APROJECT REPORT ON Quality Control &It`s necessities in Plywood Industries

SUBMITTED TO:H.N.B GARHWAL UNIVERSITY, SRINAGAR (UTTARAKHAND)IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF BACHELOR OF SCIENCE IN FORESTRY (2010-2014)

SUBMITTED BY: SIDDHARTH DAULAGUPHUB.Sc. Forestry VIIIth semester

UNDER THE GUIDANCE OFSARVESH SUYAL(HEAD OF THE DEPARTMENT IN FORESTRY)D.C.A.S.T

DEPARTMENT OF FORESTRY DOON (PG) COLLEGE OF AGRICULTURE SCIENCE AND TECHNOLOGY

CERTIFICATE

This is to certify that the project work entitled Quality Control and its necessities in Plywood Industries is a record of bonafied project work carried out by Siddharth Daulaguphu (ENROLMENT NO. G10661040) a student of B.Sc. Forestry VIIIth Semester of Doon (P.G) College of Agriculture Science & Technology, Camp Road, Selaqui, Dehradun, (Affilated to H.N.B Garhwal University) submitted in partial fulfillment of the requirement for the degree of BSc. Forestry. This project work is carried out under the supervision of Sarvesh Suyal (Head Of the Depertment in Forestry), Doon (P.G) College of Agriculture Science & Technology, Camp Road, Selaqui, Dehradun.

Date :Place : Sarvesh Suyal (Lecturer in Forestry) D.C.A.S.T

ACKNOWLEDGEMENT

I would like to acknowledge all individuals and organisation for their generous help. This project would not have been successfully completed without their contribution. Foremost,I would like to express my heartiest thanks to the directors of Janardhan Plyboard Industries Ltd. Viz; Shri. Gaurav Singhal, Shri. Sanjay Taneja, Shri. Bijindra Singh Nirwan for permitting me for the project work and facilities. I would also like to express my deep sense of gratitude to Shri. Atul Singh(Work manager, Janardhan Plyboard Industries Ltd.) for his valuable time,practical suggestion,support and guidance throughout the completion of this project. I owe my gratitude and appreciation to Shri. H.C Joshi (Quality Control In-Charge,Janardhan Plyboard Industries Ltd.) for his valuable time,fuitful suggestions and logistic support for project work and report preparation. I would also like to extend my special thanks to Shri. Sarvesh Suyal(H.O.D forestry) for his guidance and Mrs. Vishaka Saxena who arranged the industrial attachment at Janardhan Plyboard Pvt. Ltd. at Langha road. Last but not least; I would like to thank my family and friends (specially Rishi Jaiswal) for supporting me morally and spiritually throughout the project preparation.

Siddharth Daulaguphu

DECLARATION

I hereby declare that this project work entitled Quality Control and it`s necessities in Plywood Industries is a bonafied and genuine work carried out by me at Janardhan Plywood Industries Limited under the guidance of Sarvesh suyal (Head of the Department in Forestry) Doon (PG) College of Agriculture Science and Technology.

I further affirm that, the contents of this project report shall not be published in any form whatever without any prior approval of the guide and the original organisation where the work has been carried out.

Date: Place: Dehradun Siddharth Daulaguphu

CONTENTS

I. INTRODUCTION

II. JANARDHAN PLYBOARD INDUSTRIES LIMITEDIII. LOGYARD,PEELING AND BOILER

IV. SEASONING CHAMBER

V. FABRICATION

VI. DRYING SECTION AND VENEER

VII. RESIN MANUFACTURING

VIII. HOT PRESS AND DEFECTS

IX. LAB

X. FINISHING,DESPATCHING AND STAMPING

XI. QUALITY CONTROL

XII. CONCLUSION

INTRODUCTION

The use of plywood is an appreciable step in the direction rational utilization of wood. The plywood including block board, flush doors have certain advantages over solid wood in addition to some physical and mechanical properties. In developed countries wood based panels have largely replaced solid wood and have indispensable for housing. The development of wood based panels started with manufacture of plywood at the turn of the 20th century. Quality control as an effective system for integrating the quality development and quality maintenance effort of all the various groups in an organization so as to enable production of maximum unit goods of specified quality at the most economic level which allow full satisfaction(Singh and Das 1998). In wood based panel industries, especially in a plywood industries for instance the quality control would commence right from purchase of logs and involves all the processes from peeling, drying, gluing and assembling of veneers, pressing, trimming, sanding, finishing operation as well as packing and shipping.The main objective of the present study is to inform the necessities of the quality control management in plywood industries and how to control the quality at every steps of the production.

JANARDHAN PLYBOARD INDUSTRIES LIMITED (1987-Till Date)

Janardhan Plyboard Industries Limited (JPIL) begin in 1985 with just one simple idea "A smile on the face of their costumers" which has always been an obsession. JPIL takes pride in one of the most quality conscious and innovative team of professionals with rich experience in their respective area of specialization. The standards house quality system is in excess of the national standards requirement. Today after years of bard work and dedication in ensuring the smiling face of the customers, JPIL is now the flagship company of the business group.The detail of the factory is as under and the work on panel product was carried out.1. Name of factory:Janardhan plyboard Industries Ltd. Langha Road Industrial area, Sahaspur, Dehradun.

2. Year of Establishment :July 7,1987

3. Production of Factory :Wood based panel Products.

4. Constitutional:Companies Limited by Indian Companies Act.1956

5. Organizational Structure:Board of directors -

Mr.S.SGoyalM.D Mr ,Anil Goyal Exe. Director Mr,N.N Dingahal -Mr.Hikapur, Mrs S,D,Goyal Mrs Soumya Goyal

6. Marketing Strategy:By the help of sales staff

7. System of Accounting :Under control by C.A.

8. Factory working:(profit /loss)Upward Trend in profit, Bonus, Distribution to Employees

PRODUCTS PREPARED IN JPIL:-

IS: 303 Plywood for general purpose MR and BWR grade (1989) IS: 1659 Block board (2004) IS: 2202 Flush door solid core type (1999) IS: 710 Marine plywood BWR IS: 4990 Shuttering grade densified IS: 848 Resin, Glue shear strength(GSS) IS: 1734 methods of test for plywood

BRAND NAMES :-

GEE Door GEE Ply GEE Board Santro Board GEE Conplus-Shuttering GEE Construction-Marine Ply GEE Dcor GEE Corner Ply

LOGYARD AND PEELING AND BOILER DEPARTMENT

BOILER DEPT : The boiler used in the Janardhan Plywood Industries is limited to only 6 tons, it runs for the whole week except on Sunday. It generates 5 kg/hour steam in a day depending on the amount of steam needed by the industry. Waste like leaf, fodder, sugarcane waste, husk etc are used in the boiler department as fuel and also around 9-9.50 quintal of oil / hour is required to run the machine. Thermea-B is quite expensive but this industry rely only on it. Safety precaution is a very much needed process to ensure uniform and steady work for the labourers. Safety valve is attached to the boiler machine for desperate measures.A working motor pump of about 25HP is required to transport the oil(Thermea-B) to every part of the factory. The excess(ash) products are removed every Sunday and pH and TDS(impurities of water) are maintained on records.

LOG YARD: Different species used for manufacturing of plywood are given as follows: Populus spp Silver oak Mango Toon Eucalyptus Gurjan

Logs brought from the forest into the factory premises with the help of trucks are kept in log yards. Log yard is a place where logs are kept under direct sunlight for the purpose of natural air drying. They (logs)are always placed in perpendicular position towards the direction of sunlight or in other words opposite direction. In doing so, it reduces checks and splits occuring in wood. For making veneers defect free samples are used which are without knots. But in this factory veneers are mostly brought from another larger industries for saving time and labour. The logs are kept in open in the log yard and so they are prone to fungi and insects which will result in degrading the quality of the wood to be used for further veneer manufacturing purpose. For this reason chemicals such as asphalt pigments, lamp black, coal, resin, paraffin wax are use to overcome this problem. This retains high moisture content and eliminates checks.

PEELING: The logs are first immersed in water pond for few days so that the barks can be removed easily due to the increase in size. Debarking is done with the help of axe, man power is needed for this purpose. After the debarking of logs, they are than put into the log steaming chamber or tank. The logs are cooked for required time varying with the type of species. It is to be checked that no unwanted materials is to be put along with the log in the steaming chamber for it may create problem while cooking and peeling which may result in production loss. Steaming imparts plasticity to the wood for easy and smooth cutting. It improves wood colour, prevents infection in wood and makes uniform distribution of moisture in the wood. Ultimately it helps in the process of veneer drying evenly.

The logs are then turned against the sharp blades of the peeling machine in a tangential direction in archimedial spiral, concentric to the growth ring with equidistant winding. The distance between the windings equals to the veneer thickness. In this process the cutting speed and the knife cutting angle is to be maintained which varies from species to species. The thickness of veneer peeled from the peeling machine in this factory varies from 1mm to 3.5 mm. The peeling machine in this factory is not in used anymore. The veneers are brought from other larger industry which saves time and labour. A machine-operated saw is present in the log yard to separate the logs into desirable sizes of batons to be used in making of flush door, block board etc.

Segregation of veneers: Fibre roughness, death knots, head cracks etc should not be present on the veneers to be used. In other words; short length to be resized, rough core should be segregated, hard and soft core should be segregated, unusable portion such as rough area, rotten portion, death knots, holes are to be removed. If the length is found to be less than the required size then they are used as panel lines instead of the glue panel core. SEASONING CHAMBER

It is a chamber in which batons derived by cutting the logs into desired sizes are put for klin drying or drying inside enclosed walls. But mostly 25 mm thickness and 4.5 inches width size having batons are stake over one another and are put inside the seasoning chamber. Around 1050 batons (2 stakes each of 525) can be put in the chamber at a time. It nearly takes 4-5 days to complete the full process of drying or seasoning. During summer it takes 3-4 days whereas in winter 5-7 days for complete process. The coils and huge fans are attached to the walls of the chamber which helps to produce warm air. The coils gets heated by the steam transported from tube connected to the boiler. There are 6 fans in each of the 7 chamber out of which only 3 is still working. The temperature required inside the chamber can vary from 35 degree centigrade to 80 degree centigrade. A lid is fitted above the chamber which is off outmost importance because it is the only hole through which the moisture goes out of the chamber and for this it is kept open for 2 days and then closed again. The species used are mostly poplar if not then mango. The moisture present inside the batons should be 105%. Sunday the boiler remains closed so does this chamber.

PRECAUTION: There should not be any leakage of steam and the valve should be rotated to let the moisture go out every 1 hour. The wheel (motor) should be properly greased and maintained. Care should be taken so that overheating or less heating does not take place.Sometimes fibre arises so it is necessary. FABRICATION

Fabrication means the process of manufacturing an item by assembling different raw or semi-finished materials instead of making it from a readymade parts or components.

1) Rip saw section: Out here the flank are passed through the circular sawto give out smaller sizes of batons. The sizes maybe of following:

Thickness of the door/board(mm) Width(inches)

19 2,3,4,5 25 3,4,5,6 30 2,3,6 32 2,3,6 35 1,3,4 38 1,3,4 40 5

RIP SAW :- RPM - 2800 Motor - 25 H.P Motor pulley size - 10 Machine`s pulley size - 5

CIRCULAR SAW:- RPM - 2800 Numbers - 2 Motor - 2 H.P Circular disc - 12 Motor pulley size - 7 Machine`s pulley size - 3.5

2) Frame section: The batons are joined by finger joints so that it won`t break easily for frame while making flush door. And the frames are attached to each other with the help of fastner. The species used maximum for making the frames are pine, mango.

Length of the flush door frame Width 81 36,39,33,30,27 78 33,30,27 72 30 84 45,48,33,30,27

Pendulum circular saw: It has Tungstan carbide tip(TCT).

One in number Motor 25 H.P RPM - 640 Teeth/inch of blade - 3

Finger shaping machine: It is use for chipping the batons into the finger shape like which makes it able to be joint together, it helps the frame to remain strong and unbreakable.

Motor - 3H.P RPM - 2800

1) Board fabrication : All the small batons collected from rip saw section are again run through the cutter to be put in the block board and flush door in smaller sizes. While running the batons through the cutter we are to cut thin gaps on it so that if some batons are curve , could be bend and adjust to fit in the block board and flushdoor.

No. 1 Vertical band sawNo. 2 vertical band saw

Wheel size 36Wheel size 36

Blade size 3Blade size 3

Motor 10 H.P.Motor 15 H.P.

Motors pulley size 5Motor pulley size 12

R.P.M. of motor 1440R.P.M. of motor 1440

The red paper : The paper used for covering the waterproof quality of plyboard is red in colour. The width of this paper is measured in GSM girth per square meter. The cost of this paper roll is Rs. 105/kg . At a time about 400/500 kg of paper roll is used. This paper is run through the Paper impregnated drier machine. Before running into the 1st chamber, densified resin is put all over the paper which is responsible for the waterproof quality. Next it is pass through the steam chamber. The inlet steam temperature is 116C whereas the outlet steam temperature is 185C,the average or required temperature is 120C. Lastly, the fan cools down the paper when it passess from second chamber to the last one before it comes out of the machine. The paper that is already out of the machine are then cut with the help of digital caliper.

DRYING SECTION AND VENEER Veneer:- A thin layer of finely grained wood glued together in numbers to make a base for plywood manufacture can be called as Veneer. Moisture content:- For developing satisfactory glue bond, optimum moisture content in the timbers and veneers is required. As such the material should be dried to a moisture content not exceeding 12 %. Sizes of veneer:- Length(feet) Width(inches) 3 8 4 6 Species used:- 1) Eucalyptus : In this veneer moist brown, black patches is visible. 2) Poplar : In this veneer no patches is seen, in other words. It is a clean sheet or white in colour.Moisture content of the green veneer: Eucalyptus: 60-65% Poplar : 80-85% Moisture content of dry veneer: 6-8% Freshly peeled veneer or the veneers brought from another industry is are passed through the dryer for drying at 134 degree centigrade approx.Care should be taken not to overlap any veneer while placing them in the inlet of veneer. For this a suitable gap is maintained between the veneers while passing them though the dryer. The wet veneer is fed into the dryer inside which hot air (steam) in blown . As wet veneer becomes dry it moves out of the tight and compressed dryer to the discharge point of the machine becoming flat in shape. The veneers are than cut with the help of Hydraulic jointer so to make all the veneers of same sizes. Face veneer: The very thin layer extracted from the heartwood of raw timber or log which is used for putting at the topmost portion of the plyboard for decorative purpose and not for strength can be called as face veneer.Face thickness 30 mm Face veneer species which are brought into this industry from their respective places are as follows :Species NativeHollong - Arunachal PradeshGurjan - BurmaKeruing - MalaysiaBurma Teak - Burma(decorative veneer)

Size square feet square metre 8*4 32 * 2.9768 (2.44 * 1.22)7*4 28 * 2.6108 (2.14 * 1.22)6*4 24 * 2.2448 (1.84 * 1.22)8*3 24 * 2.2448 (2.44 * 0.92)7*3 21 * 1.9688 (2.14 * 0.92)6*3 18 * 1.6928 (1.84 * 0.92)

Ammonia treatment of veneer:

For this purpose the veneers are stack over one upon the other and put inside the chamber where steam is passed from the boiler. The liquid ammonia is used for this treatment. The veneers are kept inside the closed chamber for about 12 hours. When the veneers are taken out we can notice that the colour of the veneer has turned into reddish brown in colour. RESIN MANUFACTURING

P.F Phenol formaldehyde: This resin is made for applying on the core plyboard of exterior grade.

Following steps is carried out while making P.F resin :-

1) 800 litre of phenol and 1400 litre of formaldehyde is taken to be mixed in 1 solution together in the ratio of 1:1.8 ( C6H5OH : HCHO ).2) A 40 kg solid form of caustic soda is then mixed with 100 litre of water to form a solution.3) The caustic soda solution is put into the mixed solution of phenol and formaldehyde.4) The solution is cooked or heated in a double jacketed tank or cylinder for 1 hour.5) Exothermic Reaction starts and slowly the temperature will rise from 40 degree to 60C.6) When the reaction reaches 60C, the machine running the double jacketed cylinder should be stopped to cool down the reaction.7) Even though the machine is switched off at 60C reaction, it rises up to 90C automatically. 8) The machine should not be switched on at least for 4 hours. The temperature then cools down.9) The resin is then put out in a small beaker to check its viscosity with the help of B4 cup:

Water tolerance 5

Water flow - 18

Colour - Dark red

The resin is now ready to be used.

* Double jacketed Cylinder tank - 3 ton capac2500 kg glue making capacity.

U.F Urea formaldehyde : This resin is used in the manufacturing of the least quality or the interior grade ply board. The ply board made from these resin are sensitive to all the external forces like heat, water etc. Following steps is carried out while making U.F resin :-1) In a double jacketed cylinder tank 1200 litre of formalene and 500 kg urea are mixed in the ratio 1: 2.4 (NH2CONH2 : HCHO) to get a solution.2) 2 to 3 litre of caustic soda solution is then mixed into the double jacketed cylinder.3) It is to be noted that the PH of formalene should be 8.4) The steam or heating is started. The solution is to be cooked atleast for 1 hour.5) Due to the exothermic reaction the temperature will rise from 40C to 90C.6) Heating or cooking is done for again 2 more hours and the PH is checked, it should be 7 or 7.5.7) According to the PH, Acetic acid of about 2-3 litre is mixed.8) Should note the time, and the tank should be heated for the next 15-20 minutes. PH here will be 5.5 6 .9) A sample of resin is taken out to check the bonding: Water tolerant : 5 Flow or viscosity : 17 PH : Atleast 8 8.5 10) Stop the machine and let it cool down for 2 and half hour. The resin is now ready to be used. The colour is abit whitish as compared to the P.F resin.

Densified resin : This resin is best of all the quality. It is used for the manufacturing of the waterproof plywood. This resin is used for applying over the red paper which passes through the Paper impregnated dryer machine which is later pasted over the ply board. For the manufacture of this resin, the following process is to be carried out :-

1) 200 litre of phenol,240 litre of formaldehyde and 10 litre of liquid ammonia is put and mixed together in the double jacketed cylinder tank. 2) The machine is started to let the steam flow in unless the temperature rises till 60 degree centigrade to 70 degree centigrade.3) The steam flow is stopped but the temperature will rise till 80 85 degree centigrade.4) Time is noted down.5) The steam is again flowed in for 25 30 minutes into the cylinder.6) Next, we are to take out sample of the resin in a glass beaker. We will notice that the sample is divided into 2 parts ; a solid type matter which is Densified resin and liquid which is water.7) We should always check, that the sample taken out is in the ratio of 2 : 1 (Densified resin : Water).8) We closed the machine after the temperature drops to 40 degree centigrade for atleast 1 and half hour.9) We then extract the densified resin from the tank and then later remove the water which gets stock inside the tank. The resin is now ready to be used. The colour is dark red.

HOT PRESS AND DEFECTS Plywood is the term applied to glued wood construction built of veneers in such a way that the grain of each veneer is at right angle to that of the adjacent veneer. This method is called the cross band construction. The outer plies in a plywood panel are called face veneer and the inner core. Core may consist of veneer of different combinations of species of which poplar and Eucalyptus are usually used.After the application of glue on the veneers these thin sheets are then assembled at the assembly table in odd numbers of 3, 5, 7 etc; depending on thickness which is to be required for the final product. The grain in the adjacent layers lies at right angle to one another. Applied pressure = Face area of the door/Total ramp area * specific pressure Ramp area :- Dial pressure = Specific pressure * Plywood area / Ramp area Ramp area = 3.14 x d2 x number of ram / 4 D = G / 3.14 ( G girth) Normal length of core - 50 mm x 23.05Normal weight of core 780 gram ( dry)Weight of the core after P.F resin is applied 960 gram 23 gram is needed per square foot normallyTEMPERATURE MAINTAINED FOR UF IS 115C-1200C TEMPERATURE MAINTAINED FOR PF IS 140C-150C TEMPERATURE MAINTAINED FOR PF IS 140C-150C

Pressure

SizeUFPF

2.44 x1.2275100

2.44 x1.226590

1.84 x1.226075

1.54 x1.225065

2.44 x0.926075

2.44 x0.925065

2.44 x0.924560

1.84 x0.923550

1.54 x0.775065

2.44 x0.774555

2.44 x0.774050

2.44x0.773040

Normally Time and Pressure required for following sizes:-

P.F Block board 19 mm 20 minutes 12 kg pressure

P.F Flush door 30mm,32mm,35mm 20 minutes 14 kg pressure

U.F Block board - 19 mm 15 minutes 10 kg pressure

Thickness P.FCoreCoreCorePanelPressure

PoplarB`GR-poplarEucalyptusEucalyptus kg

6 mm5 ply2.1 x 2 - -1.4 x 112 kg

9 mm7 ply2.1 x 2 -2.1 x 11.4 x 212 kg

12 mm9 ply2.1 x 2 - 2.1 x 21.4 x 312 kg

16 mm13 ply2.1 x 2 -2.1 x 31.4 x 4 12 kg

19 mm15 ply1.4 x 2 -2.1 x 41.4x4+2.1x214 kg

25 mm19 ply2.1 x 2 -2.1 x 51.4 x 814 kg

P.F Block board 19 mm double core full thickness = 14 kg

ThicknesU.FCoreCore CorePanelPressure

PoplarB`GR- poplarEucalyptusEucalyptus kg

6mm 5 ply 2.1 x 2 -1.4 x 110 kg

8 mm7 ply 2.1 x 21.5 x 1 -1.4 x 210 kg

12 mm9 ply 1.5 x 22.1 x 2 -1.4x2,2.1x110 kg

16 mm11 ply2.1 x 22.1 x 3 -1.4x4

19 mm13 ply1.5 x 22.1 x 4 -1.4x510 kg

25 mm17 ply1.5 x 22.1 x 6 -1.4x7

U.F Block board core full thickness = 12 kg

Hot press - It is necessary for making the veneers flat and smooth. There are 3 hot press in the industry where pressing of panel products which includes plywood, block board, flush door etc.Flow chart for a water proof ply board is as follows:- Red paper (After passing through the Paper impregnated dryer) Face veneerGlued veneerReady ply boardDry non glued veneer Hot PressingGlued veneer Red PaperDry non glued veneerFace veneer Resin or glue appliedGlued veneerdry veneer freshlyGlued veneer Dry veneer Dry veneer Glued veneer

Hot press 1:- Capacity ( in tons ) - 650 tonsBrand - AMBIKA ( Gujarat )Delight - 10 ( 10 ,12 ,15 ,30 variety also available )Ramp area -1815 cm2No. of piston -8Temperature -115C - 120C (U.F)140C - 150C (P.F)Compression loss U.F 1 mm P.F 1.5 2 mmSpecific pressure - U.F 11kg/ cm2 P.F 14 16kg/ cm2 Block board ( 15 minutes P.F ) 19 mm (12 minutes U.F ) 19 mmFlush door ( 20 minutes P.F) 19 mm Hot press 2:- Capacity 1600 ton Ram area 528 cm2 ( d = 91 or 92 cm) Brand- INTERCON (Shri chakra equipment Engineering Bangaluru)Delight- 12 Weight of a normal board 32 kg (Without cutting)Pressure maximum - 320 kg (280 kg average) No. of piston - 8 Temperature - P.F :- 140 - 160C U.F :- 125- 135CTime required to keep the - 30 minutesFlush door, block boardUnder pressure

Time for cooling those - 10 minutesFlush door, block board

Causes of failure in adhesion :- It is dangerous to jump to conclusion on inspection of one or two defective sample. If all is not well with gluing, a thorough check on the process be made. It may well be found that a fault is due to the combination of circumstances, all of which must be considered before corrective measure be put in hand.A) Open glue joint maybe caused by:-1) Imperfect machining, preventing complete contact in the whole length or breadth of the joint.2) Poorly fitted joints.3) Pieces of warped stocked forced together under pressure.4) Excessive moisture content in wood or excessive drying.5) Uneven glue spread6) Glue dried or jellied before pressing.

B) Close,but-week joints maybe caused by :-1) Poor quality adhesive.2) Use of thick or thin mixture.3) Insufficient adhesive being used.4) Adhesive partially dissolved.5) Animal glue overcooked at high temperature.6) The adhesive being allowed to troth in the mixing.

C) Blisters under veneers may be caused by:-1) Poor quality core containing knots.2) Uneven thickness of core.3) Uneven cutting of veneer.4) Steam pocket (hot press).5) Overlapping joints of veneers.6) Insufficient conditioning and flattening of veneer.7)

D) Warping maybe caused due to:-

1) Gluing pieces of wood of varying or incorrect moisture content.2) Gluing pieces of wood of varying species, strength and porosity.3) Adding too much moisture in gluing.4) Bending in the clamp or press.5) Using poorly constructed plywood as base for veneering.6) Improper construction such as:-a) Veneering the face, not the back of the panel.b) Veneering both side, but not equalizing the build as a result of using veneering entirely different strength and thickness.c) Finishing, painting or varnishing a panel face without seating the back.

E) Various surface defects and their causes :-

a) Shrunken joints due to machine before adhesive has dried out of finished contracting.

b) Check due to:-1) Wood being glued at too high moisture content.2) Adding too much moisture in gluing.3) Finishing before wood or veneer has dried out of correct moisture content.4) Improper construction.

c) Wavy or corrugated veneered surface due to:-1) Use of core of varying species.2) Hard and soft grain core.3) Cores having planer marks surfaces.4) Cores having varying thickness.5) Cores having varying moisture content.6) The commencement of delamination as a result of exposure non-moisture resistant adhesive to moisture condition.

F) Staining due to:-1) Alkaline adhesives.2) Veneers left under pressure for too long.3) Veneers glued when too wet.4) Veneers placed under excessive pressure.5) Thin veneers under dark glue.6) Use of porous or exceptionally thin veneer without sizing before gluing.

Defects:- The change in appearance on the ply wood which reduces the strength and economic aspect of the ply wood maybe defined as ply wood defect. It can due to many reasons like uneven drying, low quality adhesive, uneven thickness of the core etc.

Some of the defects are given below:-1) Core delamination:- This defect may arise due to uneven thickness, low temperature, highly adhesive spreads etc.2) Core over :- This defect may occur due overlapping of veneers, labours carelessness etc.3) Core gap :- This occurs due to separation of veneer, low quality veneer etc.4) Core blister:- This defect may occur due to the low quality of face veneer, uneven thickness of core etc.5) Panel over:- This occur due to overlapping of panel while assembling.6) Panel gap :- This occurs due to the uneven thickness of the panel.7) Face crack :- This occurs due to high moisture content U.F- 12%, P.F-10%, low quality face, separation of fibres etc.8) Face short :- This occurs when during plywood preparation, the face veneer remains shorter than the core veneer and after the final plywood is prepared the core veneer appears on the surface where face veneer is absent.9) Face chip off :- It occurs due to low quality adhesive resin( solid content 48-50 in water proof U.F and 45-46 in P.F).10) Steam pocket or blister :- Moisture content too high in cross band and core. LABORATORY

The following lab work was done by me in the Janardhan Plywood Industry Limited :-1) Density of solid wood2) Moisture content of the wood3) Percentage of solid content in P.F resin

1) Density of solid wood:- Size of the solid wood (volume) L x B x H 10.9x1.3x7.2= 102.02 cm

Weight (mass) of the solid wood 54.5 gmDensity of the solid wood = Mass / Volume = 54.5 / 102.02 = 0.49

2) Moisture content of a given wood :- (Green wood)Initial weight of the wood 102.5 gm Oven dried weight of the wood - 60 gmIn case of green wood weight,Moisture content = green wood weight oven dried weight / green wood weight X 100 = 102.5 60 / 102.5 x 100 = 41.46 %

In case of oven dried weight,Moisture content = Oven dried weight greenwood weight / oven dried weight X 100 = 60 102.5 / 60 x 100 = 70.83 %

3) Percentage of solid content in P.F Resin ;-

Empty weight of the Petri dish = 32.650 gmWeight of the Petri dish with resin = 47.600 gmOven dry weight of the resin = 39.800 gm

Resin taken = 47.600 32.650 gm = 14.950 gm

Resin that turn solid = 39.800 32.650 gm = 7.150 gm

When 14.950 gm resin taken, the amount of resin that turn solid is = 7.150 gmWhen 1 gm resin is taken, the amount of resin that turn solid is = 7.150 / 14.950When 100gm resin taken, the amount of resin turning solid is =7.150/14.950x100 = 47.826 gm Therefore, the required percentage of solid content in P.F resin is 47.826 %

FINISHING, STAMPING AND DISPATCHING

Finishing: To complete the manufacture of ply board and give a good appearance, several last process is carried out such as:-1) Trimming : Trimming is done side wise and then length wise to give desired size. It is done by running the ply board through the DD saw( Double dimension saw). There are 2 DD saw in the industry.

No. 1 D.D. Saw No. 2 D.D. Saw

R.P.M28002800

Motor7.5 H.P.5 H.P.

Dia1818

Teeth9696

2) Gap Filling : The gap that occurs on the sides of the ply board and the crack defects on the surface are filled with putty and lappa.

Putty and lappa formulation:

China clay 2 kgT.S.P powder - 1 kgSaw dust - 500 gm ( half kg)Maida (wheat flour) 500 kg U.F glue - 200 mlWater - 1.5 litre

3) Sanding: This operation is done to make the surface of the ply board smooth and fine. It is also done to clear off the T.S.P, putty from the ply board. This operation is done by the two machine named Side sanding machine and Belt sanding machine.

No. of belt sander - 3 H.P - 5R.P.M - 1446Grit size - 60

4) Table finishing : This operation requires man labour. Worker trims off the unwanted fibres of the defects with knife, sand paper and fills it with putty.

5) Coloured finishing and preservative: The ply board then is run through a machine, when the ply board comes out of the machine it turns wet in appearance and a bit red in colour. It is due to the substance called chromic acid.

The preservatives are put over the ply board because it protects from insects and fungal attack. In this industry following preservative solution are made such as:

a) 200 litre water + 5 kg Na2Cr2O7 (sodium dichromate) + 6.5 kg CuSo4 (copper sulphate) + Chromic acid 2.5 gm. This solution is filled into a tank where the ply board is dipped as a preservative treatment. Plyboard red in color.

b) CCA( Chromated copper arsenate ) : This preservative is put on the ply board by spraying. It is the best quality used in this industry. The ply board in which this preservative is put are generally green in color.

Stamping: It is done to spread the extension of the industry in the market and among customers. Stickers and ink is stamp over the ply board according to variety and grade. Dispatching : After the stamping operation, the ply boards are stacked over each other and stored in a room temperature. But before that, with the surface and the sides of the ply board are checked if any defect is still appearing. The fibre defect over the surface of the ply board is cleaned with steel brush and the cracks and gap filled with putty. The ply board are than stack over each other and stored in the room temperature. From here on, the ply board are ready for dispatch.

QUALITY CONTROL

Plywood factories in India prepare plywood from various species using conventional synthetic resins like UF and PF. Nobody cares for the fact that lot of timber, glue and human energy are wasted in the process of plywood manufacturing. If all these accounts are taken, it is a huge loss of materials in big plywood factories where proper quality control measures at each stage of manufacture can be considerably increased. However, such quality control measures can be exercised according to following stages in a plywood factory for its manufacture:

SELECTION OF LOGS AND ITS STORAGE: Quality control applied to those products manufactured from log means obtaining highest possible value from every log cut. This process is applicable trees and timber tracts. Thus, quality control in logging means marking of logs which are supposed to yield best products with .highest possible value. Carpenter in 1953 gave a theory of quality control becoming a matter of selection.Logs for plywood manufacturing should be straight, cylindrical and free from any type of decay, knots and cracks. They have to be free from buttresses, crotches, brash wood, insect attack and any other defects which may reduce its performance. The girth of log should be above 1.5m and necessary precautions should be taken to prevent end cracking. Staining and decaying can be prevented by storing the logs in a log pond or under continuous spraying of water (Gupta, 1980).

PERMISSIBLE DEFECT:The IS: 656-1988 covers the grading rules of logs for manufacturing of plywood as follows:I. Deviation in straightness: Straightness up to 10 cm X 3 m length is permissible.II. Taper: A taper up to 1 cm per 10 cm of diameter or girth in every 2.5 m length of wood.III. Hollow or Spongy Heart: In case hollow or spongy hearts are present, diameter of about 5cm is accepted.IV. End splits and Heart shakes: A total length of 12 cm for every 3 m of the log is permissible for the longest end splits and heart shakes.V. Cup shakes: Cup shakes located within 5 cm from the centre heart (pith) of the log is permissible.VI. Knots:A) Live knots: Live knots of up to 50 mm in diameter and occurring not more than twice in length of 3 m each shall be permissible.B) Dead knots: Dead knots of up to 25 mm diameter and occurring not more than twice in length of 3 m each shall be permissible.VII. Wounds, Bird Pecks or Bark Pocket: Wounds, Bird pecks or Bird pocket not exceeding more than 10 mm in diameter and 25 mm in depth shall be permissible only twice in length of 3 m of wood. VIII. Flutes: If flutes occur during exchange of logs between purchaser and supplier, the right reduction in girth is to be made.

PRE-TREATMENT OF LOGS BEFORE VENEERING:Steaming/Boiling the logs before peeling is a common treatment. Heating pits are constructed so that the logs are not directly seamed which may increase the cracks and checks in logs. For obtaining the best quality veneer, it depends on the species gravity, diameter, MC, presence of knots, tendency to splits and colour change in wood.1. Proper storage and preventive measures.2. Rejection of already damaged wood before treatment.3. Ensuring proper moisture content depending upon the type of treatment and preservatives.4. Preconditioning or preparation of timber.5. Matching the exact standards required for wood preservation.6. Checking the solution charge for each.7. Ensuring proper functioning of vacuum-pressure gauges and thermometers and continuous recorders to control treatments.8. Chemical analysis of the treated wood. The following steps hardly require any equipments and can be done even with little knowledge or experience.ADJUSTMENT IN THE PEELING LATHE FOR VENEERING:The quality of veneers depends upon the machine settings, the gap and knife angle. The gap in the pressure bar and knife edge should be fixed on the basis of desired thickness of the veneers and the timber being peeled. For veneer processing, the following machines are used:i. Horizontal gap indicatorii. Vertical gap indicatoriii. Knife angle indicatoriv. Knife height gauge METHODS FOR ASSESSMENT OF VENEER QUALITY:The main characteristics for assessing veneer peel quality reported by Singh and Das (1998) are:i. Thickness uniformityii. Surface roughnessiii. Depth of lathe checks

i. Thick nesss uniformity : Variation in veneer thickness is due to one of the following reasons:a) Due to improper lathe setting.b) Faults in performance of rotary lathe, such as worn out or loosened feed screw, check spindle etc. The evidence of thickness variation may be observed from the following phenomena:a) Veneers peeled from outer layers of veneer block are thick, thinning as they approach the core.b) The veneer sheet is thicker in the middle than at both ends.Assessment should be made by sampling full size veneer sheets respectively from the outer layer of the blocks and near the core also by measuring at the middle and at the both ends of the veneer with a precision up to 0.01 mm. the measurement is done by thickness indicator since thickness is very important, it should be checked on a regular basis.

ii. Surface roughness: Surface roughness is due to:a) In adequate temperature and time duration of that treatment.b) Faults in the height of the knife tip, compression and other peeling parameters and sharpness of the cutting knife.Evidence of surface roughness are:a) Surface from grain or lacalised collapse.b) Waviness in large pitch appearing periodically.It will cause more consumption of the glue which may result in blister formation during hot press and improper sanding. The roughness is measured by Dial micrometer. iii) Depth of lathe checks: Using some dyes to the loose side of veneer helps the worker to make the lathe checks readily visible. The lathe checks effects the veneer ability to remain at flexible without breaking into strips when handled and it determines the amount of wood which can be removed without exposing the lathe checks when producing sanded panels as the final products.Veneer clipping : Veneer are found to be wedge shaped in width after clipping, when the process is not under control. If let pas un noticed, the finished panels have to be rejected.Veneer drying : The purpose of veneer drying is to reduce the moisture of veneer to the desired level of gluing. Under drying or over drying during veneer drying will have a serious effect o bond quality. The quality requirements of dried veneer are:-a) Moisture content shall be acceptable for gluing.b) Moisture content should be evenly distributed.c) Veneer should remain flat after leaving the drier.We can construct a control limit by taking different moisture content in a veneer and see whether the variation is under control for a given moisture range.Grading of veneer :- Grading is necessary and according to that care will be exercise, eg- Grade A,B,C. The veneer of A grade should not be put for B,C grade because it will result in non-uniformity due to uneven thickness in veneers and even a high pressure treatment in hot press might not give a good bonding to the boards.Quality control of adhesive Adhesive to be used in the production bonding of parts should be sampled and tested with a period of time not exceeding 24 hours prior to use. According to Charles (1993) production responsibility on material control are as follows :1) When the adhesive reach the production area, qualification date should be checked and the floor inspector notified before storage.2) A chart showing type of material, lot and batch number, date, result of quality test lab report should be posted near the storage area.3) Liquid adhesive should be mixed or thinned according to the applicable specifications ( IS: 848:1974) and should be accomplished in an isolated area.Gluing : The glue to be applied must have adequate viscosity depending upon the porosity of the veneer. Too much thick glue will not spread well and also would not form mechanical binding age with the veneer surface and thin glue will penetrate too much inside the pores of veneer. The percentage of wood failure and glue shear strength are the two main criteria for the judgement of ply wood bond quality. There are two main reasons for unsatisfactory gluing reported by Sing and Das (1998):a) The time allowed between glue spreading.b) Surface temperature of the veneer.( measured by photometric method).Hot pressing: The function of hot pressing is:i. To effect a tight contact of the layers under the action of pressure.ii. To evaporate the solvent contained in the adhesive and to expedite the curing of the adhesive.Two rules of application of heat and pressure during hot press are :-i. Heat applied and time of heating should be kept to minimum.ii. There should not be any attempt to speed up production by using excessive heat or pressure.Sanding and surface finishing : Defects often happens in the process of sanding are :-1) Sand through 2) Waviness in finishing3) Taper on one end of the panel4) Damage of leading end of panel5) Damage on trailing end of panelRectification of these defects and established control by adjusting driving mechanism, replacement of bearing, etc.Quality control by testing of productBefore dispatch the various products should be tested by quality controller in its well equipped laboratory according to I.S. 848-1974. Some of the test which are practiced in most of the countries are as follows:-1. The tensile glue shear strength test can alone be judge as the most adequate test for evaluating the adhesive bond quality of plywood.2. The knife test however popular it maybe in some countries, can only be treated as a qualitative test which may be used as ancillary test to verify the quality of adhesion between the plies.3. The process of scanning glue lines which involves numerous variable and almost innumerable difficulties in designing and developing the necessary equipment in the field.4. The methods of analyzing the results of tensile glue shear strength teats have to be standardized.5. Simplification of test procedures and elimination of costly equipment for determining the adhesive bond strength of ply wood should receive high priority in the research and development effort in the field.6. The torsion shear method and the plug tension method deserve to be investigated further as they seem to be promising for simplifying the test procedure.Quality control with reference to electronic instruments Shyamsundar and Victor (1980) has developed following quality control electronic instruments using indigenous components, which are as follows:a) Moisture meters : Moisture metersare used to measure the percentageof waterin wood . This information can be used to determine if the material is ready for use.b) Electronic moisture scanner: The scanner developed at IPIRTI works on the principle that the dielectric constant of wood varies with moisture constant. The variation of dielectric constant is to measure moisture content of veneers.c) Temperature indicator for hot press: A temperature indicator has been developed using the silicon device for surface temperature measurement. The junction silicon device depends on:i. Ambient temperatureii. Heat developed because of current passing through it.Importance of quality control The advantages of quality control are as follows:-1) Improvement in quality 2) Efficient use of men and machine, removal of production bottlenecks3) scientific evaluation of tolerances and process capability4) Increase in economy and reduction of wastage5) Increase in productivity and decrease of production cost.6) Maintenance of desired quality level7) Reducing the scrap so that material won`t be rejected Conclusion

Wood has been the material man used most for many purpose from the nature since early days, now in modern day the numbers of wood is depleting as the forest, whereas the demand for it is becoming more. The ply wood act as a substitute and fills the requirement of human wants, therefore it decreases the depletion of forest. And the plywood industry maybe be benefited by quality control maybe such as ; customer loyalty through satisfaction of the material they were provided, increase penetration of all markets through exemplary services in technology and cost, increase productivity in manufacturing, increase product and service quality, suitable equipment and machinery for particular process control at different stages, provisions of adequate resources including raw materials and personnel to ensure consistent product quality, well defined process and product characteristics, analysis and continual improvement. Lastly, I would like to mention that it was a great experience and opportunity to be able to get the chance to work on a project in Janardhan Plyboard Industries Limited on the topic `quality control and its necessities in the industry`. Here, I could enlighten myself about the importance of quality control for manufacturing the ply board which is used in so many different fields by man. And I would wind this up by saying that `the economical profit of the industry can be enhanced or maximized only by quality control`.