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September 1, 2003

8 Min Read
Machine components

Xaloy?s new barrier screw featuring an interchangeable dam promises processors the ability to adjust melt flow to match the material.

Eurotherm?s RVx3 Series solid state relays are able to perform in installations with higher ambient temperatures while generating only 3W per amp switched.

NPE attendees may have been eager to open their pocketbooks for cost-reducing auxiliaries and machinery, but investing in simple yet essential machine components can also save money. Good-quality machine components can create better parts, help reduce cycle time and production costs, and extend the life of the machinery.

  • Screws and Barrels

    Xaloy brought a new barrier screw featuring an interchangeable dam, giving processors the ability to adjust melt flow to match the material. Melt Optimizer barrier screws are said to provide better pressure control, reduced processing temperatures, and 20 to 35 percent more melting capacity than competitive barrier screws.

    Starting with a patented design developed by R.F. Dray, Xaloy optimized the feed and metering zones and placed an interchangeable dam at the end of the melt channel. To achieve optimum throughput, homogeneity, and melt temperature for a variety of different polymers, the dam height can be adjusted to change the screw?s pressure profile. The dam height can be set low to reduce internal pressure and increase throughput, or set higher for increased pressure and faster melting. A screw tip with mixer can be used when the L/D ratio is too short to avoid unmelted material passing through the barrier section.

    Competitors in the feedscrew market Glycon and Westland have joined efforts to create the Glycon DM2 feedscrew featuring a Westland Eagle mixing section. The configuration of undercut flights and channels in the barrier screw is designed to allow melt and pellets to homogenize without excessive pressure buildup, while producing higher output than a typical barrier screw.

    Downstream from the DM2 screw is the Westland Eagle mixing section, typically three diameters in length. The melt is mixed by alternating helical barrier and wiping lands and is enhanced by two or three notches in each of the barrier lands. The design prevents some of the melt from crossing the barrier lands, which change the melt flow direction. Between 95 and 98 percent of the melt can be accepted by the mixing section without restricting material flow.

    Worn-out screws and barrels can once again be productive through restoration and repair. Surface Engineering & Alloy Co. introduced Extreme Coatings, a new technology to fully encapsulate and repair CPM feedscrews with an XC1000 tungsten carbide coating. The coating is backed by a guarantee that it will at least double the life of the feedscrew. New feedscrews can also be manufactured with a less expensive base material and coated by the process.

    Also featuring the strength and durability of tungsten carbide is the Ultramax barrel from InductaMetals. The barrel lining alloy is heated and cooled during application to ensure more of the tungsten carbide remains on the wearing surface of the lining and to minimize the amount of iron that can migrate from the steel barrel wall into the alloy lining.

    InductaMetals shows confidence in the quality of its product by offering a lifetime guarantee. If the Ultramax barrel wears more than .01 inch diametrically for barrels with an ID less than 100 mm, or more than .015 inch for barrels with an ID greater than 100 mm during the life of the machine, the company will repair or replace it. A first-time-buyers program allows new customers to pay just 60 percent of MSRP; at the end of 12 months, you either pay an additional 45 percent of MSRP or return the barrel.

    Rexroth?s IndraDrive M modular drive system covers the output spectrum from 1.5 to 120 kW and supports all standard control communication systems.

    ABB?s ACS 800 drives use open loop direct torque control technology and require no encoder or tachometer.

  • Controls, Drives, Motors

    Good parts start with good melt, and the last best place to regulate that is within the barrel. Solid Controls displayed two lines of multiple-zone barrel temperature controls with that in mind, offering economical retrofits to get older machines up to speed. The new SmartSet line features four-zone control and three different packages (Genius, Prodigy, and Wizard) that each have a four-line LCD and from 32 to 64 inputs. The SmartHeat line includes five- or eight-zone units, where all zones are labeled, and their real-time parameters appear on an LCD screen. SmartHeat models offer PID and closed loop autotuning controls, with a five-zone model for $995 and an eight-zone running $1295. The SmartSet with enlarged screen is priced at $2950 for the unit and $12,000 for a turnkey package that includes installation.

    Eurotherm introduced a new series of solid-state relays. The RVx3 is a three-phase relay rated for 25A up to 660V a-c and offers zero crossfiring for fixed resistance loads. The relay uses thermal transfer technology to make the heat sink reportedly 11 percent more effective than Eurotherm?s previous units. The unit can operate in temperatures up to 40C without derating and generates only 3W per amp switched, so they can be installed with only .18 inch between relays.

    Combining temperature control with solid-state power relay is Gefran?s Geflex control. It consists of a control unit and a power module with aluminum heat sink. The universal temperature input can be connected to a wide variety of signal types with a reported accuracy of .2 percent. The master unit can communicate with up to nine Geflex ?slaves? by means of an internal bus. Gefran also introduced the 1200 and 1300 Series digital temperature controls with four outputs, three inputs, and RS485 communication interface. The tuning system has automatic activation to recover deviations at full power and recalculate optimum values. Serial communication takes place via Modbus RTU protocol.

    The predictive maintenance feature on Omron?s S8VS switch mode power supply can estimate its remaining service life in years to eliminate downtime. It also features an overload protection function to shut down if there is excessive current flow in the output, and an overvoltage protection feature that shuts off the power supply if there is an increase in the output voltage. The power supplies start at $99.

    A trend visible at NPE was the ability to control machinery and auxiliaries with PDA devices. Watlow developed this technology for its Series SD temperature controls. Preloaded instant HMI software allows any Palm PDA device to remotely program and control the process. The Series SD also features EIA 485 Modbus serial communications and Watlow?s Infosense sensor technology that reportedly improves sensor accuracy by a minimum of 50 percent over traditional sensors. The controls are available in four mount sizes and include a universal sensor input and up to three outputs.

    Operators can plug in and start up with RKC Instrument?s new OPC-V06 operator panel with preinstalled temperature control screens. No programming is required when connected to RKC?s multichannel PID controls such as the SR Mini and SRV. The panel features a 5.7-inch color LCD display with optional color STN and blue LCD. The standard control can store 10 job files, and an optional memory card can expand storage to 80 files.

    Showing several advances in the drives and motors category is Bosch Rexroth Corp. The company?s IndraDrive M modular drive system combines high-performance servodrive and frequency converter technology in one platform. The system covers the output spectrum from 1.5 to 120 kW and supports all standard control communication systems.

    For low power range applications between 100 and 750W, Rexroth developed the Ecodrive Cs compact servodrive. Control communications modules available include DeviceNet, Prodibus-DP. CANopen, and the Sercos interface. The drive is best used in systems with interconnected multiaxis arrangements and can be used as intelligent single axes on a standardized fieldbus.

    The new IndraDyn A induction motor increases performance in the 1- to 100-kW power range and features an IP 65 cooling fan. The motor is designed to operate well under harsh conditions and offers servicing and preventive maintenance advantages. Rexroth combines the main requirements for linear motors in a single-motor concept in its IndraDyn L Series permanent-magnet linear motor. With a compact design and very low force ripple, the motor features a high degree of both continuous and maximum output. Rexroth also introduced screw-in cartridge hydraulic valves at the show.

    Eliminating bulky gearboxes and pulse encoders, ABB has developed a new line of low-base-speed permanent magnet a-c motors. The lack of motor slip is said to provide better accuracy than standard induction motors and increase efficiency from 1 to 3 percent. ABB?s ACS 800 drives use open loop, direct torque control technology and require no encoder or tachometer, reducing the costs involved in retrofitting and installation. Units range in size from the 6.5-inch-wide, 5-hp model to the 13.8-inch-wide, 600-hp model; they are rated from 230 to 690V. ABB also has developed technology to receive e-mail alerts from motor drive systems, thanks to the NETA-01 Ethernet module. Any ABB drive providing a fiber-optic link is compatible; communication takes place through a standard Web browser.

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