MARKET SURVEY ON PLYWOOD

SUBMITTED BY :1. AAKASH BAREJA2. DIVYANG CHEVLI3. PRATIK NASIT4. RACHNA CHOVATIA5. KRISHNA PANCHANI6. PRATHNA VAGHASIYA

SUBMITTED TO:1. BANKIM DAVE2. AMEE MERCHNAT

• Defination of Plywood• Panels comprising of at least three layers (or ‘plies’) of thin wood bonded

together with an adhesive. Each ply is usually orientated at a right angle to the adjacent layer in order to improve strength and reduce the probability of shrinkage.

• The outer layers of the board are commonly referred to as the ‘face’ and ‘back’ and are graded based on quality. The intermediate layers are collectively known as the ‘core’. Plywood glue is graded for suitability for internal or external use.

• Plywood is a manufactured wood panel made from thin sheets of wood veneer. It is one of the most widely used wood products.

• It is flexible, inexpensive, workable, and re-usable, and usually can be manufactured locally.

• Plywood is used instead of plain wood because of plywood's resistance to cracking, shrinkage, splitting, and twisting/warping, and because of its generally high strength.

INTRODUCTION

There are mainly two types of PLYWOOD1) COMMERCIAL PLYWOOD.Generally a red hardwood species is known as commercial plywood. It is bonded together with an interior grade UF resin. It provides a veneered surface that can be stained to matchthe predominant species in the construction.Price Range : Rs38-78 (18mm) ,Rs31-50(12mm)

TYPES OF PLYWOOD

2) WATERPROOF PLYWOOD:-Plywood reacts with both aluminum and marine plywood is known as waterproof plywood. It is for use on both interior and exterior purposes. It has black colored shades.Price Range: Rs77-98(18mm),Rs54-75(12mm)

Marine Plywood – Exterior Glue• Produced from moderately durable species with an exterior glue line allowing this panel to

survive longer in high moisture environments.• The superiority of marine plywood for demanding end uses relates to the greater control over

types, thickness and quality of veneer and the manufacturing processes which the marine standard imposes.

• These requirements make marine grade plywood more costly than the equivalent general purpose 'exterior' type, a fact which should be borne in mind when deciding which type to specify. Price : Rs 76 onwards

Uses• General joinery, boat building, panels in exposed areas.

MARINE PLYWOOD

This ply is used to make curved surfaces ,Furniture, model making, shopfitting, barfitting, general joinery, scenery and stage construction.Thickness : 6 mmPrice: Rs 33(per sq feet) onwards

FLEXIBLE PLYWOOD

Useful for safety in public buildings , electric rooms ,high temperature zones where possibility of catching fire is more Price: 75 per sq feet for 18 mm

FIRE RETARDANT PLYWOOD

The Manufacturing of Plywood

1. Selecting the Log 2. Stripping the Bark 3. Peeling the Log 4. Making a Continuous Ribbon of Wood 5. Cutting and Stacking 6. Gluing the Wood 7. Pressing the Wood 8. Trimming, Sanding, and Finishing9. Conclusion to the Manufacturing of Plywood

STEPS

SELECTING THE LOG• Plywood is made from several different

species of trees. • The first step in the manufacturing process

of plywood is the selecting of the logs. The logs that are selected are chosen for their straightness and roundness.

• The selected logs are then stripped of their bark. According to the following picture, the logs are fed in from the right by chain conveyors. The logs are going to be stripped so therefore, they are rotated by ridged wheels as the cutting head on the track reverses the log from end to end.

STRIPPING THE BAR

PEELING THE LOG• The next step of the manufacturing process

is peeling the log. The log sections, which show the marks of the debarking knives, are fed into the lathe loader where the log revolves around on a huge lathe against a long cutter blade which is reduced to a 6-inch core or sawed into lumber or chipped (44). The following illustration shows the operation of the peeler.

• Following the peeler process, the next step in the manufacturing process of plywood is taking the logs and making them into a continuous ribbon of wood. The cutting edge of the lathe is forced against the spinning log. The wood is unwound in a continuous ribbon varying in thickness depending on how its used

MAKING A CONTINUOUS RIBBON OF WOOD

CUTTING AND STACKING• The standard size for the pieces of wood to

be cut is 4’ X 8’. The thickness of the plywood will be determined later when the sheets are glued and pressed together to a varying thickness of which ¼” to ¾” is the most common. As the sheet emerges from the peeler it is scanned automatically and then it is stacked green and is prepared for the transferring to the drying ovens

• The next step in making plywood is the gluing of the plies together in order to determine the desirable thickness of the plywood sheet. Modern methods of manufacturing use synthetic plastics such as urea resins or phenol-formaldehyde for bonding the plies together. These glues are mixed mechanically and then spread on alternate layers of lumber by passing between pairs of grooved metal or hard rubber rollers

GLUING THE WOOD

PRESSING THE WOOD• The following step in manufacturing process is the procedure of pressing the glued

sheets together to a desired thickness. One example of a hot press machine.

• Hydraulic or pneumatic presses squeeze the plies together with heat and pressure or with just pressure only. When heat is used the glue hardens within a few minutes. The glue solidifies as the plies are pressed together; and once the pressure is released, the boards are considered dry .

• Lastly the sheets have to go through a process that gets them ready to be shipped out for market. This processes involves trimming, sanding and finishing the sheets. This process also takes the sheets down to the proper size that is desirable to the consumer. This is what makes the final smooth edges that are seen in the modern lumberyard. The finished panels of plywood are then divided into two groups indicating whether they are for interior or exterior use. Plywood may carry a quality grade, which is indicated with the letters A through C, with A being the highest quality. This grade is based on requirements set by U.S. Commercial Standard CS - (35-36) (Wood 468).

TRIMMING, SANDING, AND FINISHING

CONCLUSION TO THE MANUFACTURING OF PLYWOOD

• These are the steps of the manufacturing process of plywood from the original type of tree chosen, clear to the completed sheets of plywood stamped and ready to be shipped to your local hardware stores and lumber yards. This process shows how the plywood, which the customer buys, comes from a variety of different tree species. It also shows the mechanics of how the plywood you buy is made into widths, lengths and a variety of different thicknesses depending on the use of the material. Hopefully, this illustrates the process of how a tree is manufactured into the plywood that is found in a local lumberyard.

MDF is an engineered wood product consisting of softwood fibres bonded together under high heat and pressure. MDF is a very smooth, high quality board with an equal density across all of the panel. It is easily machinable and has no 'natural defects' such as knots as seen in other panel products. MDF also has two major types1)COMMERCIAL MDFCommercial MDF is softer so it can be carved and textured MDF is also available in the market.The problem with this softer MDF is that colour does not set well over its surface bubles will be visible if coloured . Thickness : 3,4,6,8,12,18 mmPrice : 10 Rs-77Rs ( per square feet)2)WATERPROOF MDFThis is used in places where the surface is exposed to water or places where humidity is more than 65% . The advantage of waterproof MDF is that colour or duco set well on the surface of this material so it gives a beter look than commercial MDFThickness : 3,4,6,8,12,18 mmPrice : !6 Rs – 87 Rs (per square feet)

Medium Density Fiber Board

Schematic of the MDF production Proccess

1. DEBARKING2. CHIPPING 3. PULPING4. THE BLOW LINE5. MAT FORMATION 6. PRESSING 7. FINISHING

Once the MDF plant has obtained suitable logs, the first process is debarking. The logs could be used with the bark, as could any fibrous material, but for optimisation of the final product the bark is removed to; decrease equipment damaging grit, allow faster drainage of water during mat formation, decrease organic waste load by 10-15 %, stabilise pH levels ( reduces corrosion of tools ) and increase surface finish. The most popular debarker used in MDF manufacture is a ring debarker (shown below), though rosser head and drum debarkers can be used.

Though some plants accept chips directly from other operations, chipping is typically done at the MDF plant. A disc chipper, containing anything from four to sixteen blades, is used. The blades are arranged radially on a plate and the spinning plate is faced perpendicularly to the log feed. The feed speed of the logs, the radial speed of the knife plate, the protusion distance of the knives and the angle of the knifes, control the chip size.

DEBARKING

CHIPPING

MDF takes much of its characteristics from the fact that it uses wood cells, (tracheids, vessels, fibres and fibre-tracheids), rather than particles. This can be done by a Masonite gun Process, Atmospheric or Pressurised Disk refiner. The Asplund defibrator pressurised disk refinement being that primarily used in MDF manufacture. The chips are compacted using a screwfeeder into small plugs which are heated for 30 to 120 seconds (this softens the wood), then fed into the defibrator.

PULPING

After defibration fibres enter the blowline. The blowline is initially only 40mm in diameter with the fibres passing through at high velocity. Wax, used to improve the moisture resistance of the finished board, and resin are added in the blowline while the fibres are still wet, as dry fibres would form bundles, due to hydro bonding, and material consistency would be lost. The blowline now expands to 1500mm in diameter and fibres are dried by heating coils warming the blowline to about 550 F

THE BLOWLINE

In order to form a continous and consistant mat the the following problems must be over come: the fact that considerable air velocities must be maintained to

suspend fibres, fibre/air suspension does not flow laterally on a horizontal support and fibre form lumps. One way of overcoming this is a Pendistor.

The mat can either be laterally cut to size as it leaves the pendistor or it can be cut half way through its run by a synchronised flying cut off saw.

The density profile of the the panel is critical to acheiving satisfactory strength properties. CAs an example for a 16mm board:

Press closed. 20 seconds to bring mat to 28 mm.28 seconds at 26mm.23 seconds at 25mm.125 seconds at 18.3Total time of 330 seconds to bring board to 16mm, then decompression time.

After pressing boards are cooled in a star dryer, and final trimmed and sanded. They are given a few days storage to allow complete curing of resins. The boards are commonly given a coloured melamine laminate, though natural wood veneers and raw MDF are common.

PRESSING

MAT FORMATION

FINISHING

PLYWOOD MDF (Medium Density Fiber Board)

Plywood is made from solid wood and thin layers of wood veneer are glued together

MDF board is made from wood fibres.

Plywood incurs some wastage during manufacture

The wastage of wood is nil in MDF manufacturing and it can be made by mixing variety of wood fibres.

Plywood can not be coloured directly MDF boards are more attractive and you can paint it in whatever colour you want.

Plywood can be simply nailed or screwed in making furniture

MDF needs certain technique to join.

Plywood furniture are more stronger than MDF.

MDF Furniture is not as strong as that of plywood

BLOCK BOARD PARTICLE BOARD

Particle boards are made by glueing together very small chips of wood (particles of wood) and sawdust to each other using phenolic resins, and pressing the mixture firmly together to form flat boards.

Blockboards are made using solid rectangular blocks of wood laid side by side and joined end to end, and covered on either side by layers of thin plywood sheets. The blocks used are usually softwood

It can be quite safely said that blockboards are stronger and more durable than the low density particle boards

Not as strong as block boards

Working with blockboards is also much simpler than with particle boards, since the traditional methods of using nails as well as screws works with it.

Hand particle boards need only screws and working with it using traditional wood working tools is quite difficult.

while decorative laminates need to be separately glued to the blockboard as is done in the case of plywood.

Particle boards are usually laminated at the time of their manufacture (pre-laminated particle boards)

The cost of blockboards will be higher than that of particle boards but still it is lesser than the cost of plywood sheets of the same size.

Less cost