Spinning -> PM Processing (H)

Question 1

What is SPINNING?
(https://www.youtube.com/watch?v=43N44ICyuEU)

Answer 1

A sheet metal process used to create circular axisymmetric shapes

Question 2

MANDREL

Answer 2

Mold with the shape of the internal dimensions and configuration of the desired final part

Question 3

SPINDLE

Answer 3

Rotates the MANDREL at the necessary speed

Question 4

TAIL STOCK

Answer 4

Clamps the BLANK cut from the sheet metal against the end of the mandrel

Question 5

ROLLER/SCISSOR TOOL

Answer 5

Pushes the BLANK over the MANDREL to create the shape

Question 6

CNC

Answer 6

Computer Numerical Controls

Question 7

CONVENTIONAL SPINNING

Answer 7

The BLANK remains of constant thickness

Question 8

SHEAR SPINNING

Answer 8

The BLANK is thinned and the diameter decreases

Question 9

How to determined it was made with SPINNING?

Answer 9

Tell-tale manufacturing marks will be circumferential (hoop)

Question 10

DEEP DRAWING and FORMING

Answer 10

Faster than SPINNING
Leave longitudinal marks

Question 11

PLATE

Answer 11

Metal with thickness of 1/4 in or more

Question 12

EXPLOSION FORMING (https://www.youtube.com/watch?v=uYL-N01tL-0&feature=youtu.be)

Answer 12

Technique that uses explosions to force metal into dies and molds

Question 13

EXPLOSION FORMING ADVANTAGES

Answer 13

Shockwaves
Deadens Sound
Cools
Suppresses Flash
Catches Debris

Question 14

Other examples of EXPLOSION FORMING

Answer 14

EXPLOSIVE BULDGING (
HYDROFORMING (fluid pressure to shape metal)

Question 15

MAGNETIC PULSE FORMING/ INDUCTIVE PULSE FORMING

Answer 15

Shaping of sheet metal using electromagnetic fields

Question 16

Types of MAGNETIC PULSE FORMING

Answer 16

MAGNETIC PULSE BULDGING
MANGETIC PULSE CRIMPING
MAGNETIC PULSE FORMING

Question 17

POWDER METALLURGY PROCESSING

Answer 17

Powdered metal is used as stock material

Question 18

TUNDISH

Answer 18

Cup which metal is poured through to steady the stream and prevent splashing

Question 19

Which metals cannot be used for this technique?

Answer 19

TUNGSTEN (high melting point)
TITANIUM (reactive when molten)

Question 20

COMPACTION

Answer 20

Powdered metal is placed in a DIE CAVITY with the cross section of the desired part, and it is punched by a PRESS

Question 21

GREEN COMPACT (GREEN STATE)

Answer 21

Powdered metal has been fully PRESSED and highly porous. Intense stress is generated at small points of contact causing limited fusion between particles.
GREEN MEANS INCOMPLETE

Question 22

CORES

Answer 22

Only straight or tapered holes can be created (no curves or dovetails)

Question 23

ISOSTATIC COMPACTION (to make stock material for PM)

Answer 23

Powdered metal is placed in a flexible rubber bag and then sealed inside a chamber. Pressurized fluid applied in all directions uniformly densifies the bag.

Question 24

POLYMER BINDER

Answer 24

Added to metals like Tungsten Carbide to help it stay in a GREEN COMPACT STATE

Question 25

SINTERING

Answer 25

GREEN COMPACT is placed in a SINTERING OVEN to reduce the porosity

Question 26

Steps of SINTERING

Answer 26

1. PREHEAT ZONE 2. HOT ZONE (MAX TEMP -> 1/2 Melting Point) 3. COOLING ZONE

Question 27

SINTERING OVENS need

Answer 27

custom non-oxidizing atmospheres that involve HYDROGEN and/or NITROGEN

Question 28

PM PROCESSING is mainly chosen because

Answer 28

It can create EXOTIC PROPERTIES due to MIXING and DISTRIBUTION in the DIE (Two different powders MIXED together or DISTRIBUTED in layers)

Question 29

IMPREGNATION

Answer 29

Pores are filled with fluid after air is drawn out in a vacuum chamber (OIL IMPREGNATED BEARINGS) (Surface tension prevents oil from coming out)

Question 30

Another application of IMPREGNATION is

Answer 30

Titanium medical implants, where pores are filled with growth hormone to encourage anchoring by tissue growth. Used for hip and knee implants.

Question 31

Strength of PM parts is similar to that of FORGING because

Answer 31

The grain size in PM parts is the same as the powder particle size used

Question 32

PM Advantages

Answer 32

1.No waste 2.Forge-like Strength (small grains) 3.Good for refractory metals(tungsten carbide) 4.Good for reactive metals (titanium) 5.Exotic properties (mixing + distributing powders) 6. Impregnation (bearing oil and implant growth hormone) 7. Porosity (filters, mufflers and light weight)

Question 33

PM Disadvantages

Answer 33

1. High Costs of Powders 2. Only simple shapes and straight passageways 3. Shrinkage (during sintering)