STS50 Screw Spline Shaft | Twin Screw Extruder Main Drive Shaft

The STS50 screw spline shaft is the core power transmission spindle specially designed for STS50 co-rotating twin screw extruders. As the key carrier for installing all screw elements and kneading blocks, it undertakes high-torque driving, continuous rotating and material shearing loads during plastic compounding production.

Manufactured with premium 40CrNiMoA alloy steel and full five-axis CNC precision machining, our STS50 spline shaft features high toughness, strong torsion resistance and stable concentricity. After integral vacuum quenching and tempering heat treatment, the shaft maintains excellent fatigue resistance under long-term high-speed and high-load operation. It is a fully interchangeable OEM replacement part for STS50 plastic extrusion, WPC compounding, biodegradable plastic modification and masterbatch production lines.

Adopts integral 40CrNiMoA alloy forging, no welding splicing. It effectively resists torsion deformation and fracture under long-term high-load extrusion, solving the common problems of shaft breakage and tooth skipping in ordinary shafts.

Full five-axis CNC grinding ensures spline tooth uniformity and shaft concentricity. The assembly clearance with screw elements is uniform, avoiding element shaking, abnormal wear and uneven material shearing during operation.

Strict dynamic balance calibration, no vibration at high-speed rotation. It improves the mixing uniformity of plastic materials and reduces pellet defects such as uneven particle size and material yellowing.

After vacuum heat treatment, the overall hardness is stable. It adapts to high-filler, corrosive, high-temperature extrusion environments, greatly reducing replacement frequency and production downtime.

Fully compliant with STS50 original equipment parameters. Direct replacement without barrel modification, suitable for all versions of STS50 twin screw compounding extruders.

• Biodegradable plastic compounding (PLA, PBAT, starch modified plastics)
• WPC wood plastic composite granulation and profile extrusion
• Color masterbatch and functional filler masterbatch production
• Engineering plastic glass fiber and mineral powder modification
• Food, feed and pet food raw material extrusion processing
• Plastic recycling and devolatilization compounding production

All STS50 screw spline shafts pass strict spectrum material testing, hardness testing, concentricity inspection and spline precision detection. ISO9001 certified production, 12-month warranty, standard shafts in stock, customized length/spline size supportable. Export-grade anti-rust packaging and long-distance transportation guarantee.

It is the main drive spindle of STS50 co-rotating twin screw extruder, used to install conveying elements and kneading blocks, transmit power, and complete plastic material conveying, melting and mixing compounding process.

We adopt high-strength 40CrNiMoA alloy steel with integral vacuum quenching treatment, featuring high torque resistance and long service life.

Yes. We support custom shaft length, spline tooth parameters and special surface treatment according to customer equipment requirements.

100% fully interchangeable. All dimensions, spline precision and torque parameters strictly follow OEM standards for direct installation.