Electronic components are tested and validated in many different ways. At Miba Cooling, we run appropriate tests on special test benches in our in-house test center. In the process, validation secures and documents the most important properties.
The aim of the test methods used is to assess at an early stage whether the design of the heat sink meets requirements. In this way, we ensure the correct function and quality of the water coolers, air coolers, or heat pipes.
How resilient does a component need to be? What is the thermal stress at any given position and output of the electronics? Can the heat sink material withstand the pressure and thermal loads? Questions like these should be answered long before a heat sink goes into series production.
In order to ensure series production goes without a hitch, we therefore simulate various scenarios in real conditions. When running a simulation we calculate, for example, the optimum dimensions of the heat sink and the ideal flow field for water-cooled heat sinks. Various methods including mechanical, electrical, and thermal tests are carried out at our test center. Mechanical and thermal behavior is an essential part of validating Miba heat sinks. This means the level of resistance to high thermal loads throughout the component’s service life.
With experience of selecting the correct input parameters, the results of the simulation can also shorten the validation process. The validation results are used to prove that the Miba heat sink meets customer-specific requirements.
They also help to eliminate inconsistencies in product development and ensure product quality and reliability in subsequent series production. With the simulation and validation process at Miba Cooling, the heat sinks do not merely perform their tasks. The components also meet the highest quality standards.
If the heat sink goes into series production later on, ongoing tests are carried out on in-house test facilities. This ensures that the product can be reproduced according to customer requirements and meets the requisite quality standards.
Depending on the requirements, various test methods and procedures are used during series production. Miba Cooling has its own testing laboratory and can run a variety of tests for its own products. We summarize the most important test procedures below.
An automated image analysis can be created with a thermal imaging camera. For this purpose, the cooling in the water cooler is visualized using a permanently installed infrared camera. The thermal imaging camera, which integrates evaluation electronics and image processing, captures a high spatial resolution and an exact temperature resolution of 0.5 °C. The clear advantage is consistent and reliable product quality with fault detection that does not require human intervention.
This method tests the thermal resistance and hydraulic pressure loss of liquid-cooled cold plates. For this purpose, Miba Cooling's Solution Team uses various coolants such as water, ethylene, or glycol. The test bench automatically records data and can also be used in combination with the IGBT test bench.
With our helium leak test bench, we examine the heat sinks for damage. Helium helps to find leaks more easily. The test is conducted with a so-called pressure probe. Helium leak testing is a highly sensitive test bench with a leak rate of up to 10-6 mbar.l/s.
With the ultrasonic measuring device, we use an echo meter for ultrasonic measurement of the wall thickness. The measurable range of wall thickness is 1.2 to 250 mm. Ultrasonic testing is used for easy and accurate measurements in easily accessible locations. For this purpose, a probe is placed on the material, the cooling plate, and the wall thickness is measured with an ultrasonic signal.
With the Zeiss 3D coordinate measuring machine (CMM), Miba Cooling can guarantee the stipulated dimensional requirements (drilling pattern for mounting high-performance electronics) during initial parts testing. In this way, we can immediately identify and avoid production errors. The heat sink is measured to an accuracy of +/- 0.8 μm. This also allows measurement of many small characteristics, which is not only more efficient, but also reduces production costs.
The correct surface roughness of a heat sink significantly influences its functional behavior and thus contributes to meeting the component’s thermal requirements. That is why we measure the roughness of the surfaces of our heat sinks (largest peak-to-valley difference — Rz, average roughness — Ra) with optical measuring devices.
The quality of the bonding of fins in an air-cooled heat sink is checked using the pull-out test bench; the required force is determined by pulling fins out of the profile.
The Miba Cooling Solution Team carries out a series of tests using the latest testing technology in the various phases of development and production. In this way, we reduce product development times and ensure product quality during series production.
In general, it makes sense to use different test methods when developing and creating new heat sinks. Valid and meaningful data on the thermal and mechanical development of components can help to improve the service life of our customers' power electronics while reducing costs.
All the data from the tests conducted is recorded in detailed and professional test reports. Borderline measured values can be detected early and reliably, enabling prompt rectification.