Study of Deroulability in 14 Cultivars of Poplar: Analysis Cutting Force and Lathe Checks of Veneer in Micro-Lathe

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STUDY OF DEROULABILITY IN 14 CULTIVARS OF POPLAR: ANALYSIS OF CUTTING FORCE AND LATHE CHECKS OF VENEER

IN MICROLATHE

MEYLIDA NURRACHMANIA

GRADUATE SCHOOL

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STUDY OF DEROULABILITY IN 14 CULTIVARS OF POPLAR: ANALYSIS OF CUTTING FORCE AND LATHE CHECKS OF VENEER

IN MICROLATHE

MEYLIDA NURRACHMANIA

A Thesis submitted for the degree of Master of Science of Bogor Agricultural University

GRADUATE SCHOOL

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STATEMENT

I, Meylida Nurrachmania, here by stated that this thesis entitled

STUDY OF DEROULABILITY 14 CULTIVARS POPLAR: ANALYSIS CUTTING FORCE AND LATHE CHECKS OF VENEER IN

MICRO-LATHE

are result of my own work during the period February 2012 until June 2012 and

that is has not been published before. The content of the thesis has been examined

and approved by the advising committee and the external examiner.

Bogor, December 2012

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ABSTRACT

MEYLIDA NURRACHMANIA (2012), Study of Deroulability in 14 Cultivars of Poplar: Analysis of Cutting Force And Lathe Checks Of Veneer In Micro-Lathe. Under the supervision of NARESWORO NUGROHO and LAURENT BLERON.

Poplar is well known for its large wood production. Through this work, the objective of this study seeks to identify the qualities of new cultivars of poplar and classify these new cultivars in a reference quality poplar wood (by evaluating the lathe check phenomenon and measurement of cutting forces in micro-lathe). The 42 disks of 14 cultivars and three stations were conducted in 3 mm for two types of veneer, "heartwood" and "sapwood". The 14 cultivars are concerned from cultivars currently on the market of plant poplar. The micro-lathe was used to measure cutting forces. Veneer of peeling process in micro-lathe was observed using a device called SMOF for systematic and objective analysis of lathe check in the veneer. The result is shown that there no significant effect of the radial position (heartwood and sapwood) and cultivar on the cutting force (Xc/force knife vertical, Yc/force knife horizontal, Xb/force bar vertical, and Yb/force bar horizontal), depth and percentage of lathe check.

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SUMMARY

MEYLIDA NURRACHMANIA (2012), Studi Pengupasan 14 Kultivar Poplar: Analisis Cutting Force (Gaya Pemotongan) dan Lathe Checks (Retak Kupas) Vinir pada Micro-Lathe. Di bawah bimbingan NARESWORO NUGROHO dan LAURENT BLERON.

Poplar is well known for its large wood production. The statistical data on poplar cultivation available worldwide are referred to different cultural. France is the largest producer of poplar wood in European countries and an area of 236.000 ha with 1,8 m3 wood production. Production of poplar is based on the use of a large number of genetically different cultivars. One way to generate a variety of cultivars is by doing genetic engineering tree through the hybridization process. Hybrid poplars are trees that are developed by crossing two different species of poplars. Poplar wood is being destined to the production of plywood or LVL (veneer). Through this work, the objective of this study seeks to identify the qualities of new cultivars of poplar and classify these new cultivars in a reference quality poplar wood (by evaluating the lathe check phenomenon and measurement of cutting forces in micro-lathe). Order these new cultivars in the repository poplar wood quality named «Référentiel qualités du bois des cultivar de

peuplier ».

The 42 disks of 14 cultivars and three stations were conducted in 3 mm for two types of veneer, "heartwood" and "sapwood". The 14 cultivars are concerned from cultivars currently on the market of plant poplar. Therefore, the 14 cultivars are: A4A, Brenta, Koster, Lambro, Mella, Polargo, Soligo, Taro, Triplo, Trichobel, Dvina, Lena, Alcinde and I-214. Micro-lathe was an instrumented for peeling disks from 10 to 30 mm wide. The micro-lathe that can scroll experimental discs of wood and non ridges integers. This reproduces the unwinding smaller scale and it also allow measurement of cutting forces. Veneer of peeling process in micro-lathe was observed using a device called SMOF for systematic and objective analysis of lathe check in the veneer.

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vertical, Yc/force knife horizontal, Xb/force bar vertical, and Yb/force bar horizontal), depth and percentage of lathe check. There are several factors that affect the value of the cutting force veneer from timber and are derived from the engine. For derived from wood such as wood species, wood density, moisture content of wood, annual rings.

Lathe check, the phenomenon is created during peeling. Lathe checks has also an important role on the quality of the veneer. Usually lathe checks can be caused by the fractionation process during the peeling process. It can also be explained by the sharp knife (new tool or lapped, dull knife). Basically, a sharp knife will have a small nose radius so that the knife is perfectly effective, but when using a blunt knife, the tip radius becomes larger. In this case and produce a poor quality of surface and a high cracking. The depth of lathe checks appears significantly correlated with a mechanical and destructive tests only 4-point bending. Indeed, the modulus of elasticity decreases as the depth of cracking.

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Prohibited quoting part or all of this paper without mentioning or citing sources. Quotation is only for educational purposes, research, writing papers, preparing reports, writing criticism, or review of an issue, and citations will not harm the interest IPB

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Thesis Title : Study of Deroulability in 14 Cultivars of Poplar: Analysis Cutting Force and Lathe Checks of Veneer in Micro-Lathe

Student Name : Meylida Nurrachmania

Student ID : E251100161

Study Program : Master of Science in Forest Product Technology

Approved by, Advisory Board:

Supervisor Co-Supervisor

Dr. Ir. Naresworo Nugroho. M.Si Laurent BLERON

Endorsed by,

Program Coordinator Dean of The Graduate School

Dr. Ir. I Wayan Darmawan. M. Si Dr. Ir. Dahrul Syah. M. Sc. Agr

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ACKNOWLEDGEMENT

Bismillahirrahmanirrahim

It has been a great pleasure for me to have this study accomplished, which

has been a great work during these years. There are many people who have been

very helpfully in regard to this work. Therefore, I would like to gratefully

acknowledge the great contribution of the following individuals to this work. For

the first and foremost, I would like to express my gratitude and sincere to Allah

SWT for blessing with health and favor me success in my studies.

My entire study in Bogor Agricultural University and Nancy, France

(AgroParisTech, INPL Nancy Université, Université de Loraine) was made

possible with the financial support given by the Ministry of National Education

through Beasiswa Unggulan for Program "Double Degree". It is gratefully

acknowledged. I would also like to extend my special thanks to Dr. Ir. I Wayan

Darmawan, M. Si. for giving me the opportunity to obtained this scholarship.

I wish to express my sincere appreciation and gratitude to my research

supervisor at Bogor Agricultural University. Dr. Ir. Naresworo Nugroho, M. Si

and Msr. Laurent BLERON at Arts et Métiers ParisTech, Cluny, France for all

their valuable guidance and useful advice during my research work, proposal

preparation and thesis writing.

Special thanks I express to Msr. Louis-Etienne DENAUD, Msr.

Jean-Claude BUTAUD, Msr. Michael KREBS for all their helpfully guidance and

technical especially in using the machines during my research time in Arts et

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Renaud PFEIFFER, for always help me correction my French language, both oral

or written.

Special thanks I give to the external examiner in France:

1. Rémy MARCHAL, LABOMAP, Arts et Métiers ParisTech, Cluny

2. Meriem FOURNIER, LERFOB, AgroParisTech, Nancy

3. Phillippe GÉRARDIN and Stéphane DUMARÇAY, LERMAB, Faculté des

Science et Technologies, Vandoeuvre les Nancy

4. Bertrand CHARRIER, Université de Pau et de Pays de l'Adour, Mont de

Marsan.

Special thanks also- go to all the members of lectures and staffs in Bogor

Agricultural University and AgroParisTech, Nancy, France. Special thanks I give

also to all the doctoral and master student in there, for all the supports, helps and

great motivations.

I would also like to thank all my classmates, all the members of Forest

Product Technology 2010, who were all hard working, pleasure of working, with

support, with gave me a happy time to treasure, the time we spent together as well

as our friendship through these years. A lots of thanks, of course, extended to all

my friends who helped out when the pressure become too much.

Finally, the biggest thanks go to all my family, my parents, my sisters and

brothers, my grandmother, my cousins, for their support and encouragement

through the good times and hard times, words cannot fully express "how much I

love you".

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CURRICULUM VITAE

Meylida Nurrachmania, was born in Medan, North Sumatera on May 10,

1988. She is the eldest daughter of Ridwan Hasan Berdan and Farida Hanum. She

finished her elementary, junior and high schools at public schools in Medan. She

received her undergraduate degree from the Faculty of Agriculture, Department of

Forestry, North Sumatera University, in the field of forest product technology in

2009.

In the year of 2010, she is registered as one of the students to study master

at Bogor Agricultural University in science and forest product technology. She

was awarded a scholarship from the ministry of national education named

"Beasiswa Unggulan" for program "Double Degree". Through this scholarship, in

2011, she continued her master study and research in France for one year. She

finished her graduate school in 2012 and obtained double degree from Bogor

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LIST OF TABLES

Page

1. Analysis of Variance Efforts ... 14

2. ANOVA of Resultant Forces Fb and Fc Micro-Lathe and Peeling Lathe 16

3. Analysis of Variance (Mean and Standard Deviation) for Depth and

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LIST OF FIGURES

Page

1. Principe of Peeling Wood ... 4

2. Peeling Continue ... 6

3. Peeling Discontinue ... 6

4. Peeling: Effect of Compression Bar... 7

5. The Machine of Peeling ... 10

6. Cutting Force and Lathe Checks Formation During Peeling Process ... 11

7. The Stable Signal of Cutting Force ... 12

8. The SMOF Device ... 13

9. Resulting Image (Loose Face on The Top) ... 13

10.Variation of Efforts in Heartwood and Sapwood on Micro-Lathe ... 15

11.Variation Forces Resultant on The Bar and on The Knife of Micro-Lathe (Left) and peeling lathe industrial (right) ... 17

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INTRODUCTION

Background

Poplar is well known for its large wood production. The statistical data on

poplar cultivation available worldwide are referred to different cultural. France is

the largest producer of poplar wood in European countries and an area of 236.000

ha with 1,8 m3 wood production (Domenico and Giuseppe, 2011).

Quality of wood poplar has variations due to their genetic characteristics,

but also their growth conditions. Production of poplar is based on the use of a

large number of genetically different cultivars. One way to generate a variety of

cultivars is by doing genetic engineering tree through the hybridization process.

Hybrid poplars are trees that are developed by crossing two different species of

poplars (Davison and Riggs, 2003). The advantage of this diversity is to adapt

better to varying site conditions (climate and soil), but also reduce pest risks from

the use of cultivars. This diversification of cultivars is the guarantee of sustainable

poplar production.

Poplar wood is being destined to the production of plywood or LVL

(veneer) which is used for beam or headers (Davison and Riggs, 2003). The first

step in producing plywood or LVL is thus to achieve a peeling process to generate

a veneer. In veneer production, lathe checks created during the cutting process

affect the veneer quality. It can occur inside veneer during the veneer peeling.

Previous studies have determined that lathe checks are generated due to

tensile stress in bending at the rake face of the knife (Tochigi, et. al., 2005). It

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its huge effect, first on the veneer and then on the mechanical strength of plywood

or LVL (Ohya et al. 1989 and DeVallance et al. 2007 in Palubicki, et. al., 2010).

Cracking of the veneer is one of the most critical defects of veneer (resulting in

handling difficulties, excess glue consumption, poor surface veneer, etc.) .

Methods and devices for lathe check detection are not so common. The

laboratory wood school Arts et Métiers ParisTech Cluny, France, has a

lathe for this experimental as well as an industrial lathe (peeling). This

micro-lathe has been specially designed for the peeling tests. It also allows to measure

cutting forces. To measure the cracking veneer, used a device called SMOF

System® (Système de Mesure Optique des Fissuration) device developed by the

laboratory.

In this study, we are examined the lathe check (max and min depth of

checks, presentation of checks) and cutting force for knife and pression bar

(Xc/force knife vertical, Yc/force knife horizontal, Xb/force bar vertical, and

Yb/force bar horizontal) in sapwood and heartwood from new cultivar of cultivars

Poplar currently on the market poplar plants.

Objectives

The objective of this study aims to identify the qualities of sapwood and

heartwood of new cultivars of poplar and classify these new cultivars in a

reference quality poplar wood (assessing the lathe checks phenomenon and

measurement of cutting forces in micro-lathe). Order these new cultivars in the

repository poplar wood quality named «Référentiel qualités du bois des cultivar

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LITERATURE REVIEW

Poplar

Poplars are trees of the genus Populous family Salicaceae. The genus

Populous includes 35 species of temperate and cold regions of the northern

hemisphere. It also includes cottonwoods, and aspen (Davison and Riggs, 2003).

It also contains many natural hybrids or artificial (man-made). The poplar trees in

the rapid growth rarely occur in dense forest but in and around riparian wetlands

where as willows. Their root system, important, often superficial and tracing (such

as poplar Italy for example) can destroy walls, lift asphalt mixes and colonize

sewer pipes. Some species (aspen) can grow on poor sandy soils and withstand

relatively sea spray at a certain distance from the sea, however.

Poplars tend to produce tension wood quite easily (Balatinecz, 2001). The

gene has a significant influence on the tension wood. The effect of the

environment (wind and phototropism) can also promote the production of tension

wood. The presence of tension wood is accompanied by the formation of deep

radial slots. At slaughter, the trees can literally crack due to tension wood. Poplar

is one of the top three in France after hardwood oak and beech.

The Peeling of Wood

The peeling is a process of primary wood processing allows the

manufacture of veneer sheets. The peeling process consists of transforming a bolt

into veneer using a rotary peeling lathe. Prior to peeling, the bolt is debarked and

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angle is fixed on a movable carriage which is close to a regular basis of the axis of

rotation of the spindles. A continuous strip of wood, veneer, is formed (Figure 2).

The product obtained is the chip, which is the characteristic of peeling slicing as

elsewhere.

Figure1. Principe of peeling wood

The peeling is used to produce a veneer, by the combination of a rotational

movement of the timber and the in feed of the tool. The relative movement is a

spiral whose pitch (advance per turn of the knife of the ball) is equal to the

thickness of the cladding (Figure 1). The rotational movement is transmitted to the

ball by the pins of different forms depending on the hardness of the species. To

get the best wood available, it reduces the diameter of the residual nucleus using

telescopic spindles. Via a gear assembly, the advance of the knife is indexed to the

rotation of the shaft. To enter the woods in a direction 0-90, the knife must have a

cutting edge (nose) as thin as possible, consistent with the strength of the cutting

material. This is the steel is chosen, the wedge angle (nozzle) can be from 18 to

22o. The rake face of the blade to remain in abutment on the ball for a distance of

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requires a draft angle continuously varying from +2, when the log is large in

diameter, -1° to the end of the unwinding. This variation takes place

automatically, by a control device which inclines gradually when the knife

approaches the center of rotation (Juan, 2012). Obtained by peeling veneers are

generally used in the manufacture of plywood. Unwinding requires the woods are

green (filled with water beyond the saturation point of fibers) and free from large

cracks or checks, which affect the quality of the veneer.

The Knife

In wood cutting, when a knife-edge contacts a work piece being cut, the

work piece deforms elastically under the force in the neighborhood of the

knife-edge. So long as this force exceeds a certain value, the work piece ruptures at the

tip of the knife-edge, and the knife-edge continues further into the work piece.

The portion that has been separated from the work piece is compressed on the

rake face of the knife, deforming under compressive, shear, or other forces. The

types, directions of action, and magnitudes of the forces exerted on the work piece

during the cutting process have subtle dependence on numerous interdependent

factors: work piece conditions (such as fiber orientation, annual rings, moisture

content); tool conditions (such as angles of faces and edges and roughness); and

cutting conditions (such as cutting depth, cutting speed, and feed speed) (Tochigi,

et. al., 2005).

Too high a vertical dimension makes the bar more quickly inoperative as

small diameter wood, like the rest, a horizontal dimension too low may move the

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Unlike an advance too low can compress unnecessarily chip between the bar and

the rake face of the tool favoring the appearance of avulsions, cracks and large

thickness variations (Marchal, 1996).

At the beginning of the operation, the knife attack the timber intermittently

until the ball has a cylindrical shape. The first elements are posted worthless

(Chiquettes). Then we can obtain a continuous sheet (Figure 2), but you can also

practice a groove along a generator to obtain sheets (Figure 3). In this research the

knife that used was fabricated in a low alloy steel (60SMD8 composition: 0.6% C,

1.8% Si, 0.7% Mn, 0.3% Cr, 0.5% Mo, 0.2% V) (Denaud, 2006).

Figure 2 et 3. Peeling Continue and Discontinue.

The Pressure Bar

To avoid a gap spreads in front of the cutting edge, it is necessary to

compress the wood. It is the role of a compression bar, usually static, although

rotating bars are frequently used in the United States or Canada. The main role of

a bar of pressure is to exercise a local compressive stress that opposes the tensile

stresses perpendicular responsible for cracking the plating cycle. Globally, a large

majority of peeling is equipped with a bar static pressure round or angular settings

allows finer and more accurate homogeneous and dense woods. The setting of the

bar sets the compression ratio to be from 2 to 25% (Fig. 4). The angle of

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compression is 10 to 25o depending on the species. The cutting speed, peripheral

speed of the log, is from 20 to 250 m/min, but remains constant during the

unwinding of a ball, for acceleration of the speed of rotation (by a hydraulic drive)

to progressively the reduction in the diameter. Unlike other machining operations,

the cutting speed directly affects production because it is equal to the veneer film

produced per minute. High speeds require peeling handling systems and defecting

downstream performance.

Figure 4. Peeling: effect of compression bar

The Lathe Check Phenomenon

Lathe check, the phenomenon on which we focus in this project is created

during peeling. When it enters the wood, it creates a tensile stress and a slot

before it opens (Thibaut, 1988). The opening of the slot releases the tension. The

slot then stops at the edge of said stress zone. The knife passes beyond the lathe,

creates a further voltage which causes another lathe. Homogeneous in the woods,

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the knife is used to limit the local deformation of the chip and to avoid a collapse

of the edge. Yet even with this configuration, the cracking is present.

Lathe checks has also an important role on the quality of the veneer. In

almost all the peeling process, lathe checks are present at a certain level. These

lathe checks occur during the machining process. Veneer lathe checks correspond

to an area of weakness and cause excessive penetration of the adhesive. Usually,

the cracking is strongly influenced by the level of pressure and by the cutting

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METHODOLOGY Time and Location of Study

This research was carried out from February until July 2012. It is

conducted in laboratory of wood LaBoMaP (Laboratoire Bourguignon des

Matériaux et des Procédés), at Ecole National Superieure d’Arts et Matiers

(ENSAM) Cluny, Bourgogne, France.

Sampling Preparations

Prepared the disks 20-30 mm wide testing micro-lathe. The disks were

taken from different ridges from different cultivars and different sites. The study

will focus on trees 15-20 years and 35-45 cm diameter at 1,30 m. To carry out this

study, 42 disks of 14 cultivars and 3 stations were used. Therefore, the 14

cultivars are: A4A, Brenta, Koster, Lambro, Mella, Polargo, Soligo, Taro, Triplo,

Trichobel, Dvina, Lena, Alcinde and I-214. The choice of well-differentiated 3

sites for the collection of wood is essential to study the quality of of wood of each

cultivar.

Peeling in Micro-Lathe

The laboratory of wood in Arts et Métier at Cluny, France, has a

micro-lathe (Figure 5) that can scroll experimental discs of wood and non ridges

integers. This reproduces the unwinding smaller scale. It was designed by

Jean-Claud Butaud in 1994. Micro-lathe was an instrumented for peeling disks from 10

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settings are available: draft angle, horizontal and vertical ribs, angle bar pressure,

only the lack of control during cutting, the inclination of the knife is to be

deplored. Advances the engine is limited to 500 rev/min and the drive motor of

the spindle at 2000 rpm/min, which requires the effectors peeling high speed

(5000 mm/s) for large radii.

Figure 5. The Machine of micro-lathe

Process Parameters

Peeling speed and pressure bar influence the cutting efforts by modifying

the strain field on the veneer surface during peeling. The role of the pressure bar is

to create a favorable compression strain perpendicular to the cutting plane a head

of the knife in order to oppose the tension strain responsible for opening the

checks (Figure 6). The pressure bar would positively influence the veneer surface

quality while peeling speed would influence it negatively (Mothe 1988 in

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In order to only evaluate the cutting force and lathe checks in sapwood and

hardwood (were determined before peeling) peeling speed (s), and the

compression rate of the pressure bar, (Bp), were kept constant (s = 1 m/s and Bp =

5%) to achieve a nominal veneer thickness, (e), of 3 mm for all tested disks

(Figure 6).

Figure 6. Cutting force and lathe checks formation during peeling process

Process Assessment

Cutting force in micro-lathe are determined according to the four main

components of the cutting forces: on the knife (Xc/force knife vertical, Yc/ force

knife horizontal) and the pressure bar (Xb/force knife vertical, Yb/force bar

horizontal). Cutting force are linked to VisualBasic and recorded via an

application developed in Labview program then exported as files, csv. It was

providing mean, standard deviation, minimum and maximum force. For each

experimental, mean, standard deviation, maximum and minimum force were

based on the stable signal of cutting force in Figure7. Then the forces that

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Figure 7 : The Stable Signal of Cutting Force

SMOF (système de mesure d'ouverture de fissures) Device

Lathe checks have been characterized using the SMOF device (Système de

Mesure Optique des Fissuration) (Palubicki et al., 2009). This tool detects checks

with a high speed line scan camera and a LDS (Laser Displacement Sensor)

(Figure 8). It can automatically measured on the image obtained, the depth checks

and the distance between two successive checks. The resulting image (Figure 9) is

analyzed by a program developed in LabView. The boundaries of this unit were

observed: the size of the resulting image corresponds to a maximum height of 4

mm veneer. Beyond this thickness, the software fails to properly detect lathe and

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Figure 8. SMOF device

In this study, the plating thickness is observed is 3 mm. Plating passes over

a pulley to pry open cracks. A linear camera allows the acquisition of images

continuously. The resulting images are then analyzed manually using a program

developed specifically for the automatic detection of cracks. For each plating, the

maximum, minimum, standard deviation and the mean of the frequency of

cracking are calculated.

Figure 9. Resulting image (loose face on the top)

D. Analysis of Variance

The factors identified for analysis of variance are: cultivar, radial position

(sapwood and heartwood). The response of these factors are cutting forces

Yb/force bar horizontal), and lathe checks. Then, the experimental results were

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RESULTS AND DISCUSSIONS

Analysis of Cutting Force in Micro-lathe

On micro-lathe, we observed cutting forces. The cutting force plays an

important role in the process of woodworking, especially related to the life of the

tool. The Table 1. illustrates this result and shows that the cutting forces (Xc, Yc,

Xb, Yb) are not influenced by the type of the cultivar, despite some fluctuations,

which may be due to density differences between the cultivars. The same applies

to the radial position, no significant effect of forces in radial position (sapwood

and heartwood) is identified.

Table 1. Analysis of variance efforts

Effort Effet DF SS MS F P

Xc

Cultivar 13 49764 3828.03 0.13NS _0.99

Position radial 1 24 24.28 0.00 NS _0.98

Position radial*cultivar 13 24831 1910.06 0.07 NS _0.99

Errer 57 1621786 28452.38

Total 84 1696405

Yc

Cultivar 13 3038.4 2337.34 0.15 NS 0.99

Position radial 1 8902.0 8902.02 0.60 NS 0.99 Position radial*cultivar 13 12102.6 930.97 0.06 NS 0.99

Errer 57 857613.5 15045.85

Total 84 909003.5

Xb

Cultivar 13 20163.0 1550.99 0.22 NS _0.99

Position radial 1 206.4 206.35 0.03 NS _0.86

Position radial*cultivar 13 2405.9 185.07 0.03 NS _1.00

Errer 57 402523.1 7061.81

Total 84 425298.3

Yb

Cultivar 13 411143 31626.4 0.20 NS _0.99

Position radial 1 2834 2834.5 0.02 NS _0.90

Position radial*cultivar 13 154554 11888.8 0.07 NS _0.99

Errer 57 909334 159531.7

Total 84 9661835

DF: Degree of Free SS: Sum of Square MS: Mean of Square *: Significant variance at the 5%

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The study of Figure 10 shows that the wear of the pression bar has a huge

influence on the effort exerted on the bar (Xb and Yb).

(a) (b)

Figure 10. Variation of efforts in heartwood (a) and sapwood (b) on micro-lathe

Efforts obtained for the Taro, Lena, and Lambro is more low than the

others. Thus, we find a similar shape efforts to the two parts of wood (heartwood

and sapwood) represented in Figure 10. It should be noted that the natural

tendency should be opposed without the effect of wood since the actual pressure

exerted by the flank of knife and pressure bar should decrease as the diameter of

the log is reduced (purely geometric). Although small, these correlations are real

and suggest a relationship of cause and effect.

Cutting forces in heartwood and sapwood parties on micro-lathe are close

but there is a significant correlation between the radial position on the one hand

and the mean Yc and standard deviation, Xc and Yc other (Appendix 2). We find

this correlation if we integrated with the moisture content factor. In reverse, the

correlation matrix alone does not distinguish with the respective contributions of

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There are several factors that affect the value of the cutting force veneer

from timber and are derived from the engine. For derived from wood such as

wood species, wood density, moisture content of wood, annual rings (Tochigi, et.

al., 2005). While from the engine factors are, knife and pression bar (Bakar,

2004). The density of 14 cultivars studied ranged from 0.30 to 0.38, moisture

content of each type ranged between 125-167%.

The sharpness of the blade is one important factor in cutting material. The

sharpness of the blade has a significant effect on the cutting force. The sharper the

knife used the cutting force generated is also lower.

The Comparison of Cutting Force between Peeling Lathe and Micro-Lathe

A first glimpse of the profile variation of forces measured (Table 2.) shows

that for both tests (peeling lathe and micro-lathe), analysis of variance revealed no

significant effect of the radial position (heartwood and sapwood) on Fb and Fc

results.

In general, the cultivar effect is not significant since the efforts are very

similar regardless of the trees. In addition, the site effect is not significant on the

various indicators of the cutting force which corresponds to the results of the

literature. Efforts are the lowest recorded in the case of poplar. Although it is of

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[image:33.595.109.559.124.340.2]

Table 2. ANOVA of resultant forces Fb and Fc micro-lathe and peeling lathe.

Effort Effet Df micro-lathe Peeling lathe

SS MS F P SS MS F P

Fc

Cultivar 13 55889 4299,18 0,10NS₁ ₂₆₁₆₉₇ _{20130,5 0,10} NS_1,00

Position radial 1 7092 7091,79 0,16NS 0,69 62939 62939,1 0,30 NS 0,59

Position radial*cultivar 13 18718 1439,88 0,03NS₁ ₂₂₀₀₃₁ _{16925,4 0,08} NS_1,00

Erreur 57 2523709 44275,6 12057460 211534,4

Fb

Cultivar 13 441956 33996,6 0,20NS₁ ₉₄₀₄₆₂ _{72343,2 0,08} NS_1,00

Position radial 1 19397 19396,9 0,12NS_{0,74 101317 101316,7 0,12} NS_0,73

Position radial*cultivar 13 55890 4299,2 0,03NS₁ ₇₆₁₉₉₂ _{58614,8 0,07} NS_1,00

Erreur 57 9569890 167893 49717207 872231,7

NS: not significant variance

In the process of rotary cutting it must first be determined center point

disks (disks center). This disks center is not always in the pith of disks. The

purpose for this was to placed the disks on the micro lathe and for the efficiency

of veneer because the form of wood is not always cylinder.

Reverse reaction given by the wood under the track pieces (mother wood)

that acts as a cushion against the pressure of Yc as though under pressure from

two opposite directions, because the pressure of the two-way blades are in a stable

position with pressure (normal force) relatively small. As a result, the blade can

cut it with a constant trajectory so that the consistency of thick pieces of veneer

can be maintained. Yb pressure given by nose bar is essentially the same as that

received by compressed wood is peeled. Therefore, it is actually a compressed Yb

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Figure 11. Variation of force resultant on the bar and on the tool of micro-lathe (left) and peeling lathe industrial (right)

In the figure above, the efforts for each cultivar are fairly stable except for

Dvina and Soligo, one of the samples were exploded, both in micro-lathe or

peeling lathe industrial. The cutting force of cultivar Taro, Alcinde, Lena, Lambro

and Koster are little higher than the others. However, it is noted that the forces

measured during cutting Trichobel in unwinding are significantly lower than the

others, but in the micro-lathe, cutting force from the unwinding of the cultivar

Brenta are significantly lower than the others. The value in peeling lathe is higher

than in micro-lathe, it's because Bp in peeling lathe is bigger about 10%. In other

hand, knife angle also influenced the force but only to a small extent appeared to

influence the damage greatly (Kempe, 1967).

Analysis of Lathe Check in SMOF

SMOF allows the measurement of the frequency and the average depth of

cracking on strips of veneer place on the lathe or on the industrial micro-lathe.

There are two main characteristics that describe the cracking: the depths and

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below, the analysis of variance shows no significant effect on the radial position

of the depth and percentage of lathe checks.

Usually lathe checks can be caused by the fractionation process during the

peeling process. It can also be explained by the sharp knife (new tool or lapped,

dull knife). Basically, a sharp knife will have a small nose radius so that the knife

is perfectly effective, but when using a blunt knife, the tip radius becomes larger.

In this case and produce a poor quality of surface and a high cracking. These

conditions will worsen if you use a dull knife and in parallel with a large cutting

speed. In the best case you get a plating with strong Fc cracks. If the cutting speed

becomes too high, it will therefore be impossible to get a veneer.

Table 3. Analysis of variance (mean and standard deviation) for depth and percentage of lathe-checks

Effort Effet DF Mean Standard Deviation

SS MS F P SS MS F P

Depth of

lathe-checks

Cultivar 13 2.365 0.181 0.158 NS_0.99 _0.150 _{0.011 0.098}NS _0.99

Position radial 1 0.002 0.002 0.002 NS_0.96 _0.003 _{0.003 0.028} NS_0.87 Position

radial*cultivar 13 0.686 0.052 0.045 NS 1.00 0.093 0.007 0.061 NS 0.99

Errer 57 65.745 1.153 6.713 0.117

Pourcentage of

lathe-checks

Cultivar 13 222.08 209.391 0.155 NS 0.99 170.731 13.133 0.096 NS 0.99

Position radial 1 4.71 4.707 0.003 NS_0.95 _2.930 _{2.930 0.021} NS_0.88 Position

radial*cultivar 13 784.09 60.315 0.044 NS 1.00 109.456 8.419 0.061 NS 0.99 Errer 57 76631.7 1344.416 7827.788

NS: not significant variance

The high pression of pressure bar can minimize lathe checks, but increase

the friction. While the low pression of pressure bar can reduce the friction and

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Factor of knife and pression bar can affected the lathe cheks on veneer. For

the factor of knife especially in the sharpness and the angle. A dull knife can

produce lathe checks a lot (Iswanto, 2008). As for angle of sharpness, the greater

the angle the higher the checks depth. But if the angle of sharpness are too small

that can lead to fractures cause not being able to resist pressure of wood.

Consequently the thickness of veneer was uneven.

Figure 12. The percentage of cracking for each cultivar

The image above explains that there is no significant difference of lathe

checks in veneer between sapwood and heartwood. The depth of lathe checks in

the veneer is determined primarily by the rate of the pressure bar and its position

(Bakar, 2004). In this study, the compression ratio is constant (even of the

thickness equal to 3 mm), we can not see change. As for cracking, this factor

seems to depend on the thickness and place the pressure bar and can be improved

by changing the settings of peeling. Descamps (2009) explains that the depth of

lathe checks appears significantly correlated with a mechanical and destructive

tests only 4-point bending. Indeed, the modulus of elasticity decreases as the

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CONCLUSION AND RECOMMENDATION Conclusion

These experiments also allowed us to identify the quality of the veneer.

The effect of cultivar and radial position are identical. Generally, the effect of

cultivar and radial position are not significant on the various indicators of cutting

forces as efforts are very similar regardless of the trees. Moreover, these effects

are not significant for lathe checks veneers.

1. Cultivars Mella, I-214, and Trichobel, has less cutting force,

2. Cultivars Taro, Lena, Lambro, Polargo, and Koster has high cutting force

3. Cultivars Dvina, Soligo, Brenta, Alcinde, Triplo, and A4A has medium

cutting force.

4. The cultivars that have average lathe checks are Lambro, Koster, Taro, and

Mella

5. The cultivars that have low lathe checks are Dvina, Soligo and I-214,

6. High lathe checks Trichobel, Lena, Alcinde, Polargo, Triplo, A4A, and Brenta

The force in peeling lathe is higher than in micro-lathe, it's because the

compression rate of the pressure bar (Bp) in peeling lathe is bigger about 10%.

Recommendation

The presentation system, SMOF, is capable of automatically characterizing

the quality, in terms of lathe checks control, the products of a long plating

micro-lathe laboratory. Many micro-lathe checks were not taken into account, which has

significantly distorted the result. More pulley SMOF seems too open cracks. A

further test must be made to compare the percentages of cracking between the

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REFERENCES

Bakar. E.S. 2004. Study on the Influences of Nosebar Setting of a Peeler on the Compressive Forces and Cutting Quality of Veneer. Journal of Tropical Wood Science and Technology. Vol 2(2): 83-89. - Journal

Daoui A., J. Douzet, R. Marchal, A. Zerizer. 2007. Valorisation du bois de pin d'Alep par déroulage : optimisation de son étuvage. Bois et forets des tropiques. N° 294 (4). pp 51-64.

Davison, J and W. W. Riggs. 2003. Hybrid Poplar Production 1998-2003 in Eureka and Churchill Counties. University of Nevada

Denaud. L.E. 2006. Analyses vibratoires et acoustiques du déroulage. Thèse de Doctorat de L'école Nationale Supérieur d'Arts et Métiers

Descamps C. 2009. Influence des fissuration des placages sur les proprétés mécanique du LVL. Rapport de PE. Arts et Métiers ParisTech. Cluny

Domenico, C. and N. Giuseppe. 2011. Poplar Wood Production in Europe on Account of Market Criticalities and Agricultural, Forestry and Energy Policy. Trabajo Técnico. Tercer Congreso Internacional de Salicáceas en Argentina. http://www.populus.it/pdf/JS2011_COALOA_NERVO.PDF

Dupleix, A., R. Marchal, L. Bleron, F. Rossi and M. Hughes. 2010. On-line heating temperatures of green-wood prior to peeling. IWCS.

Hafida. E. L. H. 2009.0 Effets cultivar et station sur les propriétés mécaniques de LVL et contreplaqués issus du déroulage de peupliers. Th. Sciences des

Métiers de l’Ingénieur. 23 septembre 2009. Arts et Métiers ParisTech

Iswanto, A. H. 2008. Kayu Lapis (Plywood). Repository. Departemen Kehutanan. Fakultas Pertanian. Universitas Sumatera Utara

Juan. 2012. Travail mécanique du bois - Lois générales du l'usinage. Dossier Technique de l'ingénieur; l'expertise technique et scientifique de référence. pp. 21

Kempe, C. 1967. Forces and Damage involved in the Hydraulic Shearing of Wood. Skogshogskolan. Royal College of Forestry. Stockeolm

Labidi C. 2006. Amélioration de la durée de service d'outils d'usinage du bois par traitements de surface et préparation de l'arête de coupe. Thèse de Doctorat de L'école Nationale Supérieur d'Arts et Métiers

Lubis, M. R. 2010. Perlakuan Awal Kayu Poplar dengan Menggunakan Ca(OH)2.

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Palubicki. B., R. Marchal, Jean-Claude Butaud, Louis-Etienne Denaud, L. Bleron, R. Collet, G. Kowaluk. 2010. A method of lathe checks measurements. SMOF device and its software. European Journal of Wood and Wood Products. 68:2. pp 151-159

Thibaut B. 1988. Le processus de coupe du bois par déroulage. Thèse de Doctorat d'Etat. Université des Sciences et Technique du Languedoc.J.

Tochigi, T., Jun Kobayashi, Hiroya Ohbayashi, and Takao Momoi. 2005. Studies on veneer cutting at the cellular level. Faculty of Region Environment

Science. Tokyo University of Agriculture. Tokyo. Japan

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Cultivar

Site Position

Radial

Cutting Force of Micro-Lathe Lathe Check

Standard Deviation Mean Mean Standard deviation

Xc Yc Xb Yb Xc Yc Xb Yb Depth of

lathe checks Pourcentage of lathe checks Depth of lathe checks Pourcentage of lathe checks Dvina

Sainte Hermine Sapwood 16,41 22,58 8,23 45,71 -136,55 78,46 61,24 -305,22 0,950 32,910 0,274 9,480 Heartwood 23,02 22,51 8,46 56,2 -151,66 91,67 61,25 -330,15 0,825 28,439 0,260 9,014

La Réole Sapwood 11,37 17,06 10,29 51,47 -102,36 76,66 42,37 -207,93 1,267 41,827 0,404 13,484

Heartwood 0 0 0 0 0 0 0 0 0,000 0,000 0,000 0,000

Blanzay sur Boutonne Sapwood 32,29 31,03 11,58 72,35 -187,69 97,29 75,54 -384,57 0,471 16,217 0,224 7,745 Heartwood 32,27 34,22 23,46 110,5 -180,91 106,89 65,85 -369,9 0,681 23,480 0,228 7,813

Lena

La Réole Sapwood 34 30,43 14,8 66,9 -154,86 65,55 96,34 -403,77 0,787 26,317 0,209 6,868 Heartwood 90,13 127,25 26,83 154,77 -175,89 170,6 102,24 -500,11 1,232 41,629 0,444 15,407 Sainte Nicolas la

Chapelle

Sapwood 35,57 30,7 14,38 98,13 -148,96 91,6 76,11 -385,75 1,178 39,874 0,435 14,770 Heartwood 28,34 20,08 9,16 53,07 -183,01 82,38 68,09 -384,25 1,451 49,181 0,456 15,411

Soligo

La Réole Sapwood 0 0 0 0 0 0 0 0 0,000 0,000 0,000 0,000

Heartwood 0 0 0 0 0 0 0 0 0,000 0,000 0,000 0,000

Sainte Nicolas la Chapelle

Lambro

Sainte Hermine Sapwood 21,96 29,61 11,61 62,35 -161,66 154,27 83,63 -425,82 0,654 21,856 0,271 9,052 Heartwood 25,88 26,26 10,82 59,07 179,52 174,83 87,91 -482,02 0,879 30,056 0,312 10,666

La Réole Sapwood 21,5 19,29 12,22 61,69 -119,53 63,86 85,36 -360,89 0,814 27,137 0,218 7,301 Heartwood 18,87 21,1 14,26 73,23 -120,02 90,33 83,26 -391,1 0,906 30,493 0,263 8,845 Sainte Nicolas la

Chapelle

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Cultivar Site

Position Radial

lathe checks Pourcentage of lathe checks Depth of lathe checks Pourcentage of lathe checks Brenta

La Réole Sapwood 16,27 16,63 10,51 46,22 -128,54 70,01 76,2 -313,75 0,820 27,791 0,271 9,188 Heartwood 22,74 23,92 9,97 61,9 -138,21 77,83 84,59 -398,03 0,919 31,134 0,272 9,223 Sainte Nicolas la

Chapelle

Koster

Sainte Hermine Sapwood 14,94 18,07 8,22 40,19 -147,66 125,18 68,04 -348,12 0,396 13,476 0,207 7,039 Heartwood 19,62 27,61 9,45 55,01 -162,79 149,42 72,03 -395,52 0,699 24,033 0,249 8,519 La Réole Sapwood 30,02 38,35 17,47 76,54 -153,69 145,76 78,57 -361,56 0,744 25,383 0,275 9,372 Heartwood 22,52 32,8 11,84 63,82 -167,73 172,03 82,46 -429,46 1,112 38,129 0,345 11,858 Sainte Nicolas la

Chapelle Sapwood 20,92 27,05 13,09 64,14 -134,17 103,38 90,86 -399,14 0,951 32,017 0,244 8,229 Heartwood 20,62 25,09 15,35 70,94 -139,43 120,92 94,97 437,66 0,795 26,623 0,235 7,812

Taro

Blanzay sur Boutonne Sapwood 34,54 30,22 14,76 81,04 -182,05 67,51 83,14 -410,01 0,788 27,693 0,229 8,051 Heartwood 44,32 38,46 20,4 113,83 -201,58 138,89 118,88 -652,93 0,846 28,664 0,227 7,753 La Réole Sapwood 35,12 49,18 14,86 82,44 -163,32 89,46 89,43 -444,48 1,005 34,559 0,277 9,513 Heartwood 31,04 47,77 12,44 75,02 -160,82 101,6 85,14 -443,46 1,049 35,870 0,303 10,364 Sainte Nicolas la

Chapelle Sapwood 29,84 27,98 11,79 72,78 -162,72 126,88 70,53 -359,57 0,654 22,293 0,241 8,187 Heartwood 18,89 25,04 10,12 52,84 -168,11 147,15 74,96 -411,1 0,476 16,355 0,213 7,316

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Cultivar Site

lathe checks Pourcentage of lathe checks Depth of lathe checks Pourcentage of lathe checks Mella

Blanzay sur Boutonne Sapwood 28,21 26,62 11,73 62,51 -171,57 110,52 76,27 -370,75 0,558 19,127 0,210 7,148

Heartwood 0 0 0 0 0 0 0 0 0,000 0,000 0,000 0,000

La Réole Sapwood 19,24 16,66 3,14 3,95 -117,94 43,04 41,95 -3,86 1,127 38,973 0,318 11,087

Heartwood 20,83 16,36 9,16 53,84 -155,6 77,17 42,02 -269,91 1,353 46,452 0,314 10,844

Sainte Nicolas la

Chapelle Sapwood 15,18 14,99 17,24 48,16 -116,03 69,31 105,44 -319,64 0,909 31,339 0,435 14,961 Heartwood 27,93 23,13 14,94 42,53 -149,22 158,48 121,36 -401,14 0,752 26,069 0,306 10,596

I214

Blanzay sur Boutonne Sapwood 20,72 30,15 11,74 86,53 -113,78 100,87 67,95 -337,34 0,861 29,430 0,242 8,227 Heartwood 16,45 27,1 11,16 57,62 -132,96 118,03 74,59 -414,06 0,745 25,977 0,232 8,049 La Réole Sapwood 11,71 13,32 13,31 55,65 -97,79 84,74 75,72 -195,36 0,625 21,175 0,205 6,910

Heartwood 0 0 0 0 0 0 0 0 0,000 0,000 0,000 0,000

Sainte Nicolas la

Chapelle Sapwood 11,4 13,17 5,86 36,85 -115,5 89,39 53,18 -230,8 0,597 20,564 0,270 9,320

Heartwood 16,88 15,99 7,2 36,67 -140,25 98,25 56,38 -304,89 0,645 22,307 0,267 9,242

Trichobel

Vauchelle le Authis Sapwood 14,01 20,01 4,78 25,06 -111,59 89,5 37,52 -189,86 0,866 29,497 0,263 8,958

Heartwood 24,25 19,59 4,74 26,09 -124,51 64,86 28,48 -178,03 1,066 36,777 0,333 11,437

Long Sapwood 14,3 12,12 7,09 31,6 -100,55 36,32 47,31 -186,19 1,136 38,788 0,295 10,108

Heartwood 37,24 38,33 9,57 56,41 -122,59 56,46 42,09 -211,05 0,958 32,775 0,316 10,680

Le Busseau Sapwood 25,95 23,65 9,33 58,23 -113,79 78,97 63,37 -277,97 1,365 46,814 0,549 18,864

Heartwood 24,47 18,39 6,95 46,46 -115,12 69,41 46,03 -273,49 1,181 40,843 0,339 11,751

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Cultivar Site

lathe checks Pourcentage of lathe checks Depth of lathe checks Pourcentage of lathe checks Alcinde

Vervant Sapwood 14,89 17,95 10,62 45,68 -118,79 128,82 77,2 -384,38 1,143 39,609 0,249 8,650

Heartwood 17,05 25,14 10,83 55,7 -129,66 150,16 74,6 -397,58 1,332 45,480 0,304 10,405

Saint Jean d'Angely Sapwood 21,42 23,4 10,75 50,54 -173,41 58,81 68,85 -350,62 0,850 28,816 0,242 8,170 Heartwood 30,06 29,88 12,61 83,59 -189,53 57,25 76,27 -436,42 1,236 41,996 0,318 10,834 Le Busseau Sapwood 35,96 30,43 12,95 66,74 -177,15 61,82 79,03 -390,25 0,929 31,353 0,238 8,022 Heartwood 27,56 31,41 14,89 54,41 -109,14 81,59 32,75 -171,12 1,107 37,712 0,256 8,717

Polargo

Epieds Sapwood 19,08 16,12 6,62 32,36 -134,07 39,39 39,05 -174,98 0,977 33,609 0,329 11,443 Heartwood 35,17 41,02 11,07 55,17 -198,08 67,01 46,33 -351,64 0,939 32,555 0,361 12,415 Saint Jean d'Angely Sapwood 14,71 18,32 4,38 24,75 -135,7 109,54 39,39 -207,05 0,781 26,547 0,272 9,204 Heartwood 59,42 88,02 9,34 89,05 -173,47 159,64 44,32 -282,56 0,858 29,503 0,294 10,141 Bussy les Daours Sapwood 17,38 15,23 9,19 34,59 -142,72 68,53 63,09 -297,94 0,805 27,557 0,264 9,032

Heartwood 33,97 23,07 10,34 56,66 -172,81 91,38 59,18 -328,5 1,046 36,147 0,315 10,864

Triplo

Vervant Sapwood 16,93 23,65 9,1 47,28 -121,27 59,68 73,44 -335,12 0,904 31,311 0,281 9,686 Heartwood 22,76 23,8 10,19 76,58 -140,41 211,05 86,45 -462,18 0,945 32,502 0,281 9,632 Saint Jean d'Angely Sapwood 14,28 16,03 5,61 25,6 -129,46 120,87 33,74 -194,39 0,944 32,095 0,278 9,431 Heartwood 20,96 24,26 5,09 37,34 -149,22 149,12 40,92 -252,06 0,887 30,361 0,236 8,077 Bussy les Daours Sapwood 17,92 14,92 9,28 41,69 -128,91 70,98 54,36 -256,44 0,817 27,899 0,194 6,611

Heartwood 15,64 13,53 8,68 41,76 -115,28 84,63 50,28 -243,39 0,938 32,151 0,241 8,262

A4A

Clarques Sapwood 25,44 23,1 6,32 30,11 -137,51 96,35 37,34 -182,39 0,850 29,112 0,265 9,114

Heartwood 41,06 35,69 8,9 43,18 -166 118,75 40,32 -227,1 1,023 35,109 0,337 11,595

Argenton Sapwood 27,48 32,23 9,35 50,79 -140,57 79,71 50,3 -241,68 0,815 27,906 0,266 9,062 Heartwood 34,94 38,99 10,75 49,45 -157,97 116,13 54,94 -300,1 0,909 31,413 0,255 8,826 Bussy les Daours Sapwood 33,93 38,1 27,83 81,66 -123,53 107,32 55,15 -274,02 1,048 35,939 0,270 9,225 Heartwood 53,07 59,79 16,88 90,76 -142,45 142,77 57,73 -288,68 1,064 36,870 0,303 10,572

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Appendix II. Matrix of Correlations

Variable Site Cultivar position radial

Thickness MC Depth of checks

% of checks

Xc m Xc s Yc m Yc s Xb m Xb s Yb m Yc b CovYc CovXc CovYb CovXb

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ABSTRACT

MEYLIDA NURRACHMANIA (2012), Study of Deroulability in 14 Cultivars of Poplar: Analysis of Cutting Force And Lathe Checks Of Veneer In Micro-Lathe. Under the supervision of NARESWORO NUGROHO and LAURENT BLERON.

Poplar is well known for its large wood production. Through this work, the objective of this study seeks to identify the qualities of new cultivars of poplar and classify these new cultivars in a reference quality poplar wood (by evaluating the lathe check phenomenon and measurement of cutting forces in micro-lathe). The 42 disks of 14 cultivars and three stations were conducted in 3 mm for two types of veneer, "heartwood" and "sapwood". The 14 cultivars are concerned from cultivars currently on the market of plant poplar. The micro-lathe was used to measure cutting forces. Veneer of peeling process in micro-lathe was observed using a device called SMOF for systematic and objective analysis of lathe check in the veneer. The result is shown that there no significant effect of the radial position (heartwood and sapwood) and cultivar on the cutting force (Xc/force knife vertical, Yc/force knife horizontal, Xb/force bar vertical, and Yb/force bar horizontal), depth and percentage of lathe check.

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SUMMARY

MEYLIDA NURRACHMANIA (2012), Studi Pengupasan 14 Kultivar Poplar: Analisis Cutting Force (Gaya Pemotongan) dan Lathe Checks (Retak Kupas) Vinir pada Micro-Lathe. Di bawah bimbingan NARESWORO NUGROHO dan LAURENT BLERON.

Poplar is well known for its large wood production. The statistical data on poplar cultivation available worldwide are referred to different cultural. France is the largest producer of poplar wood in European countries and an area of 236.000 ha with 1,8 m3 wood production. Production of poplar is based on the use of a large number of genetically different cultivars. One way to generate a variety of cultivars is by doing genetic engineering tree through the hybridization process. Hybrid poplars are trees that are developed by crossing two different species of poplars. Poplar wood is being destined to the production of plywood or LVL (veneer). Through this work, the objective of this study seeks to identify the qualities of new cultivars of poplar and classify these new cultivars in a reference quality poplar wood (by evaluating the lathe check phenomenon and measurement of cutting forces in micro-lathe). Order these new cultivars in the repository poplar wood quality named «Référentiel qualités du bois des cultivar de

peuplier ».

The 42 disks of 14 cultivars and three stations were conducted in 3 mm for two types of veneer, "heartwood" and "sapwood". The 14 cultivars are concerned from cultivars currently on the market of plant poplar. Therefore, the 14 cultivars are: A4A, Brenta, Koster, Lambro, Mella, Polargo, Soligo, Taro, Triplo, Trichobel, Dvina, Lena, Alcinde and I-214. Micro-lathe was an instrumented for peeling disks from 10 to 30 mm wide. The micro-lathe that can scroll experimental discs of wood and non ridges integers. This reproduces the unwinding smaller scale and it also allow measurement of cutting forces. Veneer of peeling process in micro-lathe was observed using a device called SMOF for systematic and objective analysis of lathe check in the veneer.

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vertical, Yc/force knife horizontal, Xb/force bar vertical, and Yb/force bar horizontal), depth and percentage of lathe check. There are several factors that affect the value of the cutting force veneer from timber and are derived from the engine. For derived from wood such as wood species, wood density, moisture content of wood, annual rings.

Lathe check, the phenomenon is created during peeling. Lathe checks has also an important role on the quality of the veneer. Usually lathe checks can be caused by the fractionation process during the peeling process. It can also be explained by the sharp knife (new tool or lapped, dull knife). Basically, a sharp knife will have a small nose radius so that the knife is perfectly effective, but when using a blunt knife, the tip radius becomes larger. In this case and produce a poor quality of surface and a high cracking. The depth of lathe checks appears significantly correlated with a mechanical and destructive tests only 4-point bending. Indeed, the modulus of elasticity decreases as the depth of cracking.

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