Abstract Based on the analysis of the drawbacks of the existing toothed belt mechanism for proportioning adjustment in the MDM-5 low-pressure injection molding equipment produced by E. Tartler GmbH in Germany, a scheme using variable frequency speed control for proportioning adjustment is proposed. This scheme not only overcomes the shortcomings of the toothed belt mechanism for proportioning adjustment, but also has advantages such as simple operation, smooth stepless speed regulation, high control accuracy, small system size, light weight, energy saving, and easy maintenance. A control system block diagram is given, and the key points for selecting the frequency converter are pointed out. Keywords : Low-pressure injection molding equipment, proportioning, reaction, injection molding, variable frequency speed control. Detailed content: Improved research on proportioning adjustment method of low-pressure injection molding equipment.pdf