PET Special Screws and Barrels

Cooperating with an experienced Chinese manufacturer of PET Special Screws and Barrels, technical teams can achieve precise thermal control for both virgin PET pellets and high-proportion recycled PET flakes (rPET). HAPPY PLASTICS adopts multi-axis CNC thread grinding, high-density centrifugal bimetallic liner casting and mirror flow channel polishing to eliminate local over-shear heating and material retention dead zones. Whether for high-output bottle preform injection molding or continuous sheet extrusion, our screw barrel sets produce fully homogeneous melt while retaining original polymer molecular performance.

Four-Stage Custom Manufacturing Process

Ordinary general screw structures easily cause excessive shear and uneven molecular chain degradation. We customize every set of PET Special Screws and Barrels via high-precision automatic standardized workflow:

[1. Melt Rheology Analysis] ➔ [2. Multi-Axis Grinding & Flank Milling] ➔ [3. Automatic PTA Alloy Surfacing] ➔ [4. Mirror Matte Polishing]

1. Melt Rheology Analysis: Calculate matched screw compression segments according to your actual proportion of new PET pellets and recycled rPET flakes, form exclusive compression curve matching your formula.

2. Multi-Axis Grinding & Flank Milling: Professional multi-axis CNC grinders process barrier screw profiles with high-precision flight dimensions to separate solid raw materials and molten melt smoothly.

3. Automatic PTA Alloy Surfacing: Plasma transferred arc welding coats high-performance cobalt base / tungsten carbide alloy on screw flight crests to resist abrasion from un-melted recycled flakes.

4. Mirror Matte Polishing: Full flow channel mirror polishing (Ra ≤ 0.15μm), erase micro scratches where sticky PET adheres, avoid long-term thermal degradation and black speck defects.

Industry Comparative Advantages

Comparison Table

Actual Production Application Cases

Our customized PET screw barrel equipment operates stably on automatic production lines all over the world. The following real production data is provided by long-term cooperative manufacturers:

• Bottle Preform Injection Molding Factory (Mexico): 85mm PET injection plasticizing unit for mineral water bottle preforms. Ordinary full-nitrided screw barrels caused excessive acetaldehyde (AA) content and yellowing after only 9 months of operation. After upgrading to HAPPY PLASTICS bimetallic PET Special Screws and Barrels, the production line has run continuously for 18 months, AA value keeps stable at low level, finished product yield reaches 99.4%.

• Recycled PET Sheet Extrusion Line (Italy): 120mm vented single screw equipment, processing 100% cleaned waste bottle flakes into thermoforming sheets. Our customized barrier screw + multi-stage vacuum exhaust section reduces IV drop from 0.08 dL/g to stable ≤0.03 dL/g, removing the need for expensive online pre-drying equipment.

Packaging Standard & Long-Term Structural Warranty

To guarantee the screw barrels arrive straight, rust-free and ready for immediate commissioning after long-distance ocean transportation, HAPPY PLASTICS implements strict heavy-duty export packaging specifications:

• Anti-Corrosion Packaging Specification: All finished screws and barrel sections are fully coated with industrial anti-rust grease, wrapped with multi-layer VCI vapor anti-rust film, fixed in IPPC fumigation seaworthy wooden cases filled with high-density shock absorption foam to eliminate bending deformation completely.

• 12-month full structural warranty: All complete sets of PET Special Screws and Barrels enjoy 12-month warranty coverage, free replacement for manufacturing defects, body cracking and abnormal alloy delamination under standard operating parameters.

• Complete traceable inspection documents: Each shipment is attached with full quality files, including material metallurgy test report, barrel inner hole laser straightness test record and screw dynamic balancing certificate.

FAQ

Q: After complete machine purging, transparent PET sheets still have persistent black specks, what is the root cause?

A: Black specks are carbonized PET formed by long-term material retention and overheating. They mostly accumulate in mismatched assembly gaps: excessive tolerance between nozzle and transition head thread, clearance gap between barrel tip and screw head. Switch to integrative co-designed PET Special Screws and Barrels, all connecting surfaces fit perfectly flush without tiny gaps to eliminate material carbonization dead zones.

Q: We have no original extruder/injection molding machine CAD drawings, can your factory complete reverse engineering customization?

A: Yes. HAPPY PLASTICS’s global technical database stores standard structural parameters of mainstream international injection and extrusion equipment brands. You only need to provide equipment brand, model specification and production year on the nameplate. For modified non-standard equipment, we supply detailed step-by-step measurement guide to record rear spline, keyway, barrel flange bolt hole layout for fully interchangeable direct replacement parts.

Q: For PET production lines, what advantages does centrifugal bimetallic barrel have over traditional nitrided barrel?

A: Gas nitriding only forms a thin hardened layer of 0.5mm. Once recycled flakes or fillers wear through this thin layer, the soft base steel will be quickly corroded by acidic degraded substances. Centrifugal bimetallic barrel is equipped with 3.0mm thick integral alloy lining, uniform wear and corrosion resistance throughout the whole thickness, service life extended 3–5 times compared with ordinary nitrided barrels.