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.
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Capacidade de injeção (equivalente PS)
Há uma pegadinha na ficha técnica das injetoras: a capacidade de injeção é sempre dada em gramas de poliestireno (PS), de densidade ~1,05 g/cm³ — porque o canhão tem volume fixo, mas o que se especifica é massa. Ao processar outro material, a massa por shot muda na proporção da densidade: cap_equivalente = cap_PS · (densidade_material/1,05). Um plástico mais leve que o PS, como o polipropileno (0,905), rende menos gramas por shot na mesma máquina; um mais denso, como o PVC ou poliésteres carregados, rende mais. Ignorar essa correção leva a dimensionar a máquina errada — achar que cabe o shot quando não cabe, ou comprar máquina grande demais. Por isso o técnico sempre converte a capacidade nominal em PS para o material real antes de fechar o projeto. Informe a capacidade nominal em PS e a densidade do material.
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).
Plastic Injection Flow Rate
Compute the injection flow rate by dividing the injected volume by the fill time, in cm³/s. It is the speed at which the molten plastic enters the mold — a parameter that controls the shear rate, molecular orientation, surface finish and defects such as jetting or flow marks. High flow fills fast but may degrade; low flow may solidify before filling. Enter the injected volume and the fill time.
Cylindrical Silo Capacity
Calculate the storage capacity (mass) of a silo's cylindrical part, M = ρ · (π·D²/4) · H, from the product bulk density ρ (kg/m³), the silo inner diameter D (m) and the cylindrical body height H (m). The calculation combines the cylinder volume (section area times height) with the product's bulk density — the product mass per unit apparent volume, which includes the voids between particles and differs from the solid particle density. Bulk density varies with product and state: soybeans ~720 kg/m³, corn ~720, wheat ~770, cement ~1500, and it also changes with moisture and compaction. Capacity is a silo's most basic commercial and operational parameter: it sets how much product it stores, and thus the logistics of receiving, dispatch and stock turnover. This computes the cylindrical part; total capacity also includes the lower hopper volume and, in grain silos, the upper product cone above the transition line (formed by the angle of repose during filling). Correctly estimating capacity is essential in designing storage units, cooperatives and grain terminals. Enter the bulk density, diameter and cylindrical body height.
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.