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Patent Report: Kiefel patent enhances thermoforming

Issue: June 2018

Kiefel GmbH Freilassing, Germany, has patented a thermoforming line it says produces greater throughputs and more precise wall thicknesses than available technologies. The line includes a thermoforming machine, a plastic-foil-providing station, a device that delivers the plastic foil from the station to the thermoformer, a central processing unit (CPU) and at least one actuator to provide data to the CPU and a thermoformer. Significantly, it also employs two individually controlled pre-stretchers within the mold.

“The applicant has found that by using two or more individually controllable pre-stretchers in combination with a calibration element, it becomes possible to better control the wall thickness of the thermoformed product, in particular at positions where the calibration element engages the plastic foil,” the patent states. “Control of wall thickness is further improved because the second pre-stretcher at least partially surrounds the first pre-stretcher and the calibration element.”

Various iterations of the invention call for multiple actuators and calibration elements, to ensure precise wall thicknesses.

Patent 9,840,036; issued Dec. 12

Extrusion. A North Royalton, Ohio, inventor represented by Rambus Delaware LLC, Sunnyvale, Calif., has proposed an extrusion-to-sheet production line. The line envisioned by W. Scott Thielman would continuously extrude polymer sheet of a single material embossed with a pattern. It employs two rolls to calender the sheet to a preset thickness. Once the sheet passes through the nip between the second roll and a third roll, it comes into contact with a belt looped between the third roll and a fourth roll. This belt embosses shapes on the sheet as it passes between the third and fourth rolls and through a cooling flat area.

According to the patent application, the line can handle relatively thick sheet, with typical production rates ranging from about 1.5mm per second for thick sheet to about 500mm per second for thin sheet. The invention addresses the “need to be able to produce thicker polymer sheets of a single material containing a pattern of optical elements at a relatively high rate while maintaining high tolerances on the geometry of the optical elements.”

Patent application 20180036937; published Feb. 8

This oven patent includes a basket that holds molds and components during heating./U.S. Patent and Trademark Office

Mold/component cleaning. Patrizio Petrelli, an inventor in Varese, Italy, has applied for a patent for an oven used to clean molds, dies, nozzles and other metal components used in plastics processing.

The oven is designed to make it easier to load and unload molds and components from the basket that holds them during heating. In the invention, infrared lamps are arranged on the inner surface of a circular “bell.” The bell can be moved away and upward with respect to the basket to facilitate access to the basket.

Additionally, because the invention features a system to remove oxygen from the oven and replace it with nitrogen, the oven also reduces the risk of spontaneous combustion of any plastic present in the molds and prevents the formation of carbon deposits. This makes any final mold cleaning steps easier, according to the application.

Patent application 20180056550; published March 1

Blow molding. Krones AG, Neutraubling, Germany, received a patent for a bottle blow molding machine that incorporates a robot and conveying device. The system is designed to simplify, automate and speed up the process of exchanging the blow molds to make a new product.

According to the patent, the machine’s integrated robot removes and arranges the molds on the blow mold carrier. Two control devices work together to oversee the replacement of
the blow molds.

In the invention, “the first control device and the second control device are linked so that when the first control device effects a removal of a blow moulding device from the apparatus, a replacement of a blow moulding device occur[s] automatically,” the patent states.

Patent 9,925,712; issued March 27

Patents and patent applications can be viewed at www.uspto.gov

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