Injection Stroke vs. Screw Length: Understanding the Thermal Trade-Off in Injection Molding

This article examines the relationship between injection stroke and screw length-to-diameter (L/D) ratio in injection molding machines. Because the screw retracts during plasticization, a longer injection stroke reduces the effective L/D ratio, creating axial temperature gradients that cause inconsistent melt temperature and uneven part quality—especially in multi-cavity molds. Increasing the L/D ratio improves mixing and reduces axial temperature variation. The article recommends limiting injection stroke to approximately four times the diameter of the B screw and concludes that long-stroke, low-L/D designs suit single-cavity products with modest quality requirements, while constrained stroke and higher L/D ensure multi-cavity product consistency.

Injection-molding screws: What exactly distinguishes A, B, and C? This article provides all the answers.

This article explains the differences between A, B, and C injection-molding screws, which are distinguished primarily by diameter and length-to-diameter ratio. A-type screws offer high pressure and excellent mixing for engineering materials and precision thin-walled parts; B-type screws are the versatile default for over 70% of general-purpose plastics; C-type screws provide high capacity for large, thick-walled components. Three selection rules are provided: keep shot size within 30%–70% of screw capacity, choose fine high-pressure screws for transparent parts, and specify wear-resistant alloys for fiber-reinforced materials.

Four Screw Cleaning Methods for Twin-Screw Extruders in Modified Plastics Production: Principles, Operations, And Limitations

Screw cleaning is critical to product quality in modified plastics production, yet often overlooked. This article analyzes four common cleaning methods for twin-screw extruders—resin cleaning, disassembly and manual cleaning, flame cleaning, and water-based cleaning—covering their operational principles, key process steps, precautions, and limitations. It provides practical guidance for selecting and combining cleaning methods based on material characteristics, equipment condition, quality requirements, and cost-effectiveness, while emphasizing standardized operations and regular maintenance to extend equipment service life.

Screw and Barrel Wear in Plastic Processing: Causes, Types, and Predictive Maintenance