Inspection Insights Blog

Empty Container Leak Inspection: The 7 Most Asked Questions, Answered!

November 12, 2020

After 45+ years in the empty container leak inspection industry, here are the top frequently asked questions, and the answers, our subject matter experts receive in the field.



Leak Inspection Systems for Empty Plastic Containers

Empty plastic containers are manufactured in high volume to keep up with demands. Inevitably some containers will have defects that will cause leaks once the bottles are filled and shipped. Inline leak testing equipment tests plastic bottles as they move through the production line and automatically reject those with defects. By performing empty container leak inspection you identify issues before containers make it down the production line, minimizing the potential of recalls associated with container quality.

1. Why Do We Need to Leak Test?

Leak testing provides a functional test and verifies that each container will seal and hold pressure. Leak tested containers will provide a variety of benefits including:

  • Protection from random quality issues.
  • Monitors the blow molding process. Typically, the leak tester is the first machine after the blow molder, to detect and alert operators quickly to initiate corrective action.
  • Protects inventory and prevents of costly returns.

2. How Much Space Is Required to Integrate Leak Inspection into My Line?

You may be concerned with system integration and fitting within your existing manufacturing footprint.

Look for a solution that can be designed to work in unison with your existing production line. Leak detectors that can sit over the top of an existing conveyor or that can flush mount to a short conveyor section to transfer bottles on and off the detector can be ideal.

In addition, look for the ability to integrate additional inspections such as height, top-load and vision-inspection without sacrificing valuable floor space. Additionally, having optional sensors up-stream and down-stream of the line ensures the detector reacts properly to what is happening on the line for maximum efficiency.

The bottom line is that no matter your concern, work with a manufacturer that will work with your individual needs for guaranteed production success.

3. What Are the Different Types of Leak Testing?

The answer depends on the type of product you are testing and where in the process you are testing it. Are you testing filled or empty containers?

If you are testing empty containers that are not required to have a vacuum seal then pressure decay is the most efficient method. Pressure decay is also beneficial in applications where the lack of container stability allows the possibility of an empty container to collapse during testing.

If you’re testing a filled container or one that requires a vacuum seal then a vacuum decay test may be your best solution. Vacuum decay testing is a non-destructive test that detects leaks in nonporous, rigid, or flexible packages. Vacuum decay ensures that packaging containing items such as, food or beverage, are safe from possible container leakage after being filled and sealed.

While determining which type of leak testing is best for your application can seem challenging, picking a solution based on a few simple criteria can usually point you in a successful direction.

4. How Do I Know What Hole Size My Leak Detector Will Find?

Leak detectors from ALPS offer a built-in mechanism to test for reliability and hole size capability. But what if you do not have this available in your machines? You can create your own test with a test bottle you create.

First, do not physically “poke” holes in a bottle using just any sharp object. Depending on bottle temperature, material and thickness the hole will “close up” to some unknown size.

An alternative method is to drill and tap a 10-32 hole in the bottle and insert a calibrated orifice. Calibrated orifices come in a range of sizes, ensuring that you can challenge your machines to reject a specific hole size. After that, you can run your test bottle through your machine multiple times. Additionally, if you have a multiple station machine it is important to challenge every station.

Lastly, challenge your machine often. Test bottles are a simple, effective way to safeguard your inventory.

5. How Fast Can a Leak Detector Run?

The short answer is, as fast as you need it to, if it is an ALPS system. However, what matters most is accuracy in testing at the speed you need. You may have an leak inspection system that can handle the bottles at the speed you require, but that does not guarantee an adequate test.

For example, smaller bottles require less time for a pressure decay test. Larger bottles will require more time. An identical testing configuration of a larger container to a smaller container will not meet the same expectations. As a result, to keep up with production and guarantee accuracy in testing, additional stations may be required to test larger containers.

Do not settle for a leak test that barely meets your quality requirements. Among other things, hot production bottles and line delays can contribute to variations in test results making defects harder to identify. Protect your inventory and guarantee quality container-production by choosing the right leak detection system for your specific needs.

6. How Do I Protect My Product While Increasing Post-consumer Recycled Content?

If you use Post-Consumer Recycled material, or PCR, in your blow molding process, you know there are inherent risks.

Using PCR can cause pinholes and leaks in your container. During the blow molding process the walls of the container are stretched and particles of contamination can cause weaknesses, which results in holes in the container wall. The number of defects will depend on two things:

  1. The amount of contamination in the PCR resin
  2. The design and wall thickness of the preform and final bottle.

Leak inspection guarantees that only containers meeting your quality standards make it to your customer. 100% in line inspection will catch pinhole leaks, neck surface deformities, and height irregularities (including short shots).

Commitment to sustainability does not have to mean sacrificing product quality. Leak inspection provides the assurance you need to keep up with market trends, including increased PCR content.

7. How Do I Know Which Leak Detector Is Right for My Application?

When deciding which leak detector is right for your application, start by identifying a system that can handle these 3 things:

  1. The size and shape of the bottle,
  2. quality specifications,
  3. the speed of the production line.

As you keep these in mind, factor in bottle handling. How are the bottles presented to the tester? Should the test-head move with the bottle or would an indexing conveyor suffice? Will this platform need to have multiple test heads or require a rotary system to increase the allowed test time?

Think about how to minimize changeover time and complexity. Speaking about complexity, we all know good labor is hard to find. Ease-of-use is essential. Having an intuitive full-color user interface with a self-guided set-up lowers both the total cost of ownership and frustration on the floor.

Consider these factors, and for guaranteed success, now and in the future, partner with a company that manufactures multiple solutions that can be tailored for your applications and are supported by a service team that is available 24/7.

Have a question that you don’t see answered above, contact us and one of leak inspection experts will be in touch.