Main Screw (Worm Shaft): Pressure Capacity 50-200 MPa

Component Specifications

Definition

The main screw, also known as the worm shaft, is a precision-engineered helical shaft that rotates within the barrel of a continuous screw press. It progressively compresses oil-bearing materials through decreasing pitch and increasing root diameter, generating the mechanical pressure required for oil extraction. This component converts rotational torque into axial compression force while maintaining material flow consistency.

Working Principle

The worm shaft operates on the Archimedes screw principle combined with progressive compression mechanics. As it rotates, the helical flights convey material forward while the decreasing pitch and increasing shaft diameter create a compression ratio that squeezes oil from the feedstock. The continuous taper design ensures gradual pressure increase without sudden shear forces that could degrade oil quality.

Materials

Typically manufactured from case-hardened alloy steel (e.g., 4140, 4340) with surface hardness of 58-62 HRC. High-wear areas may feature tungsten carbide coatings or nitrided surfaces. Food-grade applications use stainless steel (316L) with polished surfaces.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Taper Angle	1.5-3.5 degrees
Diameter Range	100-500 mm
Surface Finish	Ra 0.4-0.8 μm
Rotational Speed	20-60 RPM
Compression Ratio	1:4 to 1:8
Pressure Capacity	50-200 MPa
Length To Diameter Ratio	8:1 to 15:1

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 12100, DIN 8589, ISO 22000

Parent Products

This component is used in the following industrial products

Continuous Screw Press for Oil Extraction

Industrial machine for continuous mechanical extraction of oils from oilseeds and nuts.

View Product Details

Engineering Analysis

Risks & Mitigation

Wear and abrasion from feedstock
Fatigue failure from cyclic loading
Corrosion in humid environments
Improper alignment causing vibration
Overheating from excessive friction

FMEA Triads

Trigger: Abrasive feedstock materials
Failure: Progressive wear of helical flights
Mitigation: Use hardened materials, apply wear-resistant coatings, implement material pre-treatment

Trigger: Improper lubrication
Failure: Overheating and seizure
Mitigation: Establish automated lubrication system, monitor temperature sensors, use food-grade lubricants

Trigger: Misalignment during installation
Failure: Vibration and premature bearing failure
Mitigation: Use laser alignment tools, implement regular alignment checks, install vibration monitoring

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.05 mm diameter tolerance, ±0.1° helix angle tolerance, Ra 0.4-0.8 μm surface finish

Test Method

Dimensional verification with CMM, hardness testing per ISO 6508, NDT inspection for cracks, performance testing with standard feedstock

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Main Screw (Worm Shaft)

Manufacturer profiles associated with Main Screw (Worm Shaft).

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the difference between a main screw and worm shaft?

Both terms refer to the same component. 'Main screw' emphasizes its primary function in the press system, while 'worm shaft' describes its helical geometry resembling a worm gear thread.

How often should the main screw be replaced?

With proper maintenance, main screws typically last 5-10 years. Replacement frequency depends on material abrasiveness, operating hours, and maintenance practices. Regular inspection for wear and surface degradation is recommended every 6-12 months.

Can main screws be repaired or refurbished?

Yes, worn screws can often be rebuilt through hardfacing, re-machining, or re-coating processes. However, severe wear affecting the compression profile usually requires complete replacement to maintain extraction efficiency.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Main Screw (Worm Shaft)