wear analysis to circular saw blades with cutting of...

Wear Analysis to Circular Saw Blades with Cutting of Carbide Metal

Stuck at Beech Processing

SPIRCHEZ COSMIN1, VALENTIN DITU

2, NICOLAE TARAN

1, LOREDANA ANNE-MARIE

BADESCU1

Department of Machines for Wood Industry1, Manufacturing Engineering2

Transilvania University of Braşov

B-dul Eroilor, 29, 500036 Braşov

ROMANIA

[email protected]; [email protected]; [email protected]; [email protected]

Abstract: - The paper presents an analysis of the wearness of circular saw blades with cutting of carbide metal

stuck at beech processing to establish lastingness and to identify the moment for resharpening.

Key-Words: - cutting wood, wear, circular saw blade, lastingness, beech, machining conditions)

1 Introduction Cutting wood with circular saw blades is

accomplished on circular cross-cut saw. The tool is a

round circular blade, which is in the area peripheral

toothed, it execute a movement of rotation

continues. Wood made a motion to continuously

advance to the cloth cutting. Through this cutting

process may accomplish in along sample, crosscut

and cutting in a angle. Mechanical wood processing

is an important act in technological assembly for

obtaining wooden products. Wood cutting with

circular saw blades represents on cutting process

used in range of 70-80%, because of the ripping,

cutting, trimming, operations. Dimensions of

circular saws are in accordance with the

characteristics and the construction of the machines

and by the characteristics of wooden species.

2 Theoretical elements One of the basic conditions in exploitation circular

saw blades is keeping capacity of cutting edges for a

long time.

Geometry of cutting edge is changing continuously

between two sharpening, due to interaction between

the wood and cutting edges. The wearness cutting

edges produced minimum of the circular saw

capacity.

The wearness cutting edges, a result of interaction

between wood and tooth, is may occur in the form of

fracture or as normal. Wearness in the form of

fracture, named wearness accidental, occurs when

the cutting forces development in tooth tensions that

stresses exceed the fracture strength of the tooth

material.

Wearness normal is occurs as a result of continuous

wear of the tooth material. In the paper analysed

mechanical wear. Mechanical wear occurs by

removal of metal particles from outer layers of the

tooth under the action of the friction forces between

them and the wood

The degree of wear and the wearness character

circular saw blade, depends on the following

parameters: physical and the mechanical properties

of the tool material, conditions of cutting, machining

conditions, quality of cutting edges,

Are presented: wearness through abrasion, wearness

through adhesion, wearness through diffusion,

wearness through fatigue, electrical wearness,

wearness through oxidation. The circular saw blade

wearness only on outer clearance face and inner

clearance face, or, and on front face. The factors that

influenced wearness the circular saw blades are:

machining conditions, geometry of circular saw

blades, wood species, state technical equipment.

The influenced machining conditions are made:

cutting speed, feed speed, cutting depth. Increasing

the feed speed occurs at intensification the wearness

because increases strengths and temperature.

Are presented the following relations for calculation

wearness[3].

1.VB = Q E/ 60 v t £ (mm),

Where: Q- quantity of heat

E- mechanical equivalent

v- cutting speed

t - cutting depth

£ - stress

2. VB = [(A ſ e –ks/ R(ſ + 273)]1/2 * (1-tgǡ * tg

Ǵ/t * tgǡ ) ½ (mm)

Where: ſ – temperature of cutting

Proceedings of the 8th WSEAS International Conference on SYSTEM SCIENCE and SIMULATION in ENGINEERING

ISSN: 1790-2769 27 ISBN: 978-960-474-131-1

Ks- transverse force

R- gassing factor ( R= 8,317j/molK)

ǡ - clearance angle

Ǵ -hook angle

Wear admissible is presented in table 1 [3]

Table 1

Type

of tool

material operation admissible

wear (mm)

Thtree

blade

steel degrosing 1….2

3 Experimental researches Attempts were made on circular saws FCT product

by enterprise Mechanics Roman with the following

characteristics: supply voltage 380 V, frequency

50Hz, 4 KW power installed, the command voltage

to 220V.

Since the circular saw is provided with a mechanical

advance on the installed device driver advance roller

(DAM), product of firm Matic Co, Af-38 Model

with 8 speeds, made 2007, supply voltage 380V.

In conducting experiments to use a circular saw

blade cutting of carbide metal stuck with the

following characteristics:

- Outer diameter (D): 300 mm

- Inside diameter (d): 30 mm

- Number of teeth (z): 24

- Thickness : 3,2 mm

- Clearance angle: 10 degrees

- Sharpness angle: 62 degrees

- Hook angle: 18 degrees

- Tooth pitch: 40 mm

- Radius of rounding of cutting: 10

Fig.1 The tooth circular saw blde with two

sharpenings

Was processed longitudinal wood species of beech

with length of 600 mm, width 160 mm, thickness 50

mm, humidity 8%.

Rotation speed circular saw blade was measured of

4215 rot/min and the feed speed was 16,72m/min.

For measuring tooth cutting used an optical

microscope. Wear circular saw blades was measured

before processing, and after 150m.

The measured data are presented hereby:

- First tooth

Initial state: very well

- The second tooth


Fig.2 Wear on clearance face or, and front face tooth

Fig.3 Wear on front face tooth

- First tooth

State of tooth after 150 m linear: very well

- The second tooth

State of tooth after 150 m linear: the blade has knobs

and edge presents wearness (0,11mm)

Fig.4 The third tooth (Initial state: very well)

- The fourth tooth


ISSN: 1790-2769 28 ISBN: 978-960-474-131-1

Knobs (0,03mm)

- The fifth tooth

Initial state:very well

Fig.5 The third tooth (State of tooth after 150 m

linear: The blade has crocks and edge presents

wearness 0,21mm).

- The fourth tooth

State of tooth after 150 m linear: Knobs (0,06mm)

- The fifth tooth

State of tooth after 150 m linear: Edge is weared

Fig.6 The sixth tooth (Initial state: Knobs 0,03mm)

- The seventh tooth


- The eighth tooth


- The ninth tooth


- The tenth tooth


- The eleventh tooth


Fig.7 The sixth tooth (State of tooth after 150 m

linear: Edge of tooth is rounded 0,06mm)

- The seventh tooth

State of tooth after 150 m linear: Edge of tooth is

rounded (0,03mm)

- The eighth tooth


- The ninth tooth


- The tenth tooth

State of tooth after 150 m linear: The tooth is

chamfer (0,15mm)

- The eleventh tooth


Fig.8 The twelfth tooth (Initial state: Knobs

0,19mm)

- The thirteenth tooth

Initial state: Edge of the tooth is rounded (0,24mm)

Fig.9 The fourteenth tooth (Initial state: Very well)


ISSN: 1790-2769 29 ISBN: 978-960-474-131-1

- The fifteenth tooth

Initial state: Very well

- The sixteenth tooth


- The seventeeth tooth

Initial state: Knobs (0,04)

- The eighteenth tooth


- The nineteenth tooth

Initial state: Knobs(0,03mm)

- The twentyth tooth


- The twenty-first tooth


Fig.10 The fourteenth tooth (State of tooth after 150

m linear: Edge of teeth is rounded 0,10mm)

- The fifteenth tooth

State of tooth after 150 m linear: Small wear

- The sixteenth tooth


- The seventeeth tooth

State of tooth after 150 m linear: Light wear of the

edge (0,06mm)

- The eighteenth tooth

State of tooth after 150 m linear: Knobs(0,05mm)

- The nineteenth tooth

State of tooth after 150 m linear: Edge of teeth is

rounded( 0,19mm)

- The twentyth tooth

State of tooth after 150 m linear: Light wear of the

edge

Fig.11 The twenty-second tooth (Initial state: Knobs

0,03mm)

Fig.12 The twenty-second tooth (State of tooth after

150 m linear: Frontal wear 0,11mm)

Fig.13 The twenty-third tooth (Initial state: Knobs

0,03mm)

- The twenty-fourth tooth

Initial State: Very well

Fig.14 The twenty-third tooth (State of tooth after

150 m linear: very strong wear)


ISSN: 1790-2769 30 ISBN: 978-960-474-131-1

- The twenty-fourth tooth

State of tooth after 150 m linear: Frontal wear

4 Conclusions The wearness of circular saw blade make continuous

and irreversible the conditions of cutting process.

The wearness phenomenon is irreversible by the

time; it means the wearness of the blade increase in

time.

The wearness study was make with the purpose to

wield the cutting process

At the beginning of processing the tooth number of

the saw blade has on average value of 66,66%, and

other 150 line meters the percentage of the tooth

wearness reached the average value of 16,66%.

The lastingness circular saw blade by cutting beech

at 150line meters is calculated with relation:

T = d/vs = 150/16,72=8,97 (min)

It is assessed the research development and

establishment of an optimal lastingness

References:

[1]Bersadski, A.I. Rezanie drevesini,

Goleszbumizdat, Moscova, 1958

[2]Ditu, V. Cercetari teoretice si experimentale

privind diagnoza procesului de aschiere, 1997

(thesis doctorat abstract)

[3]Ditu V. Bazele generarii suprafetelor si scula

aschietoare, Transilvania University of Brasov,

Publishing House, 1997

[4]Dogaru V. Aschierea lemnului si scule

aschietoare, Bucuresti Publishing House, 1981

[5]Mckenzie W.M. Wear and blunting of the tool

corner in cutting a wood based material. Jurnal

Wood Science and technology, 2004

[6]Orlowski K. Study washboarding phenomenon in

frame sawing machines. Jurnal Holz als Roh-

und-Werkstroff, 2006

[7]Taran N. Masini-unelte si utilaje pentru

prelucrarea mecanica a lemnului. Transilvania

University of Brasov Publishing House, 2004


ISSN: 1790-2769 31 ISBN: 978-960-474-131-1

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