Madeinusa

OVERMOLDED PROTOTYPES

Create models that look like they just came off the production line.

Silicone over-molded onto an FDM base model

Overmolded Prototypes

Overmolding  is a process in which a softer layer of material is bonded over a harder substrate or structural component of a part. It can be used to improve functionality or to change the look or feel of a part.

Overmolding can deliver a wide range of product benefits such as:

  • Textures that make handheld items easier to hold and use.
  • Vibration and noise reduction.
  • Greater electrical resistance.
  • Increase shock absorbency.
  • Enhanced aesthetics
  • Improved ergonomics
Urethane overmolded onto a metal assembly

Common Overmolding Applications

Overmolded prototypes are used in a variety of industries.  Examples are:

  • Metal screwdriver overmolded with a plastic handle to prevent electrical shock.
  • Plastic cell phone case overmolded with an elastomeric shell to increase grip.
  • Metal medical device overmolded with a plastic handle to increase safety.
  • Automotive connector with an overmolded gasket.
  • Sporting goods utilize overmolding for enhanced durability, comfort, and show absorption.

Overmolded Part Design Considerations

  • The wall thickness of the substrate and over-mold should be as uniform as possible.
  • Keeping 0.5 MM minimum in corners reduces localized stresses.
  • Avoid deep or un-ventable blind pockets or ribs. 
  • Transitions between wall thicknesses should be gradual to reduce flow problems.
  • The elastomeric over-molding section should be less thick than the substrate to prevent warpage, especially critical for long, flat geometries.
  • Design in a mechanical interlock when possible.

 

Elastomer overmolded onto a clear rigid urethane

Overmolded Prototype Specification Guidelines

Outlined below are the options which need to be specified when ordering an overmolded prototype. This includes overmold material, substrate material, finish and options.

Standard Material Selection:

Custom material requests welcomed.
Specification Writers: These values are a guide and not intended for use in preparing specifications.

Base Color:  Off-White

Shore A Hardness:  20A            ASTM-2240
Tensile Strength: 200 psi           ASTM D-412
100% Modulus:  27 psi             ASTM D-412
Elongation at Break:  1,000%    ASTM D-412
Die C Tear Strength: 60 pli        ASTM D-624

Base Color:  Off-White

Shore A Hardness:  30A             ASTM-2240
Tensile Strength:  450 psi           ASTM D-412
100% Modulus: 67 psi               ASTM D-412
Elongation at Break:  1,000%     ASTM D-412
Die C Tear Strength:  82 pli        ASTM D-624

Base Color:  Off-White

Shore A Hardness: 40A              ASTM-2240
Tensile Strength: 490 psi            ASTM D-412
100% Modulus:  73 psi              ASTM D-412
Elongation at Break: 1,000%      ASTM D-412
Die C Tear Strength: 85 pli         ASTM D-624

Base Color:  Off-White

Shore A Hardness:  50A            ASTM-2240
Tensile Strength: 580 psi           ASTM D-412
100% Modulus: 152 psi            ASTM D-412
Elongation at Break:  435%      ASTM D-412
Die C Tear Strength: 120 pli      ASTM D-624

Base Color:  Off-White

Shore A Hardness: 60A            ASTM-2240
Tensile Strength: 782 psi          ASTM D-412
100% Modulus:  256 psi          ASTM D-412
Elongation at Break:  581%     ASTM D-412
Die C Tear Strength:  132 pli    ASTM D-624 

Base Color:  Clear Amber

Shore A Hardness:  70A ± 5              ASTM D2240-04e1
Tensile Strength: 2,200 psi                ASTM D412-98a(2002)e1
Tensile Modulus:  800 psi                 ASTM D412-98a(2002)e1
Elongation:  860%                            ASTM D412-98a(2002)e1
Tear Strength:  300 pli                      ASTM D624-00e1
Dielectric Constant, 1 MHz: 5.84      ASTM-D150-87
Dissipation Factor, 1 MHz:  0.068     ASTM D-150-87

Base Color:  Clear Amber

Shore A Hardness:  80A ± 5              ASTM D2240-04e1
Tensile Strength :  2,800 psi              ASTM D412-98a(2002)e1
Tensile Modulus:  1,300 psi               ASTM D412-98a(2002)e1
Elongation:  720%                             ASTM D412-98a(2002)e1
Tear Strength:  350 pli                       ASTM D624-00e1
Dielectric Constant, 1 MHz:  5.55      ASTM-D150-87
Dissipation Factor, 1 MHz:  0.0614    ASTM D150-87

Base Color:  Clear

Shore A Hardness: 30A            ASTM D-2240
Tensile Strength: 725 psi          ASTM D-412
Elongation at Break:  675%     ASTM D-412
Die C Tear Strength:  54 pli      ASTM D-624 

Electrical Properties:
Volume Resistance :  >7.646E+13 ohm        ASTM D-150-98
Volume Resistivity:  >6.014E+15 Ohm cm    ASTM D-150-98
Dielectric Constant k’@100 Hz:  6.62           ASTM D-150-98
Dissipation Factor @100 Hz:  0.103              ASTM D-150-98
Dielectric Strength (V/mil):  474                    ASTM D-147-97a

Index of Refraction:  1.48822 at 20ºC,  1.48649 at 25ºC

Base Color:  Clear

Shore A Hardness: 50A            ASTM D-2240
Tensile Strength: 250 psi          ASTM D-412
Elongation at Break:  500%     ASTM D-412
Die C Tear Strength:  25 pli      ASTM D-624 

Electrical Properties:
Volume Resistance :  >7.646E+13 ohm        ASTM D-150-98
Volume Resistivity:  >6.014E+15 Ohm cm    ASTM D-150-98
Dielectric Constant k’@100 Hz:  6.62            ASTM D-150-98
Dissipation Factor @100 Hz:  0.103              ASTM D-150-98
Dielectric Strength (V/mil):  474                    ASTM D-147-97a

Index of Refraction:  1.48822 at 20ºC,  1.48649 at 25ºC

Base Color:  Translucent

Shore A Hardness:  10A                     ASTM D-2240
Tensile Strength:  475 psi                   ASTM D-412
100% Modulus:  22 psi                      ASTM D-412
Elongation at Break:  1,000%             ASTM D-412
Die B Tear Strength:  102 pli               ASTM D-624
Dielectric Strength:  >350 volts/mil    ASTM D-149
Service Temperature Range:   -65ºF to +450ºF  (-53ºC to +232ºC)

Base Color:  Translucent

Shore A Hardness:  15A                     ASTM D-2240
Tensile Strength:  537 psi                   ASTM D-412
100% Modulus:  40 psi                       ASTM D-412
Elongation at Break:  771   %             ASTM D-412
Die B Tear Strength:  112 pli               ASTM D-624
Dielectric Strength:  >350 volts/mil    ASTM D-149
Service Temperature Range:   -65ºF to +450ºF  (-53ºC to +232ºC)

Base Color:  Translucent

Shore A Hardness:  20A                     ASTM D-2240
Tensile Strength:  550 psi                   ASTM D-412
100% Modulus:  49 psi                      ASTM D-412
Elongation at Break:  620%                ASTM D-412
Die B Tear Strength:  120 pli               ASTM D-624
Dielectric Strength:  >350 volts/mil    ASTM D-149
Service Temperature Range:   -65ºF to +450ºF  (-53ºC to +232ºC)

Base Color:  Translucent

Shore A Hardness:  30A                     ASTM D-2240
Tensile Strength:  500 psi                   ASTM D-412
100% Modulus:  86 psi                       ASTM D-412
Elongation at Break:  364%                ASTM D-412
Die B Tear Strength:  108 pli               ASTM D-624
Dielectric Strength:  >350 volts/mil    ASTM D-149
Service Temperature Range:   -65ºF to +450ºF  (-53ºC to +232ºC)

Transparent encapsulant with good flame resistance.
Suitable for LED lighting encapsulation, power supplies, connectors, sensors, industrial controls, transformers, amplifiers, and relays.

Shore A Hardness:  43A
Thermal conductivity:  0.15 btu/hr ft ºF  (0.27 W/m ºK)
Dielectric Strength:  500 volts/mil ( 19 kV/mm)
Volume Resistivity:  2.9E+14 ohm*cm
Dissipation Factor at 100 Hz:  0.00257
Dissipation Factor at 100 kHz:  0.00133
Dielectric Constant at 100 Hz:  2.72
Dielectric Constant at 100 kHz:  2.68
Linear CTE (by DMA):  340 ppm/ºC
Tensile Strength:  980 PSI  (6.7 MPa, 69 Kg/cm²)
Refractive Index @ 589 nm:  1.4118
Refractive Index @ 632.8 nm:  1.4225
Refractive Index @ 1321 nm:  1.4028
Refractive Index @ 1554 nm:  1.3997
UL RTI Rating:  150ºC

Base Color: White

Shore D Hardness: 75D                         ASTM D-2240
Ultimate Tensile: 5,500 psi                     ASTM D-638
Tensile Modulus: 270,000 psi                ASTM D-638
Elongation @ Break: 7.5%                     ASTM D-638
Flexural Strength: 7,100 psi                   ASTM D-790
Flexural Modulus: 250,000 psi               ASTM D-790
Compressive Strength: 7,100 psi            ASTM D-695
Compressive Modulus: 78,500 psi          ASTM D-695
Heat Deflection Temp: 144º F / 62º C     ASTM D-648

Base Color:  Off-White

Shore D Hardness:  80D                       ASTM D-2240
Ultimate Tensile:  5,840 psi                   ASTM D-638
Tensile Modulus:  246,000 psi               ASTM D-638
Elongation @ Break:  4%                      ASTM D-638
Flexural Strength:  8,280 psi                  ASTM D-790
Flexural Modulus:  271,000 psi              ASTM D-790
Compressive Strength:  8,760 psi          ASTM D-695
Compressive Modulus:  77,400 psi        ASTM D-695
Heat Deflection Temp:  194º F / 90º C   ASTM D-648

Color:  Water Clear

Shore D Hardness:  80D
Elongation:  7%
Heat Deflection Temp:  138ºF
Tensile Strength:  6,083 psi
Elastic Modulus:  133,956 psi
Flexural Modulus:  250,992 psi
Flexural Strength, 5% Strain:  8,478 psi

Basic Finish

If SLA, layer lines ARE NOT removed. If Machined, as machined.

Standard Finish

If SLA, layer lines ARE removed - leaving a matte finish. If machined, tool markings ARE removed - leaving a matte finish. Layer lines may be present on internal or difficult to reach features.

Custom Finish Examples

Gloss finish
Textured Finish
EMI/RFI shielding
color matching
decorating
metal inserts.

Custom finish requests welcomed

Master Pattern Finishing Options

Overmolded Prototype Quote Submission

You will receive an e-mail confirming receipt of your request.

Files up to 20MB may be sent via e-mail to:  Sales@Versadyne.net