T h i n k c o s t e f f i c i e n c y , T h i n k H S S

SAWING

SAWING

BANDSAWING2 The basics of bandsawing

3 HSS and coatings

4 The bimetal concept

5 Tooth set

6 Tooth pitch and forms

7 Speeds and feeds

8 Blade break-in

9 Chips

10 Clamping of workpiece

11 Problem solving

CIRCULAR SAWING12 The basics of circular sawing

13 HSS and coatings

14 Tooth types

15 Tooth pitch

16 Speeds and feeds

17 Positioning of workpiece

18 Problem solving

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THE BASICS OF BANDSAWING2

A BANDSAW AROUNDTHE WORLD

French: une scie-ruban

German: eineBandsäge

Italian: una sega anastro

Spanish: una sierracinta

In bandsawing, a continuous bandsaw blade cuts inone direction with a uniform cutting action and evenlydistributed, low individual tooth load. Chips producedhave a constant thickness.

Bandsaws can be used for cut-off operation, straightsawing or contour sawing.

Three types of bandsawing machines are available:

• vertical, mainly used for contour sawing

• horizontal, for productive cut-off operations

• pendular machines.

HSS AND COATINGS

• Seldom used • Basic choice • For highperformance andlong tool life

• For nickel alloys,titanium alloys andhard steels

TOOL MAKER’S TIP

Use TiN coated bandsaws for longer

blade life andresistance to

abrasion

3

HSS HSS-E8% cobalt

HSS-E-PM

THE BIMETAL CONCEPT4

Bimetal saw concept

In bimetal saws, a HSS wire is welded by electron beamor laser on a steel backing

Vocabulary

HSS wireRake angle

Tooth angle

Saw blade length

Tooth back face

Tooth rake face

Tooth heightGullet

Saw bladethickness

EB or laser welding

Bimetal bladeSteel backingSteel backing

TOOTH SET5

Raker set

• 3-tooth sequence, left,right, straight

• Reduces tooth load, forheavy cutting

• Uniform set angle

• Prefered for ferrousapplications

Wave set

• Progressive sine-waveoffset pattern with fine pitch

• Reduces tooth load

• Smoother in thin wallsections

• Also for high speed cuttingat reduced cutting depth

Alternate set

• 2-tooth sequence, left,right

• Prefered for non-ferrousmetals

Variable (multipitch) set

• One unset tooth (raker) ineach repeating pitchsequence

• Only the largest tooth ineach sequence is unset

• Appropriate for mostapplications

TOOTH PITCH AND FORMS

Tooth pitch

6

Fixed pitch

• General purposeuse

• Good chip carryingcapacity

Fixed pitchpositive

• General purpose use

• Good chip carryingcapacity

Variable pitch

• Smooth cutting

• Reduces harmonicvibrations andnoise

• Good chip carryingcapacity

• Long blade life

Variable pitchpositive

• Smooth cutting

• Reduces harmonicvibrations andnoise

• Good chip carryingcapacity and easychip formation

• Good toothpenetration

• Long blade life

Hook positive

• Allows coarse pitchon narrow blades

• Easy chipformation

• Good chip carryingcapacity

• Use in cast ironand non-metallicapplications (wood,plastics,composites)

Pitch (P)

SPEEDS7Cutting speed in m/min

0 100

Special alloys

Heat resistant steels

Titanium alloys

Cast iron

Stainless steels

Valve steels

Tool steels

Aluminium bronzes

Spring steels

Carbon steels

Bearing steels

Case-hardening steels

Structural steels

Free machining steels

Bronzes

Copper

Brass

Thermoplastics

Aluminium Si >5%

Aluminium Si <5%

50 100 150 200 250 500300 350 400 450

Up to 2500Up to 1500

BLADE BREAK-IN

TOOL MAKER’S TIP

Break-in is necessaryfor long blade life

8

New blade

• Razor-sharp tooth

With break-in

• Micro-fine radius

• Break-in is done by reducing thefeed rate/force control to achieve acutting rate approximately 20 to 50% of the normal cutting rate.

Without break-in

• Premature tooth breakage

CHIPS9

Very fine or pulverized chips

• Increase the feed rate

• Or lower band speed

Thick, heavy or blue-coloredchips

• Decrease the feed rate

Loosely rolled chips

• Ideal cutting conditions

CLAMPING OF WORKPIECE10

Methods of clamping workpieces

Positioning of blade and workpiece

Right

Wrong

Select sawswith large teeth

Select sawswith small teeth

Select sawswith small teeth

PROBLEM SOLVING11

Reduce feed and increase speed. Use finer tooth pitch. Increase coolant flow. Check workpiece clamping.

Solutions

Reduce feed. Check coolant flow. Adjust blade tension and guides. Check for tooth set damage.

Inaccurate cut

Increase band tension. Increase speed. Reduce feed. Check for blade wear or chips.

Increase coolant flow. Reduce speed. Use coarser tooth pitch.

Blade stalling inwork

Chip welding

Use coarser tooth pitch. Increase feed or decrease speed. Check coolant flow.

Premature bladewear

Check blade fixture. Increase feed. Check blade break-in. Check coolant flow and type.

Premature dullingof teeth

Check speed and feed. Adjust saw guides. Check chip brush.Teeth fracture

Use finer tooth pitch and finer blade. Reduce blade tension and feed. Check coolant. Adjust speed.

Blade breakage

Problem

Tooth strippingand chipping

THE BASICS OF CIRCULAR SAWING

A CIRCULAR SAWAROUND THE WORLD

French: une sciecirculaire

German: eineKreisäge

Italian: una segacircolare

Spanish: una sierracircular

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• Circular saws are used for high performance cuttingof all forms of ferrous and non-ferrous metals: billets,tube, profile, bar, rounds, etc…

• Circular saws are available as:

- solid saws

- with HSS segments riveted onto a steel body,useful when large saw diameter is required.

HSS MATERIALS AND COATINGS13

• Basic choice

HSS et HSS-E

• For hard steels, stainless steelsand cast iron

• For materials with low thermalconductivity

• For dry cutting• For higher cutting speeds (+60%)

• Multi-purpose • For steels, tubes and

profiles• For higher cutting

speeds (up to 50%higher)

TiNGold

• Low friction coatingspreventing gumminess andbuilt-up edges

• For copper alloys, bronze,brass and aluminium

• For higher cutting speeds(up to 70% higher)

• For abrasive materials• For hard steels, titanium

alloys and stainlesssteels

• For higher cutting speeds(up to 90% higher)

TiCNGrey-violet

TiAlN Black-violet

CrN Metal

HSS-E

• For longer tool life• For difficult-to-machine

alloys

TOOTH TYPES

BW or ACME

Generally used for cutting thin walledsteel tubes (3- and 4 mm pitch)

C or Heller forms

Generally used for cutting flatsections or thick walled tubes(greater than 4 mm pitch)

BC or Chipbreaker

For cutting thin walled tubes andsmall profiles.

Improves the quality of the cut

Improves performance

14

TOOTH PITCH

Pitch choice for plain section Pitch choice for tubes and profiles

For tubes and profiles, make sure that at least two teethare in contact with the workpiece.

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Pitch (mm)

3

4

5

6

7

8

10

12

14

Materialthickness (mm)

3-5

5-10

10-15

15-30

20-35

25-40

30-50

35-60

40-80

SPEEDS AND FEEDS16

Material

Steels 35-50 kg/mm2

Steels 50-65 kg/mm2

Steels 70-85 kg/mm2

Hardened steels

Austenitic stainless steels

Martensitic stainless steels

Cold rolled profiles

Tubes with thin walls

Tubes with thick walls

Girders

Grey cast iron

Aluminium

Copper

Brass

Bronze

Titanium alloys

Hard plastics

Cutting speed(m/min)

28-35

20-28

15-22

12-18

5-12

7-10

25-40

40-80

30-50

19-30

12-25

900-1500

80-400

400-600

40-120

10-15

900-1500

Feed(mm/min)

70-160

60-120

40-100

25-50

30-45

20-35

80-130

80-150

70-130

70-130

80-110

1200-1400

400-600

800-1000

400-800

80-160

1200-1400

POSITIONING OF WORKPIECE17

PROBLEM SOLVING18

Problem

Premature wear

Causes

Pitch too large Excessive cutting speedWrong feedCooling inadapted Wrong positioning of the workpiece

Wrong pitchExcessive feed Poor cooling

Teared-off teeth

Seizing-up due to poor sharpening Excessive feed Clamping problem

Saw breakage