Theory of Metal Machining Review Questions Flashcards Preview

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Flashcards in Theory of Metal Machining Review Questions Deck (19)
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What are the three basic categories of material removal processes?

  • Conventional Machining
  • Abrasive Processes
  • Nontraditional processes


What distinguishes machining from other manufacturing processes?

Material is removed from the work part so that the remaining material is the desired part geometry


Identify some of the reasons why machining is commercially and technologically important

  • Variety of work materials
  • Variety of part shapes and geometric features
  • dimensional accuracy
  • good surface finish


Name the three most common machining processes.

  • turning
  • drilling
  • milling


What are the two basic categories of cutting tools in machining? Give two examples of machining operations that use each of the tooling types.

  • Single-Point Tool
    • Turning
    • Boring
  • Multiple-Cutting Edge Tool
    • Milling
    • Drilling


What are the parameters of a machining operation that are included within the scope of cutting consitions?

  • cutting speed
  • feed
  • depth of cut


Explain the difference between roughing and finishing operations in machining.


Used to remove a large amount of material from the starting workpart as rapidly as possible, in order to create a shape close to the desired form, but leaving some material on the piece for finishing



Used to complete the part and achieve the final dimensions, tolerances, and surface finish


What is a machine tool?

Used to hold the workpart, position the tool relative to the work, and provide power for the machining process at the speed, feed, and depth of cut that have been set


What is an orthogonal cutting operation?

Uses a wedge-shape tool in which the cutting edge is perpendicular to the direction of cutting speed motion into the work piece


Why is the orthogonal cutting model useful in the analysis of metal machining?

Simplifies the rather complex 3-Dimensional machining situation to 2-dimensions


The tooling in orthogonal model has only 2 parameters which is a simpler geometry than a single point tool


Name and briefly describe the four types of chips that occur in metal cutting.

  • Discontinous Chip
    • relatively brittle materials machined at low cutting speed
    • Separate segments, some loosely atached at times
  • Continous Chip
    • ductile work material cut at high speed and small feeds/depth
    • Long continous chips are formed, with good surface finish resulting
  • Continous Chip with Built-up Edge
    • ductile materials at low-medium cutting speeds
    • portions of work material adhere to rake faces of tool near cutting edge
  • Serrated Chip
    • semicontinous in the sense that they possess a sawtooth appearance that is produced by a cyclical chip formaton alternating from high shear strain to low shear strain
    • Associated with difficult to machine metals


Identify the four forces that act upon the chip in the orthogonal metal-cutting model but cannot be measured directly in an operation.

  • friction force
  • normal force to friction
  • shear force
  • normal force to shear


Identify the two forces that can be measured in the orthogonal metal-cutting model.

  • cutting force
  • thrust force


What is the relationship between the coefficient of friction and the friction angle in the orthogonal cutting model?

Tangent relationship


Describe in words what the Merchant equation tells us.

Defines general relationship between rake angle, tool-chip friction, and shear plane angle


Shear plane can be increased through:

  1. icnreased rake angle
  2. decrease friction angle between tool and chip


How is power required in a cutting operation related to the cutting force?

The power required in a cutting operation is equal to the cutting force multiplied by the cutting speed


What is the specific energy in metal machining>

The amount of energy required to remove a unit volume of the work material


What does the term size effect mean in metal cutting?

The size effect refers to the fact that the specific energy increases as the cross-sectional area of the chip decreases


What is a tool-chip thermocouple?

Comprised of the tool and chip as the two dissimilar metals forming the thermocouple junctions; as the tool-chip interface heats up during cutting, a small voltage is emitted from the junction that can be measured to indicate cutting temperature