COMPARISON CHART
Process Comparisons for Castings
| PROCESS |
DESCRIPTION |
SIZE RANGE |
METALS |
TOLERANCES |
GRAPHITE
MOLD |
Precision
molds are graphite. Metal is injected into the mold. Molds open & castings
ejected. Similar to Permanent Mold except no ceramic wash is needed. |
Ounces to
10 pounds |
ZA-12
(Zinc alloy) |
1st
inch +/- .005"
Additional inches:
+/- .002". Across
parting
line: +/- .005" |
| INVESTMENT (LOST WAX) |
Metal molds makes wax replicas. These are joined, surrounded by investment material, baked out & metal poured in cavity. Mold is broken to remove casting. |
Ounces to 150 pounds |
Most all castable metals |
+/- .003" to 1/4"
+/- .004" to 1/2"
+/- .005" to 3",
then add +/- .003" |
| DIE CASTING |
Molten metal is injected under high pressure into hardened steel dies, often water cooled. Solidified part is ejected from open mold. |
Ounces to 15 pounds |
Aluminum, zinc, brass, & magnesium |
+/- .002"/inch.
Add +/- .015" across
parting line. |
| PLASTER MOLD |
Plaster slurry is poured onto pattern halves, allowed to set, removed,
baked and then assembled. Metal is poured in and once cooled, broken to
remove parts. |
Ounces to 50 pounds |
Aluminum, zinc, brass, copper & bronze |
+/- .005" to 2", then add
+/- .002"/inch.
Add +/- .010" across
parting line. |
| SAND CASTING |
Sand is packed around a wood or metal pattern. Mold halves are opened
to remove pattern. Metal is poured in and mold is broken to remove cooled
part. |
Ounces to tons |
Most all castable metals |
+/- 1/32" to 6" then add
+/- .003"/inch.
Add +/- .020" - .090"
across parting line. |
| PERMENANT MOLD |
Molten metal is poured into a ceramic coated metal mold. Mold is opened
and cooled casting is ejected. |
Ounces to 100 pounds |
Aluminum, zinc, brass, bronze, lead & gray iron |
+/- .015" to 1", then add
+/- .002"/inch.
Add +/- .010" to .030"
across parting line. |
| PROCESS |
TOOLING
COST
& LEADTIME |
MINIMUM
SECTION THICKNESS |
MINIMUM
DRAFT REQUIRED |
SURFACE
FINISH |
ORDERING
QUANTITY |
GRAPHITE
MOLD |
$2,000
- $5,500
4 - 8 weeks |
.100"
(Can vary to
.060" in areas) |
2
degrees |
125
RMS or better |
Usually
300
and up |
| INVESTMENT
(LOST WAX) |
$3,000
- $10,000
10 -12 weeks |
.060" |
None |
63 to 125
RMS |
Aluminum under 1000 Others: All Quantities |
| DIE
CASTING |
$5,000 - $100,000
12 - 22 weeks |
.030" to .060" |
1 to 3 degrees |
32 to 63 RMS |
Usually 2500 and up |
| PLASTER
MOLD |
$2,000 - $5,000
6 - 10 weeks |
.070" |
1/2 to 3 degrees |
63 to 125 RMS |
1 - 250 |
| SAND
CASTING |
$1,000 - $4,000
2 - 6 weeks |
1/8" |
1 to 5 degrees |
200 to 550 RMS |
All |
| PERMENANT
MOLD |
$5,000 - $15,000
8 - 20 weeks |
3/16" |
2 to 4 degrees |
150 to 300 RMS |
500 and up |
COMPARISONS
OF CASTING ALLOYS
| ALLOY |
ZA-12 |
ZA-27 |
ZINC DIE
CAST
(ZA-3)
|
CAST
IRON
ASTM
CLASS 30 |
ALUMINUM
356 - T6 |
BRONZE
85-5-5-5 |
MECHANICAL PROPERTIES
TENSILE STRENGTH: 1000 PSI
YIELD STRENGTH: 0.2% OFFSET
ELOGATION: %
HARDNESS: BRINELL
YOUNG'S MODULUS: 10 PSI
FATIGUE STRENGTH: X1000 (@10 CY) |
45-50
39
1-3
90-105
12.0
15 |
61
53
1-3
105-125
11.3
21 |
41
--
10
82
12
7 |
31
--
--
201
13-16
14 |
33
24
4
70
10.5
8.5 |
37
17
30
60
12
11 |
PHYSICAL PROPERTIES
DENSITY: LB/CU. IN.
THERMAL EXPANSION: 68-212 (X10/F)
THERMAL CONDUCTIVITY: BTU/FT/HR/F
ELECTRICAL CONDUCTIVITY: % CU
MELTING RANGE: F
|
.218
13.4
67.1
28.3
710-810 |
.181
14.4
72.5
29.7
708-903 |
.24
15
65
27
719-728 |
.26
6
26
--
>2150 |
.1
13
87
39
1035-1135 |
.32
10
40
15
1570-1850 |
NOTE: PROPERTIES ARE BELIEVED TO BE CORRECT, BUT WE ARE NOT WARRANTED IN ANY WAY BY
CASTECHNOLOGIES, INC., P.O. BOX 478, TOWNSEND ROAD, ATTLEBORO, MA 02703-0008
TELEPHONE (508) 222-2915, FAX (508) 222-2962
CHEMICAL SPECIFICATIONS
(% BY WEIGHT)
MATERIAL
Al
Mg
Cu
Fe (max)
Pd (max)
Cd (max)
Sn (max)
Ni
Zn
|
ZA-12
10.5 - 11.5
.015 - .030
.05 - 1.25
.075
.006
.006
.003
--
BALANCE |
| INDUSTRY STANDARDS |
ASTM
UNS |
B791-88
Z35361 |
|
