The Evolution of Machine Tools
ETSU ENTC 3020
Technology & Society
Note:
These notes have not been completely converted
from PowerPoint Outline format into HTML format.
Earliest Tools
- Primitive Hand tools
- Weapons & Tools of
Mineral, Bone, & Wood
- Stabbing, Cutting, Scraping, & Drilling
Early Tools
- Wheel: Efficient Transportation
- Lever: Mechanical Advantage
- Inclined Plane & Screw
Pole Lathe
- Medieval Machine
- Turning Round Parts
- "Bodgers" (Itinerant Woodworkers)
- Carpenters, Blacksmiths, Metalworkers, & Jewlers
- Made Furniture, Home, & Farm Implements
- A-frame Pole Lathe
Wheel Lathe
- Replace Pole with a Wheel
- Hand-cranked by assistant
- Continuous Cutting & Contouring
Treadle Wheel Lathe
- Heavy Flywheel & Foot Treadle
- Solo Operation
- Continuous Cutting & Contouring
Powered Lathes
- Continuous Turning
- Water wheels
- Central, Overhead Shafts
Leather belts transfered power to individual machines
- Factory System
Engine Lathes
- English inventor Henry Maudsley in 1800 built first powered lathe with a "Lead Screw"
- Lead Screw couples rotation of the spindle to the movement of the carriage (tool holder)
- Cut accurate screw (i.e., another lead screw)
- A machine that builds itself, jump starts the...
Industrial Revolution
- Engine Lathes
make accurate cylinders & pistons for
- Steam Engines
which need to be built of
- Steel which has properties of
- Toughness for cutting tools (used in engine lathes)
- Ductility for steam boilers & rails for railroads
Modern Engine Lathe
- Electric Motor
- Geared Head for
variable Spindle Speeds (Rotation) and
variable & accurate Feeds (Tool Movement)
- Tolerances of 0.001 inch
- Make Multiple Screw Sizes
Start here
Modern Vertical Mill
Electric Motor
Variable Spindle Speeds (Rotation)
Accurate Table Position
3-Axis (X, Y, & Z)
Tilt “head”
2 Degrees of Freedom
Tolerance of 0.001”
Multiple Tool shapes
Post-World War II Era
Cold War with Soviet Union
High Performance Aircraft
Jet engines & aircraft structures
Very complex forms, mathematically determined
Computing Devices
Mechanical Using Gears and Cams
Electrical Using Circuits and Tubes
Transistors
Invented in the mid-1940s at Bell Labs
Integrated Circuits
Invented in the 1960s at Texas Instruments
Numerical Control
Integrate machine tool with digital computer
Compute Complex Cutter Paths
Accurately Control Axes Motors
Position feedback
Closed – Servo Motors & Position Sensors
Open – Stepper Motors
Limited capability
Programmed Moves
Little Intelligence
CNC Devices
CNC is “Computer Numerical Control”
Increased Capability
More Memory
Longer Programs
Complex Operations
CADD
Computer-Aided Design & Drafting
Workstation &
PC-based Systems
Accurate 2D and 3D Models
Rapid Revisions
Multiple Formats
Hardcopy Drawings
Application Data Sharing (e.g., CAM, FEA, animations, etc.)
CNC Vertical Mill
Programs
Complex
Long
Fast
Accurate
High Quality
Adaptable
CNC Router
Large Parts
4’x8’ Sign
Wood, Plastics, & Soft Metals
2-½D & 3D Contouring
CAD-CAM Software
Interface
Faster & Better
3D Modeling
Surfaces
& Solids
Import
2D Data
3D Data
Export
Virtual Models
FEA
STL
Animations
3D Rapid Prototyping
Stereolithography
3D Printing
Start with a
3D CADD Model
“Slice” Each
Z-axis Level
X-Y Part Paths
& Supports
Multiple Materials
Metal, Polymers (ABS, Nylon), Wax, Paper, etc.
“Real” Parts for Form, Fit & Function
3 Questions
Does automation kill or create jobs?
What’s more important: Quality or Speed?
Why Customize Products?
Image Credits
Image of Pole Turner from the "Mendel Housebook," c. 1436.
Available URL: http://www.his.com/~tom/sca/lathes.html
A-frame Pole Lathe image from http://www.bodgers.org.uk/images/lathe7.gif
Images of Pole Lathe workers from http://www.fencible.org.nz/avillagelife/crafts_bodger2.htm
Image of Pewterer using a Great Wheel lathe from the "Book of Trades," 1568.
Available URL: http://www.his.com/~tom/sca/lathes.html
Treadle Wheel (Flywheel) Lathe built by Thomas Rettie.
Images available from http://www.his.com/~tom/sca/lathes2.html
Maudsley portatit from http://www.banki.hu/~tkt/html/kiadv/szgt/machines/eszt2_main.htm
Images of modern era engines lathes, vertical milling machines, CNC mills & routers, CADD screenshots, and stereolitographic parts courtesy of East Tennessee State University Department of Technology & Geomatics
http://www.etsu.edu/scitech/entc