ChipType Machining Processes

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Chip-Type Machining Processes

• General Manufacturing Processes Engr.-20.2710
• Instructor - Sam Chiappone

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Chip-Type Machining Processes Class 1

• Machining - Removing unwanted material from a
  workpiece in the form of chips
• US industries spend 60 billion a year on metal
  removal processes
• Most products require some type of machining
• Direct
• Add value drill hole, mill pocket, etc.
• Rough (cleanup sand castings) to high precision
  (.0001)
• Indirect
• molds, dies, jigs, fixtures

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Why Machining Process vs. Other Manufacturing
Processes

• Accuracy is not obtainable by other methods
• Repeatability - interchangeable manufacturing
• Design requirements
• Tolerance, surface finish, mechanical strength
  requirements
• Low order quantity
• Manufacturing firms capabilities

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Process Basics

• Machine Tool
• A piece of equipment designed to accomplish a
  specific process.
• Example - a milling machine, injection molding
  machine, lathe, etc.

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Process Basics
Conventional
Computer Numerical Control
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Process Basics
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Process Basics
Conventional
Computer Numerical Control
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Process Basics
Combination Conventional / CNC
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Process Basics
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Process Basics
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Process Basics

• Machining Process
• Changes the value and quality of the raw
  material. A process typically involves a series
  of steps or operations and utilizes a machine
  tool.
• Examples include turning, milling, drilling, etc.
• Operation
• A distinct action being performed to produce a
  desired effect.
• Material handling, packaging, inspection,
  drilling, threading

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Process Basics

• Tools
• Refers to devices used to cut or deform the
  metal.
• Cutting tools - examples include end mills,
  carbide inserts, drills, grinding wheels, shell
  mills, etc.

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Process Basics

• Tooling
• Refers to holding devices
• Examples include- vises, fixtures, jigs...etc.

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Process Basics

• Cutting fluid
• Act as a coolant and lubricant
• Reduce friction between chip and tool face
• Extend tool life
• Help to remove chips from cutting area

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Seven Basic Chip Formation Processes

• Shaping
• Turning
• Milling
• Drilling
• Sawing
• Broaching
• Abrasive Machining

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Seven Basic Chip Formation Processes

• Turning

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Seven Basic Chip Formation Processes

• Milling

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Seven Basic Chip Formation Processes

• Drilling

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Seven Basic Chip Formation Processes

• Sawing

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Seven Basic Chip Formation Processes

• Broaching

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Seven Basic Chip Formation Processes

• Abrasive Machining

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Metal Removal RelatedCalculations

• To efficiently use these components, different
  input parameters have to be calculated. They
  include
• RPM of cutter
• Milling or drilling operation Rpm for cutter
• Turning operation Rpm for part
• Basically the rotating component
• Feed
• The distance in inches, feet, or millimeters per
  minute that the work advances into the cutter.

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Metal Removal RelatedCalculations

• Input parameters (cont)
• Cutting speed(CS)-the surface feet per minute or
  meters per minute, at which a metal can be
  machined efficiently. This variable has a direct
  relationship to the diameter of the cutter, in a
  milling or drilling operation, or the diameter of
  the work piece in a lathe operation.
• Example - When machining(using a milling machine)
  a medium grade steel, the cutter must achieve a
  surface speed of about 90 ft/min. The diameter
  of the cutter will have a direct relationship to
  the rpm calculation.

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Metal Removal RelatedCalculations

• Input parameters (cont)
• Depth of cut - Amount of material being removed.
• Horsepower required for cut
• Material removal rate (MRR) - volume of material
  being removed per unit of time
• In a milling operation, you also have to take
  into account the thickness of the chip each tooth
  will remover per revolution as it advances into
  the work. This value is expressed in feed per
  tooth.

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Metal Removal Problem
1.
Cutting Tools
4.
2.
3.
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Metal Removal Problem
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Factors Effecting Calculations

• Set-up conditions
• Machine conditions
• Tooling conditions
• Material conditions
• Cutting fluid