the tail(s) exit slot(s) and place the keypad flat on the mounting surface.
• Align it within the center of the recess or to the edges of the backer plate.
• Apply pressure to the face of the keypad above the exposed PSA.

STEP 3 – Carefully reach underneath the keypad and begin pulling the release liner away from the adhered part of the keypad.  While removing the liner with one hand, apply uniform pressure using a soft rubber roller.  The roller should be used to assure complete bonding and to prevent air entrapment.

STEP 4 – Hold the assembled keypad on a 45 degree angle and reflect light off of the front surface.  It should appear uniform, without bumps (air entrapment).

Note: If a keypad is misaligned or needs to be removed for any reason, the removal process will render the keypad unusable and should be discarded.

Please contact our customer service department if you require further assistance.