3. United Plate Glass
• Butler PA-based plate glass company
• Makes tempered glass, among other products
• Uses Kevlar-wrapped rollers to remove glass sheets from tempering ovens
4. Initial Conditions
• Glass shatters occasionally
• Rollers have been rewrapped by hand
• Takes about 15-20 minutes and is not simple
• Also leads to uneven wrapping; seen in image right
5. Problem Statement
Our team was tasked to create a machine that will automatically wrap the rolls
with Kevlar rope, with enough tension to ensure a tight and even wrapping.
This machine would also reduce the amount of time that it would take to wrap
each roll.
6. Details
• Capable of producing a tension between 50 and 100 lbs
• Cycle time of no more than 10 minutes, preferably under five
• Functional life cycle of 10 years, with approximately 4 uses/week
• Can handle rollers of set sizes, ranging from 72” to 102”
9. Friction applied to the Kevlar rope
• Ceramic tiles are cost-effective
• Safe and simple to thread
• Tensioning is adjusted by hand
• Requires no outside power
Clamping force
Rope
Friction Plates
12. Linear Motion Design Goals
• Design a system to transport the tensioning system the length of the roller
• Variable lengths of rollers (ranging from 72” to 102”)
• Wrap both Clockwise and Counter Clockwise Platform travels in both directions
• Variable wrap pitch
13. Common Linear Motion Design
• Driven in center
• Belt driven or screw driven
• Reliable and industry proven
• Supports on each side
• Linear bearings or profile rails
• Reliable and industry proven
14. Linear Motion Support Design
• Linear bearings/round rail on one side of carriage
• Supports most of the load
• Rail supported by two 4’ long rails
• Cost ~$1100
• Cam Follower Roller in C-channel on one side of
carriage
• Bears little load, mainly locational
• Cost ~$200
• Total Savings ~$900
Linear Support Rails
Cam
Follower
15. DriveTrain
• One motor runs the roller rotational system
and the linear motion carriage
• We geared the system together, so as to
avoid costly digital controls systems
• This motor is connected to the reverse
gearbox through a belt
• The reverse gearbox connects to the
NuVinci, which connects to the Ball Screw
17. NuVinci N360
• ContinuouslyVariable Planetary
• Enables fine-tuning of Kevlar pitch
without changing motor output
• The axles of the NuVinci are held
stationary, and the outer rings rotate.
• Controller knob varies pitch from 0.5
underdrive to 1.9 overdrive.
18. Gearbox
• Rollers need to be wound in both clockwise
and counter clockwise directions.
• To accommodate this, the tensioning unit
must run forwards and backwards.
• Solution: Kazuma Reverse Gearbox, running
the same speed forward as backwards.
19. Ball Screw
• Other options considered: Rack and Pinion, Belts
• Ball Screw system ultimately the easiest design to implement, and has a
high level of positional accuracy and mechanical efficiency
• Double Circuit Nut, ¾” Diameter, 0.5” Lead
21. Motor Sizing and PowerTransmission
• Motor calculations
• Neglects inertia of gear box and NuVinci
• Dominant factor: torque on roller shaft
• Motor desired output: 200 RPM and 0.283 HP
• Main shaft drives both roller shaft sprocket
ball screw & carriage
22. Variable Length Mounting Fixtures
• Variable position mounting
• Roller lengths of 72’, 84’, 96’, 102’
• Clamping fixtures
• Faster attach/detach
• Simplification for operator
24. Frame Purpose
• Connect all other sections together
• Create a moveable platform for portable use
• Rigid for industrial use
• Last for the duration of working life
31. Part Ordering
• Around 70 unique parts/materials ordered (mostly McMaster-Carr)
• Challenges:
• Accounting for lead times (differs for each component)
• Unexpected processing delays push back timetables
32. Part Machining
• Various parts required custom machining
(done by UPG team or shop assistants)
• Numerous manufacturing techniques used
(end mill, CNC lathe, EDM, etc.)
• Required a lot of shop time (regular + night
hours)
33. Machine Assembly
• Final assembly constructed off campus
(Dr. Keehlwetter’s garage)
• Challenges:
• Unforeseen problems required last minute
modifications/improvisations
• Logistical considerations (order of assembly,
transportation, etc.)
• Lots of time needed for testing and finalizing
38. Appendices
• BrakeTesting
• Tensioning Sketches
• NuVinci
• Kazuma Gearbox
• Motor Calculations
• Original Fastening Method
• FEA Plates
• FEA Plates with Fan
• KevlarThermal Properties
• Carriage Support FEA
39. Table of Contents
• Background – Daniel Durham
• Tensioner – Kate Mays and Philip Graybill
• Carriage and Supports – Neil Brant
• Powertrain and Ball Screw – Cameron Ebersole
• Power Selection and Roller System – Jeff Kaday
• Fastening – JoelWeischedel
• Frame – Adam Speicher
42. NuVinci Appendix
• The speed ratio difference between the input and output speed is controlled
by the angle of the ball axles relative to the transmission axis (Figure 1).
• The controller tilts the ball axis, and thus shifts the transmission (Figure 2).
Figure 1 Figure 2
Back
43. Kazuma Gearbox Appendix
• Same teeth count and diameter size for all gears
• Modifying existing gearboxes, while possible, is difficult
• Planetary reverse gearboxes are not modifiable
Back
48. Thermal Properties of Kevlar
• Kevlar decomposes at approximately 800-900°F
*In Celsius
Back
49. Carriage Support FEA
• Model max stress is approximately half of the yield stress of the material
• Model is conservative because it assumes infinitely rigid supports
• Max stress is located at the location of support
Back
Editor's Notes
Wraps in both directions
Operation from both ends of machine
Adjustable speed
Adjustable pitch
Safe:
limit switch honeywell w/Side Rotary adj rod
Surface Mount—Aluminum magnetic switches
