Laminated Densified Wood Rod

Description

Laminated densified wood rod is a high-performance engineered wood product manufactured by laminating rotary-cut beech (Fagus sylvatica) or birch veneers with synthetic thermosetting resins, then densifying under controlled high temperature and pressure conditions.

The manufacturing process creates a homogeneous, fiber-reinforced material that combines the natural strength of timber with chemical stability, moisture resistance, and tailored anisotropic properties.

Unlike conventional timber, SIDA’s densified wood rods exhibit:

Directional strength optimization through controlled veneer lamination (parallel, crosswise, or tangential)
Density grading from 0.70 to 1.40 g/cm³ based on application requirements
Near-zero moisture absorption after treatment
Dielectric constant matching transformer oil (εr ≈ 3-3.6), eliminating partial discharge risks

The rods maintain structural integrity in transformer oil at continuous operating temperatures up to 105°C, with short-term capability up to 120°C.

Manufacturing Excellence

Our production process involves:

Veneer Selection: Only FSC-certified red beech veneers meeting stringent quality specs
Resin Impregnation: Vacuum-pressure impregnation with electrical-grade phenolic resin (Type E3)
Stacking & Lamination: Veneers oriented at 0° (parallel), 90° (crosswise), or tangential configurations
Hot Press Densification: Hydraulic pressing at >1,500 psi and 150-160°C for 8-12 hours
Precision Rod Formation: CNC turning from densified wood blocks to ensure dimensional accuracy ±0.1mm
Quality Control: 100% metal contamination testing + electrical property sampling

3. Technical Data Tables

Laminated Wood Test Report
Test Items		Unit	Requirement standard	Result	Test method
Density		𝑔/𝑐𝑚³	1.2-1.3	1.33	EC 61061-3-1: 1998
Flexural strength	A direction	Mpa	≥80	99.87
Flexural strength	B direction	Mpa	≤3.0	97.05
Shrinkage	TK	%	≤0.3	1.16
	A direction		≤0.3	0.12
	B direction		≤0.3	0.19
Moisture content		%	≤6.0	2.82
Oil absorption		%	≥5	9.3
Breakdown voltage parallel to the laminations		kV	≥50	85
Test result		Pass

Note:The product specifications provided are for reference purposes only. Please refer to the actual product for final specifications. We also offer various sizes and thicknesses to meet your specific needs. For further customization, please contact us.

4. Application Scenarios

Primary Applications for Laminated Densified Wood Rods

A. Power & Distribution Transformers

Coil Support Rods: Axial support for LV/HV windings, preventing deformation during short-circuit events
Spacer Rods: Radial spacers between disc windings to maintain oil ducts and cooling channels
Lead Support Bars: Rigid supports for high-voltage leads and tap changer connections
Pressure Beam Ties: Connecting elements for top/bottom pressure beams in core-coil assemblies

B. Instrument Transformers

Core Clamping Rods: Mechanical fixing for sensitive measuring transformer cores
Insulating Stays: Internal structural elements in CTs/VTs requiring high dimensional stability

C. Cryogenic & LNG Applications

Tank Support Dowels: Thermal insulation supports for LNG vessel fuel tanks
Cryogenic Pipe Anchors: Low thermal conductivity rods for cryogenic piping systems

D. Electromechanical Equipment

Bushing Core Rods: Central support cores for oil-filled bushings
Switchgear Insulating Links: Mechanical links with electrical isolation in MV switchgear
Motor Wedge Rods: Rotor/stator wedge materials in high-voltage motors

E. Specialized Industrial Uses

Aerospace Tooling Jigs: Dimensionally stable fixture components
Racing Car Skid Board Pins: High-strength, wear-resistant fasteners
Induction Heating Coil Supports: Non-magnetic, heat-resistant structural elements

5. Frequently Asked Questions

Q1: What are the key advantages of using densified wood rods over epoxy glass laminates?

A: Densified wood rods offer superior oil absorption and compatibility, resulting in better impregnation and reduced partial discharge. They are 40% lighter than epoxy glass, easier to machine (no glass fiber dust), and provide better impact resistance. Additionally, their dielectric constant closely matches transformer oil, ensuring uniform electric field distribution.

Q2: How do I select the correct density grade and lamination type?

Grade L (0.70-1.10 g/cm³): General insulation, low-mechanical stress applications
Grade M (1.10-1.30 g/cm³): Standard transformer supports, spacers, and clamps
Grade H (1.30-1.40 g/cm³): High-compressive load applications, pressure rings

Lamination Direction:

Parallel (I): Maximum strength along rod axis for tension/compression members
Crosswise (II): Balanced strength for general-purpose applications
Tangential (X): Specialized for high radial stress applications

Q3: Are SIDA laminated wood rods compatible with all transformer oils?

A: Yes. Our rods are tested and approved for use with mineral oil (IEC 60296), natural ester fluids (IEC 62770), and silicone oils. The low dielectric loss factor (tan δ ≤0.13 at 90°C) ensures minimal oil contamination over the transformer lifetime.

Q4: What machining tolerances can be achieved?

A: As-manufactured rods achieve ±0.1mm diameter tolerance. Post-machining operations (turning, threading, drilling) can achieve IT7 tolerance grades. The material’s homogeneous structure prevents splintering and delamination during CNC operations.

Q5: How does moisture affect performance?

A: Our rods are processed to ≤5% moisture content and exhibit <3% water absorption in 24-hour immersion tests. In oil-immersed applications, the material reaches equilibrium moisture content <1%, ensuring stable electrical properties throughout service life.

Q6: What is the typical lead time for custom rod diameters?

A: Standard diameters (20, 30, 40, 50, 80, 100mm) ship within 7-10 days. Custom diameters require 15-20 days for veneer preparation and densification. Rush orders available for emergency transformer repairs.

Q7: Do you provide certification documentation?

A: Each batch includes:

Material Test Certificate (MTC) per IEC 61061
FSC chain-of-custody documentation
RoHS/REACH compliance statement
Dielectric test report for electrical grades

6. Standards & Compliance

International Standards

IEC 61061: Laminated pressboard for electrical purposes – Full compliance for types P4R, C4R, T4R
DIN 7707: Densified laminated wood for electrotechnical applications
ISO 9001:2015: Quality management system certified manufacturing
FSC® Certification: Sustainable forestry chain-of-custody (FSC-CXXXXX)

Testing Protocols

Every production lot undergoes:

Mechanical Sampling: 5% compressive & bending strength tests
Electrical Validation: 100% volume resistivity screening
Metal Detection: X-ray inspection for ferrous contaminants
Dimensional Gauging: Laser measurement of diameter uniformity
Oil Compatibility: 168-hour immersion test at 105°C