Fatigue life enhancement

Citation

(2001), "Fatigue life enhancement", Anti-Corrosion Methods and Materials, Vol. 48 No. 1. https://doi.org/10.1108/acmm.2001.12848aab.010

Fatigue life enhancement

Fatigue life enhancement

Keywords: USF Vacu-Blast, Peening, Surface treatment

Aerospace surface preparation and treatment specialist, USF Vacu-Blast International – part of the USF Surface Preparation Group – has installed two further shot peening machines at Fiat Avio's aeroengine repair and maintenance facility in Turin, northern Italy. A number of Vacu-Blast peening and other surface treatment systems are already in operation at the facility.

Both new machines – a specially designed steel shot peener and a glass bead peener based on the Vacu-Blast "Vector" design – will be used to process a wide variety of gears and shafts from various different aeroengines and transmission systems, including Sikorsky helicopter components, to enhance or restore fatigue performance.

The new CNC steel shot peener can reportedly process Rene, steel and aluminium alloy parts measuring up to 500mm diameter and 2,200mm high. It has a 2.5m x 2m x 3.5m high peening enclosure, is fully programmable and operates automatically to the highest standards of precision and process repeatability – meeting, it is stated, the strict requirements of PllTF8 S5, AMS 2340 and the Fiat specification STI-B199/01/99. The machine incorporates two high-accuracy three-axis nozzle manipulators – each with vertical, horizontal and wrist axes – which can operate independently or in tandem. The loading and unloading of parts on to and from the integral indexing component turntable is carried out by a special hoist which extends into the processing enclosure – thus avoiding the need for external handling. Special nozzle attachments are employed for the high-precision processing of small holes, slots and internal bores down to 6mm in diameter and 250mm deep.

In-cycle shot size-and-shape classification is included, to ensure that the highest peening integrity is maintained throughout each peening operation. The machine has also been designed to minimise noise levels, which are below 75dB(A) under normal operating conditions. Another important feature claimed is the high-efficiency Vacu-Blast "Waffle-Floor" pitless pneumatic recovery system which uses a downdraught of ventilation air to remove spent dust and debris, a design which uses no mechanical moving parts and eliminates maintenance.

The second Vacu-Blast machine, based on a standard Vacu-Blast "Ventus 150P" peening cabinet design, uses glass beads and can process Inconel, Rene and steel parts – typically gears and small shafts – within a working envelope of 500mm diameter x 500mm high. The programmable machine is governed and monitored by a PLC and incorporates two processing nozzles on a two-axis manipulator, with parts retained in special fixtures on a powered turntable. It also includes the "Waffle-Floor"™ media recovery system, as well as a high-efficiency media size classification and recycling unit.

Further details are available from USF Vacu-Blast International. Tel: +44 (0)1753 526511; Fax: +44 (0)1753 538093; e-mail: info@vacu-blast.co.uk