Mold Cavity Count
Compute the maximum number of mold cavities the machine can fill per cycle by dividing the machine's injection capacity by each part's mass (rounding down). More cavities increase productivity but require a larger machine and a more expensive, complex mold. It is a key calculation in production planning and mold selection. Enter the machine injection capacity and each part's mass.
Result
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Número de cavidades do molde
Por que fazer um molde com uma só cavidade se a máquina pode encher várias de uma vez? O número de cavidades multiplica a produtividade: um molde de 8 cavidades produz 8 peças por ciclo no lugar de uma. O limite básico vem da capacidade de injeção da máquina dividida pela massa de cada peça (mais os canais), arredondado para baixo. Mas há outros tetos: a força de fechamento (mais cavidades = mais área projetada = mais força), a capacidade de plastificação e o espaço físico no molde. A decisão é econômica: mais cavidades exigem máquina maior e um molde muito mais caro e complexo (com canais balanceados para encher todas as cavidades igualmente), mas diluem o custo por peça em grandes volumes. Para produções pequenas, um molde simples de 1 ou 2 cavidades compensa mais. Informe a capacidade de injeção da máquina e a massa de cada peça.
Related Tools
Mold Clamping Force
Compute the clamping force needed on a plastic injection machine, F = projected area · cavity pressure, to keep the mold closed against the molten plastic pressure. If the force is insufficient, the mold opens during injection and plastic leaks out at the parting lines (flash). It is the parameter that defines the machine tonnage required for a part. Enter the part's projected area (mm²) and the cavity pressure (MPa).
Mold Cavity Pressure
Estimate the pressure that actually reaches the mold cavity by multiplying the injection pressure (at the screw tip) by the pressure transmission factor, which accounts for pressure losses along the runners, nozzle and gates to the cavity. Typically only 40–60% of the machine pressure reaches the part. It is the cavity pressure that defines the clamping force and fill quality. Enter the injection pressure and the transmission factor.
Plastic Mold Shrinkage
Compute the final dimension of a plastic part after molding shrinkage, part_dim = mold_dim · (1 − shrinkage%/100). Every thermoplastic shrinks as it cools and solidifies in the mold — from ~0.5% (amorphous like ABS) to 2–3% (semicrystalline like PP and PA). That is why the mold cavity is machined larger than the final part, compensating exactly for this shrinkage. Getting it wrong ruins an expensive mold. Enter the mold dimension and the material's shrinkage rate.
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.