I.Overall Workflow Overview
The core objective of the equipment is to process hot-rolled wire rod raw materials in a single pass, completing straightening → continuous drawing and diameter reduction → cold rolling finishing/notching → constant tension output, replacing the traditional two-stage process of "drawing first, then separate notching." The entire process is continuous, online, and synchronous, with all workstation speeds uniformly controlled by a PLC to ensure constant wire tension and prevent breakage, diameter reduction, or uneven deformation.
II. Detailed Working Principles of Each Module
Wire Unwinding and Pre-Straightening Unit
The raw material is hot-rolled wire rod specifically for PC steel bars, which is placed on an active unwinding stand.
The unwinding stand uses closed-loop tension control, actively feeding the wire instead of passively dragging it, preventing twisting and damage to the wire rod.
The wire first enters a multi-roller horizontal straightening machine. Through multiple sets of staggered straightening rollers, it is repeatedly bent and rebounded to eliminate the coiling stress and curvature of the wire rod, ensuring that it is straight and free of torsion when entering the next station.
Some models integrate a mechanical descaling/polishing wheel to remove surface scale online, providing a clean surface for subsequent drawing and cold rolling.
Straight-Through Wire Drawing Machine – Core Diameter Reduction Principle
Unlike pulley-type wire drawing, straight-through wire drawing involves the wire passing through the dies in a straight line, without turning or repeated bending. This makes it particularly suitable for high-strength, large-diameter PC steel bars.
Die arrangement: Multiple drawing dies (generally 3-6 dies, customized according to the target diameter) are arranged sequentially along a horizontal straight line. The die cores are made of cemented carbide or diamond material.
Progressive diameter reduction: The diameter of each die is smaller than the previous one. Under tensile force, the wire passes from a larger diameter die to a smaller diameter die, undergoing plastic deformation, and its diameter is gradually compressed to the designed size. Taking the common process for PC steel bars as an example:
For example, the raw material is φ11mm, and after multiple continuous drawing steps, it is finally reduced to φ9.0mm, with a total area reduction rate of approximately 33%
Traction and Synchronization: Each mold is equipped with an independent variable-frequency traction wheel. A PLC system uniformly controls the rotational speed of all traction wheels, matching the wire passage speed at each stage to ensure consistent tension in each section of wire, preventing both breakage and slackening.
Lubrication and cooling: High-pressure spraying of drawing lubricant during the drawing process provides lubrication, cooling, and reduces die wear, ensuring a smooth surface and stable dimensions.
