Injection Cycle Time
Compute the total cycle time of a plastic injection by adding the injection time (fill + pack), the cooling time and the mold open/eject time. Cooling is usually the largest share (50–80% of the cycle). The cycle time directly determines productivity: parts/hour = 3600/cycle × cavities. Reducing it is the constant focus of optimization. Enter the injection, cooling and opening times.
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Tempo de ciclo de injeção
O tempo de ciclo é o relógio que governa a economia da injeção de plásticos: quanto menor, mais peças por hora e menor o custo unitário. Ele soma três fases: a injeção (preenchimento rápido + recalque sob pressão para compensar a contração), o resfriamento (esperar a peça solidificar o suficiente para ser ejetada sem deformar) e a abertura/extração (abrir o molde, expulsar a peça e fechar). O resfriamento quase sempre domina o ciclo — 50% a 80% do tempo — e cresce com o quadrado da espessura da parede; por isso peças mais finas e bom projeto de canais de refrigeração no molde são as maiores alavancas de produtividade. A conta é direta: peças/hora = 3600 ÷ ciclo × número de cavidades. Cortar 1 segundo de um ciclo de 20 s que roda 24 h por dia rende milhares de peças extras por mês. Informe os tempos de injeção, resfriamento e abertura.
Related Tools
Injection Shot Volume
Compute the shot volume of a plastic part by dividing the injected mass by the molten material density. The shot is the total volume of plastic injected per cycle (parts + runners), a parameter that must fit the injection barrel capacity. Together with the machine capacity, it defines how many cavities can be filled per cycle. Enter the injected mass (g) and the material density (g/cm³).
Cooling Time (Injection Molding)
Estimate the cooling time of a flat part in injection molding, t = h² ÷ (π²·α), from the wall thickness h and the polymer's thermal diffusivity α. The result, in seconds, is the dominant time of the injection cycle — the part can only be ejected after cooling enough to be rigid. The most critical factor is thickness squared: doubling the thickness quadruples the cooling time (and the cost per part). That is why thin, uniform walls are a golden rule in injection part design. Plastics' low thermal diffusivity makes cooling the productivity bottleneck. Enter the wall thickness and the thermal diffusivity.
Injection Capacity (PS Equivalent)
Convert a machine's nominal injection capacity (always specified in polystyrene, PS, density ~1.05) to the equivalent capacity in another material by multiplying by the density ratio. Since the barrel has a fixed volume, the mass it injects changes with the plastic's density — denser materials yield more grams per shot. Essential to size the machine for the real material. Enter the nominal PS capacity and the material density.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.