What the tool does
Free calculators give clamp force, shot size or cooling time one at a time. The tool joins them into one estimate and keeps every assumption visible.
- Cooling time from the largest wall, the effective thermal diffusivity and the melt, mould and ejection temperatures, with both forms of the plate formula (mean or centre temperature at ejection) and the runner as a cylinder; or your own time.
- Cycle: injection, holding, cooling, open, eject and close and other time, with the share of cooling.
- Clamp force from the projected area, cavities and runner with a factor in t/cm², US tons/in² or a cavity pressure, and a safety margin, checked against the machine.
- Shot: part × cavities + runner against the shot capacity and the window you allow.
- Price per part for up to six quantities: material with rejects, runner regrind and purge, machine hours at your rate and utilisation, labour, setup per order, the mould spread over the parts you choose or charged separately, inserts and finishing, overhead and margin.
- Quote: a one-page PDF and a workbook whose price table is formulas on the input cells.
How to use it
- Enter the part weight (or volume and density), the largest wall, the projected area and the cavities.
- Enter the process: temperatures and a_eff for the cooling time, the other cycle times, the clamp factor and the machine.
- Enter your resin price, machine rate, labour, setup, mould cost, overhead and margin, and the quantities to quote.
- Read the warnings and the price per quantity, then export the quote.
What is built in
Only the formulas. Prices, machine rates, resin properties and clamp factors differ by country, supplier and grade, so you enter them; nothing is filled in for you except in the labelled sample, whose prices are invented.
How it was checked
Before every release the engine is run on published worked examples: PP with a 2 mm wall, a_eff 0.1 mm²/s, 240, 40 and 90 °C cools in about 4.8 s (kunststoff-profi); 25 in² × 4 cavities + 10 in² runner at 3 tons/in² needs 330 tons (RJG); 380 cm² at 304 kgf/cm² needs 115.52 t; 92 in² at 4 tons/in² with 15 % margin needs 423.2 tons (RJC); 75 cm² × 2 at 0.47 t/cm² needs 70.5 t (Kruger); a 186 g shot fits machines of 286 to 744 g for a 25 to 65 % window; $85 an hour, 32 s and 4 cavities is $0.19 a part; a mould of 6 600 over 40 000 parts is 0.165 a part.
Limits
The tool does not read CAD files, simulate filling or estimate the mould cost. Theoretical cooling times can differ from the press by 10 to 30 %, so confirm cycle and scrap with a trial and the clamp force with the machine data.
Last checked 2026-10-20