TeraMetrix Explores Off-line Terahertz (THz) Measurements of Bottle and Preform Layers
Manufacturers use both on-line process control measurements, and off-line quality control measurements. The off-line measurements are typically those that take additional time, but often show detail that cannot be obtained on-line. More in-depth study early in the process can actually decrease the setup time (possibly by days) for the manufacture of a new product and help characterize product specifications (e.g., wall thickness) and effectiveness of new materials (alternatives to plastics).
Off-line measurements and optimization methods can be quite varied often providing more detailed measurements or analyses that can be used to improve the product or improve the process. An example is the fast (< 40 sec) generation of whole bottle thickness maps for total and individual layer thicknesses in a multi-layer structure. The current method requires time consuming destructive measurements at only a few places on the bottle. However, aT-Ray 5000Terahertz测量系统以1 kHz展开在线或离线，可以提供完整的瓶子详细信息，以显着缩短这些复杂多层瓶的启动周期，并提高产品的层厚度一致性。bob综合平台
Certain areas of the bottle do not provide a measurement, e.g. along seams and highly curved injection points. In the image above, the cylindrical section of the bottle is mapped in this way. The entire scan took approximately 40 seconds, but this is dependent on the resolution required.
Even very quick (1 – 2 seconds) simple scans can provide a quite complete picture of the product. A simple linear scan of an object creates a B-Scan which is a cross-sectional image of the product along the scan line. The image result can clearly reveal improper layer structure. For example, a scan line can be the circumference around the round bottle. The B-Scan image demonstrates variations in total and individual layer thickness values along the scan line.
A similar offline application of THz is the measurement of preforms used in blow molding, especially the detection of internal layers. One of the layers in a preform, with the addition of Carbon Black, can serve as a light blocking layer. It is critical that the layer extend up under the cap. THz is sensitive to Carbon Black due to the slight conductivity of the material which causes reflections of the THz pulse.
A B-Scan (cross section view) along the circumference of the preform at the heights of the Green and Red arrows help demonstrate the presence or absence of the Black layer.
However, for the full scan at the Red arrow, the consistent layer structure can only be seen for the beginning and end of the image. The loss of the layer structure between these two areas means the Black layer does not extend up to the Red arrow position for all 360º of the sample.
这种类型的THz测量，由此启用T-Ray 5000and accompanying motion hardware, is a powerful tool for the examination and evaluation of both bottles and preforms. By measuring a bottle in this manner, the manufacturer can more quickly optimize a new production line, but also maintain a high quality product in ongoing production.