Cartridge-actuated devices (CADs) and propellant-actuated devices (PADs), also known as squibs, are small explosive devices that are critical for a wide range of applications across industries such as aerospace and military. Organizations within these industries depend on a squib’s safety, reliability and operational effectiveness for their critical applications.

In-process testing is crucial to building confidence in a squib’s functionality and safety. It involves various testing methods performed frequently throughout the manufacturing process to assess component and material quality, as well as product performance and reliability.

What Is In-Process Testing?

In-process testing verifies a squib’s reliability and safety as it is being manufactured. Its purpose is to detect issues in components or materials early on to prevent defective products from progressing through production. Testing can be performed at set intervals, such as hourly or daily, or it can be based on the quantity produced.

In-process testing offers benefits such as:

  • Waste reduction: Detecting defects early minimizes waste due to rework later in the manufacturing process.
  • Quality assurance: In-process testing monitors every stage of production to maintain strict quality and performance standards and specification compliance.
  • Safety improvements: Through continual checks and tests, in-process testing ensures each CAD/PAD functions correctly to prevent accidental detonations.

In-process testing works alongside other testing methods to ensure CAD/PAD safety and reliability. Where in-process testing checks product quality throughout manufacturing, end-of-line testing validates the final product’s functionality before shipping or delivery.

Environmental testing assesses the product’s performance under various environmental conditions, including rapid temperature or altitude changes. In-process testing prepares squibs for destructive and non-destructive testing to ensure the products are able to perform at their best.

The Importance of Confidence Testing

There is no room for error in CAD/PAD performance. These squibs must reliably operate as expected, when expected, to ensure safety. They are critical components within a variety of products, including emergency devices that need to deploy immediately without interruption. Operational precision is vital for these controlled explosions.

In-process testing is an integral component of confidence testing, which builds confidence in a product’s overall performance and reliability throughout its intended life span and in its operational environment. Confidence testing generates statistical proof from failure rates and performance metrics to demonstrate that the product will perform as designed.

Confidence testing depends on accurate in-process testing results across manufacturing procedures. False positives and negatives can lead to a wide range of issues, from unnecessary rework and increased costs to safety risks and compliance issues. Robust in-process testing methodologies establish greater trust in final product quality.

In-Process Testing Techniques for Squibs

In-process testing is performed on CADs/PADs through various methods, including electrical testing, visual inspections, functional testing, leak testing, ballistic testing and propellant stability testing.

Electrical Testing

Squibs depend on reliable electrical features to ensure proper performance and safety. Electrical testing assesses CAD/PAD functionality throughout assembly to monitor electrical components and confirm that they operate as intended.

Electrical testing may include:

  • Resistance testing
  • Continuity testing
  • Insulation resistance testing
  • Voltage testing
  • Functional testing
  • Endurance testing
  • Current measurements

Visual Inspection

Identifying defects early in the manufacturing process can save time, reduce waste and ensure product safety. Visual inspections are a simple yet key component to squib quality assurance.

A visual inspection looks for physical defects or abnormalities such as:

  • Cracks
  • Dents
  • Scratches
  • Welding defects
  • Corrosion
  • Deterioration
  • Part misalignment
  • Other visible issues that would inhibit future installation and functionality

Functional Testing

Functional testing verifies the squib’s performance under controlled conditions. It simulates future operating environments to ensure the squib will function as expected. Functional testing may check factors such as:

  • Burn rate
  • Ignition time
  • Initiation energy

Leak Testing

Leak testing ensures the integrity of each CAD/PAD component to prevent leaks. It verifies that the squib’s enclosure is sealed properly so that it can function safely and as intended without any interruptions from a leak. By detecting manufacturing defects early, leak testing catches issues that could jeopardize a squib’s operation.

Leak testing is performed through:

  • Visual inspections
  • Pressure testing
  • Vacuum testing
  • Helium leak testing
  • Bubble testing
  • Dry penetrant testing

Ballistic Testing

As a type of destructive testing, ballistic testing evaluates how CADs/PADs perform against ballistic threats and other extreme conditions by simulating end item use or configuration.

Ballistic testing can be performed on a sample of squibs as part of a Lot Acceptance Test (LAT). These tests assess a group of squibs to evaluate the reliability and safety of the entire lot. Ensuring a squib’s robustness when subjected to high stress or impacts is critical to performance.

Propellant Stability Testing

CADs and PADs depend on propellants to operate, but they must have appropriate stabilizer levels to ensure safety throughout manufacturing, storage, handling and transportation.

Propellant stability testing evaluates the stabilizer material and levels to determine service life, safety and handling and storage requirements. Through this type of testing, manufacturers can decrease safety risks associated with propellant ignition.

Challenges in In-Process Testing of Squibs

In-process testing can pose a few challenges, including:

  • Testing complexity: Squibs have intricate designs and materials that need sophisticated in-process testing methods to ensure reliability and safety. Standardizing and gathering data from these complex testing methods will also require extensive time and resources.
  • Regulatory compliance: Meeting stringent industry regulations for quality management can complicate in-process testing procedures. Regulations may require additional documentation and validation that consume resources or slow production times.
  • Safety risks: In-process testing for CADs/PADs involves many safety risks since employees will be handling explosives. Testing methods depend on strict safety protocols, specialized facilities and comprehensive employee training to increase employee and product safety.
  • Appropriate resource allocation: In-process testing often has high costs since it requires skilled personnel and proper equipment to ensure accuracy and safety. Testing methods may demand more resources or time during production, leading to increased labor, time and equipment costs.
  • Production integration: Implementing in-process testing may cause workflow disruptions, requiring employee schedule and equipment layout adjustments. Some in-process testing methods may have limitations when integrating within manufacturing processes.

Contact AETC for Safe, Reliable Squibs

Having confidence in your manufacturer’s in-process testing for CAD/PAD production is critical. You need aircraft pyrotechnic products you can depend on for safety and reliable, predictable performance.

Since 1978, AETC has been a go-to original equipment manufacturer of aircraft pyrotechnics for several applications in military, private and commercial aviation. We value quality and safety, which is why we implement comprehensive testing processes, including in-process testing, to ensure our squibs are secure and reliable. We hold ourselves to exceptional design, manufacturing and qualification standards to provide the dependable products your organization requires.

Contact us today to discuss custom solutions for your unique needs.