Key Considerations in Tyre Mould Tread Pattern Design and an Analysis of Manufacturing Processes

The tyre tread pattern forms the direct interface between the tyre and the road surface, directly influencing the tyre’s grip, water dispersion, noise levels and wear resistance. As the moulding medium for the tread pattern, the design and machining quality of the tread ring in tyre moulds are of paramount importance. Drawing on Nacuan Mould’s many years of practical experience, this article shares key points regarding tread pattern design and machining processes.
I. Key Points of Tread Design
Tread design must comprehensively consider three major factors: functional requirements, manufacturing processes and mould strength. Functionally, longitudinal grooves facilitate water drainage and noise reduction, while lateral grooves enhance grip; block-pattern treads cater to off-road performance, and different application scenarios require distinct tread combinations. In terms of manufacturing processes, the way tread blocks are segmented directly affects machining difficulty and mould costs, requiring a balance to be struck between performance and cost. Regarding mould strength, parameters such as tread groove depth, draft angles and fillet radii must be designed appropriately to ensure the mould does not deform or crack under the influence of vulcanisation pressure and temperature.
Modern tread design extensively utilises CAD software for 3D modelling, enabling the rapid generation of tread patterns of various specifications through parametric design, followed by virtual assembly verification. Nachuan Mould employs advanced CAD/CAM systems, capable of rapidly completing reverse engineering and forward modelling of tread rings based on tyre tread drawings or samples provided by clients.
II. Tread Machining Processes
Tread processing is the core process in tyre mould manufacturing, primarily employing two techniques: five-axis machining and electrical discharge machining (EDM).
Five-axis machining is suitable for the manufacture of aluminium tread rings for semi-steel tyre moulds. First, a reference mould is machined using a five-axis machining centre (A/C-axis cradle-type dual-turret machine). This reference mould is then used to create a silicone mould, which is in turn used to produce a plaster mould, and finally, an aluminium tread ring blank is cast. The aluminium tread ring undergoes rough turning, semi-finish turning, sectioning, face milling, drilling of air holes, tread finishing, fitting of air hole sleeves, circular assembly, and edge turning to complete the machining process. The advantages of five-axis machining include high processing efficiency and excellent surface quality, making it suitable for high-volume production.
Electrical discharge machining (EDM) is suitable for the manufacture of steel tread rings for all-steel tyre moulds. After the ring-shaped forged blank has undergone rough turning, heat treatment and semi-finishing, the tread cavities are machined directly using an EDM machine. The advantages of EDM include the ability to machine high-hardness materials and complex shapes without being affected by cutting forces, making it suitable for the manufacture of large-scale engineering tyre moulds with deep tread patterns.
III. Key Points of Quality Control
Key quality control aspects for tread machining include: tread accuracy (dimensional tolerance controlled within ±0.05 mm), surface roughness (Ra ≤ 1.6 μm), circumferential clearance between tread blocks (≤ 0.03 mm), and vent hole patency. Nacuan Mould conducts comprehensive inspections of tread rings using methods such as coordinate measuring machines and optical scanning to ensure that every mould set meets the customer’s technical requirements.
As tyres evolve towards lower rolling resistance, reduced noise and enhanced grip, tread designs are becoming increasingly complex, placing ever-higher demands on mould machining precision. Mould manufacturers must continuously upgrade their machining equipment, optimise process parameters and enhance inspection capabilities to meet the demands of technological advancements in the tyre industry.