FAQ's | Questions and answers on the subject of electronics cooling

ALUTRONIC's portfolio includes over 250 standard profiles, which can be easily filtered and sorted by geometric and/or thermal parameters using the Heat Sink Finder.

If you still cannot find a suitable profile, you can set up customized extrusions.

This offers the following advantages:

• Optimisation of the mass-to-surface ratio leads to cost savings due to a smaller amount of material and shorter machining time during cutting.
• Optimisation of the profile cross-section leads to a more efficient cooling effect
• Assembly functions such as screw channels, sockets, plateaus or insertion slots are already integrated in the profile
• Reduction of the number of components in enclosure solutions through combination profiles
• Exclusivity through exclusive right of use
• Short delivery times at low costs through stockpiling in combination with framework agreements, provided that the minimum pressing quantity specified by the aluminium extrusion plants is adhered to, depending on the market situation.

It is important for designers to know that, especially for "large" profiles with a wrap circle of >350mm, limit dimensions and shape tolerances according to the standards below can assume values that are significantly higher than the values of the more familiar DIN ISO 2768-1 or DIN ISO 2768-2 (standard for general tolerances for length and angle dimensions as well as shape and position).
For example, the cross-sectional dimensions of a profile with a wrap circle of 200mm to 300mm may include maximum deviations of ±2.5mm; the convexity or concavity in this case may be up to 1.8mm.

The valid standards for limit dimensions and shape tolerances of extruded profiles made of aluminium and aluminium alloys are:
- DIN EN 12020-2: valid for wrap-around circles of >350mm, replaces DIN 17615-3, which is no longer valid.
- DIN EN 755-9: valid for wrap-around circles of >800mm, replaces DIN 1748-4 which is no longer valid.

DIN EN 12020-2 differs from DIN EN 755-9, apart from the size restriction, in the following aspects in particular:
- Valid for precision profiles exclusively of the alloys EN AW-6060 and EN AW-6063.
- Mainly for architectural applications
- Stricter requirements with regard to visible surfaces
- Tighter limit dimensions and shape tolerances

Since DIN EN 755-9 does not have a lower limit with regard to the wrap circle, pressing plants can also produce profiles with a wrap circle >350mm according to DIN EN 755-9 if the tolerances of 12020-2 are too low for reliable production.
In addition, special agreements deviating from the standards may be necessary between manufacturer and buyer for complex profiles. 

If the tolerances of these standards do not fit the application, ALUTRONICers are ready to work with the designer to develop and manufacture customised adaptations through machining and surface processing.

The mass and surface area of a heat sink are two important factors that can affect heat dissipation. A heat sink with a larger mass tends to be able to absorb and store more heat before releasing it to the environment. A larger surface area, on the other hand, can dissipate more heat to the environment.

The ratio of mass to surface area depends on the shape of the heat sink. A heatsink with a larger surface area relative to mass tends to dissipate heat more effectively than a heatsink with a smaller surface area relative to mass.

However, there are other factors to consider, such as the performance of the component that needs to be cooled and the environmental conditions. A small heat sink with a low mass may be more effective than a large heat sink with a higher mass and larger surface area under certain conditions.

Therefore, it is important to consider various factors when choosing a heat sink to ensure effective heat dissipation.

LME (London Metal Exchange) is the abbreviation for the London Metal Exchange, which is one of the oldest and largest metal trading centres in the world.
Along with Singapore and New York, the reference prices for metals, including aluminium, are determined here daily on the basis of supply and demand.
As a raw material price, the LME price for aluminium is a factor that fundamentally influences the costs of extruded aluminium profiles.
However, the prices of extruded profiles are not only dependent on the LME price, there are also other influencing factors such as:
 

• Exchange rate: as the aluminium price is traded on the exchange in US dollars, changes in exchange rates also affect prices.
• Billet premium: For the production of extruded profiles, the aluminium billets have to be remelted into special billets, the costs for this are called "billet premium".
• Special surcharges: These include, for example, costs as a result of sharply increased energy prices.
• Profile cross-section: The larger and more complex the profile, the higher the price usually is.
• Surface condition: A surface treatment such as anodising, coating or special optical requirements increase the costs.
• Quantity: The larger the order quantity, the lower the price per unit can be.
• Competition: If there are many suppliers of a certain type of extrusion on the market, this can lead to lower prices, while a limited number of suppliers can lead to higher prices.
• Transport costs: Transport costs can be factored into the price depending on the delivery route and transport medium.

 
In summary, the LME price for aluminium as a raw material price is an important factor in determining the cost of extruded profiles.
The actual price can deviate significantly from this for the reasons mentioned above

The production of aluminium begins with the mining of bauxite and ends with the extrusion billets required by extrusion plants for profile production. Various cost components arise along this process chain, only some of which are influenced by the global aluminium price on the London Metal Exchange (LME).
As the lingua franca in this industry is ‘English’, the technical terms are listed in both languages (German and English)

1. Bauxite mining: not yet influenced by the LME
Process: Bauxite is extracted via open-cast mining, crushed and transported to the refinery.
Cost factors:

• Mining and extraction technology
• Labour and energy costs
• Transport to the refinery
• Environmental and waste disposal obligations

Bauxite is not a listed commodity. The LME price plays no role here.
 

2. Refining into aluminium oxide (alumina): still unaffected by the LME
Process: In the Bayer process, bauxite is converted into aluminium oxide (Al₂O₃).
Cost factors:

• Caustic soda and other chemical additives
• Very high energy requirements (pressure, temperature)
• Disposal of red mud (waste product)
• Operation of refining plants

Aluminium oxide is also not listed on the LME, and therefore has no LME relevance.
 

3. Production of primary aluminium: this is where the LME comes into play
Process: Aluminium oxide is reduced to liquid aluminium via molten-salt electrolysis in the Hall-Héroult process.
Cost factors:

• Extremely high energy consumption (specific power consumption 12–17 kWh/kg) 
• Consumption of carbon anodes (graphite blocks made from petroleum coke)
• Synthesis of cryolite to lower the melting point
• Maintenance of the electrolysis cells

From this stage onwards, the LME aluminium price quoted on the exchange serves as the basis for the metal’s value.

4. Press billet production: Price basis: LME + billet premium
Process:
Primary aluminium is cast into round billets, homogenised, peeled and cut to length.
This is the typical feedstock for extrusion plants.
Cost factors:

• Remelting and alloying
• Casting facilities
• Energy costs for remelting and alloying
• Material losses (oxidation skin, chips)
• Labour costs and depreciation
• Demand in the extrusion market
• Capacity utilisation in foundries
• Ratio of primary aluminium to recycled material

The basis for the billet price is formed from: LME aluminium price + billet premium + alloy surcharges + processing costs
 

At what stage does the LME come into play?
The LME only influences the price from the point of primary aluminium production onwards; it does not affect bauxite or alumina.
Overview:

What other factors influence the prices of extruded profiles?
In addition to the LME price, the following factors come into play:

• USD/EUR exchange rate (the LME is quoted in US dollars)
• Billet premiums (costs associated with remelting, alloying, casting and homogenisation)
• Energy and special surcharges, e.g. in the event of sharply rising electricity costs.
• Profile cross-section & complexity: Larger or more complex cross-sections increase costs.
• Surface finish requirements: Anodising, powder coating or aesthetic finishes.
• Order quantity: Larger quantities = lower unit price.
• Market situation & competition: Supply bottlenecks or high demand drive up prices.
• Transport costs

According to the Arrhenius equation, the probability of failure of an electronic component doubles at a temperature increase of only 10K due to thermal ageing, and increases tenfold at 25K. For this reason, the aim should be to use every possibility of cooling the components, taking into account the generally valid rule: "As much as necessary as little as possible".

First of all, one should strive to reduce the thermal resistance of the heat sink by optimising it, e.g. by enlarging the surface and blackening it. In addition to improving the heat exchange with the air, increasing the surface area has the negative effect of increasing the pressure loss of the natural air flow, so that "at some point" a further increase in the heat sink surface area will lead to a build-up of heat. From this moment on, the heat sink can only be operated sensibly with forced air flow.

From this follows:

Forced ventilation is always worthwhile when cooling with natural convection does not make sense for economic reasons, e.g. because a special profile would have to be set up or the heat sink would have to be reworked at great expense.

Forced ventilation is mandatory if cooling with natural convection is not possible or not sufficient for technical reasons.

The performance data, or more precisely the thermal resistance Rth of heat sinks, is generally determined empirically, i.e. in the laboratory, by applying an impressed power loss PV as a heat flow to the heat sink via its baseplate and determining the temperature difference Du between the heat sink and the environment. Alternatively, this determination can also be carried out by simulation programs.

The determined value of the thermal resistance is therefore the only thermal parameter with which heat sinks of different designs, materials and manufacturers can be compared.

This is particularly worth mentioning because this "characteristic value" depends on the following influencing variables and measurement parameters, among others:

• Ratio of the heating surface of the heat source to the base surface of the heat sink
• (absolute) temperature of heat sink and environment
• Radiation losses of the heat source
• (absolute) power of the heat source
• Position of the temperature measurement point on the heat sink
• When determining thermal resistances with forced convection, further influences such as flow type and flow losses are added (see also à pressure chamber).

It is worth noting that there are neither guidelines nor standards regarding the determination of thermal resistance, according to which the data must be recorded.

A serious manufacturer of heat sinks will therefore not only state exactly under which conditions he has measured the thermal resistance, he will also choose a practical measuring method in order to be able to present realistic results.

At ALUTRONIC, all values given in the catalogue have been measured under the following conditions, unless otherwise stated in the data sheet:

• Natural convection
• Matt black anodised heat sink
• Vertical arrangement of fins
• A heat source with 40% of the floor area in the centre of the heat sink
• Temperature measurement between semiconductor and heat sink mounting surface
• Use of heat-conducting paste
• Measurement of the ambient temperature at a distance of one metre (1m) from the object to be measured

First of all: A heat pipe is not a heat sink and cannot replace one, but a heat sink is often needed to operate a heat pipe.

In somewhat unscientific, but therefore understandable terms, a heat pipe is a tubular component that exploits the phenomenon that a relatively large amount of energy is required for evaporation in order to change the aggregate state of substances, e.g. from liquid to gaseous. This amount of energy is released again when the state of aggregation is changed back from gaseous to liquid, i.e. condensation.

In scientific terms, a passive component, also generally referred to as a heat pipe, uses the enthalpy of evaporation of the medium in it as a heat exchanger between at least two points, which are referred to as heat source (= evaporator) and heat sink (= condenser). The transport zone is located between these two points.

Due to special structures in the interior that promote capillary action, the heat pipe can be operated in any position within certain limits, which distinguishes it from the 2-phase thermosiphon.

The following aspects are important in practice:

• The ability of a heat pipe to transport a certain amount of heat depends on length, cross-section, internal structure, working medium, position, thus a heat pipe should be matched to the application.
• A heat pipe can only be operated within its operating limits, which result from the application in terms of temperature and heat flow. In detail, these limits are viscosity limit, sound velocity limit, interaction limit, capillary force limit and boiling limit.
• The heat conduction is up to 1000 times better compared to a solid copper rod of identical outer geometry.
• Gravity has a positive or negative effect on the return transport of the liquid medium, depending on its position; the influence factor on the heat flow is between 0.6 and 1.6.

"Eloxal" is the abbreviation for electrolytic oxidation of aluminium. This process is used to apply a protective layer to aluminium and wrought aluminium alloys.

This protective layer serves primarily as protection against chemical (e.g. corrosion) and mechanical (e.g. wear) stress and preserves a decorative appearance that may have been achieved through pre-treatment. 

Further positive effects of the anodising process are an increase in surface hardness, improvement of tribological properties and an increase in electrical insulation.

The special process also makes it possible to colour the anodised layer. Alutronic offers the colours blue and black as standard. Due to the darker surface, the proportion of heat radiation and thus the thermal resistance of the heat sink increases with rising temperature.

In addition to the "conventional anodising process", ALUTRONIC also offers the option of hard anodising aluminium components. This special process makes the layer much thicker, denser and harder than anodising, which also significantly improves the electrical insulation or dielectric strength.

For the production of heat sinks using the cold extrusion process, pure aluminium such as EN AW-1050 (Al 99.5) or also pure copper is usually used. The thermal conductivity of pure metals is generally higher than that of alloyed metals such as EN AW 6060 (AlMgSi0.5), which is frequently used in extrusion.

Due to the forming process and the resulting minimisation of voids and air bubbles, this high thermal conductivity is even improved.

Since the air can move three-dimensionally along the surface in comparison to extruded profiles in the case of heat sinks that are frequently pressed into a pin shape, the heat dissipation performance is optimised. 

The shape retention and the surfaces are of such good quality at relatively low tooling costs that mechanical reworking is required only rarely and to a minor extent.

The production of heat sinks by means of impact extrusion is therefore always an option when it comes to rather small, customer-specific series and the heat sink as such should also be rather small with the highest possible efficiency.

The cooling performance can be further enhanced by black anodising and the installation of a fan directly in the heat sink.

The machining of a heat sink accounts for a large proportion of the costs of a heat sink, in addition to the actual material price.

It therefore makes sense to take the mechanical finishing into account and minimise it as early as the selection or design of the raw profile.

It should also be taken into account that the small heat sinks in particular often have very filigree fin structures, which can bend or even break very easily.

There are various criteria for determining the suitable and optimal heat sink, such as the geometric dimensions "width", "height", "base thickness", "length", the permissible maximum thermal resistance Rth,KK as well as the maximum power loss PV to be expected.

The Heat Sink Finder from Alutronic is the ideal tool to include these criteria completely or only partially in the selection. The results can be output as a list and optimised, for example, according to the mass coating or also the weight per metre to minimise costs. Alternatively, for each profile suggested by the Heat Sink Finder, a graph with the thermal resistances dependent on length and power loss can be created and evaluated.

The explanatory video illustrates the relationships in detail.

According to the Federal Ministry for the Environment (BMUV), the Federal Environment Agency (UBA) and the Öko-Institut, the CO2 footprint of products is the balance of greenhouse gas emissions along the entire life cycle of a product in a defined application and in relation to a defined unit of use.

The determination of the carbon footprint of heat sinks is thus intended to cover the entire product life cycle, which, in addition to production and use of the actual heat sink, also includes the production of raw materials and preliminary products as well as disposal.

Because other greenhouse gases are often taken into account in addition to carbon dioxide, the figure is usually given in "tonnes of CO2 equivalent" (T CO2-eq) in relation to the mass of the heat sink.

ALUTRONIC heat sinks have been climate neutral since the beginning of 2020!

The CO2 footprint of a heat sink is reflected, among other things, in the manufacturing process and the compensation of the emissions generated during this production. The amount of emissions in turn correlates with the mass of the heat sink produced.

The CO2 footprint of a heat sink can therefore be positively influenced on the one hand by the targeted selection of manufacturers who offer climate-neutral heat sinks. All ALUTRONIC heat sinks are climate-neutral!

On the other hand, the CO2 footprint of a heat sink can be influenced by specifically selecting a heat sink with the lowest possible mass for the respective application.

The Heat Sink Finder provides targeted assistance in this regard.

In principle, the choice of metal or alloy has a major influence on the thermal conductivity of heat sinks. In addition to this application-specific argument, economic and processing aspects also play a role, so that the following aluminium alloys are mainly used for extruded heat sink profiles:
    
EN AW-6060 (AlMgSi0.5 / 3.3206) l = 190 ... 220 W/mK  
EN AW-6063 (AlMg0.7Si / 3.3210) l = 190 ... 220 W/mK 
EN AW-6101B (E-AlMgSi0.5 / 3.3207) l = 215 ... 225 W/mK
EN AW-6082 (AlMgSi1 / 3.3215) l = 145 ... 220 W/mK
EN AW-1050A (Al99.5 / 3.0255) l = 210 ... 220 W/mK

For special requirements, heat sinks made of copper (l = 380 W/mK) on the one hand and plastic (l " 10 W/mK) on the other are used in rare cases.

Since, in addition to the thermal conductivity, the geometry, i.e. the surface, base thickness, fin height, width and spacing, as well as the colour and the thermal connection to the heat source play a significant role in the efficiency of a heat sink, the influencing factor of the thermal conductivity is present, but not as great as is commonly assumed.

EN AW-6063 (AlMg0.7Si)

Full name: EN AW-6063 (AlMg0.7Si), T5/T6
Application: Standard alloy for extruded heat sink profiles in LED, IT and electronics applications.

Alloy properties

Density: 2.70 g/cm³
Thermal conductivity: approx. 201–218 W/(m·K)
Coefficient of linear expansion: 23.4 × 10⁻⁶ /K
Modulus of elasticity: 68.9 GPa
Composition (%):

Al 97.65–98.7 %
Mg 0.45–0.9 %
Si 0.2–0.6 %
Fe ≤ 0.35 %
Zn ≤ 0.10 %
Cu ≤ 0.10 %
Mn ≤ 0.10 %
Cr ≤ 0.10 %
Ti ≤ 0.10 %

Properties:

Very good extrudability, good thermal conductivity, fine surface finish, suitable for anodising, versatile applications, good weldability, acceptable machinability.

EN AW-6060 (AlMgSi0.5)

Full name: EN AW-6060 (AlMgSi0.5) Application: Design-oriented heat sinks with a high-quality finish, e.g. visible components or housings.

Alloy properties

Density: 2.71 g/cm³
Thermal conductivity: approx. 200 W/(m·K)
Coefficient of linear expansion: 23.4 × 10⁻⁶ /K
Composition (%):

Al 97.9–98.7 %
Mg 0.35–0.60 %
Si 0.30–0.60 %
Fe 0.10–0.30 %
Zn ≤ 0.15 %
Cu ≤ 0.10 %
Mn ≤ 0.10 %
Ti ≤ 0.10 %
Cr ≤ 0.05 %

Properties:

Very good formability and surface quality, moderate strength, suitable for anodising, versatile applications, very good weldability, still acceptable machinability.

EN AW-6061 (AlMg1SiCu)

Full name: EN AW-6061 (AlMg1SiCu), 3.3211
Application: Industrial heat sinks with higher mechanical requirements or for outdoor use.

Alloy properties

Density: 2.70 g/cm³
Thermal conductivity: approx. 151–202 W/(m·K)
Modulus of elasticity: 69 GPa
Composition (%):

Al 96.8–97.9 %
Mg 0.80–1.20 %
Si 0.40–0.80 %
Cu 0.15–0.40 %
Fe ≤ 0.70 %
Cr 0.04–0.35 %
Zn ≤ 0.25 %
Ti ≤ 0.15 %
Mn ≤ 0.15 %

Properties:

High strength, good corrosion resistance, stable at high temperatures, good weldability, good machinability.

EN AW-6082 (AlSi1MgMn)

Vollständiger Name: EN AW-6082 (AlSi1MgMn), 3.2315
Einsatz: Kühlkörper mit statischer Belastung oder mechanischen Befestigungen.

Legierungseigenschaften

• Dichte: 2,71 g/cm³
• Wärmeleitfähigkeit: ca. 150–170 W/(m·K)
• Längenausdehnungskoeffizient: 23,4 × 10⁻⁶ /K

Zusammensetzung (%):

• Al 95,5–97,3 %
• Si 0,7–1,3 %
• Mg 0,6–1,2 %
• Mn 0,4–1,0 %
• Fe ≤ 0,5 %
• Cr ≤ 0,25 %
• Zn ≤ 0,20 %
• Cu ≤ 0,10 %
• Ti ≤ 0,10 %

Eigenschaften:

Hohe Festigkeit, gute Korrosionsbeständigkeit, gute Schweißbarkeit, mittlere Wärmeleitfähigkeit, sehr gute Zerspanbarkeit.

EN AW-1050A (Al 99.5)

Full name: EN AW-1050A (Al 99.5%)
Applications: Fin and flat heat sinks where maximum thermal conductivity is essential.

Alloy properties

Density: 2.70 g/cm³
Thermal conductivity: approx. 229 W/(m·K)
Composition (%):

Al ≥ 99.50 %
Fe ≤ 0.40 %
Si ≤ 0.25 %
Zn ≤ 0.07 %
Ti ≤ 0.05 %
Cu ≤ 0.05 %
Mn ≤ 0.05 %
Mg ≤ 0.05 %

Properties:

Excellent thermal and electrical conductivity, highly corrosion-resistant, low resistance to seawater and salt, low strength, good weldability, poor machinability.

EN AW-1070A (Al 99.7%)

Full name: EN AW-1070A (Al 99.7%)
Application: Electrical and thermal connectors with maximum conductivity.

Alloy properties

Density: 2.70 g/cm³
Thermal conductivity: approx. 230 W/(m·K)
Composition (%):

Al ≥ 99.70 %
Fe ≤ 0.25 %
Si ≤ 0.20 %
Zn ≤ 0.07 %
Cu ≤ 0.03 %
Mn ≤ 0.03 %
Mg ≤ 0.03 %
Ti ≤ 0.03 %

Properties: 

Highest thermal and electrical conductivity, very soft, excellent formability, highly corrosion-resistant, low resistance to seawater and salt, good weldability, very poor machinability.

EN AW-3003 (AlMn1Cu)

Full name: EN AW-3003 (AlMn1Cu), 3.0517
Applications: Stamped and folded cooling plates, housings or covers.

Alloy properties

Density: 2.73 g/cm³
Thermal conductivity: approx. 160 W/(m·K)
Composition (%):

Al 97.9–98.5 %
Mn 1.0–1.5 %
Fe ≤ 0.7 %
Si ≤ 0.6 %
Cu 0.05–0.20 %
Zn ≤ 0.10 %

Properties: 

High corrosion resistance, good formability, poor anodisability, moderate strength, good solderability, good weldability, moderate machinability.

EN AW-5052 (AlMg2.5)

Full name: EN AW-5052 (AlMg2.5), 3.3523
Application: Sheet metal and finned heat sinks for outdoor use or in damp environments.

Alloy properties

Density: 2.68 g/cm³
Thermal conductivity: approx. 138 W/(m·K)
Composition (%):

Al 96.2–97.0 %
Mg 2.20–2.80 %
Cr 0.15–0.35 %
Fe ≤ 0.40 %
Si ≤ 0.25 %
Cu ≤ 0.10 %
Zn ≤ 0.10 %

Properties: 

Very good corrosion resistance, seawater-resistant, good formability, moderate strength, good weldability, moderate machinability.

EN AW-5083 (AlMg4.5Mn0.7)

Full name: EN AW-5083 (AlMg4.5Mn0.7), 3.3547
Application: Heat sinks subject to mechanical stress in harsh environments (e.g. marine, offshore).

Alloy properties

Density: 2.66 g/cm³
Thermal conductivity: approx. 121 W/(m·K)
Composition (%):

Al 92.2–94.7 %
Mg 4.0–4.9 %
Mn 0.40–1.0 %
Si ≤ 0.40 %
Fe ≤ 0.40 %
Cr 0.05–0.25 %
Zn ≤ 0.25 %
Ti ≤ 0.15 %
Cu ≤ 0.10 %

Properties: 

Very high strength, excellent corrosion resistance, seawater-resistant, good weldability, very good machinability.

EN AC-AlSi10Mg (a)

Full name: EN AC-AlSi10Mg (a), EN 1706 (die-casting / permanent mould casting)
Application: Die-cast heat sinks with complex geometries and thin wall thicknesses.

Alloy properties

Density: 2.65 g/cm³
Thermal conductivity: approx. 130–190 W/(m·K)
Composition (%):

Al 87.5–90.0 %
Si 9.0–11.0 %
Mg 0.25–0.45 %
Fe ≤ 0.55 %
Mn ≤ 0.45 %
Cu 0.05–0.20 %
Ti ≤ 0.20 %
Zn ≤ 0.10 %

Properties: 

Very good castability, fine-grained structure, high thermal conductivity, good strength after heat treatment (T6), good machinability.

EN AC-AlSi9Cu3 (Fe)

Full name: EN AC-AlSi9Cu3 (Fe), EN 1706 (die-casting)
Application: Mass-produced die-cast heat sinks in automotive and power electronics.

Alloy properties

Density: 2.73 g/cm³
Thermal conductivity: approx. 120–160 W/(m·K)
Composition (%):

Al 82.0–88.0 %
Si 8.0–11.0 %
Cu 2.0–4.0 %
Fe 0.6–1.1 %
Zn ≤ 1.2 %
Mn 0.15–0.55 %
Mg ≤ 0.55 %
Pb ≤ 0.35 %
Sn ≤ 0.15 %
Ti ≤ 0.20 %

Properties:

Good castability, high strength, dimensionally stable, proven for large-volume heat sink production, good machinability.
 

The following calculation relates exclusively to the pure material value of the aluminium, based on the current LME (London Metal Exchange) price.
This calculation does not include any value added from production, processing, logistics or trade.
Determining the actual value-added component would – if at all possible – only be achievable with considerable effort and detailed cost analyses across all stages of production.
The aim of this presentation is to provide a transparent estimate of the raw material value per component.

Calculation method (simple & transparent)

Conversion of the LME price from USD per tonne to USD per kilogram
Optional: Conversion to EUR/kg using the current exchange rate
Multiplication by the aluminium mass of the component (component weight in kg × aluminium content in %)
Result: Material value of the aluminium per unit (excluding surcharges, processing costs or margins)

Example values

Aluminium price: approx. 2,814 USD/t ⇒ 2.814 USD/kg (LME benchmark)
Exchange rate: approx. 1.1626 USD per EUR (≈ 1 USD = 0.86 EUR)

Calculation examples

FI353 (ALMg3)

Weight (unplated): 0.0040 kg, aluminium content: 95.8%
Aluminium mass: 0.0040 × 0.958 = 0.003832 kg
USD: 0.003832 × 2.814 = $0.0108 per piece
EUR: ≈ €0.0093 per piece
PR32/38.1 (AlMgSi0.5)

Weight: 0.0158 kg, aluminium content: 99.05%
Aluminium mass: 0.0158 × 0.9905 = 0.01565 kg
USD: 0.01565 × 2.814 = $0.0440 per piece
EUR: ≈ €0.0378 per piece

Basically, a heat sink should be designed in such a way that a certain quantum of reserves is available, especially in order not to thermally overload the electronics even under difficult ambient conditions.

If it is determined that the temperature is too high, the following possibilities can be considered:

Thermal connection: Possibly the gap pad, the gap filler or the mechanical connection between the electronics and the heat sink is defective or damaged or overaged, so that a replacement makes sense here.

Contamination: Possibly the possibilities for air supply or exhaust air are disturbed or blocked or the heat sink itself is dusty or dirty, so that cleaning is necessary.

Ageing: Possibly the power loss of the electronics has increased due to ageing, so that it must be replaced.

Defective: The fan may be defective or damaged so that it no longer provides its full performance and must be replaced.

Ambient temperature: Possibly the ambient temperature has risen so far due to external or internal circumstances that the heat dissipation is no longer sufficient.

In this case, as well as alternatively in the cases mentioned above, the additional use of a fan can provide relief.

When mounting a heat sink, a few points must be observed to achieve the desired effect:

Alignment: The fins should be aligned vertically, especially in the case of natural convection, i.e. operation without a fan, so as not to obstruct convection.

Connection: If the heat source is directly connected to the heat sink, a thin layer of thermal paste should be applied in this area. The heat-conducting paste should only compensate for air pockets due to roughness or unevenness, it does not serve to compensate for gaps.

If the heat source is connected indirectly to the heat sink by means of heat conducting foil, gap pad, gap filler or similar, the manufacturer's instructions must be observed.

Fastening: The heat source and the heat sink should be fastened in such a way that the connection cannot loosen even in the event of movement, vibration, thermal expansion, etc. The heat source and the heat sink must be secured in such a way that the connection cannot loosen. ALUTRONIC offers various options for this, such as threaded holes, mounting clips, self-adhesive heat conducting foils and much more.

With forced, i.e. fan-driven cooling, the following phenomena occur, which can be reduced or minimised with a pressure chamber depending on the application: 

1. Path of least resistance: The air strives to flow through a path that is as free or low in obstructions as possible. Therefore, it can happen that the air does not flow through the heat sink as desired, but bypasses it or leaves it halfway; this is also referred to as the "bypass phenomenon".
    
2. Dead water: In the centre of the fan is the fan hub, which serves to position the motor and fix the fan blades. There is no air flow in this area, so the air behind the hub is undirected and slow. In terms of flow depth, this area roughly encompasses the hub radius and is referred to as the "dead water zone".

Especially high-performance heat sinks with a high aspect ratio (ratio between fin height and spacing) can be additionally equipped with a pressure chamber when used with a fan. This channels the air flow and compensates for the dead water, thus ensuring a more uniform flow through the heat sink by virtually storing air under pressure before it flows through; hence the term "pressure chamber".

In the field of cooling systems, Alutronic offers assemblies with and without pressure chambers in order to provide the greatest possible variety for the customer in this product line as well.

The thermal resistance Rth [K[W] describes the resistance of a body to conduct a heat flow [W] through it and thus the temperature difference [K] between entry and exit, i.e. from or to the neighbouring bodies or substances. For this reason, two components are always specified for thermal resistance, e.g. RthjC for "between chip "Junction" and case "Case"").

The heat capacity C [J/K] describes the temperature increase [K] of a body as a result of a supplied amount of heat [J=Nm=Ws].

Both quantities are object or component related, i.e. not material properties.

For each substance or material there is both a material-specific thermal resistance Rl [mK/W] (whereby in the literature the (specific) thermal conductivity l or k [W/mK] is given as the reciprocal value) and a specific heat capacity c [J/kgK].

For aluminium (99.5%), for example:

lAl = 236W/mK

cAl = 0.9kJ/kg

The heat capacity does not normally play a role in heat sink design, as the heat sink should not store the heat but dissipate it as efficiently as possible to the environment.

It can be calculated as follows:

CH = cAl x mH 

with

CH: heat capacity of the heatsink 

cAl: specific heat capacity of aluminium

mH: mass of the heat sink

When developing and manufacturing a new extrusion profile, a new extrusion tool is always required. If this is a customer-specific tool, the customer is generally charged a one-off pro rata tooling cost for this.

This has the following advantages for the customer: 

The tool and thus the extrusion profile is exclusive to the customer and is not used for anyone else.

There are no follow-up costs; any maintenance, servicing and, if necessary, repair of the tool are the responsibility of the extrusion plant.

The extrusion plant is and remains the owner of the tool.