Ensuring Accuracy with Helium Leak Testing: The Noise in the Background

Helium leak testing: from airbags to air-conditioning units and fuel rails, from anything implanted in the body to hermetically sealed enclosures for integrated circuits, there are some instances where the acceptable leak rate is so small it’s practically zero. Since air leak test methods such as pressure decay don’t have the necessary detection range to measure such small leaks, these situations call for a trace gas-based test method.

Why Should I Use Trace Gas-Based Leak Testing?

Most air leak test methods measure leaks indirectly, through the change in a physical quantity (e.g. pressure change caused by a leak). The most sensitive detection range possible with this approach is approximately 1×10-3std.cm3/sec for very small parts.

Trace gas methods, on the other hand, measure leaks directly. This allows for a much more sensitive detection range as little as 1×10-9std.cm3/sec – roughly 1 millionth of the low limit of an air leak test.

Let’s have a closer look at a leak exposed to trace gas:

Trace Gas-Based Leak Testing

The charge side is pressurized with a trace gas while the concentration of the same gas will be measured on the detection side. In many cases, the charge side is the inside of a part, but there are some cases, especially when checking hermeticity, when the outside of the part is charged.

On the charge side, it is extremely important to ensure the highest possible concentration of trace gas at the inlet of the leak as the gas exiting the leak will have the same trace gas content. If the concentration is not high enough, the leak will have a very poor chance of being detected because the gas analyzer will only detect a concentration of leaking trace gas.

In direct contrast with the charge side, the detection side should have as low a concentration of trace gas as possible before the test begins. Why? Because leak detectors can’t differentiate between the trace gas exiting a leak and the concentration of the trace gas that is already present in the atmosphere.

Using the Hard Vacuum Method for Leak Testing

This method, which most often uses helium as the trace gas, allows for the detection of the lowest leak rates. The detection side in these systems is typically at less than 1Torr (mmHg) pressure, which is achieved using a vacuum chamber.

At the end of test, the chamber is under vacuum and needs to be brought back to atmospheric pressure. Whatever gas is present during the venting of the chamber will be the one outgassing in the subsequent test. Sound chamber design practices, such as minimizing surface area, eliminating trapped volumes and reducing complexity in general, are crucial to avoid trace gas build-up problem that can skew the accuracy of future tests.

Nitrogen Purge Technology with Leak Test

This method uses an inert gas (usually nitrogen) to “carry” the leak signal from an isolated test area into a leak detector probe that samples the trace gas concentration. Because the inert gas replaces the atmosphere inside the chamber, background trace gas levels are minimized. Instead of using seals to isolate the test area from the outside world, another technology uses a gas seal created by a very small flow of nitrogen around the perimeter.

The nitrogen purge approach creates a test zone around the entire part, or a particular area of interest (e.g. joints, ports, etc.). It allows testing for leaks at a level that is comparable to a mid-range hard vacuum system without the need to create a vacuum around the test area.

Important Considerations for Using Atmospheric Methods

Atmospheric methods have gained market share over the past decade due to their lower cost and complexity. Improvements in background suppression/elimination techniques have also made these methods feasible alternatives where hard vacuum testing was once the only reliable option.

Using signal processing (zeroing) to minimize the effect of the background is very common. It is a useful feature when trying to find small leaks in a trace-gas rich environment, but it does come with a few caveats. When the zeroing function is activated, the leak detector stores the leak rate as the tare value and begins to subtract it from the readings. If the background was steady, the proper leak rate would be indicated. But because the background level is dropping, AND the measured leak rate never got below the level measured when the leak detector was zeroed, the leak detector will show a dropping leak rate, eventually no leak at all!

Due to the potential difficulties described above, many manufacturers and quality engineers prefer physical background reduction techniques. These vary by test method and can include using sniffer leak detectors or accumulation methods.

All trace gas-based test methods depend heavily on sound gas management practices. Paying attention to these details when designing a test system can save many headaches during the commissioning of the system and in production.

QualityWorX CTS DataHub: CTS and Sciemetric Release New Joint Product

QualityWorX CTS DataHub: CTS and Sciemetric have launched a new product that gives customers a simple, cost effective tool for analyzing leak test data and performing test-to-test comparisons.

19 July 2018—Harrison, OH—Cincinnati Test Systems (CTS) and Sciemetric are pleased to announce the development of a new joint product that aggregates data from multiple CTS Leak Test Instruments into an analytics database for real-time usage. The QualityWorX CTS DataHub helps users find answers to the causes of leak defects and helps optimize leak tests to meet quality, yield objectives. The system helps extend quality solutions for leak tests and monitor all processes on your production line to identify defects as they occur, so you can resolve them in a quick and cost-effective manner. Find out exactly which operations are causing leaks and use the reports to make data-driven decisions that will optimize performance.

QualityWorX CTS DataHub QualityWorX CTS DataHub features an easy setup with no software installation required. Within minutes you can start monitoring, managing, comparing and optimizing the performance of several leak testers from a single location and provide traceability at the station. The QualityWorx database is capable of handling data from up to 5 Sentinel instruments and provides up to 10 GB of active storage for quick data retrieval. The data is stored in a hierarchal tree structure to mimic line layout and provides the ability to drill down to a single part or test history.

Advantages and features of QualityWorX CTS DataHub include:

  • Collects data from multiple instruments, whether they’re part of the same station or located in different sections of the manufacturing process
  • Features a full turnkey package and easy setup that allows you to start collecting and analyzing data right away
  • Includes all test and parts data to provide full traceability, including digital process signatures
  • Utilizes advanced analytics software to visualize your data and analyze trends

QualityWorX CTS DataHub collects data from several CTS instruments starting with Sentinel I28 in July 2018, followed by C28, LPC 528 and Blackbelt in Fall 2018.

CTS and Sciemetric have over 110 combined years of experience and have installed 30,000 systems worldwide. Together, we are working to deliver innovative Manufacturing 4.0 solutions that will help manufacturers turn data into insight so they can build better products.

Visit CTS at www.cincinnati-test.com to learn more about other QualityWorX data management and manufacturing analysis software.

Electric Drive Assembly Testing: 2-Station Test System with Volumetric Fill & Pressure Decay Technology

Electric Drive Assembly Testing: In need of a way to leak test their automotive electric drive assemblies, a customer recently contacted Cincinnati Test Systems (CTS) for a solution. The parts were completely sealed, meaning that certain testing processes were not feasible. With that in mind, we provided a volumetric fill/pressure decay leak tester that is designed specifically to test sealed parts.

To maximize the customer’s testing throughput, we built a two-station, manual loading system that enables two tests to be run simultaneously. The design allows for loading/unloading of a part in one station while the other is performing a leak test; both stations can perform tests at the same time, if needed. Part loading and unloading is quick and easy, taking just a few seconds per part. These factors combine to give the customer nearly double the productivity of a single-station tester.

Flow Testing SolutionsElectric Drive Assembly Testing: Reliable Two-Station Testing with CTS Sentinel I28 Leak Test Instruments

Each test station features an independent Sentinel I28 leak test instrument. The entire system is controlled via a single, easy-to-use Siemens Simatic interface. The I28s perform and monitor testing, and all messages are communicated to the Siemens HMI and displayed on the operator panel. An integrated bar code scanner at each test station identifies and tracks parts during testing, and any rejected parts (those failing the leak test) are tracked and stored in a secured drawer.

Once a part is loaded and the test is initiated, the bar code scanner automatically reads the part ID to ensure that the part is being tested using the correct test program. The part is then clamped, the test chamber is sealed, and the leak test begins.

Each leak test is a two-step process. First, volumetric fill testing determines the part has a gross leak, as determined by pre-set upper and lower pressure limits. A part that passes the gross leak test moves on to pressure decay testing. Pressure decay testing checks parts for fine leaks, based on a pre-set leak rate pressure level.

A part that passes both tests is indicated with an “ACCEPT” message and illuminated green lights; if a part fails either the gross or fine leak test, the test cycle ends with a “REJECT” message and red illumination. This provides an all but foolproof method of monitoring good and bad parts. Additionally, all test results are automatically recorded and saved in the I28’s internal, time-stamped memory log, and are uploaded to the Siemens controller.

The World’s Best Leak Test Instruments

Cincinnati Test Systems is a world leader in the design, engineering, and manufacture of high-sensitivity leak test instruments. Our versatile and easy to use leak test systems provide accurate and reliable results in even the most demanding applications. Contact us today to discuss your leak testing needs.

CTS Solutions: Hard Vacuum Mass Spectrometer Test System with Tracer Gas Technology for Refrigerant Expansion Valve Testing

Cincinnati Test Systems (CTS) had customer in need of a test solutions: leak testing their refrigerant expansion valves. The customer needed to verify that the assembly was assembled correctly and that all the joints were leak tight. To meet the micro-leak rate specification, CTS provided a single-station mass spectrometer hard vacuum system that included a TracerMate CS instrument that functions as the gas management, system control, and test execution element. The test system uses concentrated helium as the tracer gas for leak identification, and an Inficon LDS3000 as the integrated helium gas detector.

The refrigerant expansion valve that the customer was testing features inlet and outlet ports with which to connect to the main HVAC assembly, and those ports were used to pressurize the valve for leak testing. The leak test system’s vacuum chamber is used to isolate the part from ambient atmosphere and to create a clean background for gas sampling. The test system includes two built-in leak standards: one for calibrating the system, and one for calibrating the sensitivity of the LDS3000 prior to each test cycle.

CTS TracerMate CS Inficon LDS3000CTS: Easy, Automated Leak Testing with Recorded Results

The part is loaded into the system’s test chamber, where vacuum is pulled to remove background atmosphere from the chamber and the part itself. The chamber is then isolated for testing and the part is pressurized with helium for blockage testing. After blockage testing, a gross leak test is performed using the Inficon LDS3000. If the gross leak test is passed, a fine leak test is initiated, again using the Inficon unit.

The TracerMate CS instrument makes it easy for the operator to not only execute the test cycle, but also to view and record the results. After loading the test part, one push of a button is all that’s needed to run all three test cycles. If the tested parts pass inspection, a green LED illuminates and an “Accept” message appears on the instrument’s display; if the parts fail, a red LED lights up and a “Reject” message appears on the display. Pass/fail results don’t get much easier to interpret than that! The TracerMate unit also automatically saves and time-stamps all test results in its internal test log memory.

CTS: The World’s Best Leak Test Instruments

No one engineers and manufactures better, easier to use, or more versatile leak test systems than Cincinnati Test Systems. With our full line of reliable and accurate leak test instruments and the option to integrate Inficon modules or other components, we can provide a high-sensitivity leak test solution for nearly any application. Contact us today to discuss your leak testing needs.

Apple CEO Tim Cook Visits CTS

Apple CEO Tim Cook Visits Cincinnati Test Systems

On August 24, Cincinnati Test Systems’ facility in Harrison, Ohio, received a very special visitor. Apple CEO Tim Cook stopped by to meet with employees on the manufacturing floor and to offer thanks for the CTS technology that helped make the iPhone 7 and iPhone 7 Plus the world’s first water-resistant smartphones.

“We couldn’t have done it without you,” Cook said in a brief speech during his visit, adding, “You’re a testament to all great things than can happen in this country. This is where we get inspiration to go onto the next thing.”

Cincinnati Test Systems and Apple have been working together since 2014, when the tech giant approached CTS with the task of building the first-ever leak testing system specifically designed for smartphones. To meet this challenge, we developed the MH high-pressure test system, which Apple uses to test iPhones and other smart devices for water resistance.

Cook later tweeted: “Thanks to the team at CTS in Cincinnati, manufacturers of best-in-class testing equipment for Apple.” Coming from the head of one of the world’s leading technology innovators and manufacturers, that’s high praise indeed.

CTS’ Worldwide Service & Support

Worldwide Service & Support: Cincinnati Test Systems (CTS) offers more than just the industry’s best production test systems—we also provide world-class customer service and support. With over 35 years of experience, and over 30,000 test instruments in action around the globe, we have the expertise to repair and restore your system to peak performance. From our 24/7 call-in service center to onsite equipment repair, we offer a broad range of service to meet your needs.

Worldwide Service & Support from CTSPreventative Maintenance Programs

To keep your operation up and running and help you avoid costly breakdowns, we offer preventative maintenance service for all CTS test equipment, as well as for other manufacturers’ equipment. Our preventative maintenance programs allow you to schedule service at the time that works best for your production schedule.

24/7 Call-In Center

We know how important customer service is, and to that end, our call-in customer service line is available 24 hours a day, seven days a week. A knowledgeable, factory-trained technician will answer your call, provide insights into what the problem with your CTS device may be, and offer solutions for how to fix it.

All our call center technicians have access to the CTS Sales Order Database, which allows them to quickly familiarize themselves with your system, its design, and its service history. CTS technicians can help you resolve problems, order parts, or schedule onsite service. Our 24/7 customer service line can be reached at 888-412-8033.

Leak Standard Recertification

CTS offers factory Leak Standard Recertification for all commercially-manufactured air and helium leak standards. When calibrating a leak test to a Leak Standard, the Leak Standard must be certified to provide the flow rate or helium concentration rate at one or more specific test pressures. We will check your leak standard and recalibrate it to its “as manufactured” leak rate specification at our CTS factory.

Our calibration lab is A2LA accredited (certificate number 1667.01) and ISO 17025 certified to ensure that the strictest controlled calibration procedures are followed in the manufacturing process, using instruments that are NIST-traceable.

Factory & Onsite CTS Customer Training

Training your operators and maintenance team to operate and maintain your leak test equipment can be key to your ongoing success. CTS can provide complete onsite training and customer support at your facility. Onsite training programs can be customized to the needs of your leak test system before or after your equipment goes online.

Sentinel Instrument Recalibration

For many who use CTS technology, annual instrument recalibration is mandatory to keep their quality standards up-to-date and to ensure that completed parts meet specifications. To help you maintain the accuracy of your CTS Sentinel leak test device, we offer both factory and onsite instrument recalibration services. Click here for more information.

Additional Worldwide Service & Support

In addition to these services, CTS also offers:

  • Installation start-up assistance
  • On-site equipment repair
  • New and replacement industrial seals
  • Spare parts
  • and more

Contact Cincinnati Test Systems for more information or to schedule service for your leak test equipment.

Sentinel Instrument Recalibration

Is your Sentinel leak detection system up-to-date and calibrated correctly? Cincinnati Test Systems (CTS) offers factory and onsite instrument recalibration that is fully traceable to NIST standards.

Factory or Onsite Leak Test Instrument Recalibration

For many users of CTS products, annual inspection of their leak test devices is mandatory to keep their quality standards current and to ensure that all completed parts meet specification prior to shipping. To your customers, regularly recalibrating your Sentinel leak test instruments demonstrates your commitment to quality and guarantees that part testing is performed with NIST-traceable accuracy.

Recalibration MachineTo keep your instrument(s) calibrated properly, we offer both CTS factory and onsite instrument recalibration services.

  • For CTS factory recalibration, simply disconnect your CTS leak test instrument and ship it to our facility for service and calibration.
  • For onsite recalibration, a CTS service technician travels to your facility for a scheduled service call. Onsite instrument calibration offers the advantage of reduced machined downtime, which helps get your instrument back in service with minimal delay.

Features & Benefits of CTS Recalibration Service

Our specially trained technicians will perform a thorough inspection and run the Sentinel’s self-test program(s) to determine the overall “health” of your instrument. A complete instrument system backup will be saved to a USB flash drive before and after calibration.

All CTS factory and onsite leak instrument recalibration services include testing of pressure and flow circuits to determine instrument accuracy across all pressure ranges. Each transducer range will be digitally recalibrated using multi-point pressure calibration and multi-flow flow calibration (if your system is so equipped).

All recalibration procedures are performed with certified gauges and are traceable to NIST standards. Upon completion, we will provide a CTS Recalibration Summary Certificate to document “as found” to “as left” specifications.

Contact Us to Learn More!

For more information, or to schedule factory or onsite recalibration for your Sentinel leak detection system, contact Cincinnati Test Systems today.

Sealed Device Leak Testing

What Is Sealed Device Leak Testing?

Sealed device leak testing is a method of leak testing “sealed” products that don’t have ports, valves, or any other way to apply pressure or vacuum for testing purposes. A dry and nondestructive test process, it is an effective way of ensuring that sealed products truly are sealed against contamination and leakage, and is especially important for parts that require IP67 classification.

How Does Sealed Device Leak Testing Work?

The best way to leak test your sealed products is via volumetric fill testing using Cincinnati Test Systems’ Sentinel I28 leak test instrument. To perform this type of test, the sealed device is first placed in a test chamber. The chamber is sealed, and air or vacuum is used to charge the chamber to the required test pressure. The Sentinel I28 unit monitors pressure changes inside the test chamber, with changes in pressure used to measure leak rate to determine the pass/fail condition of the part in test.

Any change in pressure indicates that either the object under test is leaking air into the chamber (if under vacuum) or that air from the chamber is infiltrating the object (if using pressurized air). If the pressure change is less than the tested product’s leak rate specification, the product passes the test; if the pressure change is greater than the specification, the product has failed.

Gross Leak Testing vs. Fine Leak Testing

Sealed devices can be tested using two different processes: gross leak testing and fine leak testing. In gross leak testing, air travels into the test chamber via the chamber’s isolation valve, and pressure is equalized between the chamber and the reference volume tank. Gross leak testing provides almost immediate results.

If a sealed device passes the gross leak test, it can then undergo fine leak testing. A fine leak test measures pressure loss in the test chamber over an extended period of time. The test chamber’s isolation valve is closed, and pressure inside the chamber is monitored for gradual loss. If the pressure drop over the programmed test time does not exceed part specifications, the part has passed the test.

Our Sentinel I28 leak test system can be used for both gross leak testing and fine leak testing, and can be programmed to perform both tests consecutively for fast, complete sealed device leak testing.

Request a quote on a Sentinel I28 system, or contact Cincinnati Test Systems to learn more about our sealed device leak testing solutions.

Click here for more information.

CTS Solves Brazed Joint Leak Testing Conundrums

Recently, an HVAC systems manufacturer was faced with a unique challenge with leak testing: they needed a way to leak test the brazed joints in one of their products at final assembly. With multiple joints of varying sizes, all of which need to be tested to rates of 1/10 ounce of refrigerant loss per year, the HVAC devices proved difficult to test by other methods. “Sniff-type” leak testers were not accurate or repeatable enough, and prior testing of similar products lead to consistent false leak failures that cost the company time and money.

Seeking an effective and reliable solution, the HVAC company turned to Cincinnati Test Systems.

A Customized Nitrogen Purge Test System

To provide the leak testing capabilities required, Cincinnati Test Systems (CTS) designed a customized solution based on our patented Nitrogen Purge leak detection technology. Built into a hand-held, clam shell casing, this custom leak tester is easy to maneuver and clamp over the brazed joints for testing.

Nitrogen purge testing provides dependable background control, and can reduce or eliminate the need for hard vacuum testing. Our nitrogen purge technology improves sensitivity in sniff-type leak detectors, reducing background to roughly 10-6 atm-cc/s for micro-leak detection and reliable repeatability. CTS offers this technology in both hand-held and benchtop configurations.Leak Testing Hand Held Clam Shell

This customized leak testing device features inner and outer chambers that surround the part test area. Ports in the chambers allow low-pressure nitrogen to fill the cavity, forcing out ambient atmosphere and creating a “helium-free” test environment for sampling and micro-leak detection.

The inner chamber of the leak tester collects tracer gas as it leaks through the part’s brazed joints. The outer chamber provides testing isolation by maintaining a low positive pressure nitrogen curtain that prevents ambient atmosphere from reentering. This atmosphere isolation improves testing sensitivity and accuracy while eliminating false leak failures.

TracerMate CS Provides System Controls

This customized leak tester uses CTS’ TracerMate CS tracer gas management system to control system evacuation, test pressure, gross leak test, tracer leak backfill, and system exhaust processes. The TracerMate CS module also makes it easy to integrate a mass spectrometer helium detector for additional control, management, and testing functions.

The Leak Test Experts

CTS provided a custom nitrogen purge solution for the HVAC manufacturer’s unique leak testing challenge. We offer standard and custom leak test devices, and will work with you to find the perfect solution for your application. Contact us today to discuss your leak testing needs.

TracerMate Leak Location System Provides Low-Cost Leak Isolation for Loop Applications

Cincinnati Test Systems has integrated the INFICON Sentrac hydrogen leak detector into our benchtop TracerMate leak location system to provide a low-cost atmospheric leak locating system. The TracerMate unit is used to execute and manage evacuation, backfill, and testing sequences with integrated pneumatics. The Sentrac INFICON hydrogen gas leak detector provides a wide range of test sensitivity for small, medium, and large leak detection.

By integrating these two instruments, CTS provides the capabilities to locate and isolate a leak with a high degree of accuracy using a simple handheld probe. This probe monitors the PPM (parts per million) of hydrogen in the air around the part, using an electronic hydrogen sensor calibrated to detect concentrations of hydrogen gas higher than normal background levels.

TracerMate leak location systemLeaks are reported by leak rate volume, with an audible alert and color status light. Pre-configured for quick and easy operation, the TracerMate system is capable of properly evacuating parts to ensure proper pressurization so that the tracer gas reaches a leak path quickly. At the end of the test cycle, the TracerMate re-evacuate and vents the part to control hydrogen background in preparation for the next test cycle.

The TracerMate CS is ideal for production and repair loops and other applications where part assemblies fail final inspection due to leaking seals and/or leaking component parts. For customers who require testing using other tracer gases such as helium, the system can communicate with other leak detection devices used for sniffing or tracer gas accumulation testing.

Cincinnati Test Systems will be demonstrating the TracerMate CS system at our exhibitor’s booth (#N10838) at the upcoming AHR Expo. The 2017 AHR Expo is scheduled for January 30 through February 1, 2017 in Las Vegas, Nevada. Plan now to stop by and see our leak test technology in action.