New metal cutting process for outer machining – ‘Pot- Broaching’

In the era of competition, continuous improvement of process and procedure is a must. In the field of metal cutting Pot Broaching has the positive advantage of being a most simple and highly productive modern machining process for machining at the outer surface or periphery of the component, where repeatable product quality is required.

In the Pot-Broaching, the material is removed by successive action of a series of transverse cutting edges arranged lengthwise in multiple broach sections, progressively increasing in size, incorporated and held in the Pot-Broach, used to machine and finish the external surfaces of the work piece in a single pass.

The essential feature of the Pot-Broaching operation is that there is no feed given to the tool as in other processes, and the teeth of the Pot-Broach are Self-Fed due to the gradual increment in the successive teeth during the rectilinear working movement between the tool and work piece. Therefore Pot-Broaching has become the simplest machining operation for metal cutting at the external surfaces or periphery of the components and the Broaching Machine is very easy to operate.

Productivity improvement of ten times or even more is achieved with the Pot-Broaching operation, as the speed of metal removal by Pot-Broaching is vastly greater as the total metal cutting including roughing, semi-finishing and finishing of the component is done just in one pass, and this pass is generally accomplished in seconds and even the clamping of job is not required, as the Broaching operation itself provides a force on the component. Therefore the Broaching operation may be completed in much shorter time as the time ordinarily taken for chucking / clamping the job is also saved.

The conventional machining operations used for metal cutting at the external surfaces are Milling, Shaping or some other machining processes are quite lengthy and even the processes do not give uniform accuracy. ThereforePot-Broaching has given the birth to a significantly superior and highly productive machining process requiring minimum manpower, extending its use in wide fields of applications with exceptional savings on Machine and Tooling cost.

The accuracy achieved and the efficiency demonstrated in heavy production by broaching is unmatched by any other process. Therefore broaching is especially suitable, rather essential for the industries where high efficiency, high level of accuracy and heavy production is required.

The broaching operations are normally used for internal shapes like Square / Hexagonal / Octagonal holes, Splines, Key-ways and some other specific shapes where the broach is pulled or pushed through a hole to remove the metal by the axial force applied by the Broaching machine to obtain the desired shape. Today, in the highly competitive market, the broaching has found its numerous applications including Surface Broaching and External Peripheral Broaching of various special / complicated shapes and Profiles. The Broaching process has become necessary for Automobile/Auto parts, Cycle Parts, Hand Tools and many other large production engineering industries for the following distinguished advantages over the other machining processes:

• Very High Productivity and most suitable for mass production.
• Consistency and accuracy in products.
• Various contours and complicated irregular shapes can be easily broached.
• Broached surfaces are highly accurate in size and shape hence close tolerances can be maintained.
• Remarkably finished face.
• Extremely economical.
• Zero rejection.
• Expertise not needed.

Crane-Bel offer a wide range of Broaching Machines, including vertical Internal Pull Broaching Machines, Push Broaching Machines, Surface Broaching machines, Low-Height Broaching machines, Table-Up Broaching machines, Horizontal Broaching machines, Continuous Chain Broaching Machines for Very High Productivity and Pot Broaching machines for high production rates, cost benefit, and ease of set up, operation and maintenance. Crane-Bel Broaching machines have earned an outstanding reputation for their productivity, reliability and economy. This reputation has been won by their unrivaled design, quality, manufacturing technology based on long experience in the field and strenuous efforts to offer distinguished broaching machines to the industry.

The author of the article, Er. Ashok Kumar Gupta, is Founder and Chairman of Crane-Bel International P. Limited, an ISO 9001:2008 certified company, engaged in manufacturing of a widest Range of Broaching Machines, Hydraulic Presses and Automation Systems for productivity enhancement.

Mr. Gupta has about 45 years of experience of helping Industries in increasing the productivity, efficiency and profitability. He has specialisation in the field of Fluid Power Technology with expertise in Broaching and Automation.

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