How to Make Paver Blocks Mould
A Practical Guide to Manufacturing Paver Block Tooling
Paver block moulds are the foundation of every concrete paving stone produced worldwide. Whether for driveways, plazas, or pedestrian walkways, the quality of the mould directly determines the quality of the paver. This guide explains how paver block moulds are manufactured, what materials and processes are involved, and what specifications matter for industrial production.
UNIK has been manufacturing paver block moulds in Quanzhou, China since 2008, with over 15 years of export experience serving 28 countries. The information below is based on documented manufacturing practices and industry standards.
Understanding the Paver Block Mould
A paver block mould is a precision steel tool that mounts onto a block making machine. It contains cavities shaped like the pavers to be produced. Concrete is fed into the cavities, compacted by vibration and pressure, then ejected as finished pavers.
The mould consists of several components:
Cavity plate – Contains the actual paver-shaped cavities
Wear sleeves – Replaceable liners that protect the cavity plate
Press head – Applies compression to the concrete surface
Core pins – Create holes in hollow or grass pavers
Mounting base – Attaches the mould to the block machine
Each component requires specific manufacturing processes and quality controls.
Step-by-Step Manufacturing Process
Step 1: Steel Selection and Raw Material Verification
The first step is selecting the correct steel grade for the application. Paver block moulds require different steel grades depending on production volume and concrete abrasiveness.
Steel Grade Application Characteristics
Cr12MoV High-volume, abrasive mixes High hardness, excellent wear resistance
9CrSi Standard production Good hardness and toughness balance
42CrMo Wear sleeves, mounting bases High strength, good weldability
Raw material verification includes checking material certificates, performing spectral analysis to confirm chemical composition, and ultrasonic testing to detect internal flaws. Only certified materials proceed to machining.
Step 2: Forging and Pre-Machining
For high-quality moulds, cast ingots undergo multi-directional forging. This process transforms the cast structure into a fine, uniform grain pattern. Forging eliminates internal voids and improves mechanical properties in all directions.
After forging, the steel block is rough-machined to remove scale and create a flat reference surface. This pre-machining stage removes approximately 2-3mm from all surfaces, preparing the material for precision CNC work.
Step 3: CNC Cavity Machining
The cavity is the most critical feature of the paver block mould. UNIK uses 5-axis CNC machining centers to cut cavity geometry directly from digital CAD models.
Key parameters controlled during CNC machining:
Cavity dimensions – Held to ±0.1mm tolerance
Draft angles – 1.5 degrees per side for clean ejection
Corner radii – 3-5mm to prevent stress concentration
Interlocking features – Machined to ±0.2mm for proper fit
For complex paver shapes such as wave patterns or hexagonal designs, specialized cutting tools and multiple passes are required. The CNC program is verified using simulation software before any steel is cut.
Step 4: Wire Cutting for Core Pins and Intricate Features
For features that cannot be machined with standard cutting tools-such as core pin holes or undercuts-wire electrical discharge machining (EDM) is used. A thin brass wire carrying an electrical current cuts through the steel with extreme precision, achieving tolerances of ±0.02mm.
Wire EDM is essential for:
Core pin holes in hollow paver moulds
Undercut features for interlocking pavers
Precision slots for wear sleeve retention
Step 5: Heat Treatment
Heat treatment transforms the steel from its machinable state into a hard, wear-resistant tool. The process follows a controlled sequence:
Spheroidizing annealing – The mould is heated to approximately 780°C and slowly cooled. This creates uniformly distributed carbide networks, providing the ideal microstructure for subsequent hardening.
Vacuum quenching – The mould is heated to 980°C and rapidly cooled in a vacuum furnace. Vacuum quenching eliminates surface oxidation, preserving the precision-machined cavity geometry. Surface hardness reaches HRC59-62.
Multiple tempering cycles – Two or three tempering cycles at 580°C eliminate residual stresses that could cause cracking during production. Each tempering cycle reduces internal stress while maintaining surface hardness.
Optional deep-cryogenic treatment – For extended service life, the mould is cooled to -196°C using liquid nitrogen. This converts retained austenite to martensite, increasing hardness and wear resistance. Service life extension of 30% or more is typical.
Step 6: Surface Finishing
After heat treatment, the cavity surfaces are finished to achieve the required smoothness. UNIK uses precision grinding and polishing to achieve Ra 1.6 surface finish or better.
A smooth surface provides two critical benefits:
Clean demolding – Pavers release without sticking or surface damage
Reduced wear – Smooth surfaces erode slower than rough surfaces
The polishing process uses progressively finer abrasives, starting with 200-grit and finishing with 600-grit or finer. Final surface quality is verified using profilometer measurements.
Step 7: Mounting Interface Machining
The mounting interface-bolt pattern, locating pins, and overall envelope dimensions-must match the customer's block machine exactly. UNIK maintains specifications for over 20 machine brands, including HESS, MASA, ZENITH, BESSER, TIGER, Quadra, KVM, and Poyatos.
For machines not in the database, UNIK machines the mounting interface based on customer-provided drawings, old moulds, or detailed measurements. The bolt holes are drilled and tapped on CNC machining centers with positional tolerance of ±0.1mm.
Step 8: Final Inspection and Quality Assurance
Every paver block mould undergoes comprehensive inspection before leaving the factory:
Raw material verification – Confirmation of steel grade with material certificates
In-process dimensional checks – Measurement of cavity dimensions during CNC machining
Hardness testing – Surface hardness (HRC59-62) and core hardness (HRC35-40) verification
Surface finish measurement – Ra value checked with profilometer
Final dimensional measurement – Complete inspection of all critical tolerances
Mounting interface verification – Alignment of bolt patterns and locating pins against a standard test plate
Only moulds that pass all inspections are shipped to customers.
Common Paver Block Mould Types
Different paver applications require different mould designs.
Paver Type Typical Size Mould Features
Rectangular paver 200×100×60mm Simple cavity, straight walls, 1.5° draft
Interlocking paver 252×252×60mm Curved or angled edges, ±0.2mm tolerance
Wave-type paver 200×100×80mm Complex curved surface, 5-axis machining
Hexagonal paver 200×200×60mm Six-sided geometry, precise edge angles
Grass paver 333×166×80mm Core pins for open cells, ±0.3mm pin alignment
Custom sizes and shapes are available upon request. UNIK produces over 1,200 mould types annually across more than 10 series.
Expected Lifespan and Maintenance
Under normal production conditions with standard concrete mixes, a properly manufactured paver block mould delivers 80,000 to 120,000 cycles.
Single shift operation (2,000-3,000 pavers/day): 18-24 months service life
Double shift operation (5,000-6,000 pavers/day): 9-12 months service life
Actual lifespan depends on:
Concrete abrasiveness (sharp sand wears faster than rounded aggregate)
Vibration intensity (higher vibration reduces mould life)
Maintenance practices (regular cleaning extends life)
Maintenance recommendations:
Clean mould thoroughly after each shift to remove concrete residue
Inspect cavity surfaces weekly for wear or damage
Check mounting bolts torque before each production run
Apply anti-rust coating when mould is not in use for extended periods
Replace wear sleeves when clearance exceeds specification
Common Problems and Solutions
Problem Likely Cause Solution
Pavers sticking in mould Rough cavity surface or insufficient draft angle Polish cavity to Ra 1.6 or better; verify draft angle
Uneven paver dimensions Worn cavity or loose mounting Replace wear sleeves; retorque mounting bolts
Cracks on paver surface Sharp corners in cavity Machine 3-5mm radius on all internal corners
Short mould lifespan Soft steel or inadequate heat treatment Use Cr12MoV with carburizing heat treatment
Inconsistent paver thickness Worn press head or uneven compaction Resurface press head; check hydraulic pressure
Why Mould Quality Matters
The mould is the only component that directly shapes the concrete paver. If the mould is inaccurate, every paver will be out of specification. If the mould surface is rough, pavers will stick during ejection. If the mould wears unevenly, paver dimensions will drift over time.
A high-quality mould from an experienced manufacturer reduces waste, minimizes downtime, and produces pavers that meet specifications consistently. The initial cost of a quality mould is higher than a cheap alternative, but the cost per paver over the mould's service life is significantly lower.
About UNIK
UNIK has been manufacturing paver block moulds in Quanzhou, China since 2008, with over 15 years of export experience serving 28 countries. The company specializes in high-quality brick machines and molds, producing over 1,200 mould types annually. All moulds are backed by CNC machining, vacuum heat-treatment, and lifetime technical support.