broaching


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broaching:

see quarryingquarrying,
open, or surface, excavation of rock used for various purposes, including construction, ornamentation, road building, and as an industrial raw material. Rock that has been quarried is commonly called stone.
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Broaching

 

a process of working metals by cutting on broaching machines using a tool with multiple blades called a broach. In light of the complexity and high cost of manufacturing broaches, the use of broaching is worthwhile for working large batches of parts, as in production of large lots or in mass production.

Types of broaching are distinguished on the basis of the order in which the final layer of stock is cut to size. In one method of cutting, all the broach’s cutting teeth remove the final layer, but they do not participate in the final shaping of the surface; this is done only by the last tooth. In a second method, each cutting tooth, in cutting the final layer of stock to size, simultaneously participates in forming the surface. A third method involves removing relatively large amounts of stock. In this method, all the teeth, which are arranged in groups of two or three, remove a layer of metal in sections rather than all at once across the entire width.

There are both free and coordinated methods of broaching. In the free method, the broach produces only the desired size and shape of the surface; in the coordinated method, the broach also produces the worked surface in the exact desired location relative to the reference surface.

In broaching, from 2 to 6 mm of stock is removed when working holes in forgings and castings. In holes produced by drilling, countersinking, countersink reaming, or boring, 0.2-0.5 mm of stock is left to be removed by broaching. The cutting speed in broaching is relatively low (2–15 m/min); efficiency is high, however, because the total length of the simultaneously cutting edges is great. Broaching produces a precision of class 3-2; the surface roughness of the worked surface varies from class 7 to class 9. A characteristic feature of broaching is the constant accumulation of chips in the depressions in front of each tooth. The teeth are often provided with grooves to break up the chips, thus improving the process of chip removal and preventing the broach from jamming.

REFERENCE

Vul’f, A. M. Rezanie metallov, 2nd ed. Leningrad, 1973.

N. A. SHCHEMELEV

broaching

[′brōch·iŋ]
(engineering)
The restoration of the diameter of a borehole by reaming.
The breaking down of the walls between two contiguous drill holes.
(mechanical engineering)
The machine-shaping of metal or plastic by pushing or pulling a broach across a surface or through an existing hole in a workpiece.
References in periodicals archive ?
The process also reduces the number of specialist cutting tools that are required, and cuts the machining time in steel alloys by between 30 and 40 per cent, compared to alternative standard milling solutions, giving a time almost equal to broaching.
The original inline process to produce a steering rack might include broaching, deburring, induction hardening, and then straightening.
Horn USA has introduced a new line of inserted broaching tools for lathes and mills.
Founded in 1942 and headquartered in Danboro, PA, PennEngineering is the corporate parent for PEM(R) Fastening Systems (PEM(R) self-clinching and broaching fasteners, SI(R) threaded inserts, PEMSERTER(R) fastener-installation presses, and the STICKSCREW(R) System for small-screw insertion); PITTMAN(R) (high-performance permanent magnet dc motors); Atlas Engineering(R) (blind threaded rivet nuts); and Arconix Group(TM) (a distributor of fastening and electronic-hardware products and a provider of comprehensive logistical and inventory-management services).
The broaching operation, similar to shaping with multiple teeth, is used to machine internal and external surfaces such as holes of circular, square, or irregular shapes, keyways and teeth of internal gears.
The Precision Broaching Press is a computer-controlled hydraulic press with data acquisition.
Ohio Broach's "table-up" broaching machine design eliminates the need for broaching pits and elevated work platforms.
Rather than specifying a broach bar from one manufacturer, a vertical broach machine from another, and second broach machine from yet another manufacturer, consumers of broaching equipment look increasingly to companies that provide complete broaching system solutions.
Those who have installed or considered installing a vertical broaching machine are sure to be familiar with the difficulties associated with its use.
Broaching is a manufacturing process in which a single round or flat tool has many individual cutting surfaces arranged in such a way as to successively rough-cut, semi-finish-cut, and finish-cut a workpiece as the broaching tool is pulled or pushed around or through the workpiece.
A 15-ton, 48" stroke, electro-mechanical pull down, internal-type broaching machine has been developed.