The need for roughness measurement
Cables, wire insulation, pipes, and tubes are manufactured by plastic extrusion in which raw plastic material is melted and formed into a continuous profile. However, even in industrial settings, plastics extrusion is subject to many destabilizing factors. Instabilities are due to, for example, extrusion barrel temperature fluctuations or improperly prepared resins.The most common problem in plastics extrusion is a phenomenon called melt fracture, often described as “sharkskin”. Melt fracture is caused by pulsations in melt pressure and skin rupture. Pressure pulsations occur when the polymer sticks and breaks loose from the metal surfaces in the die. Skin rupture, for its part, occurs when the surface of the plastic is stretched too quickly on leaving the die.
Aluminum pipes are also manufactured by an extrusion process which may have defects and surface issues.
Steel, and Inox pipes, and tubes are usually electric or laser welded. During the manufacturing process, surface finish is deteriorated and the texture changes.
Surface roughness is a measure of the texture of a surface. It is quantified by the vertical deviations of a real surface from its ideal form. If these deviations are large, the surface is rough; if they are small, the surface is smooth. Surface roughness also causes appearance differences which influence a product’s added value such as the grade and indirectly customer satisfaction. Manufacturers need a more quantitative, reliable, repeatable, non-destructive and non-contact methodology to understand the exact correlations between processing changes and surface roughness.
FocalSpec's MP900 - Inline Roughness Measurement System provides a novel solution for this challenge.
MP900 uses Line Confocal Imaging (LCI) technology that can reliably measure surface roughness of coated or un-coated cables, medical tubes, pipes, wires, fibers, glass or metal tubes in different surface conditions, including dark, matte, glossy, and transparent.
A large amount of surface roughness data produced by non-contact, optical, real-time measurement is also used to analyze the extrusion process without affecting manufacturing line speed of up to 150m/min. MP900 can be used as an efficient tool for the optimizing extrusion process with the outputs of Std and Cpk.
The MP900 is a plug and play system which is suitable for products with a minimum diameter of 1 mm and with no limitation for the maximum diameter. The MP900 works up to a maximum of 1 mm surface vibration on the lines.
The MP900 delivers around 30-nanometer level repeatability for high-quality ISO standards-based roughness measurements for Ra (up to 50 μm), Rz, and RSm parameters. MP900 system's software enables users to make, view and export measurements, as well as diagnose and calibrate the equipment. The measurement date and time is recorded from each individual measurement and can be exported.
Benefits of measuring surface roughness with the MP900
• Provides automated and continuous inline roughness measurements
• Optimizing the cable, tube, pipe, or rod extrusion or welding process
• Improving cable, tube, pipe or rod surface quality
• Detecting the changes in extrusion or other process parameters in real-time
• Cutting the need for manual product sampling and quality control checks
• Providing reliable and repeatable process data without any manual work
• Generating automated process reports for the entire production batch
• Reducing waste and the amount of rejected products
• Cutting quality-related claims and boosting customer satisfaction
The below animation shows the MP900 in action: