Injection molding ยท Process
Fill Time Calculator
Estimate cavity fill time from total cavity volume and volumetric injection rate. Use this as a documented planning estimate, then validate it against the actual machine, mold, resin, and process.
Formula and method
Fill time = total cavity volume / volumetric injection rate.
Use the complete cavity volume and the programmed/measured volumetric rate, not hydraulic pressure. The same record also gives average injection rate as volume divided by fill time.
Inputs and units
Use controlled records, CAD, measured production data, the exact resin data sheet, or machine-maker specifications. Keep the material and time basis with the result.
Worked example
96 cm3 / 40 cm3/s = 2.4 s.
What the result supports
This result is a first-pass screen for process planning. Use it to identify the next record or engineering check, not as a release decision.
Sanity check
Check the unit basis and whether all quantities describe the same cavity, shot, machine, or production window before comparing values.
Important limitation
Gate freeze, compressibility, pressure limits, and flow balance require process validation.
Reference: Autodesk: runner layout.
Next calculation
FAQ
What must be checked after using fill time calculator?
Retain the input source and compare this estimate with the applicable machine, mold, supplier, or production record before relying on it.