Block Board

Category: Education

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Presentation on Block Board BY N.KANAGARAJ BSF-06-007

Block Board : 

Block Board Blockboard is composed of a core of softwood strips (up to about 25mm wide) placed edge to edge and sandwiched between veneers of hardwood, the 'sandwich' is then bonded under high pressure.

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These blockboard that are generally known as "yellow boards" are composed of at least one base layer made of adjacent wood strips that are glued together one near the other that is along walls perpendicular or transversal to the plane along which at least a face of said board extends, at least one of the faces of the base layer and/or preferably both faces of the base layer being covered by a finish and/or protective resin layer composed of a glue, particularly melaminic or phenolic resin, or the like.

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Eco-Core Block Board: Blockboard is one of the oldest composites ever conceived.  Furniture built with this material was in fact found in the Egyptian Pyramids.  Today, blockboard panels reveal uncommon features of working versatility as they are easy to cut and reclaim, are light in weight, stable and have high mechanical features.  Besides its traditional use in joinery works, the great dimensions of the boards make it advantageous for factories manufacturing modern and quality furnishings, in particular doors and furniture, as the light weight exerts less stress onto hinges, improving furniture life.

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Source for Block Board: Blockboard is made up of a core of softwood strips. These strips may be up to about 25mm wide. The strips are placed edge to edge and sandwiched between veneers of hardwood. The sandwich is then glued under high pressure. Blockboard is not suitable for outdoor use because the glues used are interior glues. Sizes: Blockboard is sold in sheets of 2440 x 1220mm and are normally 30mm thick.

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Block Board

Instruments Used for Making Block Board : 

Instruments Used for Making Block Board The equipment detail list of blockboard product line cross cut saw, double surface fore plane, more round saw, piece together machine, glue machine, pre-press, hot press ,cutting sides saw, sanding machine , veneer dryer, veneer cutting machine, drying house.

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Cross seam machine, cross seam machine, little diameter wood which sawed and cut from horizontal and vertical and processed by series of procedures including polish by dual-plate woodworking planer, saw into specific plate bar by multi-blade round saw, connect it into real wood floor by joint machine, dual-sticky single plate, pre-pressing, hot pressing and sawing from horizontal and vertical.

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Machine for Cutting of the Blocks According to the Requirement

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Polishing Machine Pressing Machine

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Block Board Industries

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Manufacture of Block Board: Blockboard is made up of a core of softwood strips. These strips may be up to about 25mm wide. The strips are placed edge to edge and sandwiched between veneers of hardwood. These battens are then arranged systematically without any/extra gap between them. The face veneers and the core veneers are perfectly matched. Bonding Agent: These are bonded with phenol formaldehyde and urea melamine formaldehyde resin under controlled pressure and temperature to get perfect bonding. The sandwich is then glued under high pressure. The chemical treatment given to the Block Board ensures its durability and resistance.

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Arranging of Blocks Screws & Nails applied after Arranging

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There are several types of resins that are commonly used. Urea formaldehyde resin is the cheapest and easiest to use. It is used for most non-water resistant boards. Melamine formaldehyde resin is significantly more expensive, as it is moisture resistant. Phenol formaldehyde is also fairly expensive. It is dark colored and highly durable. In order to make the final product waterproof, fireproof, insect proof, or to give it some other quality.

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Fixing: Screws and nails may be used to attach blockboard and laminboard but you have to ensure that you make contact with the strips of softwood and not the gaps between the softwood strips. The edges of both blockboard are fixed with the limping and are unattractive and cannot be cleaned up well. Place softwood strips, veneers or fill and paint the edges.

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Finishing: Blockboard may be bought with a variety of applied finishes such as wood veneers and plastic laminate surfaces. If both sides are treated in the same way blockboard and laminboard have a good resistance to warping. The edges of blockboard do not clean up well and are not very attractive, so cover exposed edges with a decorative strip of softwood or fill and paint them. The surfaces of standard boards can be painted, while pre-finished boards are available with a variety of applied surfaces such as decorative wood veneers and plastic laminate facings.

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Blockboard has a good resistance to warping if both sides are left natural or painted/papered. If only one side is finished, then surface tensions build up which will cause the sheet into a bend.

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Fingering Machine Fingered Wooden Blocks

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Block Board Pressing Machine

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Applying Copper, Chromium, Boron Manufacturing Process of Block Board

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Fire & Bending Properties: The fire and bending properties of blockboard with various fire retardant treated veneers. Blockboard were manufactured using untreated fir strips and sandwiched between treated ekaba veneers at final assembly. The veneers were treated with either boric acid (BA), disodium octoborate tetrahydrate (DOT), alumina trihydrate (ATH), or a BA/DOT mixture. Modulus of rupture and modulus of elasticity tests were performed according to Standard. Blockboard were also tested for fire resistance as indicated by a cone calorimeter. Treatments had little negative effect on flexural strength; flexural stiffness was significantly lower for the highest treatment levels. Treatments resulted in a significant reduction in predicted flame spread rate.

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Moisture Resistant Block Board In the use of advanced technology and special composing to ensure totally plain and uniform boards. It ensure no gaps, overlapping or corrugation to eliminate the chance of opening up of the board when cut. These are also totally resistant to termite, borer and other wood destroying organisms.

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Boiling Water Resistant Block Board These provide exceptional strength and durability to the wall cabinets, cupboards, wardrobe and other furniture woodwork. These are user friendly and convenient to work with since they provide additional grip for screws and nails. These Block Boards are available in commercial and waterproof varieties for interiors as well as exteriors. These can be applied to interior and exterior woodwork and furniture like wardrobes, beds, tables along with partitions in offices, flooring and seats of bus bodies and railway coaches and indoor panels and shutter

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MDF Block Board: Used for Furniture, Decoration, Packing Veneered Block Board Face and back: Melamined or veneered face and back, such as sapele, cherry, beech, oak, white, grey, ect. Packing: Pallet packing or loose packing Usage: Furniture, Decoration, Packing

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Drawbacks of Block Board: In the Block boards it has been noted that due to thermal stresses, mechanical stresses and humidity, namely due to the exposure to thermal variations and/or to humidity and/or variations of sun radiation conditions or the like that is light-dark variations, in the long run leaks or cracks in finish and/or protective melaminic resin layers occur in spite of the fact that board faces are covered by melaminic resin layers. These cracks are on the surface of board faces and allow humidity to penetrate to layers made of wood strips that become impregnated with humidity. That causes the beginning of rottenness or decay processes of wood material quickly making the board useless.

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To overcome the drawbacks in the Block Board the methods used are To improve a board of the type disclosed herein before such that the board have improved resistance to thermal, mechanical and environmental stresses by means of simple and not expensive expedients avoiding cracks or leaks in the protective layer. Tearing areas correspond to areas where wood material of strips have in turn leaks, cracks, grain or the like that are by nature present in wood material of strips and they occur not only between areas where individual strips contact but also inside the individual strip.

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The structure of the board according to the invention and solving the problem comprises: At least a base layer composed of at least a layer of adjacent strips glued together one near the other; At least a finish layer composed of a non woven fabric impregnated with melaminic resin.

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Application Furniture, Kitchen Cabinets, Partitions, Exteriors uses, Bank Counters, Ship Counters, Ship Cabinets, Wardrobes Construction, Packing.

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Reference: Forest Utilization By Tribhavn Metha

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