Treatment and analysis of OSB and MDF mill

Treatment and analysis of OSB and MDF mill data (data mining) for reduction of board density variations Martin Feng February 18, 2016

List of Contents 1. Introduction of wood composite panel manufacture processes: Plywood, OSB, MDF & PB 2. Impacts of board density on product performance 3. Factors that affect board density 4. Benefits of board density reduction

Curtain Coater • Typically used for veneer based materials. • Resin is recycled. trough filter resin film veneer • Deposits a film of adhesive. • Resin curtain can break-up due to: (i) blockage in trough, or (ii) fluff on the veneer surface. pump

Interactions between Wood and Glue Mix Fundamental: Mechanical Interlocking Bonds are formed when: 1. All the resin in a droplet is cured beyond the gel point. 2. The resin has penetrated far enough into the bulk of each veneer to repair any surface damage. strand 1 glue droplet strand 2 • glue applied to one veneer only • resin penetrates into other veneer • at full cure, both veneer are mech locked together

OSB Manufacturing Process Log yard to mill Drying Jackladder Debarking Blending Forming Line Stranding Hot Pressing Green Bin Finishing Line

OSB Blending

Typically Particleboard for flat decks and MDF for Profiled Finishes Particleboard MDF

MDF density profiles

Particleboard Process Sawdust/ Shavings Resin blending Dry Refining / Hammermilling Drying Mat Forming Pressing Laminating Sieving Sanding / Resaw Coating

MDF Process Flow Chart

Fibre Preparation Logs must be converted to chips. Shavings and sawdust reduce costs (over 10 fold reduction in raw material cost). Fibres must be softened before they can be refined to long thin fibres. Raw materials are conditioned with steam at about 10 bars in a digester (steam vessel) that is directly connected to a refiner.

Refining Knowledge borrowed from Pulp and Paper Industry

Adhesive Resin is a Major Cost • Interior Application: Urea-formaldehyde resin • Exterior Applications (not common): Phenol-formaldehyde or MDI • Resins custom formulated mill by mill due to species variation effects and the acidity of the wood

Drying

Simplified MDF Process Flow Chart Wood Furnish Presteam Board Resin Refiner Continuous Press tube dryer

MDF Panel Manufacturing

PB Panel Manufacturing

Board properties affected by density 1. 2. 3. 4. 5. 6. 7. 8. Internal bond strength Bending strength Thickness swell Paintability Machinability Formaldehyde emissions Tendency to warp Panel weight

Factors that affect board density & density variations 1. 2. 3. 4. 5. 6. Wood species Fine content Mat forming Mat moisture content & distribution Adhesive loading rate Press temperature distribution

Benefits of reduction of board density variations 1. 2. 3. 4. Lower target board density Lower variable costs across the board Lower shipping cost Lighter products in service and applications

Student project work Project for reduction of board density variations in OSB and MDF production would involve: • Understanding of OSB and MDF production processes. • Collection of mill data related to board density variations • Data treatments and analyses for trends and correlations (obvious and hidden) • Presentation of findings • Documentation of the work (reports and thesis)