Device for calibration of hot air welding machines

Plastics hot air welding techniques involve measuring and maintaining certain values of three physical quantities: temperature, clamping force and the dwell time of the product under load. Technical regulations of the last century do not specify the clamping force value. The value was kept by the mass of the active element of the technology equipment only. The paper considers the newly developed and studied device for calibration of hot air welding machines by clamping force. The device provides calibration of various types of machines with an operating gap of 13 mm and more. The calibration device itself was calibrated by the method of loading with standard weights using a special device. The functioning of the controller board adder was also studied, which allowed controlling the clamping force characteristics of hot air welding machines in case of inhomogeneous distribution of force and non-ideal geometric shape of clamping elements. It is shown that the new device allows controlling one of the main characteristics of hot air welding machines of various designs and manufacturers. The device made it possible to periodically control the actual value of the clamping force of the active element of the machine during the technological process realization. If in a specific model of the machine the measured value is the pressure in the pneumatic system instead of the clamping force, then during the initial calibration the clamping force against the pressure in the pneumatic system matrixes is generated, and its stability is then controlled.