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January 2, 2006

6 Min Read
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Husky drives multimaterial molding into automotive

In an effort to push multimaterial molding into automotive, Husky Injection Molding Systems Ltd. (Bolton, ON), in cooperation with Tier One supplier Lear Corp. (Southfield, MI), has introduced a machine technology that allows large interior parts, like instrument panels, to be overmolded with tactile materials like TPE.

Called the Quadloc-Tandem-Index (QTI) by Husky, and the One Step Manufacturing Process (OSMP) by Lear, the technology was on display at Husky?s Novi, MI tech center where a 3470-ton press molded a 10-lb instrument panel that consisted of a polypropylene substrate and a TPE overmolding running across the entire top portion. The system has since been delivered to Lear, which will use it for a TPO door panel and an instrument panel in 2006.

The QTI represents an amalgamation of three successful Husky lines: the base system is Husky?s large machine line, the Quadloc, which ranges from 1500 to 8800 tons; the clamping system applies Husky?s Tandem technology where a center platen allows two standard molds to be used, duplicating a stack mold without special tooling; and finally, the center station actually rotates around a vertical axis in the same manner as Husky?s PET Index system.

The indexing function allows the machine to inject a substrate material into the first side, spin that part 180°, and overmold another material via a second injection unit. The second unit rides along linear bearings with the moving platen. While that overmolding phase of the cycle occurs, the first injection unit can simultaneously mold another substrate in the first cavity. Husky says the entire system isn?t much larger than a standard 3500-ton press, making it easier for automotive suppliers to integrate into their plants. By situating the second injection unit along the side at an angle, Husky was able to keep the overall length at 65 ft, versus the 80-85 ft it says other large multimaterial machines require, which locate the second unit behind the moving platen.

The QTI is able to hold a 50,000-lb mold on each side of the center turret, using a hydraulic motor to spin the center platen, and pneumatic and hydraulic locks to hold it in place. At the Novi open house, the QTI had a 440-oz main injection unit shooting the 8 lb of polypropylene, and a 220-oz second injection unit for the nearly 2 lb of TPE. For larger second material outputs, the QTI can also be fitted with dual 440-oz systems. Substrates 2.5-3.5-mm thick and 1.5-mm thick overmoldings have been created with flowlength-to-thickness ratios of 500:1.

While the display system only used two of the four sides of the turret, Husky officials said there?s no reason all four sides couldn?t be used, for an even greater increase in output. For more information, contact Husky Injection Molding Systems at www.husky.ca.


Additional line allows variable extrusion

Custom profile extruder Extrusion Technology Co. (Lakewood, WA) has further enabled its variable-extrusion capabilities through the installation of an AK Ultra 3.5-inch extrusion machine. The line is the five-year-old company?s sixth and reportedly required minimal installation work before production could begin.

Extrusion Technology?s variable-extrusion capability allows the company to change the size and shape of certain profile areas while a continuous supporting section is maintained. In a 6-ft automotive window-seal extrusion, the company is able to change the size and shape four times in order to fit the window?s dimensions, with weight variations within the part of as much as 60%.

Extrusion Technology says that a stable extrusion process, including all variables, is required for the process to work. The AK system the company installed features as standard a Steward barrier screw with Colmonoy 56 hard-faced flights; digital pressure indication with automatic high-pressure drive shutdown; heated single-bolt swing-out clamp for fast die changes; and heater-burnout detection. In addition, Extrusion Technology says the company supplied more than $1000 worth of spare mechanical and electrical parts. For more information, contact American Kuhne Inc. (Norwich, CT) at www.americankuhne.com.


Six-axis robots add flexibility to molder's cells

Faced with a shortage of skilled labor and an interest in controlling long-term costs, an English molder opted for two six-axis robots, forming the nerve center for two manufacturing cells that could largely operate without human intervention. PRP Polymer Engineering (Bicester, England), a division of the Reevite Group, operates a facility in Hereford with 15 employees and six Arburg injection molding machines, ranging from 25 to 50 tons.

Early on, David Wilkins, PRP?s managing director, opted for six-axis robots over Cartesian-style units on the basis that the robots would not only have to demold and degate parts but would also need to reorient them for exit via conveyor. After trials with several manufacturers, PRP decided on Stäubli robots.

The company started with an RX90 featuring CS8 controls, which was configured with an Arburg 270S machine molding PVC and TPE. Soon after, a second cell was created around an Arburg 320S, which undertook more complex moldings including running some family tools. For more information contact Stäubli at www.Staubli.com.


Thermoformer replaces 5-axis CNC center with router trimmer

Thermoforming often requires extensive trimming of large parts, with 5-axis CNC routers often employed, in spite of high costs. Medallion Plastics, a custom thermoformer in Indiana that supplies parts to communications, defense, automotive, and recreational vehicle customers, among others, had been using a 5-axis CNC machine for trimming but wanted greater repeatability at lower cost. The company moved to a large-capacity RoboTrim router trimming system from Robotic Production Technology (RPT; Auburn Hills, MI).

Based on Medallion?s needs, RPT created an enclosed RoboTrim router-trimming system featuring an R-2000 robot and servocontrolled two-position table. The system can handle parts as large as 100 by 49 by 21 inches. The two-position table allows parts to be removed by operators outside the enclosed trimming area. Given that Medallion is a custom thermoformer creating a variety of different parts at any given time, the system needed to be flexible.

To achieve this, the RoboTrim system includes RPT?s TrimPro offline programming and Accuracy Enhancement software to deal with component variations.

The TrimPro program offers simulation and programming for the Fanuc robots used, allowing users to import CAD models of parts and create a virtual work cell, including machine, part-transfer devices, and any other encumbrances that may be present. The accuracy software offers a fixture-ID system where the robot recognizes what fixture is in use and pulls up the appropriate program. For more information contact Robotic Production Technology at (248) 829-2800.

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