General Description of the Application
For the inspection of round long or continuous products such as wires, bars, and tubes, a traditional eddy current method uses differential encircling probes.
This is a low-cost EC solution to detect defects in the circumference of round products.
This EC solution is used for a large range of diameters typically extending from about 0.5 mm to 75 mm.
Each probe covers a range of diameters in increment between 70% and 90% of the probe diameter.
This is an excellent method to detect short defects in high-speed process in nonmagnetic and magnetic alloys. For magnetic alloys, a magnetic saturation can be operated.
Performance and Objectives of the Inspection
• High-speed inspection (10 m/s and more, depending on the size of the defects)
• Surface inspection
• Subsurface inspection: thin wall with magnetization if ferrous materials
• Defects: cracks, inclusions, holes, etc.
• Compact device Description of the Inspection System
The product to be inspected is run through the probe and guided by a centering device to avoid lift-off variations.
The encircling probe is made with an emitter coil and two differential receiver coils.
Set of encircling probes and their mechanical support.
Parts to Inspect
• Wires in the cold or hot step of the process
• Tubes in the extrusion process
• Bars coming from lamination process
Defects to Be Detected
• Short cracks, inclusions, holes, etc.
• Examples of smallest defects:
- 0.4 mm (1/64 inc.) holes in aluminum tubes from Ø 6mm to 25 mm (0.25 in. to 1 in.)
- 0.8 mm (1/32 in.) through-wall holes in steel tubes with magnetization
- Voids in tin wire Ø 1 mm (0.04 in.) 
Natural defect detected on aluminum alloy tubes.
Notes:
• The sensitivity is limited by the diameter of the products
• Differential encircling probes are not well adapted to detect long defects.
Equipment and Service
• QuickScan EC 1-1 including alarm option for paint marker, PIM21, encoder and electronic interface
• MultiView software
• Up-to-date industrial PC with at least a 17-in. monitor
• Industrial 18-in. cabinet with air conditioning
• Mechanical support
• Set of probes and centering guides adapted to the diameters
• Quadrature encoder and electronic interface (optional)
• Integration setup and test on samples
• Acceptance and training at R/D Tech Québec
• Installation and training at the customer's site
|
Industrial inspection of round long or continuous products
