The Full Wiki

Guillotine (metalwork): Wikis

Advertisements

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Encyclopedia

(Redirected to Shear (sheet metal) article)

From Wikipedia, the free encyclopedia

There are many types of shears used to shear sheet metal.

Contents

Types

Advertisements

Alligator shear

Bench shear

A bench shear

A bench shear, also known as a lever shear,[1] is a bench mounted shear with a compound mechanism to increase the mechanical advantage. It is usually used for cutting rough shapes out of medium sized pieces of sheet metal, but cannot do delicate work.[2][3] Usually this type of shear can handle steel sheet metal up to 3 mm (0.12 in) thick.[4]

Guillotine

Mechanical Shear 4310.jpg

The machine used is called a squaring shear, power shear, or guillotine. The machine may be foot powered (or less commonly hand powered), or mechanically powered. It works by first clamping the material with a ram. A moving blade then comes down across a fixed blade to shear the material. For larger shears the moving blade may be set on an angle or "rocked" in order to shear the material progressively from one side to the other; this angle is referred to as the shear angle. This decreases the amount of force required, but increases the stroke. A 5 degree shear angle decreases the force by about 20%. The amount of energy used is still the same. The moving blade may also be inclined 0.5 to 2.5°, this angle is called the rake angle, to keep the material from becoming wedged between the blades, however it compromises the squareness of the edge.[5] As far as equipment is concerned, the machine consists of a shear table, work-holding device, upper and lower blades, and a gauging device. The shear table is the part of the machinery that the workpiece rests on while being sheared. The work-holding device is used to hold the workpiece in place and keep it from moving or buckling while under stress. The upper and lower blades are the piece of machinery that actually do the cutting, while the gauging device is used to ensure that the workpiece is being cut where it is supposed to be.

The design of press tools is an engineering compromise. A sharp edge, strength and durability are ideal, however a sharp edge is not very strong or durable so blades for metal work tend to be square-edged rather than knife-edged. Typical workpiece materials include aluminum, brass, bronze, and mild steel because of their outstanding shearability ratings, however, stainless steel is not used as much due to its tendencies to work-harden.

Other types of geometrical possibilities include the squaring shear, angle shear, bow-tie shear and bar shear. All of these have many different uses and are all used regularly in certain manufacturing fields.[citation needed]

Power shears

A power shear is electrically or pneumatically powered hand tool designed to blank large pieces of sheet metal. They are designed to cut straight lines and relatively large radius curves. They are adventaeous over a band saw because there is not a size limit. Large versions can cut sheet metal up to 12 gauge.[6]

Throatless shear

Throatless shear
Closeup of shear jaws

A throatless shear is a cutting tool used to make complex straight and curved cuts in sheet metal. The throatless shear takes its name from the fact that the metal can be freely moved around the cutting blade (it does not have a throat down which metal must be fed), allowing great flexibility in shapes that can be cut.

Tin snips

See also

References

Bibliography

  • Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, ISBN 0-471-65653-4. 

Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message