Molding

Question 1

what is directional solidification?

Answer 1

when the metal begins at the point furthest from the metals entrance at the downdate. it will progressively freeze/solidify towards down gate.

Question 2

Sections of mold

Answer 2

Drag, Cheek, Cope

Question 3

Ferrous gating system

Answer 3

pour cup, down gate, choke, cushion, ingates, relief gates, runner, ceramic brick
“well/bowl”

Question 4

methods of gating

Answer 4

molded & slot

Question 5

ingates & quality/yield

Answer 5

-allows metal to reach mold cavity
-best gates/risers use less metal
-allows more metal to be poured
-saves time/money

Question 6

universal strength machine

Answer 6

-tensile strength (psi)
-breaking (pressure)

Question 7

why do we test sand for moisture?

Answer 7

-permeability
-bonding
-gas defects

Question 8

sieve test

Answer 8

gives AFS gfn

Question 9

qualitys of core sand

Answer 9

-must be able to collapse at the end of a job
-permeability
-strength
-refractoriness
-collapsibility

Question 10

silica sand

Answer 10

-rams best
-round
melts at 3250 degrees
ADVANTAGES: affordable, plentiful, retains heat

Question 11

sand grain shape effect on mold

Answer 11

-amount of bonding
-compactability
-flowability
permeability

Question 12

High AFS gfn

Answer 12

DEF: American foundry society grain fineness number
-fine sand
-low permeability
-gas defects

Question 13

Rubbish

Answer 13

aids in venting/collapsing of cores by creating more space between the sand surfaces

Question 14

parting materials

Answer 14

zip slip, white powder

Question 15

shake out process with “no bake” sand

Answer 15

helps chemicals burn out

Question 16

molding time

Answer 16

5-30 minutes

Question 17

sand mill

Answer 17

mixes different resins with different sand types

Question 18

Refractorness

Answer 18

-ability to withstand extreme heat
-sand has a refract temp of 3,000-3,300 degrees

Question 19

Permability

Answer 19

ability of a substance to allow air/gas through it

Question 20

what conditions must be present to allow a riser to do its job?

Answer 20

-partial vacuum
-metallostic head
-atmospheric pressure

Question 21

riser diameter/inches in height

Answer 21

for every 1 inch in diameter, you need 1/2 inches in height

Question 22

side riser

Answer 22

-pipes less
-has to turn at bottom

Question 23

where are risers placed?

Answer 23

thickest part of the casting

Question 24

purpose of feeder core

Answer 24

create the geometry that promotes piping

Question 25

top riser

Answer 25

better feeding range

Question 26

3 things that affect feeding distance of risers

Answer 26

1.the alloy being poured
2.thickness of casting to be fed
3.rates of progressive and directional solidification

Question 27

percentage of metal loss due to bowl shape

Answer 27

25%

Question 28

why do you “key” the mold when clamping?

Answer 28

it expands the flask, expansion locks clamps in

Question 29

Telltale

Answer 29

indicator to create an indention in the mold that can be matched when the core is set in place, preventing backwards placement

Question 30

how do you align the alignment balls when they are not visable?

Answer 30

1. apply wash to all 4 corners, edge of cope and drag
   2.trowel to mark straight vertical lines in was on all 4 corners
2. marks used to align the cope/drag by aligning the vertical lines

Question 31

3 types of shrinkage

Answer 31

1.liquid
2.solid
3.solidification

Question 32

casting modulus

Answer 32

volume and surface area

Question 33

blind/open risers

Answer 33

blind: more disadvantages
open: more advantages