LECTURE PRESENTATION

Reading Assignment

• 27.1 Introduction to Other Machining Processes
• 27.2 Shaping and planing
• 27.3 Introduction to Broaching
• 27.4 Fundamentals of Broaching
• 27.5 Introduction to Sawing
• 27.7 Introduction to Filing

Recommended

• Study Guide – Sawing Broaching Filing
• Broaching
• How to weld a bandsaw blade (video)
• Rotary Broaching (video)
• Lenox Guide to Bandsawing (pdf)
• Bahco Bandsaws & Metal Cutting Tools (pdf)
• Simonds File Facts (pdf)
• Wonkee Donkee  – What is a file?
• KMSTools File ID Chart

Outline

Sawing

Types of Saws

• Power Hacksaw
• Circular Saw
• Bandsaw
• Abrasive Chop Saw

Hacksawing Machines

Horizontal or Vertical

Automated Hacksaws

• Feed stock through vise or fixture
• Gage length to required dimension
• Close and lock clamping vise or fixture
• Feed blade through the stock
• Raise blade at end of cut
• Open vise or fixture

Power Hacksawing

(Pros)

• Low capital investment
• But accessories can add up quickly
• Easy to set up
• Simple operation
• Low tooling costs
• Simple design – easy maintenance
• Versatile
• Fair to good accuracy

(Cons)

• Slow
• Noncontinuous motion
• Reciprocating action
• No blade support near actual cut
• May cause bowing, inaccuracy
• Blade wear is uneven

Hacksaw Blades

• Have a single cutting edge
• Proper tension required
• Materials
  • Through Hardened Tool Steel
  • HSS with hardened teeth
  • HSS Cutting edge + Alloy backing
    • (Composite blades)

Circular Sawing

(Pros)

• High Production Rate
• High Accuracy
• Fast Changeovers
• Burr-free Surfaces Possible
• Low Tooling Cost
• Low Operating Costs
• Relatively Safe

Circular Sawing (Cons)

• Higher Capital Investment
• Higher Horsepower Required
• Increased accuracy and productivity may overcome these
• Saw blades more expensive, but can be re-sharpened.
• Greater loss of material

Horizontal Bandsaws

• Scissor-type (video)
• Post-type (video)

Advantages

• Rapid cutting
• Safe and easy operation
• Raw material savings
• Low cost
• Can be automated
• Energy requirements lower (smaller kerf)

Disadvantages:

• Less precise than circular saw
• More floor space required

Vertical Bandsaws

Advantages

• Versatility
• Conventional sawing
• Friction sawing
• Diamond-band machining
• Electroband machining
• Band filing
• Band Polishing
• Scallop-edge, wavy-edge, knife-edge sawing
• Spiral Bandsawing (omnidirectional cutting)
• Abrasive wire bandsawing

Vertical Bandsaw Operations

• Contour Cutting
• Slotting
• 3-D Cutting
• Stack Cutting
• Shaping
• Ripping
• Slabbing

Abrasive Chop Saw

Advantages

• Fast
• Clean cut (with burr)
• Versatile
• Inexpensive

Disadvantages

• Heat
• Sparks
• Mess

Saw Blade Geometry

• Tooth Spacing or Pitch
  • Distance between teeth or teeth per inch (TPI)
• Tooth Geometry
• Tooth Set
  • Raker Set
  • Alternate Set
  • Wave Set
• Blade Thickness
• Kerf Width
• Body
• Gullet
• Rake Angle
• Flank
• Clearance Angle

Broaching

Broaching uses a tool with teeth whose depth of cut gets deeper incrementally.

Advantages

• High productivity rates
• Close tolerances
• Good Finishes
• Economical Operation (for many applications)

Disadvantages

• Only certain workpieces are suitable
• There cannot be any obstruction in the path of the tool.
• Tapered holes cannot be broached
• Parts must be able to withstand high thrust force.
• Require rigid machines and workholding

Broaching Machines

•  Vertical  Surface
• Vertical Internal Pushdown
  • Pullup
  • Pulldown
• Horizontal Internal
• Horizontal Surface
  • Continuous/chain broaching machines

Broach Geometry

• Pilot
• Roughing Teeth
• Semifinishing Teeth
• Finishing Teeth
• Rear Pilot
• Follower End

Files and Filing

File Types (by tooth geometry)

• Single Cut Files
  • Evenly spaced parallel teeth
• Double Cut Files
  • Two sets of teeth
• Rasp-Cut
  • Individual teeth
• Vixen-Cut
  • Curved teeth

File Terminology

• Tang – the pointed part of the file that is inserted into the file handle
• Heel – the part of the file that comes next to the tang – also known as the shoulder
• Point – the end of the file opposite the tang
• Length – the distance between the point and the heel – also known as the body
• Teeth – the cutting ridges on the file’s surface
• Side – the wide file surface – used for most filingEdge – the narrow file surface – may be round or square in shape
• Back – the rounded side of all half-round files
• Safe – refers to an edge or side with no teeth cut

File Grades

• Dead smooth
• Smooth
• Second
• Bastard
• Middle
• Rough

File Types (by body shape)

• Needle Files
• Riffler Files
• Swiss Pattern Files
  • Sharper points
  • Variety of shapes
  • Wide range of cut coarseness
  • Closer tolerances

Filing Technique

• Cross Filing
• Draw Filing

File Types

Single Cut Files
Evenly spaced parallel teeth
Double Cut Files
Two sets of teeth
Rasp-Cut
Individual teeth
Vixen-Cut
Curved teethDraw Filing