🚪 Acoustic Rating: ISO 10140 Sound Reduction 28 dB – 34 dB 🚢 Factory Export: 1,400 – 1,800 Door Slabs per 40'HQ FCL Container
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Architectural Door Core Engineering

Tubular Particle Board for Internal Flush Doors

High-performance extruded tubular hollow-core particle board slabs for hotel guestrooms, commercial office towers, and premium residential flush doors. Up to 60% weight reduction, certified 28 dB to 34 dB acoustic sound isolation (ISO 10140), and permanent zero-warp planarity.

⚡ Quick Engineering Summary: Tubular Particle Board Flush Door Cores

Internal Flush Door Infill Engineering requires lightweight yet rigid cores that eliminate seasonal door leaf warping, provide substantial acoustic privacy, and sustain heavy daily impact without surface puncturing. Cuzi Particle Board manufactures extruded tubular hollow-core particle board slabs in thicknesses from 28mm to 44mm. Delivering a 60% weight reduction compared to solid timber cores (340–420 kg/m³ core density), our tubular cores provide certified 28 dB – 34 dB sound transmission loss (ISO 10140), arch-bridge puncture resistance (>20 kg/cm²), and calibrated ±0.15mm thickness tolerances for automated high-speed door production lines.

Available Core Thicknesses: 28 mm, 33 mm, 34 mm, 38 mm, and 44 mm (Calibrated ±0.15 mm)
Acoustic Insulation Index: Rw 28 dB to 34 dB Sound Transmission Loss (ISO 10140-2 / ASTM E90)
Weight Advantage: 60% Lighter than Solid Wood (Effective Core Density: 340–420 kg/m³)
Arch Puncture Resistance: > 20 kg/cm² (1.96 N/mm²) Compressive Face Resistance
Modular Door Dimensions: 2050×800 mm, 2050×900 mm, 2100×1000 mm, 2440×1250 mm
40ft HQ FCL Capacity: 1,400 to 1,800 Slabs per Container (Maximized Cube-Out)

Solves Door Sag, Seasonal Warping & Airborne Sound Transmission

Door manufacturers constantly balance three conflicting requirements: lightweight handling, acoustic privacy, and resistance to seasonal warping. Low-cost paper honeycomb infill feels flimsy, delivers poor sound attenuation (Rw < 20 dB), and easily punctures under normal shoe or shoulder impacts. Solid timber or solid chipboard cores feel luxurious and soundproof, but their 45–55 kg deadweight causes hinge pull-out, frame sagging, and severe bowing under seasonal humidity swings.

Cuzi Particle Board extruded tubular particle board resolves this dilemma through horizontal ram extrusion mechanics. Precision tubular voids displace 60% of the internal wood volume, lowering average core density to 340–420 kg/m³. The continuous cylindrical voids break sound wave vibration paths while acting as stress-relieving expansion chambers that keep the finished door leaf permanently flat within ±1.0mm.

  • ✓ Acoustic Privacy for Hospitality: The alternating solid wood-particle arches and dead-air chambers deliver 28 dB to 34 dB sound reduction, satisfying hotel brand acoustic guidelines.
  • ✓ Hardware Longevity: Reducing door leaf weight from 50 kg to ~22 kg significantly extends the duty cycle of concealed hinges, pivot closers, and magnetic latch bolts.
  • ✓ Arch-Bridge Physical Resistance: Withstands heavy commercial impact (>20 kg/cm²) without telegraphing core ribs or puncturing thin 3mm HDF face skins.
  • ✓ Precision Thickness Calibration: Double-sanded to ±0.15mm tolerance to prevent telegraphing read-through during automated hot-press or membrane vacuum skin lamination.
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Interior flush door with an exposed tubular particle board core

Standard Door Core Parameters

Available Thicknesses:28mm, 33mm, 34mm, 38mm, 44mm
Standard Widths:800mm, 900mm, 1000mm, 1250mm
Standard Heights:2000mm, 2050mm, 2100mm, 2440mm
Effective Core Density:340 – 420 kg/m³ (60% weight reduction)
Acoustic Sound Rating:28 dB – 34 dB (ISO 10140 compliant)
Thickness Tolerance:±0.15 mm (Calibrated Sanded)
Emission Grade:CARB Phase 2 / EPA TSCA Title VI / E1
Container MOQ:1 × 40'HQ (~1,400 to 1,800 slabs)
Door Infill Engineering Analysis

Comparative Analysis: Door Core Technologies

Comparing extruded tubular particle board against traditional paper honeycomb, solid timber staves, and solid chipboard infill across structural and acoustic metrics.

Performance Metric Cuzi Tubular Particle Board Paper Honeycomb Core Solid Wood Stave Core Solid Particle Board
Effective Core Density 340 – 420 kg/m³ 80 – 120 kg/m³ 500 – 620 kg/m³ 680 – 720 kg/m³
Finished Leaf Weight (2050×800×38mm) 19 – 23 kg (Optimal Feel) 10 – 13 kg (Too Lightweight) 38 – 45 kg (Heavy) 48 – 55 kg (Hinge Fatigue)
Sound Insulation (Rw / ISO 10140) 28 dB – 34 dB (Acoustic Privacy) 18 dB – 22 dB (Poor Isolation) 26 dB – 29 dB (Solid Resonance) 30 dB – 33 dB (Good Sound Mass)
Puncture & Impact Resistance > 20 kg/cm² (Arch Bridge) < 3 kg/cm² (Prone to Craters) > 25 kg/cm² (Rigid) > 25 kg/cm² (Rigid)
Resistance to Seasonal Warping Exceptional (≤ 1.0mm Bowing) Moderate (Frame Dependent) Poor (Grain Anisotropy Sag) Good (Isotropic Core)
Landed Material Cost Moderate (Best Value/ROI) Lowest Initial Cost High (Timber Grade Costs) High Sea Freight Weight Cost

Acoustic Chamber Resonance Damping

Solid cores conduct sound via physical vibration resonance. Tubular particle board alternates high-density cured resin bridges with continuous dead-air channels, creating acoustic impedance mismatches that absorb high-frequency conversation and footstep reverberation.

Thermal Insulation Performance

The sealed dead-air cavities function as natural thermal insulation cells, yielding a low thermal conductivity coefficient (λ = 0.08–0.10 W/m·K). This helps minimize thermal transmission between air-conditioned hotel suites and ambient corridors.

Automated Factory Pressing Speed

The uniform sanded face skin provides instantaneous glue penetration with PVAc D3 or PUR glues. Door plants can operate multi-daylight hydraulic hot presses at 80–110°C with cycle times under 90 seconds without board blowing or skin delamination.

Manufacturing Process Engineering

Automated Door Leaf Construction Anatomy

Standard industrial framing and skin bonding architecture for high-capacity flush door manufacturing lines.

01. Perimeter LVL / Wood Framing

Kiln-dried finger-jointed pine or Laminated Veneer Lumber (LVL) stiles and rails (28–35mm width) form the structural perimeter frame. LVL stiles eliminate timber twist and provide reliable edge anchoring for weatherstripping and flush rebating.

02. Precision Core Slab Infill

The Cuzi tubular core is precision-cut to fit flush inside the wooden frame. Tubes run vertically (parallel to the door height) to provide maximum column compression strength and facilitate internal wiring channels for electronic hotel keycard locks.

03. Solid Lock Block Reinforcement

A solid timber or dense particle board block (typically 75 × 300mm) is fitted adjacent to the tubular core on the lock stile. This provides solid structural anchoring for deep mortise lockcases, escutcheons, and door handle spindle screws.

04. Hydraulic Skin Lamination

Door skins (3.0mm, 4.0mm, or 6.0mm HDF/MDF or natural wood veneer faced boards) are roller-coated with PVAc D3 glue (120–150 g/m²) and pressed at 90–110°C under 0.4–0.6 N/mm² pressure, creating a rigid, squeak-free sandwich composite.

💡 Technical Recommendation: Electronic Hotel Lock Conduit Routing

When designing smart guestroom doors with RFID card readers or biometric locks, the tubular core's vertical hollow chambers provide readymade wiring conduits. Low-voltage power wires and data cables can be routed directly down the tube channels without requiring messy horizontal core drilling or risking skin telegraphing.

Factory Dimension Matrix

Standard Core Thicknesses & Acoustic Performance

Certified engineering specifications across our complete range of extruded tubular door core thicknesses.

Core Thickness Tube Diameter (Hole Pitch) Effective Density (kg/m³) Finished Door Thickness (with Skins) Acoustic Rw (ISO 10140) Typical Application Sector
28 mm Tubular Core Ø 18 mm (Pitch 28 mm) 410 ± 20 34 – 35 mm (3mm skins) 27 – 29 dB Residential interior room doors, sliding pocket doors, wardrobe pass-doors
33 mm Tubular Core (Popular) Ø 22 mm (Pitch 32 mm) 380 ± 20 38 – 40 mm (3–3.2mm skins) 29 – 31 dB Standard European 40mm interior doors, private bedrooms, residential rental towers
34 mm Tubular Core Ø 22 mm (Pitch 32 mm) 370 ± 20 40 – 42 mm (3–4mm skins) 30 – 32 dB Commercial office conference rooms, boutique hotels, high-end residential suites
38 mm Tubular Core (Standard) Ø 27 mm (Pitch 38 mm) 350 ± 20 44 – 45 mm (3–3.5mm skins) 31 – 33 dB Standard UK & Commonwealth 44mm architectural doors, 4-star & 5-star hotel rooms
44 mm Tubular Core (Heavy-Duty) Ø 32 mm (Pitch 44 mm) 340 ± 20 50 – 54 mm (3–5mm skins) 32 – 34 dB Hospital patient rooms, recording studios, luxury executive suites, soundproof partitions
Factory Wholesale Logistics

40ft High Cube Container Loading & Pallet Specifications

Optimized export packing engineered to prevent transit compression damage and ensure seamless forklift destuffing at destination door factories.

Standard Slab Format Core Thickness Slabs per Pallet Pallets in 40'HQ Total Slabs per 40'HQ Payload Volume Gross Weight (MT)
2050 × 800 mm 33 mm 64 slabs 28 pallets 1,792 slabs 58.4 m³ ~22.5 MT
2050 × 900 mm 34 mm 60 slabs 26 pallets 1,560 slabs 57.3 m³ ~21.8 MT
2050 × 900 mm 38 mm 54 slabs 26 pallets 1,404 slabs 57.7 m³ ~21.2 MT
2100 × 1000 mm 44 mm 46 slabs 26 pallets 1,196 slabs 59.1 m³ ~20.5 MT

Tube End Seal & Corner Protectors

Exposed tubular openings at the ends are sealed with protective paper barriers to prevent dust ingress. Pallet corners are reinforced with 5.0mm thick heavy cardboard edge angles and tensioned steel or PET strapping to ensure zero transit damage during sea transit.

ISPM 15 Certified Solid Skids

All wooden skids and runners undergo heat treatment (HT) complying with ISPM 15 international customs regulations. Stack height is engineered precisely to maximize vertical clearance in 40ft High Cube containers without pallet crushing.

Commercial & Engineering Q&A

Frequently Asked Questions (B2B Buyer FAQ)

Direct answers on tubular core engineering, acoustic testing, framing construction, and container logistics.

Traditional solid lumber stiles and solid wood cores undergo anisotropic hygroscopic expansion and contraction, creating differential stress across door skins that causes door leaves to bow, cup, or twist. Tubular particle board is an engineered composite manufactured through horizontal ram extrusion. Its continuous cylindrical channels break internal lateral tension while maintaining isotropic dimensional stability, keeping door leaves flat within ±1.0mm over a 2100mm height under fluctuating indoor relative humidity (30% to 80% RH).

A standard 33mm to 38mm tubular particle board core laminated with 3mm to 4mm HDF door skins delivers an airborne sound reduction index (Rw) of 28 dB to 32 dB under ISO 10140-2. A 44mm architectural tubular core with 6mm skins achieves 32 dB to 34 dB. This dramatically outperforms hollow paper honeycomb cores (which only provide 18 dB to 22 dB) and meets commercial privacy acoustic standards for hotel guestrooms, executive offices, and residential bedrooms.

In automated industrial door manufacturing, finger-jointed pine, fir, or laminated veneer lumber (LVL) stiles and rails (typically 28mm to 35mm wide) form the perimeter frame. A solid hardwood or LVL lock block (typically 75 × 300mm) is inserted into the latch side to anchor mortise locksets. The pre-calibrated tubular core slab is positioned into the frame cavity, and 3mm to 6mm HDF, MDF, or plywood door skins are laminated over both faces using PVAc D3 glue or PUR adhesive under hydraulic hot-press pressure (0.4 to 0.6 N/mm²).

Extruded tubular cores utilize arched bridge physical mechanics. The solid arch walls between hollow tubes provide compressive puncture resistance exceeding 20 kg/cm² (1.96 N/mm²). Unlike paper honeycomb doors that easily puncture or crack when kicked or subjected to shoulder impacts, tubular core doors maintain structural integrity, preventing face-skin cratering in high-traffic school, hospital, and hotel environments.

Cuzi Particle Board manufactures standard door core slabs in thicknesses of 28mm, 33mm, 34mm, 38mm, and 44mm with double-sanded thickness calibration tolerances of ±0.15mm. Standard modular widths include 800mm, 900mm, 1000mm, and 1250mm, with heights of 2000mm, 2050mm, 2100mm, and jumbo lengths up to 2440mm for bespoke oversized door leaves.

By incorporating hollow tubes that displace 60% of solid panel volume, tubular core density ranges from 340 to 420 kg/m³, compared to 680 to 750 kg/m³ for solid particle board or solid timber. A standard 2050 × 800 × 38mm door leaf weighs approximately 19 to 23 kg instead of 45 to 55 kg. This lightweight mass significantly reduces mechanical wear on concealed hinges, magnetic latches, and overhead door closers, while cutting inland transport and container shipping costs by over 40%.

Cuzi tubular door cores are certified to US EPA TSCA Title VI, CARB Phase 2, and European Class E1 (≤ 0.05 ppm under EN 717-1 chamber testing). For healthcare, luxury hospitality, and LEED v4 certified projects, we offer ultra-low-emitting formaldehyde (ULEF) and 100% NAF (No-Added-Formaldehyde) MDI resin formulations that qualify for EQ credits.

Because tubular cores are lightweight (340–420 kg/m³), shipping containers cube out before hitting highway weight limits. A 40ft HQ container accommodates approximately 1,600 to 1,800 slabs of 33mm/34mm cores, 1,400 to 1,500 slabs of 38mm cores, or 1,200 to 1,300 slabs of 44mm cores, loaded on ISPM 15 heat-treated export skids with corner edge guards and multi-layer stretch wrap.

Upgrade Your Door Factory with Mill-Direct Tubular Cores

Partner directly with Cuzi Particle Board Industrial Ltd. for custom slab sizes, calibrated thicknesses, and mixed container sea freight shipments to your manufacturing facilities worldwide.

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