BROACHING MACHINE

        BROACHING PROCESS


Points to know:-
  • Tool-high speed steel,brazed carbide,alloy steel.
  • Work piece-light material like aluminium, plastic, brass etc.
  • Tool cutting rate 20-100 feed/minute.
what is broaching?
  • Broaching is a conventional (tool-work piece in contact) machining process of removing material from work piece with the help of broach tool.
  • The broach tool can perform two operations:-
1.     Linear broaching
2.     Rotary broaching
  • Linear broaching:-
In linear broaching the broach tool moves in linear direction against the work piece surface.
  • Rotary broaching:-
In such broaching operation broach tool is made to rotate on the axis and pressed against the work piece and cut or produce axis symmetric shape.

2.  What is a broach tool?
 Fig:-Broach tool

The broach tool can be divided into three section:-
1.              Roughing zone--Big teeth
2.              Semi-finishing zone---Small teeth.
3.              Finishing zone---Fine teeth.
The slot is provided near the pull end of tool for attachment in lathe/screw machine. At the beginning of rough teeth, chip breakers are present. These are provided for fracturing the work piece at initial stage.

The broach teeth size increases gradually in size. More is the number of teeth, higher will be the material removal.

          Fig:-broach teeth close look

The feed per tooth determines the material removal rate. The broach tool has unique function of cutting and finishing the work piece in single stroke/feed.

The small and gradually increasing size teeth are made for cutting and larger size tool are made for finishing operation. Each cutting teeth removes small amount of material and larger teeth shapes the work piece to good surface finish.

The machining takes place in forward direction only and no material is removed in return stroke.

3.  Why we use cutting fluid during broaching?
  • The reason of using cutting fluid are:-
1.Removes burr/cut particles from cutting region.
2.Carry away heat which is generated due to friction between tool and work piece.
3.Provides lubrication effect to machine parts.

4.  What are classification of broaches?
  • Broaches on the mode of usage can be classified as:-
1.Internal broaches.
2.Surface broaches.

In order to machine internal surfaces or key ways various broach operation like solid broach, key way broach, modular  broach are used.

Surface broach is used to produce upper machined surface of work piece. The various process include slot broach, counter broach etc.

APPLICATION:-
  • Engine parts, internal components are machined.
  • Used in steel industries. etc
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