Interlocking Paver Block Mould Design

Overview
Interlocking pavers are only as good as the mould that forms them. A well-engineered mould delivers:
Perfect "lock-to-lock" fit (eliminates lippage)
Uniform density (≥ 22 MPa compressive strength)
Fast de-moulding (< 8 s cycle time)
Long service life (≥ 200,000 cycles)
Below UNIK shares the critical design points we apply to every interlocking paver block mould, from 60 mm thick drive-way units to 100 mm permeable pavers for car parks.
Material Selection – Start with the Steel
42CrMo forged block for the wear sleeve → hardness 48-52 HRC after quenching/tempering
Mn18 alloy for the entire cavity shell → work-hardening under vibration, giving natural anti-abrasion
Through-hardened dowel pins (60 HRC) keep inter-lock geometry within ± 0.15 mm over life
Cavity Geometry – Lock, Draft & Tolerance
1.5° draft angle per side → smooth hydraulic ejection, no under-cut stress
0.3 mm pre-compaction allowance → steel rebounds 0.1 mm, paver width stays within ISO 8350 tolerance
0.8 mm radius on all internal corners → prevents stress concentration & micro-cracks in the paver
Feeding & Venting – Fill in 3 Seconds
Multi-stage vent slots (0.15 mm × 25 mm) under each lock nib → air escapes before trapped pressure forms weak edges
"Wave-feed" entry profile → concrete flows to the farthest lock first, density difference < 1 % (ASTM C140 test)
Optional color-face insert (2 mm Cr plate) → bottom feed for through-color pavers, top feed for two-layer pavers
Heat Treatment & Surface Engineering
Vacuum quenching 980 °C + tempering 580 °C → uniform hardness, zero distortion
Plasma nitriding 0.03 mm diffusion layer → 3× corrosion resistance, ideal for colored cement with TiO₂
Final polishing Ra ≤ 0.4 µm → glossy paver surface, less release-agent consumption
Quick-Change Feature – Reduce Down-Time
Mould is split into cavity plate + wear sleeve + lock insert; individual parts can be swapped in < 15 min
Dowel + bolt pattern identical across UNT400 / UNT600 / UNT800 platforms → one set of spares covers multiple machines
RFID chip embedded → mould life data auto-upload to UNIK IoT dashboard, predictive maintenance alerts sent before critical wear
Cycle-Time Optimisation – From Lab to Field
50 Hz resonance frequency designed to match UNT servo vibration table → energy transfer efficiency 94 %
3 mm elastic polyurethane strip on stripper head → cushions final 0.5 s de-mould impact, cutting micro-cracks by 30 %
Result: 200 × 100 × 60 mm S-shape paver, 12 s cycle, 28 MPa strength, 0.8 % water absorption (average of 50 samples)
Sustainability & Cost
90 % of steel sourced from recycled automotive scrap → 0.47 t CO₂ saved per tonne of mould
Modular design means only worn sleeves replaced → 35 % lower lifetime tooling cost compared with mono-block moulds
Longer life = fewer mould changes → less downtime, higher ROI for the producer
Typical Mould Specification Sheet (supplied with every UNIK machine)
Profile: S-Shape, 200 × 100 × 60 mm
Weight: 195 kg (including wear sleeve)
Hardness: 48-52 HRC
Expected life: ≥ 200,000 cycles
Cycle time: 11-13 s on UNT400 servo table
Strength achieved: 22-32 MPa (depending on mix design)
Conclusion
A precision-engineered interlocking paver block mould is the fastest route to high-strength, good-looking, defect-free pavers. UNIK's design philosophy-correct steel, correct geometry, correct treatment-translates directly into lower unit cost, higher customer satisfaction and stronger brand reputation for the producer.
Ready to upgrade your moulds or design a new profile? Contact UNIK's mould engineering team at sales@unikmachinery.com or visit www.unikblockmachines.com for a free consultation and quotation.