Optimal Cavities Calculator
Determine the optimal number of injection mold cavities based on annual production volume, machine costs and cavity cost. The calculator balances tooling investment against operating costs — a critical decision at the design stage.
Input Parameters
Results
Fill in the data and click Calculate
ARGUS automatically optimizes cavity count based on a full cost model
Cavity count is a trade-off between tooling investment and operating costs — ARGUS balances them automatically taking available machines and production schedule into account.
How do we calculate the optimal number of cavities?
The optimal number of cavities is a trade-off between mold cost (which increases with cavity count) and machine cost per part (which decreases with cavity count). More cavities mean a higher tooling investment but shorter production time and lower machine cost per part. The optimum is found by minimizing total production cost (mold + machine).
The calculator uses a cost optimization model — comparing total cost (tooling + operation) for different cavity configurations.
n — number of cavities
Ccavity — cavity cost [EUR]
V — annual volume [pcs]
tcycle — cycle time [s]
Rmach — machine rate [EUR/h]
Typical cavity configurations: 1–2 cavities (prototypes, small batches <10K), 4–8 cavities (medium batches 50K–500K), 16–64 cavities (high volumes >1M, small parts). More cavities require a larger machine (higher clamping force, larger barrel), which increases the machine rate.
Factors Affecting Cavity Count
Part complexity — complex parts limit cavity count
Available machines — clamping force and tie-bar spacing set limits
Required quality — tight tolerances favor fewer cavities
Delivery deadline — short lead time may require more cavities
Rule of thumb: doubling the cavity count increases mold cost by 60–80% (not 100%, because some costs — plates, cooling system — are shared). It simultaneously doubles output, reducing machine cost per part by ~50%. The optimum depends on the ratio of cavity cost to machine rate.
Practical Constraints
Cavity count should be a power of 2 (1, 2, 4, 8, 16…) for a symmetric runner layout. An odd number of cavities is possible but makes flow balancing more difficult. For hot runner molds the limiting factors are the number of nozzles and manifold size.
ARGUS automatically optimizes cavity count based on available machines and production schedule
See for yourself — book a presentation and explore production optimization in ARGUS.