The 416 group at Boeing designed an automated system to replace inserts in large end mills used to machine titanium aircraft parts. The system includes a carousel that stores 85 inserts, a pneumatic arm that removes inserts from the mill and places them in the carousel, and a screwdriver operated by servo motors that loosens and tightens inserts. A linear actuator moves the end mill into position and a stepper motor rotates it. The system is controlled by PLCs and an HMI interface to automate the time-consuming process of replacing inserts.

1. DESIGN PROBLEM
Boeing is one of the leading companies for the design and
manufacturing of the highest quality aircraft. Many of the
parts have to be created out of titanium, and must be crafted
to a low tolerance. Large end mills with many tungsten
carbide inserts are used to cut the metal. Machinists are
responsible for the upkeep of these end mills, which includes
the removal and inspection of each insert, and then replacing
certified inserts back into the mill. This process takes a great
deal of time and effort, and Boeing is seeking to automate this
process. The members of the 416 group set out to solve this
problem.
CAROUSEL
The carousel subsystem handles the
removal, replacement and storage of
cutter inserts and screws.
● 85 insert carousel, 10 3D printed
parts
● Programmed stepper motor and one-
off 3D printed gear drives carousel,
cycling through inserts
● Designed suction head, contoured to
insert geometry
● Top-mounted components and
hinging vertical columns
● Stand created to seamlessly integrate
systems
● 5/3 valves handle suction and linear
pneumatic actuator to control insert
motion into place
A pneumatic linear actuator will extend,
and suction will be applied to grasp the
insert as soon as it is unscrewed from the
mill. The pneumatic arm then brings the
insert and its screw back into the
carousel ring, where it is deposited until
it is inspected. A stepper motor then
turns the ring one slot increment, and
repeats the process.
SCREWDRIVER
Once the end mill is in place, the
screwdriver goes to work.
● Small Festo servo motor lowers and
raises the screwdriver using a ball
screw linear actuator
● Big Festo servo motor provides
necessary torque to tighten/loosen
screws to/from the required 35 in-lbs
● Flexible shaft allows transmission of
torque without cantilevering heavy
load
To loosen the inserts, the screwdriver
will lower into position once the tool is in
the correct alignment. The two servo
motors will simultaneously raise and
rotate counterclockwise. To tighten the
inserts, the screwdriver will again allign
itself in the correct position. The two
servo motors will simultaneously lower
and rotate in the clockwise direction.
LINEAR ACTUATOR
The linear actuator subsystem is responsible for moving the end mill into
place. A stepper motor turns a belt, which acts as a linear actuator, driving the
end mill toward the carousel. A stepper motor turns a worm gear which
rotates the end mill slightly, allowing the next insert to be level with the
suction head. The belt then drives the mill slightly, to bring the insert in line
with the suction head.
PROGRAMMING AND INTEGRATION
This system is operated using two progammable logic
controllers (PLC) and a touch screen human-machine
interface (HMI). The user can control the operation using
the HMI to start, pause, reset, or stop the program.
Ladder logic code programmed onto the PLCs controls the
sequence, timing, and movement of the 3 stepper motors,
2 servo motors, and 2 pneumatic valves on the machine.
The ladder logic is written in Totally Integrated
Automation (TIA) Portal, and the FESTO motors each
require additional configuring via the software Festo
Configuration Tool (FCT).
AUTOMATED END MILL INSERT REPLACEMENT SYSTEM
MEMBERS: KISA BROSTROM, ANDREW CLEMENTS, JOSEPH MCKENNA, CONNOR MCBRIDE, CONOR MOLONEY, TREVOR DOUGLAS,
AARON THONNEY, JOSIAH WAI, SCOTT OLIVARES, NICHOLAS WOOD