Ordinary thermal grease is a non-curing thermal interface material used to fill microscopic air gaps between a heat-generating component and a heat sink. For most general-purpose electronics, the right product is selected by comparing thermal conductivity, thermal impedance, operating temperature, viscosity, electrical behavior, dispensing format, and supply requirements—not by choosing the highest advertised conductivity alone. I recommend matching the grease to the assembly process, surface condition, reliability target, and purchasing volume before requesting a quotation.
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This guide is intended for procurement teams, thermal engineers, contract manufacturers, maintenance departments, and distributors sourcing general-purpose thermal grease. It is especially relevant when a project needs a practical interface material for power electronics, LED assemblies, processors, sensors, control modules, or industrial equipment. I use “ordinary” to describe a standard, non-specialty grade rather than a product with no performance requirements.
Ordinary thermal grease can be suitable for many assemblies, but it is not automatically the best choice for every design. Applications involving high mechanical movement, long-term pump-out risk, very high temperatures, strict dielectric requirements, or a defined bond may require a phase-change material, thermal pad, thermal adhesive, or another engineered interface solution. The final choice should be supported by the component manufacturer’s requirements and the supplier’s validated data.
Ordinary thermal grease generally consists of a base fluid or oil combined with thermally conductive fillers. Silicone-based systems are common because silicone fluids can provide broad temperature capability and stable handling, while non-silicone systems may be selected when silicone migration or contamination is a concern. The grease normally remains pliable rather than curing into a rigid adhesive.
Its primary function is to replace air trapped between mating surfaces. Air has much lower thermal conductivity than most interface compounds, so removing air gaps can reduce contact resistance; however, the actual thermal result depends on surface flatness, mounting pressure, bond-line thickness, coverage, and material stability. ASTM D5470 provides a recognized method for measuring thermal transmission properties of thermal interface materials, but results should be compared only when the test conditions are comparable.
For each application, I first confirm whether the grease will be exposed to vibration, repeated thermal cycling, outdoor conditions, dust, chemicals, or vertical mounting. These factors can affect migration, separation, contamination, and long-term contact. A product that performs well in a laboratory coupon test may still require assembly-level evaluation before production approval.
The following specifications are commonly reviewed during supplier qualification. The values below are evaluation examples, not universal specifications for every ordinary thermal grease, so I recommend requesting the exact current technical data sheet and test method for each candidate.
| Specification | Example data point or range | Why it matters |
|---|---|---|
| Thermal conductivity | Approximately 1–5 W/m·K for many general-purpose grades | Provides an initial indication of heat-transfer capability, but does not equal total assembly performance. |
| Thermal impedance | Reported in °C·cm²/W or an equivalent unit | Better reflects resistance through a defined test configuration. |
| Operating temperature | Example: approximately -40°C to 150°C, subject to the product datasheet | Shows whether the material is suitable for the expected thermal environment. |
| Viscosity | Reported in mPa·s, Pa·s, or a supplier-defined test scale | Influences screen printing, dispensing, spreading, and bond-line control. |
| Density | Often reported in g/cm³ | Supports packaging calculations, weight control, and automated dispensing setup. |
| Electrical behavior | Volume resistivity may be reported in Ω·cm | Helps determine whether the grease presents an electrical insulation risk. |
| Storage life | Example: 12 months at a specified storage condition | Supports inventory planning and prevents use beyond the supplier’s stated period. |
Thermal conductivity is often expressed in watts per meter-kelvin, but it should not be used as the only purchasing criterion. ASTM D5470 emphasizes controlled thermal testing, and the reported value can vary with pressure, sample thickness, temperature, and test configuration. I therefore ask suppliers to state the measurement method, test temperature, specimen thickness, and whether the value is typical, nominal, or guaranteed.
Some thermal greases are electrically insulating, while others contain conductive fillers or may become problematic if they migrate onto exposed contacts. Buyers should request volume resistivity, dielectric-strength information where relevant, and compatibility statements for nearby plastics, elastomers, coatings, and metals. IEC 60093 is an established reference for volume resistivity and surface resistivity testing of solid insulating materials, although the supplier should clarify whether its reported value was obtained using that standard or another method.
Viscosity affects how much force an automated dispenser requires and how consistently the material spreads over a contact area. A low-viscosity grease may be easy to apply but can be more difficult to retain in a vertical or high-temperature assembly, while a high-viscosity grade may support retention but require higher dispensing pressure. I recommend evaluating oil separation, pump-out, dry-out, evaporation, and thermal-cycling behavior when the product will operate for thousands of hours.
Record the component heat load in watts, expected operating temperature in °C, heat-sink material, contact area in mm² or cm², mounting pressure, and target service life in hours. Also document vibration, shock, thermal cycling, orientation, and whether the assembly will be opened during maintenance. These details help the supplier recommend a grade based on real conditions rather than a generic product description.
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Define minimum acceptable thermal performance, maximum viscosity, electrical requirements, and temperature limits before reviewing quotations. If the design has a strict thermal budget, request assembly-level testing or samples for a controlled comparison. A grease with a nominal conductivity of 3 W/m·K may be more suitable than a nominal 8 W/m·K product if it provides better wetting, lower interface resistance, or more consistent dispensing in the actual assembly.
Identify whether the grease will be applied by syringe, cartridge, screen printing, stencil, manual spreading, or automated dispensing. Specify the target application mass or thickness where the process can control it, because excessive material can increase the interface distance rather than improve heat transfer. The supplier should provide packaging options and handling instructions that are compatible with the selected equipment.
Use representative components, heat sinks, mounting hardware, and production-relevant application conditions for validation. Measure thermal behavior, dispensing repeatability, voiding, contamination, and post-aging condition where appropriate. I do not treat a supplier’s brochure value as a substitute for an internal qualification plan, particularly when the product is used in safety-relevant or high-value equipment.
Another common error is failing to define change control. A change in filler, base fluid, manufacturing location, packaging, or test method can affect process behavior even when the product name remains similar. I recommend requiring advance notification for material or process changes and retaining an approved reference sample when the application is sensitive.
For market access, buyers may also need to review substance restrictions and documentation requirements. For example, the European Union’s Restriction of Hazardous Substances framework is established under Directive 2011/65/EU and related amendments; compliance should be confirmed for the exact formulation and destination rather than assumed from a generic product category. I recommend asking the supplier to identify the applicable declaration scope and document version.
Thermal grease pricing depends on filler type, formulation, packaging, order quantity, testing, customization, and shipping conditions. Minimum order quantity can differ substantially between standard stock packaging and private-label or customized formulations, so I ask for separate quotations for samples, pilot quantities, and recurring production volumes. Lead time should be confirmed in calendar days or working days, including formulation approval, packaging preparation, quality release, and export documentation.
For a meaningful total-cost comparison, calculate cost per usable gram, expected application mass per unit, packaging waste, storage losses, freight, and line-change time. A lower unit price may not be economical if the grease causes dispensing instability or requires more frequent process adjustment. Buyers should also confirm whether the quoted price is based on EXW, FOB, CIF, or another agreed Incoterm.
At Kanronics, we approach ordinary thermal grease sourcing as a specification-matching process rather than a one-size-fits-all sale. I can work with your team to organize the required thermal, electrical, rheological, packaging, and regulatory criteria before a product recommendation is made. Where the application information is incomplete, I recommend beginning with a conservative technical review and representative samples instead of making an unsupported performance promise.
For an inquiry, please prepare the component type, heat load in W, operating temperature in °C, contact dimensions, application method, expected annual quantity, preferred package, destination market, and any electrical or compliance requirements. This information allows Kanronics to evaluate suitable ordinary thermal grease options, clarify available documentation, and structure a quotation around your actual procurement conditions. Final approval should remain based on your own assembly validation and the agreed supplier specifications.
The best ordinary thermal grease is the product that satisfies the complete application requirement, not necessarily the one with the highest headline thermal conductivity. Start by defining heat load, temperature, interface geometry, mounting conditions, electrical behavior, dispensing method, and service life. Then compare equivalent data sheets, validate samples under representative conditions, and evaluate the supplier’s documentation, packaging, MOQ, lead time, and change-control capability.
As a next step, I recommend creating a one-page purchasing specification with minimum thermal conductivity, required thermal impedance or test method, viscosity range, operating temperature, electrical limits, shelf life, package size, and quality documents. Send that specification to Kanronics for a structured review and quotation. This process helps reduce sourcing risk while keeping the final decision aligned with engineering evidence and production needs.
Contact us to discuss your requirements of Ordinary Thermal Grease. Our experienced sales team can help you identify the options that best suit your needs.