KEVOS® MAKEOS · Manufacturing
Press Flywheel and Motor Check (Stroke Energy, Rim Mass, Rim Stress, Motor Power)
For a mechanical press, does the existing flywheel store enough energy for each stroke, is its rim speed safe, and is the motor big enough to recover it between strokes?
Check of a press flywheel and drive motor: the energy per stroke from peak force and working travel or entered directly, the average power, the energy the flywheel must give up during the cut for the allowed speed drop, the rim mass needed and the rim section, and the rim hoop stress from its speed (as the press flywheel sizing tool), against the rim mass fitted, your allowable rim stress and the motor power with drive efficiency.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Energy per stroke from | choice | Work out the energy from force and travel, or enter it. |
| Peak force | kN | Peak press force during the cut. |
| Working travel (e.g. plate thickness) | mm | Travel over which the force acts (about the stock thickness for shearing). |
| Energy per stroke (entered) | kJ | Energy per stroke when entered directly. |
| Strokes per minute | Strokes per minute. | |
| Time of the actual cut | s | Time the cut itself takes. |
| Flywheel | ||
| Mean rim diameter | m | Mean diameter of the flywheel rim. |
| Flywheel speed | rpm | Flywheel speed. |
| Speed reduction during the cut | % | How far the flywheel may slow during the cut. |
| Rim material density | kg/m³ | Density of the rim material (cast iron about 7200). |
| Rim depth ÷ width | Rim section depth divided by width. | |
| Rim mass fitted | kg | Mass of the rim on the press (0 if none fitted yet). |
| Allowable rim stress | MPa | Allowable hoop stress in the rim for its material and construction. |
| Motor | ||
| Motor power | kW | Rated power of the drive motor. |
| Drive efficiency | % | Efficiency of the belts and gears between motor and flywheel. |
Method and formulas
- E = F s or as entered; average power = E × strokes ÷ 60 (as the press flywheel sizing tool).
- Energy from the flywheel E₁ = E (1 − t_cut ÷ t_stroke); rim mass = 2E₁ ÷ (v₁² − v₂²); hoop stress = ρ v₁².
- Motor power needed = average power ÷ drive efficiency.
- Example: 162.7 kJ per stroke needs 2,984.1 kg of rim and 60.26 kW of motor.
Limitations
- Rim mass only; arms and hub add a little inertia, which is on the safe side.
- Average power; the motor must also accelerate the flywheel at start-up.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a press for a thicker or stronger blank
- Check a motor change on an old press
- Size a flywheel rim for a new drive
Who it is for
- Press tool designers
- Maintenance engineers
- Manufacturing engineers
What you get
- Energy per stroke and average power
- Rim mass needed, section and stress
- Rim and motor against the press
Interpreting the result
- Allowing more slowdown cuts the rim mass sharply but puts more slip and heat into the motor.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 3004–3006, 182–186. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
