Straw Cutting Process Improvement
Industrial Engineering Designer: Matthew Estock (Project Manager)
Mechanical Engineering Designers: Ian Balbresky, Tyler Banta, Mark Vaughn
Client Coordinator: Wayne Geith
Supervising Professor: Dr. Matthew Marshall
Rochester Institute of Technology
76 Lomb Memorial Drive
Rochester, NY 14623
INTRODUCTION
The primary goal of the ArcWorks Straw Cutting Device project was to design, build, and deliver a
functional straw cutting device to ArcWorks which will be able to cut multiple polypropylene copolymer
(PPCO) straws to desired lengths with minimal deformation and burring. The device will have to follow
ISO 9001 guidelines, along with complying with OSHA standards and being accessible to employees with
a wide range of developmental disabilities. These straws are used within an assembly process at the
ArcWorks facility which provides wash bottle assemblies for customers like Thermo Fisher and Nalgene.
The current process at ArcWorks utilizes one automated machine along with a manual process to cut the
raw material straws to the appropriate lengths. With the addition of our automated machine an increase in
overall productivity at ArcWorks within their wash bottle assembly process will be seen; the increased
productivity will benefit workers who are paid by the piece, and will also allow ArcWorks to reduce
inventory levels.
SUMMARY OF IMPACT
The current device (shown in Figure 17) is able to safely cut 12 straws at a time, and is capable of cutting
1400 straws/hr, compared with the existing device’s 700 straws/hr capability, meaning that employees can
increase their production and ArcWorks can reduce their safety stock. Unfortunately, the quality level of
the cuts is not up to the standards set by ArcWorks.
Figure 17. Straw cutter design. Clockwise from top right: blade carriage, trap door/height adjustment,
vacuum attachment, and cutting plate. 4”, 2-column
TECHNICAL DESCRIPTION
The new device is a pneumatically-driven machine that cuts 12 straws at a time, safely and with minimal
physical exertion, and removes the debris from the cutting area. The straw cut is completed using a single
blade with a double bevel that is angled at 45 to the direction of motion (as shown in Figure 17). The
straw pattern was laid out to maximize blade utilization and to ensure that only one new cut is initiated at a
time. The blade is mounted on a blade carriage system that is driven by a 300 lb cylinder with a 3 in stroke.
The cylinder operates on a 100 psi compressed air supply, already available in the ArcWorks facility. The
cylinder is triggered with a two hand anti-tie down switch, and a mechanical switch only allows actuation
when the lid is closed. The pneumatic system design is shown in Figure 18. The cut quality does not
currently meet ArcWorks’s requirements, possibly due to the double bevel on the new cutting blade. The
blade cuts through approximately half of the straw satisfactorily, but beyond that point, the straw bends and
the remainder of the cut has the appearance of a tear, rather than a clean cut (Figure 19). The team has
developed recommendations, including applying slight pressure to hold the straw in place and prevent
bending, and using a different blade type; these will be investigated before delivering the machine to
ArcWorks.
Figure 18. Pneumatic system schematic 2.4” final height, 1-column
Figure 19. High-speed images of straw cut. 1.7”, 2-column
The device was required to be capable of cutting 9 different straw lengths, so an adjustable trap door
mechanism was designed to support the straws during cutting. The height of the trap door can be changed
to any of the 9 required length settings, and after a cut is complete a 12 lb pneumatic cylinder, with 1 in
stroke, opens the door and allows the cut straws to fall down for removal. The trap door does not currently
function as designed, so a backup block (Figure 20) was created to support the straws until further work on
the device can be completed. The block does not allow the 9-length adjustability, but does allow the
machine to function.
Figure 20. Straw support block. 2” final height, 1-column
The total cost of the project was $1541.63
More information is available at https://edge.rit.edu/content/P11008/public/Home
Leak Test Station Process Improvement
Industrial Engineering Designer: Andrew Lawlor
Mechanical Engineering Designers: Adam Janicki, Christopher Somers, and John Zeffer
Client Coordinator: Dennis Hezner
Supervising Professor: Dr. Matthew Marshall
Rochester Institute of Technology
76 Lomb Memorial Drive
Rochester, NY 14623
INTRODUCTION
The goal of this project was to design and build a pressure test device for use by employees at ARCWorks,
a light manufacturing facility employing individuals with developmental disabilities. The existing test
fixture relied on water to pressure-test, so it was messy, subjective, and it slowed down the assembly line.
The current process involves an employee taking a cap, screwing it onto a bottle, plunging the bottle under
water, and looking for air bubbles that may be escaping, which would indicate a leak. Employees are
generally paid on a per-piece basis, so it is important to make the process as clear, safe, and efficient as
possible.
SUMMARY OF IMPACT
The team took a two-pronged approach to the problem. First, they designed a new test fixture for
employees on this line to use. The fixture is still under development, and is expected to be completed over
the summer. It will allow a worker to run two tests simultaneously, and provides a very simple, objective
indication system: A green LED indicates a good part, a red LED indicates a bad part, and a yellow LED
indicates that a test is in progress. The second aspect of the project was to improve the manufacturing
process. The team implemented a 5S (Sort, Set, Shine, Standardize, and Sustain) system in two phases,
which gave the operators a sense of ownership and pride in their accomplishments.
Figure 10. Pressure test fixture.
TECHNICAL DESCRIPTION
The design team chose a vacuum pressure approach, because it would be the simplest for the operators to
use. The pressure test fixture the team designed and built is shown in Figure 11. The cap sits upon a soft
rubber to create a seal. The two red buttons seen at the front left and right of the base plate are for the
operator to initiate the test. The use of two buttons ensures that the worker will not run the risk of injuring
their hands or interfering with the test. Shown behind the cap, at the top of the back plate, are the red and
green light indicators. These indicators show the results of the test: red for a bad part and green for a good
part. The yellow light is illuminated when the test is in progress. Below and behind the fixture (not
shown) is a differential pressure sensor to measure the speed of pressure drop and a vacuum pump to
pressurize the fixture.
Operation of the machine is simple and intuitive for the operator to use. The operator will take a cap from
their “incoming” lane. The operator will then place the cap onto the test fixture. Next the operator will
press the two-hand start button. This will allow the machine to run unaffected by the operator. The
vacuum will then run and determine if there is a good seal on the cap. If the seal is bad, a red light will
indicate to the operator that the part is bad, and if the part is good a green light will appear. The vacuum
will then release its pressure, allowing the operator to remove the cap and place in its respective bin. This
process can be run simultaneously on both of the stations on the machine. Examples of good and bad part
pressure curves are shown in Figure 12.
To allow the system to function autonomously from a PC interface, the team used a Programmable Logic
Controller (PLC) to control the system. The PLC will turn on the vacuum pump, read the pressure sensor,
and control the indicator lights according to the pressure readings (pass, fail, or in-progress). The PLC also
reads in a user-set switch position that indicates the particular configuration of cap being tested.
The final system testing indicated that the vacuum test fixture resulted in more rejected parts than the water
test system, partly because workers did not formerly hold the caps under water for a specific amount of
time, and some leaks only become apparent over time. However, the new system did allow two parts to
pass that actually failed the water test. Final work on this device is being done during the Summer of 2010.
Figure 11. Actual pressure test system built.
Figure 12. Examples of good and bad vacuum test data.
The total cost of the project was $2106.
More information is available at https://edge.rit.edu/content/P10008/public/Home