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PERFECTIONPERFECTION MOVES MOVES USUS

BROACH SEMINAR

2 PERFECTIONPERFECTION MOVES MOVES USUS

● CUTTING METHOD:

• Formed –[cutter profile = gear profile] : Milling cutter: involute,spline(inv,parallel_side),sprocket,worm, BROACH, gear endmill, serra. c/t

• Generated-[cutter profile ≠ gear profile] : Hob, Pinion c/t ,Shv c/t ,Rack c/t,Bevel gear c/t

• Plastic Method : generated -rolling dice

Classification Of Gear Cutting Tools

BROACH PROFILE GRINDING


1. Definition

- External & Internal Gear Cutting Tool.

- With Roughing, Semi_finishing, Finishing Teeth.

- Formed Method Type

2. Features

1.Less machining time.

2.High accuracy.3.Easy machining for complex shapes.4.Fine roughness.5.Lower Cost.6.No need special skills.

Definition & FeaturesOf Broach


Nomenclatures Of Broach


Features Of Each Broach

• ROUND BROACH

• SPLINE BROACH

• SERRATION BROACH

• KEYWAY BROACH

• ANGLE BROACH

• SPECIAL BROACH

• COMBINATION BROACH


• HELICAL BROACH

• STEERING RACK BROACH

• TREE BROACH

Features Of Special Broach


• BROACH DESIGN : Be designed SMALL and ACCURATEOtherwise à difficult manufacturing,

deterioration of accuracy, higher cost, inconvenient for handling

• PULL END & RETRIEVER : the model of broaching machine, size of PULL HEAD.- Reference : (JIS B4237),(DIN1415)

• FRONT PILOT : the front pilot length > the cutting length of gear, fitness : IT g7

• Length to the first tooth : The first tooth must not touch workpiece, ask for user’s spec.of broaching machine- JIS,DIN Standard.

• Cutting Length :- Pitch selection & engaged teeth

• Tatal amount of cutting : finish dia. – min dia.

Selection of Major Dimensions


• UT : Consideration of quality,hardnessof work,the type & size of broach, the capacity of broaching machine.-differences among roughing,semi_finishing,finishing part.

• PITCH : Kx√ (L)– Depending on the cutting length, to avoid chip jamming.

K:1.2—2.0(coefficient)per 0.5

L/P > 2 (integer) – engaged teeth.

• Chip Space Shape := CHIP VOLUME x 6~10L=0.25~0.3PH=0.3~0.5PR1=0.4~0.6H

• RAKE ANGLE &CLEARANCE ANGLE:• SIDE FACE RELIEF • REAR PILOT PART• RETRIEVER• NICK(CHIP BREAKER) ;ZIGZAG• OVERALL LENGTH

Selection of Major Dimensions


• Estimated Load(KN)= width of cut x UT x Engaged cutting teeth x specific cutting force (KN/mm2)

• SAFETY LOAD(KN)= 1.8 x Estimated Load(KN)

Force of Broaching

Exam) Parallel spline 20x16x4x6SP

Material :Alloy steel, length of cut : 25mm

1)Broach Pitch=1.5x√ 25 = 7.5

2)Engaged cutting teeth =25/7.5=3.3è4

3)Cutting depth each tooth (UT)=0.025mm

4)specific cutting force : 2.94KN/mm2

5)Estimated Load = (4x6)x0.025x2.94x4= 7KN

6)safety load = 1.8x7=12.6KN


• Hardness of work material : approximately HB200-240.1)Soft steel : Adhesion,Scuffing and Tears2)hard steel : Wear,Shorten Tool Life.

• Prepared Hole : Big influence of Roughness, Accuracy, Longevity1)Be right_angled to datum clamp face

– Broach bending & cannot be obtained Accuracy & Size2)small & large – cannot be passed through & obtained Eccentricity

• Cutting Speed : Influence of Roughness, Tool life, Accuracy. considering machinability.

- Usually : 2-8M/min- Recently : 15-40M/min

• Cutting Oil : Big influences of Broach longevity.- to improve roughness. - to improve accuracy & size.- to control wear of cutting edge. - to make removal of chip easier.

• Wall Thickness Of Workpiece – Spring Back

- Elastic and Plastic Deformation

Notices of Broach Processing


1) BROACH TRANSFER TYPE

BROACHING TYPE #1


BROACHING TYPE #2

2)WORKPIECE TRANSFER TYPE(RAM)


Broach Length & Machine Stroke

*.Length of cutting teeth + Rear shank length < Max.Machine stroke – Length of cut

*.Required stroke = Length of cutting teeth + Rear shank length + Length of cut <

Max.Machine stroke


Regrinding of Round Broach

• D =0.85*d*sin(β-r)/sin(r)Wheel dia. D

d : Dia. Of broach

β: Grinding wheel

inclination angle

r : Rake Angle


Check Point Of Ordering

• Broaching Machine : Force, Stroke, Manufacturer, Model No.

• Broach Dwg. : Currently in use.Shape, Dimension Of PULL END & REAR END.

• Pull Head : Broach Dwg. Shape.

• Broach Holder : Broach Dwg.

• Broach Horn : Shape & Dimensions.

• Retrieving Head : Broach Dwg. Shape, With Or Without

• Clamping Jig : Clamp Model No.

• Cutting Fluid : Water Or Not Water,

Ouput Pressure, Volumn, Position.

• Chip Removal System : Used Or Not Used

• Miscellaneous : Surface Treatment, Marking

broach seminar - factory · pdf filebroach seminar . 2 perfectionmoves us ... classification...

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