Epoxy Fill: CTE 20-50 ppm/°C, Pot Life 30-60 minutes

Component Specifications

Definition

Epoxy fill refers to specialized epoxy resin formulations applied in liquid or paste form to completely surround and embed electronic components, wires, and connections within sensing probe/head assemblies. Upon curing, it forms a rigid, durable solid that provides electrical insulation, mechanical support, environmental sealing against moisture, dust, chemicals, and vibration damping. It ensures long-term reliability by preventing short circuits, corrosion, and physical damage in harsh industrial environments.

Working Principle

The working principle involves mixing a resin with a hardener to initiate a chemical cross-linking reaction (curing). When applied, the liquid epoxy flows into cavities and around components, then hardens into a solid, non-conductive matrix through polymerization. This creates a hermetic or semi-hermetic seal that immobilizes internal parts, dissipates heat, and blocks environmental ingress, maintaining the probe's electrical integrity and mechanical stability.

Materials

Two-part epoxy systems (resin + hardener); may include additives like silica fillers for thermal conductivity, flexibilizers for stress relief, or pigments. Common base resins: bisphenol-A, bisphenol-F, cycloaliphatic. Hardeners: amines, anhydrides. Specifications: viscosity 500-5000 cP, cure time 2-24 hours, glass transition temperature (Tg) 80-150°C, thermal conductivity 0.5-2.5 W/mK, dielectric strength >15 kV/mm.

Technical Parameters

Parameter	Typical range	Notes & selection driver
CTE	20-50 ppm/°C
Pot Life	30-60 minutes
Cure Time	4-8 hours at 25°C
Shore Hardness	D70-D90
Volume Resistivity	>1e14 ohm-cm
Operating Temperature	-40°C to 150°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 1675, ISO 4587, DIN 16945, ASTM D2471

Parent Products

This component is used in the following industrial products

Sensing Probe/Head

The detection element of a speed sensor that directly interacts with the target to measure rotational or linear velocity.

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Engineering Analysis

Risks & Mitigation

Incomplete curing leading to soft spots
Thermal expansion mismatch causing stress cracks
Outgassing contaminating sensitive elements
Void formation reducing insulation

FMEA Triads

Trigger: Incorrect resin-hardener ratio
Failure: Poor curing, reduced mechanical strength
Mitigation: Use automated mixing/dispensing systems and verify ratios

Trigger: Thermal cycling in harsh environments
Failure: Cracking or delamination
Mitigation: Select low-CTE epoxy with flexibilizers and conduct thermal shock testing

Trigger: Moisture ingress prior to curing
Failure: Electrical leakage or corrosion
Mitigation: Control humidity during application and use moisture-resistant formulations

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.1 mm for fill height, no voids >1% by volume

Test Method

ASTM D257 for resistivity, IPC-TM-650 for moisture resistance, thermal cycling per IEC 60068-2-14

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Epoxy Fill

Manufacturer profiles associated with Epoxy Fill.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the purpose of epoxy fill in a sensing probe?

It protects internal electronics from environmental factors like moisture, chemicals, and mechanical stress, ensuring accurate and reliable sensor operation.

How is epoxy fill applied?

It's mixed as a two-part system, dispensed into the probe housing around components, and cured at room or elevated temperature to form a solid barrier.

Can epoxy fill be removed or repaired?

Once cured, it's generally irreversible; repair requires destructive removal and reapplication, so design should consider serviceability.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Epoxy Fill