SZ / SZL Conical Twin-Screw Gearboxes

A conical twin-screw page centered on dual-output geometry and alignment rather than generic reducer language.

Suggested opening copy

SZ and SZL gearboxes are designed for conical twin-screw extrusion systems, where the drive must reduce motor speed and distribute power to two coordinated screw outputs. Correct selection therefore depends strongly on output geometry, spline/interface data and alignment with the twin-screw machine.

Why conical twin-screw gearboxes are structurally different

A conical twin-screw extrusion drive has to reduce motor speed and deliver coordinated power to two screw outputs. The gearbox system therefore includes a reduction function and a distribution function. The relationship between these sections and the two screw interfaces is part of the machine geometry.

SZ and SZL families

The current CHINFAR technical system treats SZ and SZL as conical twin-screw gearbox families. They share the same application category but have distinct dimensional arrangements and model variants. The correct family has to be matched to the extruder interface rather than selected from a model number alone.

Output spline geometry is a critical identifier

For twin-screw gearboxes, the output connection is one of the fastest ways to identify whether a candidate can match the existing machine. Variant suffixes can correspond to a real interface change, so the complete spline designation and the two-output geometry should be recorded instead of relying on the basic model code.

Alignment affects the whole driveline

Misalignment between gearbox outputs and screw interfaces can load bearings and splines even if the gearbox itself is correctly sized. During installation or replacement, verify mounting datum, output center geometry, coupling/spline engagement and the condition of the mating machine parts.

What to send for a twin-screw replacement

Provide the gearbox nameplate, motor data, screw model or machine model, complete output/spline information, center distances and mounting dimensions, plus photos of the installed gearbox and screw-side connection. A drawing is strongly preferred when the line is being rebuilt.

Recommended technical figures

Use only the verified/sanitized engineering figures already cleared in the final technical-document system or new CHINFAR-owned visuals. Do not recreate unverified mechanical geometry.

• SZ dimensional reference
• SZL dimensional reference

FAQ