Extrusion And Drawing: Manufacturing Processes

Extrusion and Drawing Manufacturing Processes

Outline Extrusion Extrusion of Metals Extrusion Defects Extrusion Equipment Extrusion of Nonmetals Drawing Drawing Process Drawing Equipment

Extrusion A compression process in which the material is forced to flow through an opening to produce a shape with a specific crosssection input

die product

pump

Examples of Extruded Parts

Extrusion Metals

Nonmetals

Metal Extrusion Direct Extrusion A ram compresses the material, forcing it through the die Indirect Extrusion The die is mounted on the ram; the material is forced out in the opposite direction of the ram movement

Direct Extrusion

Indirect Extrusion

Extrusion

Extrusion

Metal Flow

Example of an Extrusion Machine

Extrusion

Extrusion Hot Extrusion Involves pre-heating the material above the recrystallization temperature to increase ductility Cold Extrusion Does not pre-heat material; used to produce parts in finished or near-finished form

Extrusion Cold extrusion advantages: - Improved mechanical properties from work-hardening - Good control of dimensional tolerances - Improved surface finish (no oxide film) - No heating required - Competitive production rates and costs

Extruded Metals Typical extruded metals (hot or cold) Aluminum, copper, magnesium, zinc, tin and alloys of these Steel alloys are usually extruded hot; softer steels may be extruded cold

Others such as titanium and refractory metals may be extruded, but with difficulty

Extruded Metals

Extrusion Temperature Ranges Lead Aluminum and its alloys Copper and its alloys Steels Refractory alloys

200-250 °C 375-475 °C 650-975 °C 875-1300 °C 975-2200 °C

Extrusion Defects

Extrusion Dies

Extrusion Dies

Example of an Extrusion Die

Extrusion of Nonmetals Materials rubber plastic solvents candy glass

Products window seals door seals hose and tubing wire insulation candy canes

Hot Feed and Cold Feed Extrusion

Ribbon Cold Feed Extrusion

Heating/melting Hot Feed Extrusion

Temperature zones

Pellets

Extrusion of Nonmetals Candy Canes cone rollers candy

Extrusion of Nonmetals Window Seals Cold Feed Extrusion

input windup

die

extruder takeaway belt die

Extrusion of Nonmetals Plastic Bags extruder die

air

cutting and sealing

Example of a Dual Extruded Product

Dual Extrusion Opposed Head

extruder

extruder

die

Piggy Back

die extruder extruder

Dual Extrusion – White Side Wall Black rubber die

White rubber die

Exit die

Wire, Tube, Bar, Rod Drawing

Extrusion pushes the material through the die; drawing pulls the material through the die

Drawing Products electrical wire cable wire stock for fences, hangers, shopping carts etc. rod stock for nails, screws, rivets, springs etc. metal bars

Drawing Process

Advantages: - Close dimensional control - Good surface finish - Improved strength and hardness - Adaptability to mass production

Drawing of a Wire

Drawing

Drawing Preparation of the work material: 1. Annealing 2. Cleaning 3. Pointing

Single and Multi Stage Drawing

Gold Gold is the most ductile metal that exists. 4 pounds of gold can be drawn into a wire that stretches across the country.

Tube and Bar Drawing

Draw Bench Production Process

Summary Extrusion and drawing provide ways to form shapes with uniform cross sections at high production rates