Prices for cold plate can vary quite a bit; understanding why can help you reduce your costs and still get the performance you need to properly cool your application. The two biggest cost driving factors in cold plate manufacturing are thermal performance requirements and the annual demand, which generally thermal engineers and the manufacturing engineers have little or no control over. But you can cut costs by understanding how flatness, hardness, roughness, surface topography, mounting features, and liquid connections specifications affect the cost of a liquid cold plate. By involving your cold plate manufacturers early in the your custom cold plate design process, you will be able to identify the manufacturing cost driving factors and select the most cost effective design.
Most liquid cold plates are made of aluminum, while some new technologies use copper. Although copper has better thermal conductivity than aluminum, aluminum is used more often because it is cheaper, lighter, and easier to use. It is very difficult and expensive for machining copper. Aluminum is usually the best material if it meets thermal performance specifications
The most popular aluminum cold plate technologies are pressured tubed, vacuum-brazed, friction welding. Pressured tubed cold plates are usually copper or stainless steel tubes pressed into a channeled aluminum plate. They are cost-effective and provide good overall thermal removal for low and medium watt densities. Vacuum-brazed cold plates consist of two metal plates bonded together with internal fin. They are available in all sizes and have extremely high performance, making them ery suitable for applications of heat loads concentration. Friction welded cold plates make the water channel design more free, sealing reliability better, at the same time can be used hard anode surface treatment. With both pressured tubed, friction welded and vacuum-brazed cold plate technologies, the labor time is limited. Therefore, for moderate volumes, we are a China cold plate manufacturers , the labor cost is lower than that in European and American countries, and the Chinese cold plate technology is mature, the production time is short, so the cost is lower, so our company exports a lot of cold plates to European and American countries every year.
The biggest cost driving factors for aluminum cold plates, after those mentioned above, are machining time and the additional processing steps. Cold plate manufacturers usually have a cost associated with machining time. This includes the depreciation costs of the machine, power supplies, consumables, and maintenance. Therefore, the longer the liquid cold plate sits in the machine, the more costly it is. Moreover, each additional processing step continues to increase the cost.
Extrusions and Castings
To minimize machining time and reduce cost, it is best to use extrusion and casting as much as possible. An extrusion is produced by pushing metal through a die to produce an object with a fixed cross section. Dies for a new extrusions are relatively cheap, Also, any channels or features must be straight.
Liquid cold plate manufacturer can also use a combination of extrusions and machining to reduce costs. An extrusion can be made for some features and then some more complicated features, for which extruding is not an option, can be machined. Another option for prototyping processing is to machine the cold plate for lower quantities and then, once the cold plate design is proven and fixed, make the die for the extrusion. This will help reduce extrusion costs, If you you design the plate with the extruded features in mind.
Another option is to cast cold plate. However, there are several disadvantages to castings. First, the thermal performance are slightly degraded. The degrade may be up to 10%. Second, there are limits to the tolerances that can be achieved. For example, extrusion can easily maintain a tolerance of ±0.005 inch/inch, while a sand casting is more likely going to maintain ±0.03 inch/inch. A sand cast die typically costs is effective for hundreds of cold plates. Dies for higher technology applications are made by an investment cast process and It can cost up to 10 times as much as sand casting. Also, casting and machining can be used together. For example, if the casting cold plate is not flat enough, the secondary operation to get the cold plate to the required flatness specification will be necessary. It is important to note that sand castings are not an option for vacuum brazing cold plates as the melting point of most alloys is below the vacuum brazing temperature. Their use is strictly limited to the tubed cold plates. It is recommended to obtain quotes on the two production processes and weighing the pros and cons is recommended.
In general, the minimum purchase for extrusion or casting is high, so you need the right application to justify using these processes. Both extrusion and casting offer significant overall cost savings .However, they are hard to change, so if you expect changes in the future, it might make sense to choose other alternative production methods.
One requirement that can add significant cost without impact on performance is surface roughness (finish). Roughness on cold plates is an uneven, ridges, or projections on the surface that result in an unevenness on the thermal transfer surface. Contrary to some opinions, roughness has relatively little impact on thermal performance of cold plates. In most applications, the surface contact between the cold plate and the component is less than 10% and the air gap is more than 90%...
Most applications use a thermal interface material (TIM) between components or plates and the cold plates to help to minimize the gaps. The TIM should be as thin as possible, as the TIM's relatively high thermal resistance greatly overshadows any electrical conductivity improvements from having a smoother surface. Increasing the clamping force of a component or plate to the cold plate can also help to offset the higher roughness, but this may increase the stress on the plate or component. Clamping stress can also increase the influence of influence as the cold plate and component or plate heat up.