Contact us How to reach us Partnership Weight Calculator
English
Version
Go to English version
Versione
Italiana
Passa alla versione Italiana

Moulding dies

Index

Technical data sheets

Aluminium because

Aluminium alloys are used since many years for the manufacturing of low to medium pressure injection moulding dies, and additionally dies for blow forming, Resin transfer moulding, expansion forming, of technical polymers and rubbers.

The earlier exercises were relevant to applications for prototypic or small series production, where paramount importance is associated to minimising non recurring costs (manufacturing cost of dies) and total manufacturing time of tools, whilst problems related to wear and mechanical and thermal fatigue of dies are marginal.

The availability of high strength alloys, developed originally for aerospace, and the development of specific materials for moulding dies performed by the main mills on the basis of such alloys, allows the possibility of advantageous usage of aluminium for the manufacturing of moulding dies for medium and mass series production, in the field of many hundred thousands closures of the dies.

The competitiveness of aluminium dies versus traditional steel dies comes from the following main factors:

Back to index

Cost

The above mentioned factors set a favourable costs trade-off for the manufacturing of aluminium moulding dies wherever it is allowed by the solution of the technical problems connected to the injection technology (process parameters, design of dies, selection of proper material):

For prototypical and small series productions this is due mainly to lower non recurring machining costs of dies, as shown in the following graph, referring to total cost of parts for small series (cost of tools + workmanship, excluded cost of polymer).

costo

Back to index

Productivity

For medium and mass production the benefits coming from elevated thermal conductivity of aluminium alloys become of importance, since it allows faster injection cycles, with time reductions up to 35%, so that the aluminium solution becomes profitable even in the limit situation of re-making of dies after some hundreds thousands closures, as shown in the following graph, showing the total cost of parts for medium and mass production (cost of tools + workmanship, excluded cost of polymer).

 

Back to index

Time to market

Machining time reduced compared to traditional tool steels and ease of work reduce to about one half the time required for dies manufacturing, and allow to consistently reduce the time to market; this is of paramount relevance in case of prototypical productions and for certain products families.

 

Back to index

Aviometal because ...

Aviometal, who are on the market since more than 50 years as supplier of aerospace companies, besides of the machinery industries, not only selects and delivers blocks for moulding dies cut to size in Just In Time environment, but also make available to customers their experience and knowledge of aluminium alloys and relevant technologies for machining, joining, surface protection for the best selection of optimum material for the most critical and special applications.

 

Back to index

Aluminium when ...

The use of aluminium moulding dies is absolutely advisable for moulding processes performed at medium-low pressure (not exceeding 600 Bar); for processes operating at very high pressures and temperatures or for resins with hard fillers a tailored design of the die and selection of the alloy are required.

For the typical injection moulding process the appropriateness of using dies in aluminium alloys and the number of closures achievable comes from the following factors:

Injection pressure shall match compressive strength of die material at the injection temperature of resin, in order to avoid premature problems of distortion of internal surface of die and premature wear.

Additionally, in conjunction with the operating temperature of die, it id the basis for static and fatigue stress analysis.

The following table gives an example of the limit operating conditions for a die in a medium strength aluminium alloy suitable for elevated temperatures (2219-T851); Pi and Ti are the maximum injection temperature and pressure not to be exceeded at the shown die operating temperature Ts.

Should any filler be used, the wear phenomena of the inner surface of the die could speed up.

Therefore it is always strongly advisable to operate the process using values of injection pressure and temperature and of die operating temperature as low as possible, provided that moulded parts can be correctly obtained.

The table below shows typical data for various resin materials.

Materials and closures
Resin Closures max
103 104 105 >105
Low Density Poly Ethylene XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
High Density Polly Ethylene XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Poly Propylene XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Poly Styrene XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
High Impact Poly Styrene XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Styrene Acrylo Nytrile XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Acrylonitrile Butadiene Styrene XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Poly Vynil Chloride XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Cellulasics XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Poly Amide 6 XXXXXXXXX XXXXXXXXX XXXXXXXX XX
Poly Amide 11 XXXXXXXXX XXXXXXXXX XXXXXXXX XXXXXXXX
Poly Amide 6/6 XXXXXXXXX XXXXXXXXX XXXXXXXX XX
Poly Amide 6 filled glass XXXXXXXXX XXXXXXXXX    
Poly Phenilene Oxide XXXXXXXXX XXXXXXXXX XXXXXXXX  
Poly Methyl Metacrylate XXXXXXXXX XXXXXXXXX XXXXXXXX  
Poly Acetals XXXXXXXXX XXXXXXXXX XXXXXXXX  
Poly Carbonate XXXXXXXXX XXXXXXXXX XXXX  

Back to index

Technological properties.

Aluminium alloys for moulding dies are delivered in form of plates or blocks coming from casting or hot working (rolling or forging), heat treated (where applicable) in order to achieve optimum properties, and (where applicable) mechanically stress relieved through stretching or cold compression in order to achieve optimum stability after machining.

Since these products are basically the same alloys used in aerospace, or anyway very close to these materials, the demanding quality standards applied can assure high consistency of properties, absence of surface and internal defects, minimum levels of established mechanical and technological properties.

Back to index

Mechanical and physical properties

Mechanical and physical properties of aluminium products depend on factors like:

And are influenced by operating temperatures, even in the field of temperatures typical of processing of polymers and elastomers.

During design phase it is advisable, whenever possible, to address minimum guaranteed values for each individual product instead than "typical" values.

The following table refers to some products currently available in stock at Aviometal, and specifically to rolled plates, 100 mm thick; the mechanical properties are for LT direction (parallel to rolling).

For detailed figures see technical data sheets of specific products.

Alloy

Properties

AUQG

(2219)

AJQY

(5083)

AJQ4

(50XX)

ARQF

(6082)

AZQI

(7010)

AYQK

(7075)

Ultimate strength (Mpa)

414

275

275

295

540

456

Yield strength (Mpa)

304

 

100

240

490

373

Elongation (%)

5

 

7

7

5

3

Brinell hardness

130.

86

86

89

175

150

Young's modulus (Mpa)

72500

71000

71000

69000

72000

71100

Specific gravity (g/cm3)

2,85

2,66

2,66

2,70

2,83

2,80

Thermal conductivity (W/m C)

117

117

117

200

153

131

Linear thermal expansion coefficient (mm/mm C)

22 x 10^-6

24 x 10^-6

24 x 10^-6

23 x 10^-6

24 x 10^-6

23 x 10^-6

Back to index

Machining

Machinability of aluminium alloys is much better than traditional tool steels, and allows reductions of machining times from 30% up to 50%.

In order to optimise the benefits coming from use of these materials in terms of machining time, during rough cutting it is generally advisable to use high cutting speeds and feeds, and to reduce the depth of cut to match the power of the machine, whilst for finish cutting high cutting speed and low feed are used to optimise surface finish.

For machines designed for machining steel the upper limit for the cutting speed is in general the maximum available speed of the spindle; special-to -type machines are available for machining aluminium alloys, with spindle speeds of more than 20000 RPM.

It is advisable to use cutting fluids, mineral or emulsified, with pH whenever possible neutral and in any case between 5 and 8, chloride free, in order to avoid corrosion in case of no or late removal from the surface of finished parts.

Tool life is in any case at least 20 times longer than for steel.

Back to index

Milling

To improve removal of the great volume of chips per unit time it is advisable to use tools with number of cutters reduced respect to steel (1 or 2 cutters for end mills).

Recommended cutting parameters are shown in the following tables.

High Speed Tool Steel mills

Parameter

Rough

Finish

Cutting speed (m/min)

70 ¸ 90

100 ¸ 120

Feed rate (mm/cutter)

0,1 ¸ 0,3

0,03 ¸ 0,1

Cutting depth

(1)

£ 0,5

Edge angle (°)

20

20

Rake angle (°)

6 ¸ 10

6 ¸ 10

 

Carbide tipped tools

Parameter

Rough

Finish

Cutting speed (m/min)

400 ¸ 1500

400 ¸ 3000

Feed rate (mm/cutter)

0,1 ¸ 0,3

0,03 ¸ 0,1

Cutting depth(mm)

(1)

£ 0,5

Edge angle (°)

15

20

Rake angle (°)

6 ¸ 10

6 ¸ 10

Depending on power available.

Back to index

Drilling

Generally drilling operations do not raise particular problems; the recommended cutting parameters are shown in the table below.

Parameter

HSS tools

Carbide tools

Cutting speed (m/min)

40 ¸ 60

150 ¸ 300

Feed rate (mm/round)

0,02 ¸ 0,6 (1)

0,02 ¸ 0,6 (1)

Edge angle (°)

120 ¸ 140

120 ¸ 140

Helix angle °)

25 ¸ 40

25 ¸ 40

Rake angle °)

8 ¸ 10

8 ¸ 10

(1) Higher values refer to bigger diameters.

Back to index

Reaming

Reaming operations are performed both manually and mechanically, with straight or spiral flute reamers; the recommended cutting parameters are shown in the table below.

Parameter

HSS tools

Carbide tools

Cutting speed (m/min)

20 ¸ 40

80 ¸ 150

Avanzam.(mm/giro) F < 25

25 < F < 40

F > 40

0,03 ¸ 1,0

0,1 ¸ 0,2

0,2 ¸ 0,3

0,05 ¸ 0,2

0,1 ¸ 0,3

0,2 ¸ 0,4

Edge angle (°)

5 ¸ 7

5 ¸ 7

Helix angle (°)

10 ¸ 15

10 ¸ 15

Rake angle (°)

6 ¸ 8

6

To obtain better surface roughness use lower values of cutting speed and feed rate.

Back to index

Tapping

It is recommended to use ground taps, without clearance surface; the recommended cutting parameters are shown in the table below.

HSS tools

Parameter

Value

Cutting speed (m/min)

15 ¸ 20

Rake angle °)

18

Back to index

Grinding

Grinding operations are seldom required, since usually proper machining with metal or carbide tools, performed with the right parameters, can give the required surface properties.

In case of prismatic parts, the part can be fixed on the magnetic worktable between two steel blocks, after applying two sided adhesive paper on the surface in contact with the worktable.

To avoid scratches due to presence of hard foreign particles, pay attention to the following:

Back to index

Polishing

Polishing, both manual and mechanical, allows to obtain mirror-like surfaces, with roughness down to 0.1 µm, and working effort of only 25 to 30% respect to steel.

It is recommended to start polishing with 320 abrasive paper, and then to go on with increasing finer meshes, till 1200; if required polishing can be complete with clothes and diamond paste from 2 to 6 µm

Back to index

Electrical Discharge Machining

MThrough EDM results not worse than those obtained with steel can be achieved, with working times lower from 20 to 50%.

For shaped electrode EDM the same tools typical of steel parts can be used; to improve the surface finishing it is recommended to reduce the metal removal rate in finishing phase.

Back to index

Turning

The upper limit of the cutting parameters is limited only by the power of the machine and stiffness of the cutting tool; the recommended cutting parameters are shown in the tables below.

HSS steel tools

Parameter

Rough

Finish

Cutting speed (m/min)

100 ¸ 120

400 ¸ 1500

Feed (mm/round)

0,2 ¸ 0,6

0,05 ¸ 0,2

Cutting depth (mm)

3 ¸ 15

0,3 ¸ 3

Edge angle (°)

20

20

Rake angle (°)

6 ¸ 8

6 ¸ 8

 

Carbide tipped tools

Parameter

Rough

Finish

Cutting speed (m/min)

400 ¸ 1500

400 ¸ 1500

Feed (mm/round)

0,3 ¸ 0,6

0,05 ¸ 0,2

Cutting depth (mm)

3 ¸ 15

0,3 ¸ 3

Edge angle (°)

25

25

Rake angle (°)

6 ¸ 8

6 ¸ 8

Back to index

Materials

Below the technical data sheets of materials recommended for the manufacturing of moulding dies and accessories.

The mechanical properties listed are, if not differently specified, minimum guaranteed properties, and are relevant to the nominal thickness of products; actually the typical properties of products are generally about 10% higher.

NThe data sheets refer to the thickness range of practical interest for the manufacturing of dies; lower thickness, that could be used for miscellaneous workshop tooling, show generally higher properties.

The US terminology is adopted, where

Ftu ultimate tensile strength

Fty yield tensile strength (conventional, 0.2% permanent deformation)

Fcy yield compressive strength (conventional, 0.2% permanent deformation)

Fsu ultimate shear strength

Fbru ultimate bearing strength

Fbry yield bearing strength

e elongation after rupture

E Young's modulus, tensile

Ec Young's modulus, compressive

G Shear elastic modulus

The physical properties are generally typical values, drawn from official documents or indicated by materials manufacturers.

The technological properties refer to the following rating:

very good

good

fair

poor

The elevated temperatures mechanical properties are given as a percentage of the mechanical properties of the product at room temperature for different holding times at indicated temperature; attention shall be paid to the fact that in certain intervals the reduction of properties increases with increasing holding times.

To obtain the value of the property at the indicated temperature, multiply the value of such property at room temperature, for the intended thickness, by the value coming from the curves, and divide by 100.

Successive exposures cumulate the effect.

The fatigue properties are shown using the US terminology; the curves are for room temperature, and show the value of maximum alternating stress Smax versus number of cycles to failure.

The curves refer to pulsing fatigue (R = 0, where R= Smin/Smax), to alternating fatigue (R = -1) and to other two typical cases (R = ± 0,5); the test results are for unnotched (Kt = 1) and notched test pieces, with different notch sensitivities (Kt > 1).

Back to index

Availability ex stock

Thickness

Material

140 150 160 180 200 220 240 250 260 300 350 400 500
AUQG     # # #     #          
AJQY   # # # # # #   # # # # #
ARQF   # # # # #   #          
AZQK       # #     #   # #    
AYQK # # # # # #              

Back to index

Back to index

Technical data sheets

In the following data sheets the materials were identified with the internal Aviometal codes.

 

General features

General purpose material, it is an Al-Mg alloy with medium mechanical properties, very good corrosion resistance, good weldability, high dimensional stability.

Supplied in form of rolled plates up to 250 mm thickness, and in form of cast and machined plates up to 350 mm thickness.

 

Typical uses

Machinery components, tools, even if very large and medium stressed, where elevated starting thickness is required.

Large moulding dies, for forming technologies where forming pressure is not very high, or for prototypes and small series.

Parts to be embodied into welded assemblies.

Minimum mechanical properties at room temperature

Thickness mm from to

a

100

150

151

250

251

350

Rm (MPa) L

LT

275

275

240

240

220

220

Rp0.2 (MPa) L

LT

105

105

100

100

100

100

A5 LT

8

7

6

E (MPa)

71000

Ec (MPa)

71700

G (Mpa)

26400

Physical properties

Specific gravity: 2.70 g/cm3

Thermal conductivity: at 20 C 120 W/m C

Specific heat: at 20 C 0.215 Cal/kg C

Linear thermal expansion coefficient: at 20 C 22.3 x 10-6 mm/mm C

From 20 to 100 °C 24,2

From 20 to 200 °C 25,0

From 20 to 300 °C 26,0

Technological properties:

Machining: very good

Polishing: fair

Welding: good (TIG - MIG)

 

Available sizes

  • Cut-to-size blocks
  •  

     

     

    Powered by Antelma  -  Designed by Paolo Mandirola