Analysis of Modern Optical Inspection Systems for Parts Manufactured by Selective Laser Melting

Area of Science:

• Metrology and Inspection
• Additive Manufacturing
• Optical Measurement Systems

Background:

• Metal additive manufacturing (AM) enables complex, topologically optimized parts for aerospace, automotive, and medical sectors.
• High metrological requirements in these industries pose challenges for inspecting AM parts.
• Non-contact inspection, particularly Optical Measurement Systems (OMSs), is vital for rapid verification in Industry 4.0.

Purpose of the Study:

• To analyze the suitability of five different OMSs for Geometric Dimensioning and Tolerancing (GD&T) verification of Selective Laser Melting (SLM) parts.
• To compare OMSs based on laser triangulation, conoscopic holography, and structured light techniques.
• To identify the most accurate optical inspection methods for SLM-manufactured components.

Main Methods:

• Designed and manufactured a test part using Selective Laser Melting (SLM) in 17-4PH stainless steel.
• Performed contact-based measurement to establish reference GD&T values.
• Evaluated five different Optical Measurement Systems (OMSs) for dimensional and geometrical accuracy and inspection speed.

Main Results:

• Compared the performance of laser triangulation, conoscopic holography, and structured light OMSs.
• Assessed inspection speed and GD&T accuracy for each optical technique.
• Identified two portable systems as the most accurate for SLM parts.

Conclusions:

• Handheld laser triangulation and structured blue-light scanners are the most accurate optical techniques for inspecting SLM parts.
• These portable OMSs meet the stringent metrological demands of high-requirement industries.
• Optical measurement systems are effective for GD&T verification in the context of Industry 4.0 for AM components.