Variable Frequency AC Motor & Drive

Various motor/drive classifications and cooling methods are available depending upon your application and environment. Motor sizing is based on the specific energy and max screw rpm selected for your product or the extruder maximum allowable HP (Kw). Unless otherwise specified the motor is targeted to operate at ≤~80% full load while producing the targeted rate.

Torque Limiting Coupling

A mechanical torque limiting coupling produces an accurate and consistent torque setting ensuring reliable and repeatable torque overload protection. The coupling is test certified at the factory. Mounted between the motor and extruder gearbox, when the gearbox input shaft exceeds torque set value, the torque limiter instantly disengages the driving and driven inertias. A proximity probe is provided to sense coupling disengagement and feedback to the control system.

Gearbox Features

NFM / Welding Engineers, Inc. has partnered with world leaders in gearbox design and precision craftsmanship. Gearboxes for the TEM Series extruders are designed for optimal splitting and transfer of the torque to both screw shafts. Gearboxes are designed with easily exchangeable reduction gear sets. Gearbox housings are designed for optimal thermal transfer and sound dampening.

Helical Gears

Helical Gears are manufactured from AISI 9310 steel and carburized to 58 – 60 RwC. All gears are certified for depth and hardness. Gear teeth are ground to very high quality level AGMA12 (DIN 4) ensuring incredibly quiet operation and greatest efficiency at high speeds.

Temperature Controlled Lube System

All gearboxes are provided with a distribution system for direct lube feed on bearings and gear teeth. Many options are available to optimize your gearbox lube system based on your thermal and oil filtration requirements.

Barrel Design

The TEM Series of extruders feature a standard 4:1 L/D barrel section, though shorter and longer barrels are available based on your process requirements. Standard designs include Feed, Closed, Vent, Injection, Side Feed, and De-watering (not shown above). Various inserts and ports are also available for optimal vent design, injection and instrumentation.

Standard barrels are manufactured from mild carbon steel and HIP’d with bimetallic bore materials based on your material’s wear and corrosion resistance requirements. NFM offers a variety of barrel options including various base materials (tool steels, stainless steels, duplex, Inconel, etc.), various bore materials (Nitrided, Stellites, Colmonoys, Carbides, etc.) and external treatments (nickel plating, chrome plating, etc.).

Process Temperature Control

Cooling:  TEM barrels are cored for cooling medium transfer close to the barrel bores for optimal thermal transfer and precise temperature control. The barrel closed loop cooling system includes all manifold piping, copper plumbed supply & return lines (not flex hose), solenoid valves, check valves, centrifugal pump, motor, and reservoir. The entire unit is mounted on the extruder base.

Heating: Electrical barrel heaters are used to maintain precise barrel temperatures.  Controlled by thermocouple feeding back to the control system. Heater wattage and voltage are designed to suit the process and environment.

 Screw Design

Optimized to suit your formulation and process conditions. Standard high wear resistant screw elements made of mild carbon steel soft core creating ductility in the spline section with an outer 10V-420 HIP’d material (~55RwC ) for the process section. Other materials for different environments are available upon request.

High Torque Involute Splined Shafts

Manufactured from specialty high carbon remelt forged aircraft quality steel.

Screw Tips

Screw tips are are used to clamp and lock the screw elements in place. Conical tip designs are standard coming in a one or two-piece design. For temperature sensitive polymers various mixing tip designs can be utilized to generate turbulent tip flow which helps prevent polymer stagnation and burning at the screw tip.

 Screw Tip Cooling

For further improved performance of temperature sensitive polymers, NFM offers proprietary designs which allow for cooling media to transfer down the screw shafts to the screw tips. Because the screw tip is where materials can see a sharp temperature rise and/or flow stagnation, these is often where polymer degradation can be severe. NFM’s screw tip cooling utilizes internal shaft tubing to transfer cooling media directly to the screw tip to help control melt temperatures.  The cooling media can also be made to cool the screw shaft on the return flow.

All NFM side feeders are mounted on robust support stands and are readily portable for storage when not in use. Side Feeders include an intermeshing twin screw design available in solid or segments screws. Screw and barrel metallurgy range from basic nitrided hardened to HIP’d bimetallic wear resistant materials.

All side feeders are variable speed, integrated into the extruder PLC and sequenced for safety and proper start-up procedures.

HSF Series Side Feeders

The HSF Series side feeders are NFM’s standard line of downstream side feeders with models available for every TEM extruder size. These high speed, high free volume feeders enable you to maximize processing throughput. This series of side feeders are used globally for downstream feeding of mineral fillers (talc, calcium carbonate, mica, fly-ash, wollastonite, etc.), glass-fibers, chemical additives, etc.

DSF Series De-aerating Side Feeders

The DSF Series Side Feeders allow enhanced feeding of small micron talc, fumed silica, precipitated calcium carbonate and other low bulk density fillers. This technology utilizes adjustable levels of vacuum to pull air out of the material feed stream prior to entry into the extruder.

VVS Series Vacuum Vent Stuffers

NFM’s VVS Series can be mounted horizontally or vertically to prevent fouling of vent port openings.

Learn more about NFM’s Side Feeder technology which can be retrofitted for any OEM extruder.