Silirtant variables in custom silicone mold development. A product may look correct in the 3D drawing, but if shrinkage is estimated incorrectly, the molded part may be too small, distorted, out of tolerance, or unable to assemble with other components.

This issue is especially important for:

• Precision silicone seals
• O-rings and gaskets
• LSR connector seals
• Silicone keypads
• Medical silicone components
• Baby and feeding products
• Overmolded silicone parts
• Optical silicone components
• Multi-cavity molded products

As a professional silicone manufacturer, we do not treat shrinkage as one fixed percentage that can be applied to every project. The final dimensional change depends on the silicone grade, curing system, mold temperature, cavity pressure, gate position, product thickness, flow direction, demolding temperature, post-curing process, and part geometry.

Good shrinkage control therefore begins before mold steel is cut. It requires cooperation between material selection, product design, mold design, sampling, measurement, and production process control.

What Is Silicone Shrinkage?

Silicone shrinkage is the reduction in dimensions that occurs as the material cures, leaves the hot mold, cools to room temperature, and completes any required post-curing process.

For liquid silicone rubber, the material is injected into a heated mold. It expands while exposed to the high mold temperature and begins forming a crosslinked elastomer network. After demolding, the part cools and contracts.

The finished part may therefore be smaller than the corresponding mold cavity.

Shrinkage can be expressed as:

Shrinkage (%) = (Mold Dimension − Part Dimension) ÷ Mold Dimension × 100

If the expected shrinkage rate is known, an initial mold dimension can be estimated using:

Mold Dimension = Target Part Dimension ÷ (1 − Shrinkage Rate)

For example, if a finished dimension must be 50.00 mm and the expected shrinkage is 2.5%:

Mold Dimension = 50.00 ÷ 0.975 = 51.28 mm

This calculation provides an initial tooling value. It does not replace material trials or mold validation because silicone shrinkage is not always uniform in every direction or every section of the product.

Is There a Standard Silicone Shrinkage Rate?

There is no universal shrinkage rate for all silicone rubber.

For many conventional LSR materials, an initial estimate may fall around 2% to 3%. However, individual material data sheets may show lower or higher values.

Shrinkage may also change when the silicone contains:

• Reinforcing fillers
• Flame-retardant additives
• Conductive fillers
• Color masterbatch
• Oil or self-lubricating additives
• High-density functional fillers
• Adhesion promoters
• Optical modifiers

The mold designer should therefore use the shrinkage data for the exact silicone grade whenever possible.

Even material-supplier data should be treated as a starting point rather than a guaranteed finished-part result. Data-sheet values are normally measured under defined laboratory conditions. The actual part may have different thickness, geometry, gating, molding pressure, cure time, and post-curing requirements.

Why Does Silicone Shrink?

Several mechanisms contribute to dimensional change.

Thermal contraction

Silicone is molded at an elevated temperature and measured after cooling. The material contracts as its temperature drops.

Crosslinking

During curing, polymer chains form a three-dimensional network. This changes the molecular structure and can affect the final volume.

Pressure release

Material inside the mold is subjected to pressure. After the mold opens, this pressure is released, and the part can change dimensions.

Post-curing

If the product requires oven post-curing, additional crosslinking and volatile removal may produce further dimensional change.

Internal stress relaxation

The part may retain internal stress after molding and demolding. As the stress relaxes, the dimensions may continue changing.

For precision components, the part should not be judged immediately after demolding. It should be conditioned for a defined time and measured under controlled conditions.

Main Factors Affecting Silicone Shrinkage

1. Silicone Material Grade

The selected silicone grade is the first major shrinkage variable.

Different silicone formulations may contain different polymer structures, silica levels, additives, catalysts, pigments, and functional fillers. These differences change:

• Cure behavior
• Thermal expansion
• Flow characteristics
• Hardness
• Density
• Elastic recovery
• Post-cure response

A general-purpose 50 Shore A LSR should not be assumed to shrink exactly like a high-tear-strength, self-lubricating, flame-retardant, optical, conductive, or fluorosilicone grade.

The final production material should be selected before the mold shrinkage allowance is finalized.

Changing the silicone grade after the mold has been made can create dimensional problems even when the nominal hardness remains the same.

2. HCR and LSR Processing Differences

HCR and LSR can both be molded into silicone products, but they behave differently during processing.

HCR silicone

High-consistency rubber is a solid, gum-like silicone compound. It is commonly used for:

• Compression molding
• Transfer molding
• Extrusion
• Calendering

Material quantity, mold loading, pressure, cure time, and part placement can influence dimensional results.

LSR silicone

Liquid silicone rubber is normally a two-component, platinum-cured material processed using a metering and injection system.

It offers:

• Automated material mixing
• Fast filling
• Rapid heat curing
• High repeatability
• Complex part capability
• Thin-wall molding

However, its low viscosity makes cavity pressure, venting, gate location, mold temperature, and flash control especially important.

Shrinkage data from HCR should not be directly applied to LSR, and shrinkage data from one molding method should not automatically be used for another.

3. Mold Temperature

Mold temperature affects both curing and dimensional change.

A higher mold temperature may:

• Accelerate curing
• Increase the temperature difference between the molded part and room temperature
• Change the point at which the product is demolded
• Affect internal stress
• Change the effective shrinkage after cooling

If different areas of the mold have different temperatures, the part may shrink unevenly.

This can cause:

• Warpage
• Ovality
• Uneven flatness
• Cavity-to-cavity differences
• Local dimensional variation

The mold should have balanced heating channels and sufficient temperature control. Large molds or multi-cavity molds may require several heating zones and regular temperature verification.

4. Demolding Temperature

A silicone part may continue curing while it remains in the mold.

If it is demolded too early, it may be:

• Too soft
• Under-cured
• Easily deformed
• More sensitive to stretching
• Less dimensionally stable

If it remains in the mold longer, it may experience a different degree of cure and a different demolding temperature.

The manufacturer should define a stable curing and demolding window instead of allowing operators to open the mold at inconsistent times.

5. Cavity Pressure

Cavity pressure can influence the final dimensions because the material is compressed while filling and curing.

Higher effective pressure may reduce apparent shrinkage in some conditions. Lower or unstable pressure may produce greater dimensional variation.

Cavity pressure is affected by:

• Injection pressure
• Injection speed
• Gate size
• Runner design
• Material viscosity
• Mold venting
• Clamping force
• Filling balance
• Curing speed

Unlike thermoplastic injection molding, conventional packing and holding behavior may not work in exactly the same way for LSR. The process must be optimized for the selected silicone and tooling system.

6. Gate Location and Flow Direction

Silicone shrinkage may differ in the direction of material flow and perpendicular to the flow direction.

This means shrinkage can be anisotropic rather than perfectly uniform.

Gate location can affect:

• Flow length
• Filler orientation
• Pressure distribution
• Weld-line position
• Air evacuation
• Local cure timing
• Directional shrinkage

For a long rectangular seal, the shrinkage along its length may not be identical to the shrinkage across its width.

The mold designer may need separate compensation values for:

• X direction
• Y direction
• Z direction
• Critical local features

Applying one uniform scale factor to the entire 3D model may not be sufficient for precision parts.

7. Product Thickness

Wall thickness has a significant influence on shrinkage and dimensional stability.

Thin and thick sections cool at different rates. Thick sections may retain heat longer and cure differently from thin sections.

Uneven thickness can lead to:

• Uneven shrinkage
• Warpage
• Sink-like deformation
• Stress concentration
• Different hardness readings
• Longer stabilization time

A design with a thick central mass and thin surrounding walls is more difficult to control than a design with relatively uniform thickness.

Where possible, designers should:

• Maintain consistent wall thickness
• Avoid unnecessary solid masses
• Use gradual transitions
• Avoid sudden thickness changes
• Use ribs carefully
• Remove non-functional material
• Balance structural strength and moldability

8. Product Shape and Geometry

Simple flat parts usually shrink more predictably than complex three-dimensional parts.

Shrinkage becomes more difficult to control when the product contains:

• Deep cavities
• Tall cores
• Thin membranes
• Asymmetric walls
• Large flat surfaces
• Long unsupported edges
• Undercuts
• Multiple thickness zones
• Internal ribs
• Sharp corners
• Metal or plastic inserts

The geometry may physically restrict shrinkage in one direction while allowing greater movement in another.

For example, a circular silicone gasket may contract toward its center. A molded silicone sleeve around a rigid insert may be prevented from shrinking freely in the radial direction.

The design should therefore be reviewed for both free shrinkage and constrained shrinkage.

9. Post-Curing

Post-curing is an additional oven treatment used for certain silicone parts.

It may be required to:

• Reduce volatile components
• Improve compression set
• Complete curing
• Stabilize material properties
• Meet food-contact or application requirements
• Improve heat-aging performance

Post-curing can cause additional shrinkage.

The amount depends on:

• Silicone grade
• Product thickness
• Post-cure temperature
• Post-cure duration
• Oven airflow
• Part arrangement
• Degree of cure after molding

If the finished component will be post-cured, the mold shrinkage allowance should include the final dimensions after post-curing, not only the dimensions after primary molding.

A sample that meets tolerance before post-curing may be undersized afterward.

10. Pigment and Additive Loading

Color masterbatch normally represents a small portion of the silicone formulation, but it can still affect processing and appearance.

Functional additives may have a greater effect.

Examples include:

• Conductive carbon
• Metal-filled conductive systems
• Flame-retardant fillers
• Thermally conductive fillers
• Ceramic-forming fillers
• Self-lubricating additives

High filler loading can change viscosity, density, cure rate, thermal behavior, and shrinkage.

If the final material will contain functional additives, shrinkage tests should use the complete production formulation rather than an unfilled standard silicone.

11. Insert Molding and Overmolding

Shrinkage behaves differently when silicone is molded around:

• Metal
• Plastic
• Glass
• Fabric
• Electronic components
• Previously molded silicone

The insert restricts movement and creates a mismatch between the thermal expansion of the silicone and the substrate.

Possible results include:

• Warpage
• Internal stress
• Edge lifting
• Bond failure
• Insert movement
• Seal deformation
• Dimensional distortion

The mold designer should evaluate:

• Insert material
• Insert temperature
• Insert positioning
• Mechanical locking features
• Bonding area
• Silicone thickness around the insert
• Cooling behavior
• Substrate heat resistance

The finished assembly should be measured as a complete overmolded component.

How to Compensate for Shrinkage in Mold Design

Step 1: Identify Critical Dimensions

Not every dimension requires the same level of control.

The project team should identify:

• Sealing diameters
• Assembly interfaces
• Hole spacing
• Connector positions
• Flatness
• Wall thickness
• Overall length and width
• Insert location
• Compression dimensions
• Optical surfaces
• Functional gaps

Critical-to-quality dimensions should receive priority during tooling compensation and sampling.

Decorative or non-functional dimensions may allow a wider tolerance.

Step 2: Confirm the Final Material Before Tooling

The manufacturer should confirm:

• Material supplier
• Material grade
• Shore hardness
• Cure system
• Color
• Functional additives
• Post-cure requirement
• Regulatory requirement

Tooling should not be finalized using a general shrinkage value if the final material is still undecided.

Step 3: Review Material-Supplier Data

The raw-material technical data sheet may provide a typical linear shrinkage value.

This value should be reviewed together with:

• Test method
• Sample thickness
• Cure conditions
• Post-cure conditions
• Hardness
• Material composition
• Measurement timing

The data-sheet value becomes the initial estimate, not the final guaranteed mold factor.

Step 4: Use Previous Production Data

Historical production data is often more useful than a general reference value.

A manufacturer may review similar products made with the same:

• Silicone grade
• Hardness
• Thickness
• Mold temperature
• Molding process
• Post-curing condition
• Product geometry

Previous results can help establish a more realistic initial compensation rate.

However, data from a small round seal may not accurately predict shrinkage for a large rectangular housing gasket.

Step 5: Apply Directional Compensation

For simple products, a uniform initial scale factor may be acceptable.

For precision or elongated products, the mold designer may apply different compensation values along different axes.

For example:

• Length compensation
• Width compensation
• Height compensation
• Hole-spacing compensation
• Local feature compensation

This approach is especially useful when the gate creates a clear flow direction.

Step 6: Design the Tool Steel-Safe

A steel-safe strategy leaves additional metal in areas that may need later dimensional adjustment.

It is generally easier to remove steel than to add it.

For example, if an internal diameter may need to become larger, the mold can be designed so the corresponding steel feature can be carefully reduced after sampling.

The tool designer should identify:

• Dimensions that can be adjusted by machining
• Dimensions that would require welding
• Replaceable inserts
• Adjustable cores
• Removable cavity blocks
• Areas with limited correction options

This reduces the risk of rebuilding the entire mold after the first trial.

Step 7: Use Replaceable Inserts for Critical Features

Replaceable inserts are useful for:

• Precision holes
• Sealing diameters
• Logo areas
• Thin membranes
• Connector openings
• Critical assembly features
• High-wear areas

If the first sample shows an incorrect dimension, the insert can be modified or replaced without remaking the complete tool.

Step 8: Balance the Runner and Gates

In a multi-cavity mold, every cavity should fill under similar conditions.

An unbalanced runner system can cause:

• Different cavity pressures
• Different filling times
• Different cure timing
• Different dimensions
• Cavity-to-cavity shrinkage variation

The runner and gate layout should provide balanced flow to each cavity.

For precision LSR molds, a cold-runner and needle-valve system can provide better control, but nozzle temperature, shutoff timing, material balance, and gate design must be properly managed.

Step 9: Control Mold Temperature Uniformity

Heating-channel design should support even temperature distribution.

The tool may require:

• Multiple heating zones
• Cartridge heaters
• Temperature sensors
• Thermal insulation
• Cooling around cold-runner sections
• Thermal simulation
• Regular calibration

Hot spots and cold spots can cause uneven curing and dimensional variation.

Step 10: Design Effective Venting

Venting does not directly create the nominal shrinkage allowance, but it strongly affects filling stability and cavity pressure.

Poor venting can produce:

• Trapped air
• Short shots
• Burn-like marks
• White edges
• Incomplete filling
• Local under-curing
• Flash caused by excessive pressure

Stable filling conditions make shrinkage results more repeatable.

Because LSR has very low viscosity, vents must be precise enough to release air without creating excessive flash.

Step 11: Plan the Parting Line and Demolding Direction

The parting line affects:

• Gate position
• Vent location
• Flash
• Demolding
• Part deformation
• Which mold half retains the part

The product should release in a controlled direction.

If operators must stretch or pull the part excessively during demolding, the measured dimensions may vary even when the cavity is correct.

Automatic demolding systems should also avoid deforming thin membranes or long flexible edges.

Step 12: Account for Post-Cure Dimensions

The product drawing and inspection plan should clearly state whether dimensions are measured:

• Immediately after molding
• After cooling
• After 24-hour conditioning
• After post-curing
• After final assembly
• After environmental conditioning

For products requiring post-curing, final acceptance should normally be based on the post-cured and conditioned part.

Recommended Mold Validation Process

1. Produce an Initial Trial

The first mold trial should use the planned production material and realistic process settings.

Record:

• Material batch
• A/B ratio
• Pigment ratio
• Mold temperature
• Injection pressure
• Injection speed
• Cure time
• Demolding time
• Cavity number
• Post-cure condition
• Room temperature
• Measurement time

Without complete records, dimensional differences are difficult to analyze.

2. Stabilize the Process Before Judging the Mold

The first several molding cycles may not represent stable production.

The mold needs time to reach thermal balance. The material-feed system also needs stable pressure and temperature.

Dimensions should be evaluated after:

• Mold temperature has stabilized
• Material flow is stable
• Cure conditions are repeatable
• Flash and filling are under control
• Several consecutive cycles have been produced

3. Measure Multiple Parts and Cavities

One sample is not enough.

The measurement plan should include:

• Multiple cycles
• Every cavity
• Several parts per cavity
• Different positions on the product
• Critical dimensions
• Part weight
• Flatness and warpage

This helps separate mold-size problems from process variation.

4. Use a Defined Conditioning Time

Silicone parts should be measured after a controlled conditioning period.

The project may compare dimensions:

• Shortly after demolding
• After cooling to room temperature
• After 24 hours
• After post-curing
• After final conditioning

The same measurement timing should be used for all approval samples and production inspections.

5. Calculate the Actual Shrinkage

Actual shrinkage can be calculated for each critical dimension.

For example:

• Mold cavity dimension: 51.28 mm
• Conditioned part dimension: 49.85 mm

Actual shrinkage:

(51.28 − 49.85) ÷ 51.28 × 100 = 2.79%

If the target is 50.00 mm, the mold correction should be based on the actual result and the tool’s adjustment direction.

6. Separate Material, Process, and Tooling Causes

An undersized part does not automatically mean the mold cavity is wrong.

Possible causes include:

• Incorrect material
• Excessive mold temperature
• Low cavity pressure
• Early demolding
• Different post-curing
• Process instability
• Measurement timing
• Tooling dimension error

The process should be stabilized before permanent steel changes are made.

7. Perform a Controlled DOE When Necessary

For tight-tolerance projects, a design of experiments can evaluate the influence of:

• Mold temperature
• Cure time
• Injection speed
• Injection pressure
• Material temperature
• Demolding time
• Post-cure time
• Post-cure temperature

The goal is to find a process window that provides stable dimensions, not simply one machine setting that produces one acceptable part.

8. Modify the Mold Gradually

Large tooling corrections should be avoided unless the cause is clear.

It is safer to:

1. Confirm the measurement system
2. Stabilize molding conditions
3. Confirm the material
4. Calculate the dimensional trend
5. Make a controlled steel adjustment
6. Repeat the trial

Measurement and Tolerance Control

Use the Correct Measurement Method

Soft silicone can deform under measurement pressure.

Possible measurement equipment includes:

• Optical measuring systems
• Coordinate measuring machines
• Vision systems
• Non-contact scanners
• Custom inspection fixtures
• Low-force thickness gauges
• Go/no-go gauges

Standard calipers may compress soft parts and create inconsistent readings.

The measurement method should match the:

• Product hardness
• Geometry
• Tolerance
• Functional requirement
• Measurement force

Define the Datum System

Flexible products can change shape when placed on a table.

The drawing should define:

• Measurement datums
• Part orientation
• Restraining method
• Inspection fixture
• Applied force
• Free-state or assembled-state measurement

Without a defined fixture, two inspectors may obtain different results from the same part.

Validate the Measurement System

Before changing the mold, confirm that the inspection method is repeatable.

A measurement-system analysis may be useful for tight-tolerance components.

Variation can come from:

• Operator technique
• Fixture positioning
• Instrument force
• Temperature
• Part orientation
• Measurement timing
• Software alignment

Controlling Shrinkage During Mass Production

Once the mold is approved, dimensional control depends on process consistency.

The manufacturer should control:

• Silicone grade and batch
• Material storage
• A/B mixing ratio
• Pigment or additive ratio
• Mold temperature
• Injection pressure
• Injection speed
• Cure time
• Demolding time
• Clamping force
• Post-curing
• Measurement timing
• Cavity identification

First-Piece Inspection

At the beginning of each production run, first-piece parts should be checked before full production continues.

Cavity Identification

Multi-cavity parts should be traceable to their cavity. If one cavity produces a different dimension, the issue can be isolated more quickly.

Process Monitoring

Critical parameters should be recorded and monitored. Sudden changes may indicate:

• Heater problems
• Material-feed imbalance
• Gate blockage
• Vent contamination
• Mold wear
• Machine variation

Periodic Dimensional Checks

Critical dimensions should be checked at defined intervals rather than only after the order is complete.

Retained Samples

Retained samples from approved and production batches help with:

• Repeat-order comparison
• Complaint investigation
• Mold-maintenance decisions
• Long-term dimensional analysis

Common Mistakes in Silicone Shrinkage Control

Using One Shrinkage Rate for Every Silicone

Different grades and formulations can shrink differently. The final production material must be evaluated.

Scaling the Entire Product Uniformly

Complex parts may require different compensation values in different directions or local areas.

Ignoring Post-Cure Shrinkage

A part may meet dimensions before oven treatment and fail afterward.

Measuring the Part Too Early

Dimensions immediately after demolding may not represent the stabilized product.

Changing the Mold Before Stabilizing the Process

Process variation can be mistaken for an incorrect cavity dimension.

Ignoring Product Thickness

Uneven wall thickness can cause uneven contraction and warpage.

Using a Different Material for Sampling

A trial made with a substitute material may not predict the final production dimensions.

Measuring Soft Silicone with Excessive Force

The inspection tool may deform the product and create a false result.

Ignoring Flow Direction

Long or directional parts may shrink differently along different axes.

Failing to Identify Each Mold Cavity

Cavity-specific variation becomes difficult to trace.

What Information Should Buyers Provide?

To evaluate silicone shrinkage and mold compensation accurately, customers should provide:

• 2D drawing
• 3D model
• Critical dimensions
• Tolerances
• Datum system
• Product application
• Silicone grade
• Target hardness
• Color
• Required certifications
• Post-cure requirement
• Operating temperature
• Assembly method
• Mating-component dimensions
• Insert material
• Expected annual quantity
• Functional test requirements

For sealing products, the customer should also provide:

• Groove dimensions
• Compression rate
• Sealing pressure
• Medium
• Temperature range
• Installation method

A mold cannot be optimized only from the exterior product shape. The functional assembly requirements must also be understood.

Working with a Professional Silicone Mold Manufacturer

Effective shrinkage control requires cooperation between:

• Product designer
• Material supplier
• Mold engineer
• Process engineer
• Quality team
• Customer

A professional silicone manufacturer should review:

• Whether the tolerance is realistic
• Whether the product has uniform wall thickness
• Whether the material has been finalized
• Whether shrinkage may be directional
• Whether post-curing is required
• Whether the part can be measured reliably
• Whether critical features should use replaceable inserts
• Whether the mold can be adjusted steel-safe
• Whether multi-cavity balance is achievable
• Whether inserts will restrict shrinkage

The correct development sequence is:

1. Confirm the application
2. Finalize the silicone material
3. Review the product structure
4. Define critical dimensions
5. Estimate initial shrinkage
6. Design an adjustable mold
7. Produce trial samples
8. Stabilize the process
9. Measure conditioned parts
10. Calculate actual shrinkage
11. Modify the mold where necessary
12. Validate mass-production capability

Final Thoughts

Silicone shrinkage cannot be controlled by selecting one percentage and enlarging every mold dimension equally.

Reliable dimensional control requires an understanding of:

• Material behavior
• Thermal contraction
• Curing
• Cavity pressure
• Flow direction
• Product thickness
• Mold temperature
• Demolding
• Post-curing
• Measurement conditions

The material data sheet provides the starting point. Historical manufacturing data improves the estimate. Steel-safe tooling, replaceable inserts, controlled trials, and stable inspection methods allow the final mold to be refined.

For buyers, the most important step is to define the final material and critical dimensions before tooling begins.

For manufacturers, the key is to treat shrinkage as a measurable process variable rather than a fixed material constant.

When product design, material selection, mold compensation, process control, and dimensional validation are handled together, silicone parts can achieve more stable tolerances and more reliable assembly performance.

FAQ: Silicone Shrinkage and Mold Design

1. What is the typical shrinkage rate of LSR?

Many conventional LSR grades may show shrinkage around 2% to 3%, but the exact value depends on the material, molding conditions, product geometry, flow direction, and post-curing. The technical data sheet and actual mold trials should be used.

2. Does silicone shrink inside the mold?

LSR behaves differently from thermoplastics. It expands in the heated mold and then contracts mainly after demolding and cooling. Its final dimensions should be evaluated after conditioning.

3. Does post-curing increase silicone shrinkage?

It can. Post-curing may produce additional dimensional reduction as curing is completed and volatile components are removed. The amount depends on the material and post-cure conditions.

4. Do harder silicone materials shrink less?

Not necessarily. Hardness alone does not determine shrinkage. Filler content, polymer formulation, cure system, processing conditions, and geometry must also be considered.

5. Can the same shrinkage value be used for HCR and LSR?

No. HCR and LSR use different material forms and molding processes. Shrinkage should be evaluated separately for the selected material and process.

6. Why does one dimension pass while another dimension fails?

Shrinkage can be directional. Gate location, material flow, part geometry, wall thickness, and constraint may cause different shrinkage along the length, width, and height.

7. Why are different cavities producing different dimensions?

Possible causes include an unbalanced runner system, uneven mold temperature, different venting, gate variation, cavity pressure differences, or machining variation.

8. When should silicone parts be measured?

The measurement time should be defined in the inspection standard. Precision parts are commonly measured after cooling and a controlled conditioning period, and after post-curing when post-curing is part of the production process.

9. Can mold temperature be adjusted to correct shrinkage?

Process settings can influence dimensions, but they should not be used to hide a major tooling error. The process must remain within a stable and validated range.

10. Why should critical mold features use replaceable inserts?

Replaceable inserts allow important dimensions to be adjusted without rebuilding the complete mold. They reduce tooling risk during sampling.

11. How should soft silicone parts be measured?

Soft parts should be measured using a controlled fixture, low-force contact method, vision system, optical system, or another method that avoids deforming the part.

12. Can shrinkage be predicted completely by simulation?

Simulation can help evaluate flow, temperature, and filling behavior, but actual material trials and mold sampling are still required to confirm final dimensions.