Exam 2 Manufacturing

What is the definition of metal forming?

Metal forming is a manufacturing process in which metal is plastically deformed to change its shape without adding or removing material.

What types of stress do materials experience during metal forming?

Materials experience compressive, tensile, and shear stresses during metal forming.

What are the desirable material properties for metal forming?

High ductility, low yield strength (for easier forming), high toughness, and adequate strain hardening capability.

What are the two metal forming categories?

Bulk deformation processes and sheet metalworking processes.

What is the ratio used to differentiate between bulk and sheet metal forming?

The ratio of surface area to volume of the workpiece.

What are the main processes in each category?

Bulk deformation: Rolling, forging, extrusion, drawing.Sheet metalworking: Bending, deep drawing, shearing.

What are the benefits of increased temperature in metal forming?

Reduced yield strength, increased ductility, decreased force and energy required, improved material flow.

How does friction affect metal forming processes?

Friction increases required force, can cause defects, and affects material flow.

What are the benefits of lubrication in metal forming processes?

Reduces friction and wear, lowers force required, improves surface finish, and helps control temperature.

What is rolling in bulk metal forming?

A process where metal stock passes through rolls to reduce thickness.

What is forging in bulk metal forming?

A process where metal is compressed between dies to shape it.

What is extrusion in bulk metal forming?

A process where metal is forced through a die to create a specific cross-sectional shape

) What is drawing in bulk metal forming?

A process where metal is pulled through a die to reduce its diameter and increase length.

What are the two main functions of the opposing rolls in rolling?

Reduce thickness and impart shape to the material.

What are the three intermediate shapes for starting materials in rolling?

Bloom, billet, slab.

What is draft in flat rolling analysis?

The reduction in thickness of the material.

How is draft calculated?

Draft = initial thickness - final thickness.

What is another way to express draft?

As a percentage reduction in thickness.

How is the maximum draft calculated?

Maximum draft = coefficient of friction² × roll radius.

How is true strain in rolling calculated?

True strain = ln(initial thickness / final thickness).

How is the force for rolling calculated?

Force = width × average flow stress × contact length.

What is the velocity relationship between materials and rolls during rolling?

Before the neutral point: material moves slower than rolls;After the neutral point: material moves faster than rolls.

What is the no slip point?

The point where the material and rolls move at the same velocity.

Is friction positive or negative in rolling?

Both — it's needed for traction but excessive friction increases forces and wear.

What are the desirable features of roll material?

High hardness, wear resistance, toughness, fatigue resistance, thermal conductivity, dimensional stability.

Why are these roll material features important?

To resist wear, deformation, cracking, and thermal damage during rolling.

hat are common rolling defects?

Wavy edges, zipper cracks, edge cracks, alligatoring.

What are three ways to classify forging?

Open-die forging, impression-die forging, flashless forging.

What is open-die forging?

A process where metal is compressed between flat dies without full containment.

What is upsetting?

Increasing diameter and reducing length of a workpiece by compression.

How does friction affect upsetting?

It restricts metal flow outward, causing barreling.

Does temperature influence upsetting?

Yes — higher temperatures reduce friction effects and improve metal flow.

How does friction affect force calculation?

Friction increases the required force

At what point is force at maximum during upsetting? Why?

At the end of the stroke (maximum contact area and material resistance).

What is impression-die forging?

Metal is compressed in dies with a shaped cavity to form near-net shapes.

What is the influence of flash in impression-die forging?

Flash helps contain material flow and fills die cavity fully.

What are advantages and limitations of impression-die forging?

Advantages: complex shapes, high strength parts.Limitations: higher die costs, more precise control needed.

How do impression-die forces compare to open-die forging?

Forces are generally higher due to die constraints and flash formation.

What is flashless forging?

Forging where the entire material volume is enclosed in the die with no flash.

What is critical in flashless forging?

Precise control of workpiece volume.

What are advantages and limitations of extrusion?

Advantages: complex cross-sections, good surface finish, continuous process.Limitations: high forces, die wear, limited to ductile materials.

How is optimal die angle determined?

By balancing material flow and minimizing extrusion force.

What are effects of smaller die angle?

surface area is large, whichincreases friction at die-billet interface• Higher friction results in larger ram force

What are effects of larger die angle?

more turbulence in metalflow during reduction

ow does complex die orifice shape affect extrusion force?

It increases force and pressure required.

What stress is experienced during drawing?

Tensile stress.

What is the main difference between wire and bar drawing?

Difference in stock size

What is the purpose of each die feature?

Entry guides material, approach reduces area, bearing controls size, exit releases material.

What are features of a drawing die?

Entry, approach angle, bearing surface, exit.

How is starting end prepared for drawing?

It is tapered or pointed to fit through the die.

What is metal machining?

Material removal process using cutting tools to produce parts.

What are advantages and disadvantages of machining?

Advantages: precision, complex shapes. Disadvantages: waste material, slower process.

What is a cutting tool?

A tool that removes material from a workpiece via shear.

What are important features of a cutting tool?

Hardness, toughness, sharpness, wear resistance.

What are cutting conditions?

Cutting speed, feed rate, depth of cut.

What is the difference between roughing and finishing cuts?

Roughing: removes large material quickly (low speed, high feed).

Finishing: produces smooth surface (high speed, low feed).

What is the orthogonal cutting model?

A model of 2D cutting where the cutting edge is perpendicular to cutting direction.

What is the shear plane angle?

Angle where shear deformation occurs.

What are basic types of chips?

Continuous, discontinuous, segmented, built-up edge.

How do material properties affect chip type?

Ductile materials form continuous chips; brittle materials form discontinuous chips.

How do cutting conditions affect chip type?

Higher speed and lower feed promote continuous chips; low speed and high friction promote built-up edges.

What is rapid prototyping (RP)?

A process of fabricating prototypes quickly by adding material layer by layer.

Why has the name changed to rapid prototyping and manufacturing?

Because the technology is now used for end-use products, not just prototypes.

What are other names for this technology?

Additive manufacturing, 3D printing.

What are the three types of starting materials?

Liquids, powders, and solid sheets.

What is the common approach to prepare control instructions in RP?

Converting CAD model into STL file and slicing it into layers.

What are applications of additive manufacturing in design?

Creating prototypes for form, fit, and function testing.

What are applications in engineering analysis & planning?

Making physical models to evaluate manufacturability.

What are applications in tooling and manufacturing?

Producing jigs, fixtures, molds, and custom end-use parts.

What are some limitations of additive manufacturing?

Limited material selection, slower production rate, and surface finish quality.

Which of the following is not one of the three most common machining processes?

A) Milling

B) Planing

C) Turning

D) Drilling

B) Planing

In terms of categories of cutting tools in machining, traditional turning uses _______ point cutting tools

single

In terms of categories of cutting tools in machining, milling uses ______ cutting edge tools

multiple

In production machining, different types of cuts are usually made to create the final geometry of a part. Often times, initial cuts are made to remove large amounts of material from the starting work part. This initial set of cuts is commonly referred to as _______ . Subsequent cuts are then made to achieve final dimensions, tolerances and finish, to complete the geometry. This second stage of cutting is commonly referred to as ________

roughing, finishing

What is an advantage of machining over other processes?

A) It is cheaper in mass production

B) It is applicable to most materials

C) It can achieve closer tolerances than most processes

D) Both b and c

E) All of the above

D) both b and c

Which of the following is not a parameter of machining operations that is included within the

scope of cutting conditions?

A) Speed

B) Feed

C) Depth of cut

D) Whether or not a cutting fluid is used

E) These are all parameters that are included

E

What is one of the required elements for something to be categorized as a machine tool?

A) It must be powered by either electricity or fossil fuels.

B) It must move the work piece

C) It must move a tool relative to the work piece

D) It must perform one of the three most common machining processes.

C ) It must move a tool relative to the work piece

Each machining operation produces a characteristic part geometry due to two main factors, the first factor being the relative motions between the tool and work part; and the second factor being the shape of the cutting tool. Machining operations that primarily achieve a given geometry through the first factor, where the part geometry is created by the feed trajectory of the cutting tool are referred to as _______. Some example processes fitting with this first factor are _______.

Generating; taper turning and contour turning

What type of metal would be most likely to produce a continuous chip when metal cutting?

Ductile material

Which of the following is not one of the four forces that act upon a chip during orthogonal metal cutting and cannot be measured.

A) Friction force

B) normal force to friction

C) Shear force

D) Rake force

E) all of these are forces that act upon a chip during orthogonal metal cutting

D) rake force

If the rake angle is decreased and the friction angle is increased, what does the Merchant

equation predict will happen to the shear plane angle?

It predicts the shear plane angle will decrease

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

A) The length of the cutting surface

B) The cutting energy

C) The cutting speed

D) The rake angle

C) The cutting Speed

What is face milling?

A) Cutting is accomplished by the outside periphery teeth of the milling cutter and the tool axis is parallel to the work surface

B) Cutting is accomplished by the flat end of the cutter and the tool axis is perpendicular to the work surface

C) Cutting is accomplished by the outside periphery teeth of the milling cutter and the tool axis is perpendicular to the work surface.

D) Cutting is accomplished by the flat end of the cutter and the tool axis is parallel to the work surface.

B or C

Is it desirable to have flash in impression die forging?

A) Yes b/c the flash constrains the metal in the die

B) Yes b/c the flash reduces friction in the process

C) No b/c that means that piece was at the wrong temp for forging

D) No b/c then you used too much material

A

Which is not a type of forging operation?

A) Open die forging

B) flashless forging

C) Expulsion die forging

D) Impression die forging

C

Is friction desirable in metal forming?

A) Yes b/c it reduces tool wear

B) Yes the increased temp caused by friction improves the material properties

C) No it causes residual stresses and product defects

D) No it helps increase metal due to increase temperatures

C

In what way are hammers different from presses in forging?

A) Hammers are much smaller than presses

B) Hammers use impact force while presses increase pressure gradually

C) Presses require dies while hammers do not

D) Hammers require much less power to operate as opposed to presses

B

Which statement is false?

A) in upsetting friction between the work and die surfaces increases lateral flow of the work

B) In open die forging a barreling effect is common and due to friction

C) In upsetting a barreling effect is even more pronounced when we increase the temperature of the work

D) In hot open-die forging, heat transfer at the contact surface between the die and work can increase resistance to deformation.

A

Describe where the maximum force is required in 1 downward stroke of the cold upset forging press.

Max force is at the bottom-most point of the downward stroke

List 2 reasons why the starting work volume must equal the die cavity volume within a very close tolerance in flashless forging

if too small the cavity wont fill and if too large there is excessive pressure

Which product isnt generally produced on a rolling mill?

A) Flat sheet stock

B) I beams

C) Rod stock

D) Tubes and pipes

D

How can you reduce force in flat rolling?

A) Increase temp of the work

B) Increase draft in each pass

C) Use larger rollers

D) Decrease temperature of work

A

T or F: Strength and rigidity are important characteristics of the rolls used in rolling and affect dimensional accuracy

True

T or F: In rolling a defect called alligatoring sometimes occurs, which can result from inhomogeneous deformation of the material during rolling.

True

Select the most accurate statement:

A) at very low die angles contact surface area is small, which decreases friction at the die-billet interface.

B) At very large die angles turbulence is smallest, which assists with extrusion resulting in lower ram force requirements.

C) At very low die angles friction is the greatest and at very high die angles turbulence in metal flow is the greatest, both of which result in high ram force requirements.

D) Maximum ram force is required at an optimum intermediate value of the die angle where friction and turbulence are the lowest.

C

Which product was likely not produced using drawing?

A) wire for making a coat hanger

B) heat sink

C) bar stock for use in forging

D) rod stock for making a spring

B

T of F: Direct extrusion cannot be used to produce parts with hollow of semi hollow cross sections.

False

Which is not a bulk deformation process?

A) Rolling

B) Drawing

C) Forging

D) Extrusion

E) Bending

E

T of F: Strain is maximum in forging when the cylindrical work has been reduced in height the furthest.

True