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Die Casting Calculation

1. The document provides calculations for die casting including determining the shot weight, gate velocity, fill rate, gate area and dimensions, runner area and dimensions, locking force, plunger diameter, and ejector pin requirements. 2. Key inputs include the weight and density of the casting, projected area, wall thickness, and alloy being cast. 3. Tables provide reference values for specific injection pressure, gate velocity ranges, maximum fill times, recommended gate thicknesses, and metal/die temperatures.

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566 views4 pages

Die Casting Calculation

1. The document provides calculations for die casting including determining the shot weight, gate velocity, fill rate, gate area and dimensions, runner area and dimensions, locking force, plunger diameter, and ejector pin requirements. 2. Key inputs include the weight and density of the casting, projected area, wall thickness, and alloy being cast. 3. Tables provide reference values for specific injection pressure, gate velocity ranges, maximum fill times, recommended gate thicknesses, and metal/die temperatures.

Uploaded by

prisimparam
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOC, PDF, TXT or read online on Scribd
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DIE CASTING CALCULATIONS

1. Wt of casting (gms) 2. Density(gms/cc): based on alloy used for casting. Al- 2.6 to 2.7; Zn- 7.8; Cu-9; Mg- 1.7 3. Projected Area Casting 4. Volume of Casting cm 3 : Surface Area (cm2) : (Wt of Comp) / Density

5. Shot Weight = Wt of Casting + (Wt of Runner + Overflow) + Wt of Biscuits Wt of Runner + Overflow 10% of Wt of Casting Wt of Biscuits 20% of Wt of Casting 6. Gate Velocity (Vg) in m/sec (Refer Table 2) 7. Gate Thickness Hg (mm) , Hg = n/3 n/4 , n thickness of casting 8. Volume of metal through gate : P (cm3) . P = vol of casting + vol of overflow (10% of vol of casting)

9. Fill Rate (Q) cm3/sec . Q = (P x 1000) / t ; t fill time in milli secs

10. Gate area (Ag) (cm2) . Ag = (Q) / (100 x Vg)

11. Gate Length Lg (mm) . Lg = ( Ag x 100 ) / Hg

12. Runner Area Ar (cm2) . Ar = 1.25 Ag 1.6 Ag

13. 13 Runner Depth D (mm) D = (Ar / 1.6)(1/2) - (Ar / 2)(1/2)

14. Runner Width (W = 2D) (mm) 15. Locking Force F (Metric Tonnes) . F = ( A X P) / 1000 i. A Projected Area (cm2) ii. P Specific injection pressure ( kg / cm2) 16. Machine Specification:- Select Machine based on the locking force. 17. Effective Plunger Stroke (cms) : Maximum plunger stroke 20/25 mm for biscuits 18. Plunger Diameter d (cm) . . . . . Shot wt = Plunger Area x Eff. Plunger Stroke x 0.75 x 2.5 (gm) Shot wt = [ ( X d2 ) / 4 ]x Eff. Plunger Stroke Plunger x 0.75 x 2.5 (gm) 4 x Shot wt = ( X d2 ) x Eff. Plunger Stroke x 0.75 x 2.5 (gm) d2 = ( 4 x shot wt) / ( X Eff. Plunger Stroke x 0.75 x 2.5) d=

[ ( 4 x shot wt) / ( X Eff. Plunger Stroke x 0.75 x 2.5) ]

TABLE I Specific Injection Pressure Decorative Parts Engineering Parts Pressure Tight Parts TABLE II Gate Velocity Ranges Thinnest Wall Thickness (mm) 0 0.762 1.27 1.525 1.905 2.286 2.54 2.794 3.175 3.87 4.572 5.08 3.75 - Above Gate Velocity Range (m/sec) 46 55 43 52 40 49 37 46 34 43 31 40 28 35 Zn 100 200 200 300 250 400 Al or Mg 200 400 400 600 800 1000

Use lower values for warmer dies and hot metals Use higher values for colder dies and colder metals TABLE III METAL & DIE TEMPERATURE Alloy Zn Alloy Mg Alloy Al Alloy Die Filling Time For Zn, Al, Mg Alloys Average Wall Thickness (mm) Max Die Filling Time (milli sec) 1 10 30 1.5 10 35 1.8 20 40 2.0 30 60 2.5 40 90 3 50 100 4 50 120 For higher values fill time 7ms for every 0.5mm wall thickness For Brass Average Wall Thickness (mm) 1.5 1.75 2 2.5 3 4 Highest value apply for Al Medium value apply for Zn Lowest value apply for Mg TABLE IV Gate Thickness Wall Thickness (mm) 0.75 1.5 1.5 2.5 2.5 4 Gate Thickness (mm) Al Mg 0.5 0.8 0.5 0.6 0.8 1.25 0.6 0.85 1.25 1.6 0.85 1.35 Max Die Filling Time (milli sec) 20 25 25 30 25 35 30 40 35 45 40 50 Metal Temperature 393 C (740 F) 657 C (1215 F) 657 C (1215 F) Die Temperature 393 C (740 F) 332 C (630 F) 332 C (630 F)

Ejection System Assuming ejecting area to be 4% of the area of the casting Total Ejecting area = Projected area of Component X 4% Area of selected Ejector Pin Diameter = A Area of Ejector Pin = ( X A2 ) / 4 No of Ejector Pins Required = Total Ejection Area / Area of Ejection Pin

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