Sheet metal stamping is a common metal processing method, widely used in many fields such as automobiles, aviation, electronics, and home appliances. In actual production, accurately calculating the pressure required for stamping is of great significance for mold design, equipment selection, and process optimization. This article will introduce in detail the calculation method of pressure in sheet metal stamping processes and related factors.



I. Basic Concept of Shearing Pressure



The pressure in the stamping process usually refers to the force required to complete processes such as shearing, deep drawing, and bending. Different processes involve slightly different calculation methods, among which the calculation of shearing force is the most common and typical.



Shearing force refers to the maximum pressure required to separate metal materials under the action of the die. It is mainly affected by factors such as material thickness, strength, shearing contour length, and die clearance.



II. Calculation Formula for Shearing Force



The general formula for calculating shearing force is:



$$

F = K \cdot L \cdot t \cdot \tau

$$



Among which:



- $ F $: Shearing force (unit: N or kN)

- $ K $: Safety factor, generally taken as 1.1~1.3

- $ L $: The total length of the sheared contour (unit: mm)

- $ t $: Material thickness (unit: mm)

- $ \tau $: The shear strength of the material (unit: MPa)



For example, if a certain part requires a cutting contour length of 200 mm, the material is Q235 steel (shear strength is about 300 MPa), the material thickness is 2 mm, and the safety factor K=1.2 is taken, then its cutting force is:



$$

F = 1.2 \times 200 \times 2 \times 300 = 144,000 N = 144 kN

$$



3. Pressure calculation of other stamping processes



In addition to cutting, sheet metal stamping also commonly has deep drawing, bending, flanging, and other forming processes, and their pressure calculation methods are also different.



# 1. Deep drawing force calculation



The deep drawing force is the force required to pull flat material into the mold to form a hollow part, and the commonly used formula is:



$$

F = \pi \cdot D \cdot t \cdot \sigma_b \cdot C

$$



Among which:



- $ D $: The diameter of the deep-drawn part (mm)

- $ t $: Material thickness (mm)

- $ \sigma_b $: The tensile strength of the material (MPa)

- $ C $: Correction coefficient, usually 0.6~0.8



# 2. Bending force calculation



The calculation of bending force is related to factors such as the mold structure, material properties, and bending angle. The commonly used empirical formula is:



$$

F = \frac{2 \cdot b \cdot t^2 \cdot \sigma_s}{d}

$$



Among which:



- $ b $: The width of the bending part (mm)

- $ t $: Material thickness (mm)

- $ \sigma_s $: The yield limit of the material (MPa)

- $ d $: The radius of the convex mold or the mold opening width (mm)



4. Factors affecting the stamping force



1. Material properties: The shear strength, yield strength, and tensile strength of the material directly affect the required stamping force.

2. Material thickness: The thicker the material, the higher the required pressure.

3. Mold clearance: Reasonable mold clearance can reduce the stamping force and improve the mold life.

4. Stamping speed: High-speed stamping may cause material dynamic strengthening, thereby increasing the required pressure.

5. Lubrication conditions: Good lubrication can reduce friction and lower the pressure required for forming.



5. Summary



In sheet metal stamping processes, accurately calculating the stamping force is an important link to ensure the feasibility of the process and the correct selection of equipment. Different stamping forms (such as cutting, deep drawing, bending, etc.) require different calculation formulas, and actual factors such as material properties, mold design, and lubrication conditions also need to be considered. Only by considering these factors comprehensively can an efficient, economical, and stable stamping production process be achieved.



With the development of computer simulation technology, finite element analysis software (such as AutoForm, Dynaform) is increasingly used in modern stamping processes for pressure prediction and process optimization, which provides more accurate guidance for actual production.