Pneumatic Air Cylinder Force Calculation

As the core component of the actuator in the field of precision machinery and automation control, the air cylinder has many series, and each series of cylinders has different models. Do you know how to choose the most suitable size among the various cylinders? How to calculate air cylinder force according to your actual needs?

To choose the right cylinder bore, you need to perform air cylinder force calculation with some vital parameters.

First of all, it is the key to select the cylinder to clarify the actual load(the actual force generated by the cylinder). By accurately calculating the load size and combining the force formula of the cylinder, we can reversely deduce the appropriate cylinder bore range, and then select within this range.

The output force of the cylinder is related to three main parameters, namely the Working pressure P, the Theoretical force F₀, and the Sectional area of cylinder S.

Among them, the Working pressure P is generally between 0.4MPa and 0.8MPa, the Theoretical force F₀ can be reversed according to actual needs, and the Sectional area of cylinder S can be obtained according to the cylinder bore using S = πr².

After obtaining the main parameters, we can solve the problem by using the formula F = P x S.

Next, we use an example to understand the actual force calculation process.

Calculation1

Try to calculate the actual thrust of a cylinder with a cylinder diameter of 50mm (π=3.14) 

The Working pressure is generally taken as 

P = 0.6MPa ≈ 6kgf/cm²

Sectional area of cylinder

S = πr² = 3.14 x 25 x 25 = 1962.5mm² = 19.625cm²

Then the Theoretical force 

F₀ = P x S = 6 x 19.625 = 117.75kgf

Due to factors such as energy loss and margin, the theoretical force cannot be fully converted into the actual force, so we multiply the theoretical force by a coefficient A less than 1 to obtain the final actual force 

 A = 0.8

Then the actual force 

F = F₀ x A = 117.75 x 0.8 = 94.2kgf

Through the above calculation, we can get the actual force of the 50mm cylinder is about 94.2kgf, and we also understand the calculation method of the cylinder force.

However, in practical applications, we often need to select the cylinder bore when the actual force is known. Can this be achieved by reverse calculation?

Of course, this is also possible. In fact, we only need to know two of the three main parameters to calculate the third main parameter.

Similarly, let's use an example to understand the calculation method of this situation.

Calculation2

If we now know that in actual work, the cylinder needs to generate at least 170kgf of force.

Then we know 

F ≥ 170kgf 

Then the Theoretical force is 

F₀ = F / A = 170 / 0.8 = 212.5kgf

The Working pressure is 

P = 0.6Mpa ≈ 6kgf/cm²

The required Sectional area of cylinder 

S = F₀ / P = 212.5 / 6 ≈ 35.4cm²

From S = πr² ,we can know the cylinder barrel radius is 

Then the cylinder bore is 

d = 2r = 33.58 x 2 = 71.16mm 

The cylinder model is not continuous. Generally, the cylinder bore is 25mm, 32mm, 40mm, 50mm, 63mm, 80mm, 100mm, etc. Therefore, a cylinder with a cylinder bore of 80mm or more should be selected.

Generally, larger diameter cylinders operate slower and more expensive due to inertia loads and friction losses. So there is no need to select the cylinder with too large cylinder diameter to meet the demand. Therefore, in the above example, a cylinder with a bore of 80mm is generally selected.

However, in some situations, due to various factors, such as material restrictions, environmental protection requirements, gas source stability, system adaptability, etc., a cylinder with a larger cylinder diameter may also be selected.

Sometimes, due to installation conditions, speed requirements, and other limitations, it is also possible to choose cylinders with smaller diameters by increasing the supply pressure, or to choose special types of cylinders such as compact cylinders, mini pneumatic cylinders or other piston air cylinder.

After understood the thrust calculation method of the cylinder, we can inversely deduce

Then, the cylinder diameter can be quickly calculated with this formula.

Cylinders play a vital role in modern industry and machinery. You can also click here to visit our Blog page, where we provide a series of articles, pictures, videos and other resources to help you better understand the work principles, characteristics, applications and other aspects of pneumatic cylinders and components.