There is a noticeable trend towards the use of aluminium alloys for medium- to high- volume production in recently years.

 

The principal advantages of this material are:

 

The main disadvantages of this material are:

 

The service life of aluminium alloy mould tools can quite readily achieve around 100,000 shots depending on the moulding conditions. There are a few notable exceptions to this where longer service lives of up to a million shots are achieved for straightforward parts, although certain mould parts may have to be replaced because of damage and wear.

 

There is also an increasing use of hybrid aluminium–steel mould tools in which the advantages of both materials are used to best effect – steel for high-wear areas and aluminium for less critical are as and where high rates of mould cooling are desirable.

 

Comparison of aluminium with other mould materials

Material	Additional description	Coefficient of thermal expansion	Thermal conductivity	Density (lb/in3)	Hardness	Yield strength (KSI)	Weldability
QC-7	Aluminium Alcoa	12.8	91	0.102	167 HB	74–79	A
7075-T6	Aluminium	13.1	75	0.101	150 HB	48.73	A
6061-T6	Aluminium	13.1	96	0.098	95 HB	40–42	B
P20	Mold steel	7.1	20	0.284	28–37 Rc	130–135
S7	Alloy tool steel	6.99	21	0.283	59–61 Rc	210	C
H13	Hotwork die steel	6.1	14.4	0.28	52–54 Rc	228	C
420	Stainless steel	5.7	20	0.28	52 Rc	215	C
MOLDMA X	Beryllium–copper brush Wellman	9.7	60.75	0.302	30–40 Rc	140–155	C
AMPCO	Copper Ampco metal	9.7	125	0.315	210 HB	75	D

HB = Brinell hardness; Rc = Rockwell hardness. Higher numbers indicate increased hardness levels. 

 

Weldability:

A: Moderately weldable, large repairs shoul be avoided.
B: Readily weldable.
C: Moderately weldable, preheat and postweld heat treatment required.
D: Weldable with proper technology.

Related Tags :

• Material
• Aluminum

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