Diameter measurement and surface inspection in medical tubing extrusion
Clear tubing leaving the cooling bath passes through the measuring head and line-scan ring. Outer diameter and ovality are measured along orthogonal axes and wall-defect positions are tracked; the defective section is separated after cutting.
Diameter trends and defect line positions are sent to the PLC; cutting and reject commands for the defective section are matched to its position, and measurement and image records are shown on the operator display.
- 01 Diameter measurement
- 02 Wall scanning
- 03 Position matching
- 04 Cut and reject
The tube passes through the two-axis silhouette head.
- Outer diameter
- —
- Ovality
- —
- Defect position
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
The clear tube wall transmits the background and water droplets can resemble defects. Tube sway and an oval section affect a single-axis diameter reading; the defect decision must reach the correct cutting position.
Solution approach
Orthogonal telecentric camera-backlight pairs measure outer diameter and ovality from silhouettes. Line-scan cameras around the tube use dark-field light to track scattering from gel, spots and bubbles. Encoder position links defects to the cutter; wall thickness is assessed separately at the end section.
Process steps
- 01
Diameter measurement
The tube passes through the two-axis silhouette head.
- 02
Wall scanning
Line cameras scan the wall under dark-field lighting.
- 03
Position matching
The defect position is tracked to the cutter.
- 04
Cut and reject
The section with a black spot is cut and sent to the reject path.
Related applications
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