Today we are going to start a very important topic here with the help of this post i.e. metal cutting tools: definition and classification.
So, let us first understand here the basics of metal cutting tool
Metal cutting tool: Definition
Metal cutting tool is basically defined as a device
used in metal cutting processes on machine tools for removing the layers of
materials from the workpiece or blank in order to secure the product of
specified size and shape with specified surface finish and accuracy.
Now we will see here the classification of metal
cutting tools
Classification of metal cutting tools
The metal cutting tools are classified on the basis of
number of cutting edges as mentioned below.
- Single point cutting tools
- Multi point cutting tools
- Forms tools
Single point cutting tools
A single point cutting tool will have an effective
cutting edge and it will remove the excess materials from the workpiece along
the cutting edge.
Single point cutting tools will be usually used on lathes, shapers, planers, etc.
Single point cutting tools are classified as mentioned below
- Forged tool
- Mechanically fastened tipped tool
- Brazed tipped tool
- Solid tool
- Tool bit inserted in the tool holder
- Right hand tool
- Left hand tool
- Round nose tool
Forged tool
Forged tools are manufactured from high speed steel or
high carbon steel. The required shape of the tool is given by forging the end
of a solid tool shank and further the cutting edges will be grounded to shape
to provide the required tool angles.
Following figure displayed here indicates the forged
tool.
Mechanically fastened tipped tool
To ensure rigidity, tips are sometimes clamped at the
end of a tool shank by means of a clamp and bolt as displayed here in following
figure.
Brazed tipped tool
In brazed tipped type cutting tool, the cutting edge
will be in the form a small tip made up of stellite and cemented carbide tool
materials, which will be welded to the end of a carbon steel shank by brazing
operation.
Brazed tipped tool is displayed here in following
figure.
Solid tool
Solid tools are made up of high carbon steel, forged
and ground to the required shape. They are directly mounted on the tool post of
a lathe.
A lathe tool post is used to hold the metal cutting
tool.
Tool bit inserted in the tool holder
In case of tool bit inserted in the tool holder, metal
cutting tool will be inserted in a forged carbon steel tool holder and will be
clamped in a position by bolt or screw as displayed here in following figure.
There are various advantages of tool bit over solid
tool such as tool bit will be cheaper as compared to solid tool, regrinding of
tool will be quite easy.
A tool bit will be easily withdrawn and replaced in
position without disturbing the setting.
Right-hand tool and left-hand tool
A metal cutting tool will be said to be a right-hand
tool or left-hand tool, if its cutting edge is on the right-hand side or left-hand
side respectively when viewing the tool from the point end.
Multi point cutting tools
A multi-point cutting tool will have two or more than
two cutting edges. For example, metal cutting tools used in the operation of
drilling, milling and broaching will be considered as multi-point cutting
tools.
In multi-point cutting tools, all the cutting edges
may either operate one by one or engage simultaneously.
Each cutting edge of a multi-point cutting tool will
be considered as a separate single point cutting tool with almost all the
features of single point cutting tool.
Form tools
A form tool is basically a metal cutting tool which is
shaped in such a way that it imparts a prespecified profile to the workpiece.
Form tools are usually ground on cutting tool elements
as a replica of the work profile. These tools are used to shape short jobs for
turret lathes.
Classification of form tools are displayed here in following table
Therefore, we have seen here the basics of metal
cutting tool i.e. definition of metal cutting tool and also the classification
of metal cutting tools with the help of this post.
Now, we will be interested further to understand a
very important concept in manufacturing process i.e. nomenclature of single point cutting tool with the help of our next post.
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Reference:
Production Engineering, By K C Jain and A. K. Chitale
Image courtesy: Google
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