• Conventionally available slit masks are not flexible where such slit masks are made from thin sheet metals that are glued which can eventually fall off.
• Thin masks will deform in time, thereby changing the desired wavelength.
• A number of processes are involved conventionally for implementing the masks for inspection which are time consuming and expensive
• Therefore, there is an unmet need for slit masks with improved flexibility, time/cost effectiveness and efficiency.

The present technology involves method for efficiently generating and/or mixing laser generated narrowband ultrasonic waves using an integrated or permanent slit mask.

Method:

1. Scanning the powder or a wire with laser to form a printed desired 3D component
2. Scanning the powder or a wire with a laser to form a printed desired 3D slit mask.

The method is given by the following steps:

• Providing a powder bed of selected powder on a substrate
• Scanning the powder with  laser, forming a melt pool
• Fusing the powder onto a desired shape to form a first layer of component
• Formation of a subsequent layer
• Replenishing  and repeating to form final desired 3D component and separate from substrate

The system includes:

• A non-contact energy source for localized heating in the additively manufactured component to generate ultrasonic waves;
• An ultrasound receiver for receiving the ultrasonic waves;
• An instrument to display the signals.
• A computer to process the signals.

Fig.1 Represents a schematic view of the additive manufactured integrated slit mask concept

Fig.2 is photograph of additively manufactured test specimen with the integrated slit mask

Fig.3 is an An illustration (top view) of a combinational dual wavelength slit mask for wave mixing

Fig 4 is an illustration of a possible configuration for Lamb wave mixing using slit masks

Fig 5 is graph showing signal in frequency domain clearly showing the fundamental and higher harmonics