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Ensuring the performance of optical curtains

Redesign of circuit boards to increase their resistance and durability



An international company, a longtime leader in the field of aerospace and military and civil defense, was looking to improve the performance of one of its equipment, intended for the quality control of projectiles.

The optical curtains used to detect the passage of projectiles play a key role in the manufacturing process of the bullets, since they allow to calculate their speed of movement and to ensure that it complies with the specifications of the product manufactured by our client. However, this equipment is subjected to significant mechanical stress due to the shock waves produced by the passage of the bullet. The vibrations generated eventually form cracks, which render the circuit inoperative, and cause production downtimes, which generates delays as well as financial losses.



When a bullet passes through a first optical curtain, the optical intensity is reduced and detected by an electronic circuit which forms a first pulse. A second optical curtain, installed a few metres away, in turn detects the passage of the bullet, producing a second pulse. By measuring the time between the two pulses and knowing the distance between the two optical curtains, the speed is calculated.

The main issue is that the firing power creates a shock wave that damages circuit boards over time. Early repairs or replacement of parts can cause a forced shutdown of equipment, disruption of quality testing and production delays.

Our teams therefore first considered the choice of materials used for the printed circuits in order to increase their resistance to shocks and vibrations. In particular, we chose to add layers of copper to the printed circuit, which had the effect of increasing its solidity. The addition of mechanical support was also favoured to eliminate resonance when projectiles pass through the optical curtain and thus better protect the entire circuit from vibrations.

Finally, we introduced redundancy in certain more critical circuits, so as to ensure the correct operation of the optical curtain, even in the event of failure of certain parts.

The combination of these actions helped increase equipment life and availability, avoiding unplanned downtime and potential delays in running quality tests.



By improving the availability and durability of the equipment, our mandate translated into greater efficiency for our client, who was able to reduce the costs related to the obsolescence of parts and optimize its quality control process.

This mandate, which is part of a business relationship that has been firmly established for several years with this company, has enabled our teams to demonstrate their expertise in the field of mechanical stress, applied to the design of printed circuits.


Project Services and Industries

Electronic Design

Electrical engineering

Mechanical engineering

Civil and military armament

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