random stuff to mem

Chvorinov’s Rule

Tts = Cm * (V/A)^2

Buoyancy Force (Casting)

Fb = Wm - Wc = V * g * (rho_metal - rho_core)

Flow Curve (Instantaneous)

Yf = K * epsilon^n

Average Flow Stress

Yf_bar = (K * epsilon^n) / (1 + n)

True Strain (Deformation)

epsilon = ln(ho / hf)

Maximum Draft (Rolling)

d_max = mu^2 * R

Chip Thickness Ratio

r = to / tc

Shear Plane Angle (Geometric)

tan(phi) = (r * cos(alpha)) / (1 - r * sin(alpha))

Merchant Equation (Theoretical)

phi = 45 + (alpha/2) - (beta/2)

Shear Strain

gamma = tan(phi - alpha) + cot(phi)

Material Removal Rate (Turning)

RMR = v * f * d

Cutting Power (from Energy)

Pc = U * RMR

Gross Power (Motor)

Pg = Pc / E (where E is efficiency)

Misrun

A casting that has solidified before completely filling mold cavity (caused by low pour temp or slow pouring)

(gen def)

Cold Shut

Two portions of metal flow together but fail to fuse; caused by premature freezing

(general defect)

Cold Shot

Metal splatters during pouring and forms solid globules trapped in the casting; caused by turbulence

(general defect)

Shrinkage Cavity

Depression / internal void near surface caused by solidification shrinkage that restricts amount of molten metal available in last region to freeze (needs better riser design)

(general defect)

Sand Blow

Balloon-shaped gas cavity caused by release of mold gases during pouring; caused by low permeability or high moisture

(sand defect)

Pin Holes

Formation of many small gas cavities at or near casting surface (caused by entrapped gases in the molten metal)
(sand defect)

Penetration

When fluidity of liquid metal is high, it may penetrate into sand mold or core, making the surface a mix of sand and metal

(sand defect)

Mold Shift

A step in the cast product at the parting line; caused by sidewise displacement of the cope relative to the drag

(sand defect)

Friction Force (F)

F = Fc * sin(alpha) + Ft * cos(alpha)

Normal Force to Friction (N)

N = Fc * cos(alpha) - Ft * sin(alpha)

Shear Force (Fs)

Fs = Fc * cos(phi) - Ft * sin(phi)

Normal Force to Shear (Fn)

Fn = Fc * sin(phi) + Ft * cos(phi)

Coefficient of Friction (mu)

mu = F / N = tan(beta)

Chip Thickness Ratio (r)

r = to / tc (used to find shear plane angle phi)

Reduction or Draft Ratio (r)

r = d / to (describes the percentage of thickness removed; d = draft)

Draft in Sand Casting (Expendable)

1° angle; Purpose: To facilitate the removal of the pattern from the mold without damaging the sand mold

Draft in Permanent Mold Casting

2° to 3° angle; Purpose: To aid in the removal of the solidified part from the metal mold

Specific Energy (Unit Horsepower) Correction

CF = Kcf * to^-0.21 (or f^-0.21); used to adjust energy requirements based on the feed/thickness.