Broaching

Broaching • Broaching is the process of removing metal with

a tool which has “teeth” arranged in a row. Each tooth is successively higher than the previous tooth and removes more material. In broaching, one stroke or cycle of the machine produces a finished part.

• Broaching is used to produce both internal and external features. Production rates are high and tolerances of +/- .0005” are possible.

Broaching

Broaching

Broaching

An hydraulic vertical type broaching machine

Purpose of Broaching

Broaching is done when the profile of the work piece cannot be achieved by normal conventional machining processes

Broaching can be done both externally as well as internally

Various Various types of types of broachesbroaches

Spline BroachingSpline Broaching

Spline broachingSpline broaching::

As the name states spline broaching is used to make internal splines on the gears or blanks. For broaching of either straight sided spline or involute spline, regular spline broaches are used. Straight sided splines can be broached by normal key way broaching procedure when the quantity of broaching is small.

Types of profiles that a spline broach can formTypes of profiles that a spline broach can form

A spline broach A spline broach

For small quantities the spline broach resembles For small quantities the spline broach resembles the key way broach; except the top side will be the key way broach; except the top side will be reduced corresponding to that outside the mating reduced corresponding to that outside the mating shaft. shaft.

The regular spline broach design is like that of a The regular spline broach design is like that of a round broach, with teeth gradually increasing in round broach, with teeth gradually increasing in diameter until the final broach is reached. All diameter until the final broach is reached. All cutting is done outside diameter and not the sides cutting is done outside diameter and not the sides of the teeth.of the teeth.

Prior to broaching, a minor pre finished hole is Prior to broaching, a minor pre finished hole is required. How ever if close concentricity is required. How ever if close concentricity is required between minor and major diameters a required between minor and major diameters a combination broach can be used.combination broach can be used.

The finishing spline teeth are of the same The finishing spline teeth are of the same diameter, but the first 3 to 4 take a light cut and diameter, but the first 3 to 4 take a light cut and the final 3 to 4 finish the hole.the final 3 to 4 finish the hole.

Spline Broach ToolSpline Broach Tool

Splines broachedSplines broached

Broaching

Tool Feed DirectionGullet

Workpiece

Depth ofcut per tooth

Tool

Advantages & DisadvantagesAdvantages & Disadvantages

–AdvantagesAdvantages• Rough to finish in one pass• Production rates are high• Cutting time is quick• Rapid load and unload of parts• Any form that can be produced on a broaching tool

can be produced• Production tolerances are excellent• Operator skill is low

Advantages & DisadvantagesAdvantages & Disadvantages

–DisadvantagesDisadvantages• Tooling cost can be high• In some cases--not suited for low production rates• Parts to be broached must be strong enough to

withstand the forces of the process• Surface to be broached must be accessible• The spline broach tool itself is very expensive • Broaching cannot be done for lengths more than 3

meters

Some pictures showing Some pictures showing spline broaching spline broaching

A spline componentA spline component

Rings used in the gear box which have Rings used in the gear box which have splined profile which are directly splined profile which are directly mounted on the spline shaft which mounted on the spline shaft which transmits motion on the gears.transmits motion on the gears.

Broach toolBroach tool

Splines on the toolSplines on the tool

A Spline broach toolA Spline broach tool

The splines are located in The splines are located in helical pattern on the toolhelical pattern on the tool

A vertical A vertical broaching broaching machinemachine

Various spline broaching toolsVarious spline broaching tools

Spline broach insertsSpline broach inserts

A spline component A spline component

Spline broach nomenclatureSpline broach nomenclature