Electronics Incorporated - The Shot Peener - Shot Peening Library
Title: Generation of Wheel-Blast Shot Velocity
Author: David Kirk
Source: TSP Volume 21 / Issue 2, Spring 2007
Publication year 2007
Document number: 2007012
Number of pages: 4
Abstract:
INTRODUCTION
Shot velocity is of primary importance because it governs the kinetic energy of the impacting shot and hence the peening intensity. Wheel-blast shot acceleration is much
more energy-efficient than air-blast shot acceleration - which accounts for its continued appeal. A variety of wheel types have evolved but the mechanics involved are
generally similar. Normally, blades attached to a rotating wheel throw shot at components. Shot velocity is achieved in two stages: accelerator drum and throwing blades.
Particles are fed into peripheral slots formed between the accelerator and a stationary control cage. Centrifugal force keeps the particles pressed into the slots as the
accelerator drum rotates. At this stage the shot particles have the rotational velocity of the drum. When a slot reaches the outlet slot in the control cage some shot
particles escape onto a throwing blade for the second stage of acceleration, see fig. 1.
This article is an account of the mechanics involved in generating the final shot velocity. Equations are presented that allow estimates to be made of the thrown shot
velocity, direction and angular range when leaving the wheel. These equations accommodate the variations in wheel speed and diameter, blade length, number of blades and
control cage that occur with different wheel designs.
It is shown that the radial velocity is a large percentage of the tangential velocity. The ratio of radial/tangential velocity deternmines the direction of individual thrown
shot particles.
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This page last revised: 04/24/2008