How to reduce costs in cold plate production

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The liquid cold plate is a common component in industrial cooling systems. We all want to equip our projects with high-quality cold plates and efficient heat dissipation systems to ensure that our equipment can maintain good working conditions for a long time. However pursuing efficient heat dissipation does not mean you must use the best materials and spend the highest price. There are different ways to save money on customization in the production of cooling panels. In this article, cold plate manufacturer Winshare will share two ways with you to reduce the cost of customizing cold plates.

1. Use extrusions and castings

It is best to use extrusions and castings whenever possible to minimize processing time and reduce costs. Extrusion is the process of pushing metal through a die to create an object with a fixed cross-section. Dies for new extrusions are inexpensive, and extrusion dimensions are limited to approximately 9 inches (22.86 cm) wide. Extrusion wall thicknesses need to be relatively uniform, and any channels or features need to be straight.

A combination of extrusion and machining is used to reduce costs. Some features can be extruded, and more complex features can be machined. Another option for prototyping is too-cold machine plates to reduce quantities, and then, once the design has been verified and fixed, the dies for extrusion can be made. If you design the plate with extrusion features in mind, this will help reduce extrusion costs.

Another option is to combine casting and machining to make cold plates. For example, if the casting is not flat enough, a secondary operation will be required to bring the cold plate to the desired flatness specifications. It is important to note that sand castings are not suitable for vacuum brazing cold plates because most of the alloys used have melting temperatures below the vacuum brazing temperature. Their use is strictly limited to tubular cold plates. It is recommended to obtain quotations for production processes and to weigh the advantages and disadvantages.

Typically, the minimum purchase for extrusions or castings is high, so you need the proper application to justify using these processes. Both extrusions and castings can result in significant cost savings overall.

2. Specify local surface flatness

Surface flatness has a greater impact on the thermal performance of a cold plate than surface roughness because if the plate is not flat, the contact area is greatly reduced. The standard flatness specification is 0.001 inch/inch (0.003 cm/cm). Therefore, within one inch of the measurement point, the lowest point of the cold plate will not be 0.001 inches (0.003 cm) lower than the highest point. If your specifications call for flatness better than 0.001 inch/inch (0.003 cm/cm), one way to save money is to specify partial flatness rather than tight flatness across the board. For example, if you are mounting multiple insulated gate bipolar transistors (IGBTs) on a cold plate and each IGBT requires 0.001 in/in (0.003 cm/cm) across the entire substrate, specifying the local flatness of the individual IGBTs rather than requiring the entire plate to be very flat.

The flattening process for cold plates usually involves a hydraulic press. Skim cuts can be used to improve flatness. With a skim cut, the machine determines the lowest point of the cold plate and scrapes away very little metal at the lowest point and as much metal as possible in the higher areas to obtain a flat surface. Although skim cutting a piece of aluminum is easy, skim-cutting the tubular side of a vacuum-brazed cold plate or tubular cold plate is more complicated. The cooling surfaces of tubes in vacuum-brazed cold plates and tubular cold plates are usually fragile to optimize thermal properties. If the cold plate is not flat, the skim cut may be too deep, and the walls will either be thin or may become too weak to withstand pressure and even rupture. Or, you can start with a thicker cold plate to eliminate the possibility of leaks, but you will sacrifice some performance.

If you would like to save more money in ordering your cold plate, feel free to contact Winshare, we can customize the cold plate cooling solution that best suits your project at the lowest price.

Reprinted from Winshare Thermal - “How to reduce costs in cold plate production”