Automakers and their suppliers will invest billions of dollars in manufacturing and assembly operations to meet the growing demand for electric and hybrid vehicles in the next 10 years.

In the process, some manufacturers have found that they can recycle equipment used to produce internal combustion engine parts to manufacture electric vehicle-related components, thereby saving a lot of time and money.

Nowadays, leak testing helps improve quality and reduce warranty costs for key components that are an important part of the production process. As the industry transitions to electric vehicles (EV), these tests will become more important.

For example, electric vehicle sensors and other electronic devices are more sensitive than components in vehicles powered by internal combustion engines and require tighter tolerances. Thomas Parker, INFICON's North American automotive sales manager, said that the EV leak detection system needs to meet more stringent performance requirements. They must also adapt to changes in vehicle structural design, material use, and key transmission systems.

Some manufacturers find that they do not have to purchase a brand new leak detection system. Automakers and component suppliers are learning that they can save a lot of time and money by reusing and modifying existing ICE (internal combustion engine) equipment for electric vehicle applications.

The reuse of robotic leak detection systems can reduce costs by as much as two-thirds. A brand new system may cost US$500,000 to US$1 million or more, so it can save a lot of money.

INFICON is a company cooperating with KUKA, which is the first in North America to develop and switch to an automobile leak detection system. Chip Darling, head of technical experts at the KUKA Product Performance Group in Michigan, points out that the benefits of recycling can exceed the cost of the basic test bench. Additional savings will come from the reuse of gantry, processing lines and other equipment and floor space.

"The company wants to make the most of what they already have," Darling said.

"But of course, there must be a solid business case. Our job is to find the best solution and show the facts to our customers."

The first step in converting a leak detection system to an EV program is to conduct a process capability study, including a detailed analysis of equipment, vehicle design specifications, and leak test requirements.

"Companies need to know the capabilities of their current leak detection systems and compare them with the new plan's requirements for test sensitivity, speed, and repeatability," Parker said. "Electric vehicles may require lower leakage rates, faster cycle times or different metering certainties."

Engineering research will determine what can be reused and what changes need to be made. From new vacuum pumps and larger chambers to different sealing tools or additional processing steps, everything needs to be considered. The robotic leak detection system will include test benches and subsystems, such as programmable logic controllers, tracer gas vacuum processing units, and test instruments. All of these can be modified to varying degrees.

Depending on the size and complexity of the system, it can be modified directly in the manufacturing plant, or it can be modified off-site by the test unit supplier. The work itself may take several hours to several months.

After the equipment is updated, the prototype EV components will be tested to prove that the new equipment is operating as expected. This means detecting leaks and proving that the process and measurements are repeatable within the specified time limit.

INFICON and KUKA worked together to install their first modified EV leak test system at the end of 2020. The modified device is being used in a transmission plant in Michigan, which is converting from a traditional automatic transmission to a single-speed device.

Due to the high operating temperature, the EV gearbox has internal glycol-water cooling circuits, while the automatic ICE gearbox does not have these circuits. "Electric vehicle fluids, sensors, and pressure rates all require low leakage rates," Parker said. "Problems that are not found through proper leak testing during the manufacturing process can easily lead to costly and more serious problems after the vehicle is put into use."

KUKA's modified transmission test system required improved sealing tools and extensive changes to the vacuum processing chamber, partly due to changes to the central motor housing. Only minor changes are required to the existing control system and INFICON's LDS 3000 helium leak detector.

Darling said that although the number of cavities tested in the new EV gearbox is less than half, the layout is more challenging because the openings of the electric drive and the controller are adjacent. "We have to check the external leakage of each cavity and the internal leakage between them. The stakes are also higher. The external oil leakage of the automatic transmission may cause warranty issues, but the premature failure of the electric vehicle control unit can be catastrophic. of."

The test changes of the new retrofit system are relatively simple, but they require a lot of re-pipelines and new process sequences. KUKA completed the renewal of its electric vehicle transmission plan at a plant in Michigan in approximately 12 weeks.

Hardware changes are the easiest part of the repurposing process. Parker said that the bigger challenge is to change the manufacturing culture and make people accept that EV gearboxes are different from multi-speed automatic gearboxes.

"Switching to EV component testing requires a real learning curve," he pointed out. "Everything leaks in different ways. We educate customers on the theory of leakage rates and how aluminum pore leakage is different compared to mechanical fasteners or welded joints. This takes time, but ultimately customers will realize that cast aluminum Pore ​​leakage in the housing is different from welding leakage or rotating seal leakage."

Helium leak testing also has some teachable moments. The helium system is ideal for EV components with a leak rate tolerance of up to 30%. The company found that they could not meet the more stringent requirements of EV gearboxes with pressure decay or air testing systems. A cost-saving option is to mix helium with air. This mixture is not as accurate as pure helium, but it is more economical. For example, INFICON's LDS 3000 can detect these two gases.

"Advanced test systems can also be integrated into emerging Industry 4.0 modules," Parker said. "Leak detection can provide important data to help companies identify potential quality issues and make more informed decisions." For example, INFICON provides flexible bus modules and device-specific connections. This feature can be added during the reuse process, which allows information to be shared with production equipment and operators to quickly identify potential problems and make changes immediately.

"The more data you have, the better you can use it," Parker added. "Leak testing is very suitable for Industry 4.0."

The transition to electrified drive systems is progressing smoothly in Asia and Europe, and it is gaining momentum in North America. U.S. electric vehicle sales are expected to double in 2021, accounting for 3.5% of the new car market, higher than last year's record of 1.8%. By 2025, the market share of electric vehicles is expected to reach 10% and continue to grow by the end of the decade.

Parker predicts that the repurposed leak detection equipment will follow a similar growth path. It is currently possible to retrofit more than 100 systems in North America and 1,000 systems globally.

"Now, it's all about cost-effectiveness and fast-tracking," he concluded.

Edited by industry report editor Bill Koenig based on materials provided by INFICON