How to calculate thick blanking force
F impulse = KLT τ ， Where f -- blanking force, K -- coefficient; The safety factor is generally taken as 1.3 considering the wear of the cutting edge of the blanking die, the fluctuation of the clearance between the punch and the die (the variation or uneven distribution of the value), the lubrication condition, the variation of the mechanical properties of the material and the thickness tolerance, etc. L -- total length of blanking periphery, mm; T -- material thickness, mm; τ—— Material shear strength, MPa
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extended data:
stamping advantages
1. High proction efficiency, convenient operation, easy to realize mechanization and automation. This is because stamping depends on the stamping die and stamping equipment to complete the processing. The stroke times of ordinary press can reach dozens of times per minute, and the high-speed pressure can reach hundreds or even thousands of times per minute, and each stamping stroke can get a stamping part
2, stamping, stamping die ensures the size and shape accuracy of stamping parts, and generally does not destroy the surface quality of stamping parts, and the life of dies is generally longer. So stamping quality is stable, interchangeability is good, and has the same characteristics. p>
3. Stamping can process parts with large size range and complex shape, such as the second hand of clock and watch, the longitudinal beam and panel of automobile, and the cold deformation hardening effect of material ring stamping, the stamping strength and stiffness are higher
Stamping is a kind of material saving and energy-saving processing method, and the cost of stamping parts is lowP = FLT σ B
where f is the empirical coefficient, generally 0.6-0.9; L is the length of the trimming line, mm; T is the sheet thickness, mm; σ B is the shear strength of plate, MPa
refers to the maximum resistance of the material to the die ring blanking.
where: K is the coefficient, generally equal to 1,
L is the circumference of the proct after stamping, in mm
t is the material thickness, in mm< br /> Г It is the shear strength of the material. Unit MPa
the calculated result is the unit of Newton. After dividing the result by 9800n / T, the result is the number of T.
this can only be calculated roughly. For the sake of safety, multiply the above value by 2, so the calculated value also conforms to the punching force calculation formula of compound die
P = k * L * t* τ
P flat edge blanking force (n)
tmaterial thickness (mm)
L blanking perimeter (mm)< br /> τ Material shear strength (MPA); K safety factor is generally k = 1.3.
calculation formula of punching shear force
F = s * L * 440 / 10000s workpiece thickness l workpiece length generally, this formula can be used
the punching pressure refers to the minimum pressure that the
press should have ring blanking
P stamping = P blanking + P unloading + P pushing + P blank holder force + P drawing force
the punch force is to select the tonnage of the punch press to determine the die strength. Stiffness check basis
1? Blanking force and its influencing factors: the main factors influencing the blanking force are as follows:
2. Calculation of blanking force P = Lt σ B
where p blanking - blanking force L - peripheral length of blanking part T - sheet thickness σ B-material strength limit σ The unit of result is kn
3? The force to unload the workpiece or scrap from the punch PX = kxp
where the reference number of KX - unloading force coefficient KX - is 0.04, and the calculated result unit is kn
4? The force to push the workpiece or scrap out of the die along the blanking direction Pt = ktpnkt - pushing force coefficient n - the number of pieces left in the die hole
the blanking force is not less than the cutting force of cutting workpiece + pressing and returning force
cutting force = shear strength of material * cross-sectional area
taking a circle with a diameter of 100 mm cut on a 3 mm thick Q235 steel plate as an example, the calculation method is as follows:
cutting force of steel plate = 350 n / square mm * 3.14 * 100 * 3 = 329700 n
blank holder Return force: estimated 80000 n
press pressure: 32900 + 80000 = 409700 n
selected press: 63 t press
L refers to the length of the trimming line. For example, if a square hole is punched, the length of the trimming line is the sum of the lengths of the four sides of the square hole, which is just its perimeter
t refers to the material thickness, unit: mm
F is the blanking coefficient, generally 1.3
F is the blanking coefficient σ B refers to the tensile strength of stamping steel plate material
this formula is the punching force calculation formula of punch press.
Blanking force is the pressure exerted by the punch on the sheet metal in the blanking process. It changes with the depth of the punch into the material (punch stroke). Generally speaking, the blanking force refers to the maximum value of the blanking force, which is one of the important basis for selecting the press and designing the die. When blanking with ordinary flat edge die, the blanking force F is generally calculated as follows:
Blanking force is the pressure exerted by the punch on the sheet metal in the blanking process. It changes with the depth of the punch into the material (punch stroke). Generally speaking, the blanking force refers to the maximum value of the blanking force, which is one of the important basis for selecting the press and designing the die. When blanking with ordinary flat edge die, the blanking force F is generally calculated as follows:
where
F -- blanking force
L -- punching peripheral length
T -- material thickness
-- material shear strength
k -- coefficient
Thecoefficient K is a correction factor given considering the influence of the fluctuation and non-uniformity of die clearance value, the wear of cutting edge, the fluctuation of sheet metal mechanical properties and thickness in actual proction. Generally, k = 1.3
in order to simplify the calculation, the blanking force can also be estimated according to the following formula: