Lecture 16-17: Manufacturing Engineering Processes

A set of vocabulary flashcards based on the lecture on manufacturing engineering processes, focusing on deformation processes and hot-working methods.

Deformation Processes

Processes that exploit plasticity to shape materials without cutting, resulting in little to no waste since material is moved. No need to handle molten material, solidification. High force and expensive machinery/tooling. Almost all metal products undergo metal deformation

Hot-Working Processes

Plastic deformation of metals at temperatures above their recrystallization temperature.

Recrystallization Temperature

The minimum temperature at which metal begins to undergo recrystallization during hot working.

Forging

A manufacturing process that shapes metal by applying compressive forces, typically using dies.

Extrusion

metal is compressed and forced to flow through a die (toothpaste), more shapes produced than rolling, dies cheap, easy conversion, but cross section needs to be uniform for entire length.

Rolling

A metal forming process where the material is passed through rollers to achieve desired thickness.

Open-die Forging

A forging process that allows unrestrained flow of material, suitable for large products. cheap, big size products, slow not for large scale, simple shapes, further machining, operator skill based

Closed-die Forging

A forging process with shaped dies that control material flow, producing complex shapes. metal flows and completely fills die, less machining, expensive, and small to medium

Hydrostatic Extrusion

An extrusion method where high-pressure fluid surrounds the workpiece to facilitate the process.High efficiency, temps are limited bc of fluid

Strength and Ductility

Material properties that can be enhanced through hot working processes.

Die Friction

The friction between the die and the material being extruded, which must be minimized.

Plasticity

The ability of a material to undergo permanent deformation without breaking.

hot working examples

Includes rolling, extrusion, and forging.

hot working temp

Temp is higher than 0.6 times melting point.

cold working processes

includes squeezing through rolling, extrusion, cold forging, bending, shearing, and drawing.

cold working temp

temp lower than 0.3 times the melting point

max temp determined by

excess oxidation, grain growth, etc

recrystallization

decrease in strength, increase in ductility, decrease in rate of strain hardening

ring rolling

produces seamless rings, high pressure applications

extrusion shapes

direct extrusion

solid ram through stationary die, lots of friction

indirect extrusion

hollow ram through stationery confined billet, least friction

mandrels

produce hollow shapes or ones with multiple longitudinal cavities good for support

roll forging/swaging

external hammering to reduce diameter