An extruded aluminum heat sink is a thermal component made by pushing heated aluminum alloy through a shaped die to form a base and fins in one continuous profile. To select one, start with the heat your component generates, the maximum temperature it can tolerate, the available space, and the cooling conditions. Then compare profile geometry, alloy, finish, mounting method, and production requirements against those constraints. At Onlink, we recommend treating the heat sink as part of the complete thermal path—not choosing a profile by appearance or dimensions alone.
This guide is for machinery manufacturers, equipment designers, and purchasing teams evaluating an extruded aluminum heat sink for a new product or redesign. It is especially relevant when a power supply, motor drive, LED assembly, control unit, or other heat-generating component must fit inside a defined enclosure. Engineering teams can use the selection framework to prepare a useful design brief, while buyers can use it to compare suppliers on more than unit price. The right specification depends on the application, so the guidance below should be confirmed against your actual operating conditions.
The base of a heat sink receives heat from an electronic or mechanical component, usually through a mounting interface. Heat spreads through the base and travels into the fins, where it can transfer to surrounding air by convection. More exposed surface area can support greater heat transfer, but the result also depends on airflow, fin spacing, orientation, surface condition, and the temperature difference between the heat sink and its environment. A larger profile does not automatically perform better if its fins restrict airflow or its base makes poor contact with the heat source.
Aluminum alloys used for extruded profiles offer a practical balance of thermal performance, weight, manufacturability, and cost. As a general reference, 6063 aluminum is commonly cited with thermal conductivity around 200 W/(m·K), though the actual value depends on alloy condition and supplier specification. Confirm the proposed alloy and temper on the supplier’s material documentation rather than assuming that every aluminum extrusion has identical properties. Profile geometry—including base thickness, fin height, fin thickness, and spacing—must also suit the intended manufacturing process and cooling method.
Natural convection relies on air moving around the fins without a fan, while forced convection uses a fan or system airflow. Natural-convection designs may need more surface area or a different orientation to achieve the required cooling, whereas forced airflow makes fin direction and pressure drop more important. A compact fin pitch can increase surface area within a given footprint, but closely spaced fins may limit airflow, particularly in dusty or obstructed machinery environments. Consider maintenance access and contamination as part of the thermal design, not as an afterthought.
Begin with the heat source and the conditions in which the equipment will operate. Record the component’s heat dissipation in watts, expected ambient temperature, allowable component temperature, available installation volume, and whether airflow is natural or fan-driven. Include duty cycle and nearby heat sources when they affect the enclosure temperature. If any input is uncertain, identify it as an estimate and ask engineering to validate it before finalizing the profile.
A simple first check is the relationship between heat load, thermal resistance, and temperature rise: temperature rise is approximately power multiplied by thermal resistance. For example, a 60 W heat load through a total thermal resistance of 0.5 K/W produces an estimated rise of 30°C across that defined thermal path. This is an illustrative calculation, not a prediction of a particular heat sink’s performance; the total path may include the component interface, heat sink, and air-side resistance. Use detailed analysis or testing when operating margins are tight, airflow is complex, or component reliability depends on a precise temperature limit.
In machinery, vibration, enclosure layout, and service requirements can influence selection as much as thermal capacity. A long profile may need multiple mounting points to support stable contact, while a compact control cabinet may restrict fin orientation or fan placement. Where dust or oil mist is present, ask whether fin spacing and cleaning access are appropriate for the environment. These application details help prevent a design that works in an open test setup but is difficult to install or maintain in the finished machine.
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Fin height and spacing should be chosen together because they affect surface area, airflow, stiffness, and manufacturability. Base thickness influences heat spreading and mechanical support, but increasing it also adds material and weight. The interface between the heat source and the base matters: flatness, contact area, mounting pressure, and thermal interface material can all affect the overall temperature rise. Ask the supplier to review the full cross-section and intended assembly instead of evaluating isolated dimensions.
Surface treatment should be selected for a specific functional reason, such as appearance, corrosion requirements, or electrical isolation, rather than assumed to improve cooling in every case. Likewise, machining features such as tapped holes, cutouts, and precision mounting faces can add process steps that affect cost and schedule. Provide the drawing revision, tolerances, and inspection expectations at quotation stage so suppliers can identify feasibility questions early. Where the design is not yet fixed, distinguish essential requirements from preferences.
The cost of a custom extruded heat sink can include profile design, extrusion tooling, raw material, cutting, machining, finishing, inspection, packaging, and freight. Tooling charges and minimum order quantities vary with the profile, production route, supplier, and project volume, so request a quotation based on your drawing and forecast rather than relying on generic price ranges. A profile that uses a standard or adaptable extrusion may have different startup economics from one requiring dedicated tooling. Ask suppliers to separate one-time tooling charges from recurring part costs where applicable.
Lead time also depends on factors such as tooling status, material availability, process complexity, order quantity, and approval cycles. To reduce avoidable delays, share a complete drawing, target quantity, annual demand estimate, required finish, packaging expectations, and destination early. If you need samples or a pilot run before production, state that in the request for quotation. Confirm the supplier’s quoted schedule and the events that start the lead-time clock before placing an order.
A suitable supplier should be able to discuss both profile manufacturability and the requirements of the finished component. Ask how they will review alloy, cross-section, tolerances, machining, finishing, and inspection needs, and request clarification whenever a proposal changes the specification. For a thermal design, also ask what information they need to assess suitability and whether the offered scope includes only extrusion or additional machining and finishing. A clear division of responsibilities helps prevent gaps between the heat sink supplier, component designer, and equipment manufacturer.
Selecting an extruded aluminum heat sink starts with the heat load, allowable temperature, airflow, and installation space; profile choice follows those requirements. Alloy and geometry matter, but so do the component interface, mounting, enclosure, finish, and production route. Treat calculations and typical material values as screening references, then validate the complete assembly under representative operating conditions. This approach helps engineering and purchasing teams compare options on performance, manufacturability, and total sourcing requirements.
To evaluate a solution with Onlink, prepare a drawing or preliminary cross-section, heat-load information, operating environment, target quantity, and required finishing or machining details. Our team can review the supplied requirements and discuss extrusion feasibility, customization, and quotation scope. If the design is still being developed, share the known constraints and mark uncertain values clearly so the next design step can be based on the right information.
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