UWE Bristol Engineering showcase 2015

Liam Lane
BSc (Hons) Engineering
Project Supervisor
Dr. Richard Stamp
Joint Strike Fighter bearing heater process improvement study
Introduction
This study is to achieve a cost improvement for Rolls-Royce PLC ,
Bristol when assembling the bearing components which are used
to build the JSF135 3BSD module. This is the Joint Strike Fighter
aircraft which is a fighter jet which is used by the USA. It is similar
to the harrier jump jet as it takes off vertically. It achieves this from
rotating a swivel exhaust duct over 90 degrees to face the ground
during take-off and returns facing the rear of the aircraft when in
flight. This exhaust duct is built at Rolls-Royce PLC ,Bristol and is
called a 3BSD (Three Bearing Swivel Module. This module is built
up from three scarfed casings and three bearings. An interference
fit is carried out to build up part of the bearing module and this
uses a heater to carry out a heat shrink interference fit. This study
aims to identify and implement a cost saving to the component
heating process of this assembly.
JSF 135- Joint Strike Fighter
3BSD – Three Bearing Swivel duct
Original bearing heat-shrink process
The original bearing heater that was used only had the capacity to heat one
bearing component at anytime and caused a job queue. The heater was also
immobile and took up a lot of space on the shop floor build line. It couldn’t be
moved around and was located on the ground and presented itself as a health
and safety trip hazard.
Original bearing heater
Bearing heat-shrink process solutions
Three independent heating methods were
reviewed and analyzed in terms of cost and
time savings to replace the original bearing
heat process. Concepts were designed to
replace the original heating process and the
original heater to eradicate any health and
safety issues. Three solutions were compared
and the chosen solution was to use the ‘dual
bearing component’ heating method. Tooling
trails were then undertaken to prove this
tooling.
Tooling Trials
With the dual bearing component heater equipment procured, tooling trials were
carried out to ensure the heater worked effectively so that it could prove tooling
repeatability and could operate to heat the bearing component as required. The
trial consisted of heating the bearing component to its required temperature as
normal and thermocouples were placed at three equi-space positions on the
bearing component to measure the temperatures during the trials. The tooling
worked effectively for one of the tooling trials but not enough repeatable results
were concluded from the three trials, so re-work and re-testing will be required. It
is concluded that thermocouple errors and heater controller units caused the
tooling problems.
Project summary
The Rolls-Royce PLC,Bristol is responsible for building
The Joint Strike Fighter three bearing swivel duct
module. This module is moving to Rolls-Royce
Indianapolis in July 2015 for a increase of production
and a cost improvement activity is required to reduce
the build cost.
This project investigated and developed solutions for
saving cost/time when carrying out an interference fit
as part of a bearing build process. The interference fit
is carried out but heat shrink fitting the components.
A review of the heating process has been completed.
Project Objectives
•An investigation to implement a process
improvement to reduce by costs into the Joint Strike
Fighter build line, by reviewing inefficient bearing
interference fitting methods.
•Research and review methods of heat shrink fitting
and design three new heating methods to carry out
the required an interference fit.
•Finalize a new bearing heater method and
demonstrate cost savings to the business and carry
out tooling trials to prove new tooling.
Project Conclusion
The conclusion result in a new method of component
heating being used with a new heater design. The
new heating method saves Rolls-Royce PLC
approximately 35% of the cost compared to the
previous heating method and saves Rolls-Royce PLC
50% of the build time taken.
Tooling trials for the new tooling proved that the new
tooling operated as required, but the test result were
not repeatable so re-work and re-testing is required
so that the tooling can be implemented into the build
process.