An automated helium leak test system must identify parts that exceed the specified leak rate before they leave the production line. Spectro Physics, based in Roy, Utah, reports more than 300 systems in operation, each configured for the parts and leak-rate limits its customers need to verify.
Start with the leak rate the part must meet and what a false accept would cost. Those requirements point to the test method and, together with the line’s output, set the chamber size, detector configuration and cycle time the builder must demonstrate before acceptance. A medical device component may need a stricter reject limit and more detailed records than a refrigeration coil, for example. Part identification, recordkeeping, calibration and maintenance belong in the same specification and should be settled before the system is built.
How an automated helium leak test system works on a production line
An automated helium leak test system uses helium as a tracer gas. A mass spectrometer leak detector measures the helium escaping from the test part, and the system compares that leak rate with the specified limit and records a pass or fail.
In a vacuum chamber test, the chamber is evacuated after the part is sealed inside. Helium goes into the part through a fill port or, for a sealed component without one, during an earlier bombing step. Any helium escaping into the chamber reaches the mass spectrometer, which measures the leak rate. The automated station loads and unloads parts and routes rejects away from accepted production.
Helium makes up about 5 parts per million of the atmosphere, so the detector works against a low background when it picks out helium escaping from a test part. Its small atomic size also helps it pass through fine leak paths.
Spectro Physics builds custom leak detection systems for medical device, life-support, automotive and other manufacturers in the United States and Mexico. The company reports that some installations have exceeded tens of millions of test cycles.
Set the reject limit and the false-accept rate first
The reject limit, the leak rate above which a part fails, should come from the part’s function and the consequences of a leak in service. A false accept lets a leaking part pass and possibly reach a customer, while a false reject pulls a conforming part out of production, adding retest time and sometimes scrap.
Specify the maximum acceptable false-accept and false-reject rates, then agree with the builder on the test procedure, production conditions and statistical evidence that will demonstrate each one. Detector checks against a calibrated leak standard and challenge tests on master parts with known leaks come first, and production data later shows how often the system accepts or rejects parts under the agreed conditions. A datasheet sensitivity figure is only one input to that evidence.
An independent statistical study by one large user of Spectro Physics equipment found a 1-in-100-million chance of the system on its line passing a bad part, under that customer’s part and test conditions.
“A lot of people talk about one in a million,” said Greg Hill, operations manager at Spectro Physics. “You need a couple more zeros on that. A lot of our systems are testing life-saving equipment, and it’s critical that bad parts just aren’t shipped.”
Match the test method to the part: vacuum chamber, sniffer, accumulation or bombing
Method selection depends on the part’s construction, the required leak rate and whether the test must locate a leak or only confirm whether one exists.
- Vacuum chamber testing measures total leakage from a helium-filled or previously bombed part. It gives a pass/fail result but does not locate the leak.
- Sniffer testing uses a probe to find escaping helium on a pressurized part’s surface, which makes it the choice when the leak’s location matters.
- Accumulation testing measures helium collected around a pressurized part over a defined interval.
- Helium bombing introduces helium into small sealed parts without access ports before they are leak tested.
Pressure decay is suitable when it can verify the specified leak limit within the available cycle time. Larger part volumes, temperature variation and short test windows can make that difficult, prompting manufacturers to evaluate helium testing. Spectro Physics puts the practical floor for pressure decay at leaks of about 10-3 mbar·L/s, compared with leaks as small as 10-12 mbar·L/s for helium detection.
For high-volume production of small sealed parts, Spectro Physics combines helium bombing with automated leak detection. Operators can prepare up to several hundred parts in one batch, while the detector tests smaller batches, and the bombing stage is sized to keep pace with the detector.
Before choosing a method, have the builder test representative parts at the required leak limit and production cycle time.
Size chambers and detectors to the line's throughput
The specification starts with the required good parts per shift and the station’s available cycle time, plus every part number the system must accommodate and the expected retest rate. Loading, unloading, changeovers and retests all belong in the builder’s throughput estimate. Depending on the part and the required output, Spectro Physics configures its systems for single-part or batch testing.
In January 2026, Assembly magazine reported that Spectro Physics built a system that tests eight EV pouch batteries at once using an Inficon ELT3000 leak detector and insulated chambers designed to prevent electrical shorts.
Specify the conveyor, robot and control-system interfaces alongside the leak test cycle. Where a line needs it, Spectro Physics can build robotic or pick-and-place handling into the system itself.
Part-level traceability belongs in the first specification
Specify how each part will be identified and how its test result and final disposition will be recorded. For manufacturers of medical devices and life-support and safety products, that record supports their own quality and regulatory requirements and lets them show which parts passed, when and on which equipment. For U.S. medical device lines, FDA’s Quality Management System Regulation, in effect since Feb. 2, 2026, incorporates ISO 13485:2016, whose clause 7.6 covers calibration of measuring equipment and validation of measurement software.
Spectro Physics says its systems can integrate barcode scanners and RFID antennas and can accommodate traceability requirements so every tested part is properly dispositioned. The specification should identify where records will reside (a local database, the plant’s manufacturing execution system or both), which fields they will contain and how long they will be retained. It should also cover interrupted cycles, rejected parts and test program changes, so the record identifies the result used to determine each part’s disposition.
Plan calibration and maintenance before the system ships
A calibrated leak standard provides a known leak rate for checking the detector’s response. If its certified value is inaccurate, the resulting checks may give a misleading picture of detector performance. The standard’s calibration certificate should state the measured leak rate, the uncertainty of that measurement and the traceable standards the laboratory used.
Before acceptance, agree on the detector-check procedure and its pass/fail tolerance, and build both into the system’s installation, operational and performance qualification (IQ/OQ/PQ). The procedure should also specify corrective action after a failed check, including how the manufacturer will identify potentially affected production.
Spectro Physics distinguishes between calibrating the leak standard at a laboratory and checking the detector against that standard, and the company reports that annual calibration is the most common interval it encounters. The interval still depends on the application: standards used to control or monitor a process are generally calibrated more often, the cost of a failure weighs more heavily in safety and medical device production, and a reservoir leak’s interval also depends on how fast its gas depletes. Ask the supplier what interval it recommends for the application and why.
Spectro Physics operates a calibration laboratory accredited by A2LA (certificate 6461.01) to ISO/IEC 17025:2017 that calibrates new leak standards and recalibrates leak standards from all major manufacturers, including leaks it did not make. The company can therefore supply the test system and also calibrate the leak standard used to check its detector.
Request the preventive maintenance schedule before purchase, along with the spare-parts list and an allocation of maintenance responsibilities between plant staff and the builder. Spectro Physics says it designs its systems to be low maintenance and supplies replacement filters and valve rebuild kits for them.
Questions to ask a custom leak test system builder
Settle these with each builder before requesting quotes:
- How will the false-accept rate for our part be demonstrated, and with what data?
- Which test method do you recommend for this part, and why not the alternatives?
- What throughput will the design sustain at our cycle time, including load, unload and retest?
- How does the system identify each part, and where are test records stored?
- Which calibrated leak standard does the detector check, who calibrates it and how often?
- Which maintenance parts do you supply, and how is the system adapted when a new part design arrives?
- What is the build and delivery timeline?
Frequently asked questions
Question: How long does it take to build a custom automated leak test system?
Answer: In a January 2026 Assembly magazine article, Spectro Physics owner Dwane Williams estimated the company could deliver an automated leak testing system for EV batteries as fast as 20 to 26 weeks, if the leak detection hardware and PLCs are available, and a machine similar to a previous build for pouches of similar size and throughput maybe even as fast as 16 weeks.
Question: Can one automated leak test system handle a new part design?
Answer: One system can test a new part design once its chambers, fixtures or test programs are adapted to it. Spectro Physics says new chambers for new part styles are among its most common requests, and it adapts new chambers to fit existing Spectro Craft systems. When specifying a new system, ask what each of those changes costs in time and engineering.
Question: What should a manufacturer have ready before requesting a quote for an automated leak test system?
Answer: Have part drawings/models or samples ready, along with the required leak limit and throughput. Include the station’s available cycle time, the part numbers to be tested and the interfaces needed to connect the system to existing production equipment and data systems. Spectro Physics takes quote requests through its website.