Membrane Switch Embossing Specifications For Design

Thickness Minimum EMBOSSING

Embossing is required for functional as well as aesthetic purposes. Functionally, embossing is incorporated in the graphic overlay for switch assemblies utilizing tactile feel.

TYPICAL TYPES OF KEY EMBOSSING:
  1. Pillow Emboss
    For various key shapes
  2. Ridge or Ring Emboss
    For various key shapes
  3. Spherical Emboss
    For round key shapes
emboss Samples for membrane switch design

Custom features such as trademark symbols, LED lenses, Braille and others can be embossed.

MATERIALS:

  1. Polyester gloss, textured
    1. Thickness.005" through .008" thick
    2. Maximum embossing height 1 times material thickness
    3. Embossing is not recommended on hard coated or selectively textured material
  2. Polycarbonate gloss, matte, textured
    1. Thickness .005", .007 and .010" thick
    2. Maximum embossing height 1.5 times material thickness
    3. Embossing is not recommended on hard coated or selectively textured material

EMBOSSING DESIGN CRITERIA:

emboss Height and width samples

Widths: The following is a guide to typical minimum widths relative to material thickness:

Material Thickness

 

Minimum Widths

.005"- 007"
.008" -.010"

 

.040"
.050"

Note: Line widths less than these can result in warping or buckling of the graphic overlay.

emboss line height sample

  1. Height
    1. Polyester: 1 x material thickness
    2. Polycarbonate: 1.5 x material thickness

emboss spacing and density sample

  1. Spacing/Density
    A minimum space of .187" is required between outside edges of emboss to emboss, and emboss to internal or external die cuts. Typically density is not a concern if proper spacing and embossing criteria are observed.

emboss configuration sample

  1. Emboss Configurations
    1. The inside and outside corners, and any intersecting lines must maintain a minimum radius of .060" radius. The inside and outside corners should use the same center for the radius.
    2. The radius at the end of any line will be a function of the line width.

Note: Excessive emboss heights and sharp corners increase the risk of material failure.

  1. Tolerances: With consideration to material properties (characteristics), process and tooling tolerances. the following could be experienced.
    1. Standard registration of emboss to printing
      +/- .015"
    2. Standard registration of emboss to finish cut of internal and external features +/-.020"
    3. Height of emboss: (material dependant)
      Heights of .006" through .010" +/-.003"
      Heights of .011" through .015" +/-.005"

 

OTHER FEATURES

  1. Switch construction to permit insertable legends
  2. Venting
    1. Externally vented utilizing patented silver scavenger to prevent oxidation
    2. Internally vented to meet sealed switch requirements


      3. Note: Design may require additional area to provide a plenum

      1. Heat forming of film base tail
      2. Mounting of various components on rigid base designs
      3. Daughter board to provide electronic packaging interface to Switch panel
      4. Full function testing utilizing customer supplied electronics as required
      5. Backlighting
        1. Electroluminescent
        2. Fiber optic
        3. LED or incandescent

TOLERANCES

  1. Steel rule die Cuts
    1. External and internal features +/-.015"
    2. Die cut to screen printed image +/- .020"
    3. Class "A" hard tool
      1. External and internal features +/-.005"
      2. Screen printing to die cut +/- 015"
      3. Sheered or trim Cut tolerance of +/- .030"
      4. Internal and external routing +/- .010"
      5. Screen printing
        1. Non critical paint pass +/- .015"
        2. Critical paint pass +/-.005"
      6. Layer to layer +/- .015"