Design for Plastic Film Measuring Device to Improve Accuracy and Repeatability of Print Repeat Measurement

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Bandel-Komorofsky, Logan A.
Corneau, Jonathan A.
Nepomuceno, R Jorrel E.
Zhan, Yang
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The objective of this report was to develop a design that would improve Winpak’s current process of measuring the distance between repeated graphics printed on plastic packaging film. This to verify that the film graphic spacing is within the tolerance zone as specified by Winpak’s clients. The most important requirements for the design were as follows: •Must be accurate to ± 0.5 mm •Measure up to 1650 mm in length •Must be a repeatable measurement •No sacrifice to operation time The final design was sub-divided into four main sections; film flattening, measurement method, device raising mechanism, and eye mark alignment. The team sourced a vacuum table with a surface area of 1800mm by900mm to flatten the film prior to the measurement. The vacuum table has an air flow adjustment valve to vary the suction force to account for different plastic film thicknesses. The surface of the vacuum table is anodized to prevent oxidation, and is finished with an anti-static agent to eliminate accidental static charge to the operator. A Mitutoyo® linear scale was sourced as the measurement device. This scale is fixed in the center of the table, and has an overall effective measurement range of 1700mm, which exceeds the requirement of 1650mm. The linear scale has a detector head that can travel along the total length. As the detector head moves, its position is displayed on the compatible digital readout (DRO) counter. This counter can zero the measurement of the detector head at any location. Additionally, the counter can output the data to a computer if so desired, but this was out of the project scope. This linear scale is accurate up to ±7?m,which is well within the requirements of ±0.5mm. A raising mechanism was designed to lift the linear scale off the table surface to allow for placement of the film. The raising mechanism has triangular brackets that extend from the back edge of the table to the linear scale. The back of the bracket is attached to friction hinges which will keep the scale from dropping onto the table surface, causing damage. Finally, the team designed an...