powerpoint of plywood manufacturing

8/22/2019 powerpoint of plywood manufacturing

1/33

Plywood Manufacturing

By: Group V


2/33

Contents of the report

Introduction

Brief History

Types of Plywood

Types of Adhesives

Manufacturing Processes


3/33

Introduction

PLYWOOD: AN IMPROVED WOOD


4/33

In1500 B.C.,Egyptian craftsmen bonded thin pieces oebony wood to the exterior of a cedar casket found in the King Tut-Ankh-Amon

. In the 1600s, the Greeks and Romans made the decorating furniture with thin pieces of wood became knveneering, and the pieces themselves became known as ve

Until the late 1700s, the pieces of veneer were cut entihand

In 1797, Englishman Sir Samuel Bentham applied for covering several machines to produce veneers.

Brief History


5/33

. In about 1890, laminated woods were first used to build doo

In 1928, the first standard-sized 4 ft by 8 ft (1.2 m by plywood sheets were introduced in the United States for ugeneral building material.

. In the following decades, improved adhesives and new metproduction allowed plywood to be used for a wide va

applications.

Today, plywood has replaced cut lumber for many conspurposes, and plywood manufacturing has become a muldollar, worldwide industry.


6/33

Plywood

It is a manufactured wood panel made from thin of wood veneer

It is a sandwich of thin layers of wood held togethglue, with the grain of each layer at right angles to tthe one next to it.

Plywood is used instead of plain wood becauplywood's resistance to cracking, shrinkage, splittintwisting/warping, and because of its generallystrength.


7/33

Plywood

It is flexible, cheap, workable, re-usable, and can u

be locally manufactured.

Plywood is also strong; since it consists of an odd nof firmly joined layers in which the grains are atangles to one another, it has nearly equal strength

directions.


8/33

Layers of Plywood

Plywood may consist of 3, 5, 7, 9 oreven more plies or layers.

The innermost layer or center is thecore. On each side of the core are

crossbands.

The two outside layers are thefaces; these may be of decorativewood, if desired, thus supplying

beauty as well as utility.


9/33

Types of Plywood

There are two types of plywood

A. Softwood Plywood

B. Hardwood Plywood


10/33

What Are

Veneers?

In woodworking, veneerslices of wood, usually thinn(1/8 inch), that typically a

core panels (typically wboard or medium-density fproduce flat panels such and panels for cabinfloors and parts of furniture

Veneer is obtained eitherthe trunk of a tree or byrectangular blocks of woflitches


11/33

SoftwoodPlywood

These are made of Dhemlock, pine, and othewoods.

Softwood plywood is mby gluing several laysoftwood veneers togetadhesive.

Softwood plywood is usesiding, sheathing, roof dconcrete form boards, flocontainers.


12/33

SoftwoodPlywood

The interior grade hasoybean glue as the bonAlthough this type resists moisture for a w

prolonged or repeatedloses its strength and more suitable for buildings where moisexcessive

The exterior grade is bsynthetic resin gluewaterproof. .It is morthan the interior grade adhesive is more expenprocessing more complic


13/33

HardwoodPlywood

Hardwoods generally corrdeciduous species. plywood commonly use woinclude oak, poplar, map

and larch.

Hardwood plywood in genmaterial of the cabindesigner, and architect. Itcolors and diversity of funlimited.

Hardwood is graded accits resistance to moistmoisture resistance of high, of Type II moderaType III low.


14/33

Types of Adhesives

The type of adhesives used affects the ability of plyto resist moisture, bacteria and heat. The strength o

joint depends upon the fact that glue, while liquid,into the cavities of wood structure and then solidifies

The glues and adhesives used in woodwork and plyincludes animal, vegetable, casein, soybean,albumin, and synthetic resins.


15/33

1. Animal Glues

These are among the oThey are made from hitrimmings or bones of the

Animal glues are usuallywater and melted. They shhot to prevent decombacteria.

For best results, the wopreheated before the glue

Because of their high glues are used only withand highly figured veneer

They have little, if any, moisture and are attacked


16/33

2. Vegetable Glues

These are made from a usually the cassava root

They are inexpensive,

joints, can be used coldkept in good working cmany days.

Besides being difficult tbrush, however, they pieces of veneer and lacto water and bacteria.

Their use in plywood to indoor paneling and phumidity does not vary


17/33

3. Blood AlbuminGlues

The blood of cattle is usource of these glues.

While their resistancis high, they are attack by bacteria. they stain veneer, havand require considerabpreparation for use.

When used cold, thesejoints of moderate when hot pressed, joinvery strong.

In former years textensively used manufacture of plywood, but now theonly to extend and foglues.


18/33

4. Casein Glues

For moisture resistancasein glue obtained milk is used. This typinexpensive and easily

tends to dull the edgcarpenters and cabinetm

Since it may decay, a is usually added to pro

Although casein glue strength when woccasionally, it loses strcontinuous exposure to

Plywood made with finds widest use inside in places where moistuare not severe.


19/33

5. Soybean Glues

This adhesive is madmeal that remains soybean has been squee

of its oil. It is almost as water-re

strong as casein glurequires a preservativdecay.

It is less expensive thatbut produces weaker used on dense hardwood

Serious staining occursused on thin veneers.


20/33

6. Synthetic ResinGlues

Exterior walls, borefrigerator cars lininboth that retain str

durability under waconditions, even aftewetting.

For such purposes thresin glues, which ar

of the chemical labooutstanding.

These resins also resdecay.


21/33

5. Soybean Glues

This adhesive is madmeal that remains soybean has been squee

of its oil. It is almost as water-re

strong as casein glurequires a preservativdecay.

It is less expensive that

but produces weaker used on dense hardwood

Serious staining occursused on thin veneers.


22/33

The PlywoodManufacturingProcesses


23/33

Step 1: LogDebarking andCutting The log emerges fbarker after h

been strippedbark.

It is also cut intolength to enable

processin


24/33

Step 2:Log Heating The logs a

conditioned steam or hot w

improve peel q


25/33

Step 3: Lathing At the lathe, ablade peels thnow called a

into a continsheet of ven


26/33

Step 4:VeneerDrying The dryer redumoisture conDrying is don

uniform tempe

and also desmicroorgani


27/33

Step 5: Gluingand assembly Wide cross core and long panelare layered an

to give the plygreater strengdimensional st


28/33

Step 6: Pre-pressor Cold Press The Pre-press is uniexpands and stabilayer to give a waproduct. It also euniform spread

specially formulatedwithin the lay


29/33

Step 7: Hot Press Each board is put seinto hot-presspolymerization at temperature. This

uniform density at

in the plywood. Afpressing the boards for 24 hour


30/33

Step 8: DimensionCutting /Trimming The boards are thorizontallyvertically. A utechnique of

cutting is usedthe final cuttensure dimen

accuracy


31/33

Step 9: Sanding Surface sandingin an automatibelt sanding mThis gives a s

surface to the pwhich helps insurface finish r

for interio


32/33

Step 10:Packaging andShipping The plywood is

and dispatchedvarious destin


33/33

The PlywoodManufacturingProcesses Video

Presentation

powerpoint of plywood manufacturing

Documents

Transcript of powerpoint of plywood manufacturing