Elastomers for Flexible, Sealing and Overmolded Parts
Explore elastomer materials commonly considered for soft-touch components, sealing features, flexible parts and overmolding applications. Review material direction together with manufacturability, bonding behavior and molding practicality.
- Flexible material options for functional part design
- Support for sealing, grip and overmolding applications
- Project-based review of material and process fit
What They Mean
What Elastomers Usually Mean in Plastic Part Design
Elastomers are materials commonly considered when a part needs flexibility, compressibility, grip, sealing behavior or soft-contact performance. In product development, they are often used where rigid plastics cannot provide the required touch, fit, deformation or interface function.
Depending on the application, elastomers may be molded as standalone parts or combined with rigid substrates through overmolding. Material direction is usually evaluated based on part function, hardness range, environmental exposure, assembly needs and production method.
Flexible Part Behavior
Used when the part must bend, compress, recover or accommodate movement.
Sealing and Contact Function
Often reviewed for parts that need to close gaps, cushion contact or improve interface fit.
Soft-Touch or Overmold Role
Commonly considered for grip surfaces, protective areas and multi-material part designs.
Why Customers Choose Them
Why Customers Choose Elastomers for Custom Parts
Elastomers are usually selected when the part must do more than hold shape. Common project needs may include the following.
Grip and Comfort
A softer surface may be needed to improve handling, control or user contact.
Sealing Performance
The part may need to compress against another surface to help reduce leakage, dust entry or interface gaps.
Impact or Surface Protection
A flexible material may be used to cushion contact, protect edges or absorb minor impact.
Repeated Flexing or Deformation
Some parts must bend or recover repeatedly during normal use.
Overmolding & Multi-Material Design
Elastomers are often chosen when a soft functional layer is added over a rigid plastic component.
Bottom Line
Elastomers are chosen for functional behavior, not simply because the part needs to feel soft.
Material Options
Common Elastomer Material Options Commonly Considered
Different elastomer families offer different balances of softness, resilience, durability, appearance and process compatibility. Depending on project requirements, commonly reviewed options may include:
TPE
Often considered for soft-touch parts, flexible features and overmolding applications where processability and design versatility are important.
TPU
Commonly reviewed when abrasion resistance, toughness and elastic performance are important.
TPV
May be considered for parts requiring flexibility together with improved resistance in more demanding service environments.
TPR
Often used for soft-contact or grip-oriented applications depending on design and performance needs.
LSR
Typically reviewed for specialized molded parts requiring elastic behavior, temperature capability or application-specific compliance.
Custom Hardness / Project-Specific Grades
In many projects, material choice also depends on hardness range, bonding needs, color, texture and end-use conditions rather than elastomer family alone.
The right elastomer choice depends on how the part needs to feel, deform, seal, bond and perform in actual use.
Processing
Processing and Overmolding Considerations
Elastomer projects often require different molding considerations compared with rigid plastics. Depending on the material and part design, project review may involve hardness selection, flow behavior, flash control, parting line strategy, surface finish, demolding behavior and dimensional tolerance expectations.
For overmolded parts, compatibility between the elastomer and the substrate is also important. Bonding behavior, interface design, part geometry and process sequence may all affect production stability and final part performance.
Hardness and Part Function
Material feel and flexibility should match how the part will compress, bend or contact other surfaces.
Flash and Parting Line Control
Soft materials may require closer control of shutoff areas and molding details.
Demolding Behavior
Part geometry and undercut strategy can affect release and part consistency.
Surface and Texture Expectations
Appearance, matte/gloss feel and touch response may influence material choice.
Overmolding Compatibility
Bonding to a rigid substrate depends on material pairing, interface design and process setup.
Production Repeatability
Consistent molding of soft parts may require tighter control of process conditions and tool quality.
In short: With elastomers, part performance depends heavily on how the material, geometry and molding process work together.
Applications
Typical Applications for Elastomer Parts
Elastomers are often considered when the part must provide flexibility, contact function or surface interaction that rigid materials cannot deliver on their own. Common application directions may include:
Seals and Gaskets
Flexible features used to help close interfaces, improve fit or manage contact between mating parts.
Grips and Handles
Soft-touch areas added to improve user handling, control or comfort.
Protective Covers and Caps
Flexible parts used for dust protection, edge coverage or interface shielding.
Buttons and Contact Features
Parts designed for repeated pressing, flexible movement or controlled tactile response.
Bellows, Sleeves and Flexible Connective Parts
Components that must bend, deform or accommodate movement in assembly.
Overmolded Functional Components
Multi-material parts combining rigid structure with soft contact, sealing or grip features.
Elastomer materials are most useful when the soft material supports a specific functional role in the final part.
Evaluation
How to Evaluate the Right Elastomer Direction
Choosing an elastomer is usually more practical when the part's real function is clearly defined. The right material direction may depend on how soft the part should feel, how much it needs to deform, what surfaces it contacts, whether sealing is required, and whether the part is molded alone or overmolded onto another substrate.
In many cases, material review also involves hardness range, bonding needs, environmental exposure, expected cycle use, surface expectations and production consistency. If the exact material is not finalized yet, the drawing or sample often provides a better starting point than material names alone.
Not sure which elastomer direction fits your part?
Share your drawing or sample for review.
Project Review Checklist
Questions worth reviewing early in the project
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01
Does the part need to bend, compress or recover?
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02
Is sealing or interface contact part of the function?
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03
Is grip, touch or user contact important?
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04
Will the elastomer be overmolded onto another plastic?
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05
Are abrasion, repeated use or environmental exposure concerns?
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06
Is hardness range already defined, or still open?
FAQ
Frequently Asked Questions About Elastomers
What is the difference between elastomers and rigid plastics?
Elastomers are typically selected when a part needs flexibility, compressibility, grip, sealing behavior or soft-contact function that rigid plastics do not provide.
Can elastomers be used in overmolding projects?
Yes. Many elastomer materials are considered for overmolding, but compatibility with the substrate, interface design and process setup should be reviewed carefully.
How do we choose between TPE, TPU and other elastomer options?
The best direction depends on part function, softness range, wear expectations, bonding needs, surface feel and the production method.
Do elastomer parts have tighter molding challenges?
They can. Depending on the design, molding may involve closer attention to flash control, demolding, dimensional consistency, bonding behavior and surface quality.
Can you help evaluate hardness and material direction if we are not sure yet?
Yes. If you share the drawing, sample or application details, material direction can be discussed based on part function and manufacturing practicality.
Can elastomer materials be color matched or customized?
In many projects, color, hardness and texture may be discussed depending on the material family and project requirements.
Need Help Reviewing Elastomer Material Options for Your Part?
Share your drawing, sample or application requirements with us. We can review possible elastomer directions together with part function, overmolding compatibility, tooling considerations and molding practicality.
Project-based support for custom flexible and overmolded components.