To select a ball screw electric cylinder, start with the force, travel, and speed required in each part of the machine cycle. Then check whether the same cylinder configuration can meet those requirements at the intended duty cycle and mounting orientation. A model’s maximum thrust and maximum speed are not necessarily available at the same time.
1. Calculate the axial force the cylinder must deliver
Separate the moving mass from the process force. For a horizontal axis, the required thrust may include acceleration force, guide friction, and the force needed to push or pull the workpiece. For a vertical axis, include gravity and check both upward and downward movement. If the load changes during the stroke, identify where peak force occurs and how long it lasts.
For example, an assembly station might extend quickly with little resistance, then slow down and apply force only during the last part of the stroke. Specify these as two operating points: approach speed and load, and working speed and force. That is more useful than asking for one headline thrust figure.
2. Separate usable stroke from installation length
Usable stroke is the distance the machine needs the rod to travel. Installation length is the space available between the mounting points. Record the required working travel and the available space in both the retracted and extended positions. Allow for mounting hardware, rod-end connections, sensors, and cable routing.
For longer strokes or compression loads, ask the supplier to check the allowable load for the actual mounting and extension. Do not assume that a force rating from a short-stroke model applies to a longer configuration.
3. Verify speed under load
Give the target speed for extension, the working move, and return if they differ. If you only know the cycle time, provide the travel distance and time allowed for each move. The average speed alone is not enough when acceleration and deceleration take up a significant portion of a short move.
Check the manufacturer’s performance data for the proposed screw lead, motor, and drive. Ask for confirmation that the required thrust is available at the intended working speed. If speed and thrust are both demanding, review the complete configuration before changing screw lead or motor size.
4. Describe the duty cycle and holding conditions
Start by dividing powered movement time by total cycle time. For example, a machine that moves for 4 seconds in a 10-second cycle has a 40% movement duty cycle. This is a starting point, not proof that a cylinder is suitable. If the motor remains energized to hold the load during a dwell, or if the cylinder presses against a part while stationary, report that separately.
Also provide the longest uninterrupted operating period, ambient temperature, and expected cycles per shift. Duty-cycle limits can depend on load and operating conditions. For a vertical or overhauling load, confirm what happens on power loss and whether a brake or other load-holding provision is required. Do not assume a ball screw is self-locking.
5. Check mounting and side loads
Keep the cylinder’s thrust aligned with the rod axis. If the load creates a side force or an overturning moment, use a suitable external guide unless the cylinder manufacturer explicitly rates the assembly for those loads. Check the rod-end connection, mounting points, and alignment throughout the stroke. A layout drawing can reveal side-load and clearance problems before a model is selected.
What to include in a ball screw electric cylinder RFQ
- Load: Moving mass, peak and sustained axial forces, and direction of force.
- Motion: Usable stroke, extension and return speeds, and time per move.
- Cycle: Cycles per minute, dwell or hold time, and expected operating hours.
- Installation: Orientation, retracted and extended space, mounting and guide arrangement.
- Controls: Available drive or controller interface, feedback requirements, and power-off holding needs.
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