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Procon system measures melt temperature

Issue: November 2018

Procon Training and Consulting LLC, Phillips, Wis., has invented a system for measuring the temperature of the polymer melt in an injection molding machine. It consists of a housing with a cavity and a cup that partially fits within the cavity and has a series of apertures. The apertures define a flow path in which a temperature probe is positioned. The housing is configured so that it can be fitted to a machine platen.

Accurate measurement of the melt temperature is important because the strength of the product and the flow characteristics of the material through the mold are highly dependent on the temperature of the molten resin.

Traditional systems for measuring melt temperature can be inaccurate “due to the temperature variations in the shot flow induced by heat transfer into one or more components of the injection molding machine and/or the measurement system,” the patent states.

The melt-temperature-sensing kit provides measurements that are more accurate than traditional techniques due to the location in which the measurements are taken and because the cup keeps the shot flow molten for a longer period of time, according to the patent.

Patent 10,065,351; issued Sept. 4

Ultrasonic welding. Sonics & Materials Inc., a Newtown, Conn., maker of ultrasonic welding equipment, was awarded a patent for an ultrasonic welding system employing two converters. The converters are located on opposite sides of the sonotrode to boost the power it delivers and to do so effectively by ensuring that they deliver vibrations that are in phase. Vibrations that are out of phase could negate or decrease the potential power advantage provided by multiple converters, according to the patent.

Ultrasonic welding units typically include a press that applies pressure to the two parts to be joined; an anvil to hold the parts in place; an ultrasonic stack that includes a converter that changes an electrical signal into a mechanical vibration; an optional booster to modify the vibration’s amplitude; a sonotrode that directly applies the vibration to the parts to be joined; a power supply; and a controller.

The patent maintains that while previous patents have proposed using multiple converters (or transducers), none have stated that the converters must be in phase.

The converters’ piezoelectric elements may be quartz crystals. In some embodiments of the invention, the second converter’s piezo elements are arranged in a manner reversed to the arrangement within the first converter’s piezo elements.

In some embodiments, a booster may be mounted between the first converter and the proximal end of the sonotrode, with a second booster mounted between the second converter and the distal end of the sonotrode. The first booster may be of a different length than the second booster, so that the second booster provides a half-wave phase difference from the first booster.

Patent 10,052,714; issued Aug. 21

Film recycling. A system for recycling LDPE and LLDPE films that are used to wrap and secure bales, pallets and shipping containers has been patented. The system, from Wisconsin Film & Bag Inc., Shawano, Wis., produces material of near-virgin quality suitable for making new blown film, the patent states. Traditionally, post-consumer LDPE and LLDPE film has not been suitable for use in new film because of contamination that causes processing issues and unacceptable characteristics in the end product, such as discoloration and unpleasant odors.

The invention includes a shredder configured to tear and delaminate the film and a multi-stage washing system that uses hot water and detergent. The washing system also has a sink-float tank to separate heavy materials from the delaminated film. Additionally, to further ensure the purity of the end product, the invention includes a metal detector and a hydrocyclone to remove contaminants.

After washing, the wet film is ground, dried and compacted into granules.

Patent 10,022,725; issued July 17

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

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