【2026 Cylinder Selection】Calculation for cylinder selection

Step 1: Analyze work requirements. This is the basis for making a selection, and the following points need to be clarified: 1. Load weight: How heavy is the object that needs to be moved. 2. Movement mode: Horizontal push/pull? Vertical lifting? Or a tilting motion? 3. Installation space limitations: What are the maximum allowable length, diameter, and stroke of the cylinder? 4. Working speed: How fast does the cylinder rod need to move? (Unit: mm/s). 5. Operating frequency: How many times per minute does the cylinder move? This is related to the cylinder’s lifespan and heat generation. 6. Operating environment: · Temperature: normal temperature, high temperature, or low temperature.  ·Medium: Whether it is corrosive (such as in seawater or acid mist environments), and whether oil-free conditions are required (such as in the food and pharmaceutical industries).  ·Protection level: Presence of dust, moisture, cutting fluid, etc.

Step 2: Determine the cylinder type and installation method. 1. Cylinder type: · Single-acting cylinder: It has only one inlet; it extends (or retracts) due to air pressure, and returns thanks to spring force. It has a simple structure and low gas consumption, but the output force is asymmetric and the stroke is limited.  ·Applications: Clamping, ejector pins, door opening, and other applications requiring one-way force application.

·Double-acting cylinder: It has two air inlets, and extension and retraction are achieved by alternating air supply. It features high output force and a wide range of stroke, making it the most commonly used type.  ·Applications: The vast majority of pushing, pulling, and lifting applications.

2. Installation type: The installation type determines how the cylinder is fixed and the stress conditions it is subjected to. ·Basic type: No fixed supports; the mounting components need to be designed and installed by the user. ·Flange type: · Front flange: The flange is located on the cylinder head side; the mounting screws are subjected to tensile forces, resulting in a favorable stress condition, and this type is the most commonly used.  ·Rear flange: The flange is at the end of the piston rod. ·Earring type: ·Single earring: Can swing around a pivot shaft, suitable for situations where the cylinder itself swings.   ·Double earrings: More stable fixation. · Base type: · Axial base: The base is coaxial with the cylinder.  ·Tangential base: The base is on both sides of the cylinder.

Selection principle: The installation configuration should ensure that the forces acting on the cylinder are as much as possible along the axial direction, avoiding lateral or radial forces, as otherwise it will significantly reduce the cylinder’s lifespan.

Step 3: Calculate the cylinder diameter and piston rod diameter 1. Theoretical force calculation First, determine the required theoretical thrust or pull force based on the load and motion conditions. ·Thrust (F₁): The force exerted when the cylinder extends.  F₁(N) = Cylinder cross-sectional area (A₁) × Operating pressure (P), or F₁≈ 0.785 × D²× P (D: Cylinder diameter, in mm; P: Operating pressure, in MPa). · Tensile force (F₂): The force exerted when the cylinder retracts (due to the area occupied by the piston rod, this is a tensile force) 

2. Actual output and load rate: The actual output of the cylinder must be greater than the force required to overcome the load. However, considering factors such as friction and inertial forces, it is necessary to introduce the load factor (η). Actual available force = Theoretical output × Load factor. Principles for selecting the load factor (η): · Static load (clamping, pressing): η ≤ 80% · Dynamic load (horizontal movement): η ≤ 60% · Dynamic load (vertical movement): η ≤ 50% · High-speed, high-frequency movement: η ≤ 30%. Formula for calculating the minimum required cylinder diameter: D ≥ √(·D: Cylinder diameter (mm) · F: Actual required thrust or pull force (N) · P: Working pressure (MPa) · η: Load factor)

Example: To horizontally push an object weighing 100 kg, the working pressure is 0.6 MPa, with a load factor of 60%. Required thrust F = m × g ≈ 100 × 10 = 1000 N. D ≥ √3538 ≈ 59.5 mm. Based on the standard cylinder diameter series (such as 32, 40, 50, 63, 80, 100), a 63 mm cylinder is selected.

3. Piston rod diameter · Typically, the piston rod diameter of standard cylinders follows a fixed ratio to the cylinder diameter (such as Φ32/Φ16, Φ63/Φ20). ·During long strokes and under compressive loads (such as vertical lifting), it is necessary to verify the buckling stability of the piston rod to prevent bending. If stability is insufficient, a cylinder with a larger rod diameter or a thick-rod/dual-rod cylinder should be selected.

Step 4: Determine the stroke. The stroke refers to the length of movement of the piston rod. ·It is determined based on actual work requirements. ·The travel distance should not be too long, otherwise it will reduce the stability of the pressure rod. For long-stroke applications, extended-stroke or rod-guided cylinders can be considered. ·Choose the standard itinerary; custom itineraries are costly and have longer delivery times.