Blow Molding Machine’s Scissors Not Cutting: Reasons and Solutions

blow molding machine's scissors not cutting

Today, let’s analyze the reasons and solutions for the plastic barrel blow molding machine’s scissors not cutting.

When the plastic barrel blow molding machine does not cut the scissors, we must first consider the material supply and eliminate it step by step from the process flow.

The first reason is that the cutting installation is unreasonable, the cutting edge of the scissors is not sharp enough, the scissors handle is larger, and the scissors spray too much water to reduce the temperature of the gob tip. There is a scissor-type reclaiming device on the blow molding machine, which includes a fixing mechanism, a lifting mechanism, a translation mechanism, and a clamping mechanism. The fixing mechanism further includes a horizontal fixing plate and a vertical fixing plate, which are fixedly connected in a vertical shape. We can adjust the cross-section of the support frame to be triangular, which is beneficial to the balance between the components to realize the clamping and cutting of the blow-molded product. The opening and closing process of the clamping rod is adjusted by its opening and closing angle, and the action stroke is short and easy to control.

The second reason is that the raw material temperature is too low, the melting and homogenization is not good, and the yin and yang materials and crystal nuclei materials appear. As a result, the shape of the parison is inappropriate, and the head is too sharp and too thick to be cut. We can increase the material temperature to a suitable temperature, and then start the blow molding after the raw material is evenly plasticized to ensure that the blown plastic barrel has a uniform wall thickness and qualified quality, and it is also convenient to cut the flash.
The third reason has an important relationship with the cooling method of blow molding equipment. The cooling of the plastic barrel blow molding machine is generally divided into screw cooling, body cooling, and product cooling.

The screw cooling function is to eliminate the heat generated by long-term friction, make the pressure of plastic extrusion more stable, make the strength of stirring the plastic more uniform, and improve the quality of plasticization. However, it needs to be appropriate in use, especially not excessive, otherwise, the plastic melt in the barrel will suddenly cool down, causing serious accidents. The screw cooling is not allowed before extrusion, otherwise, it will cause serious accidents. The function of the body cooling is to improve the heat dissipation of the barrel, so as to overcome the temperature rise caused by frictional overheating. Because this temperature rise cannot be stopped during the plastic extrusion process, even after the heating power is cut off, it cannot be maintained for a long time. The temperature needs to increase the heat dissipation so that the barrel can be cooled down to maintain the heat balance during the extrusion process. The airframe cooling is carried out in sections, mainly fan cooling, which takes into account the different functions of each section of the airframe. Pay special attention to the use of cooling in the homogenization section. Product cooling is an important measure to ensure product geometry and internal structure. After the plastic extrusion layer leaves the machine head, it needs to be cooled immediately, otherwise, it will deform due to gravity. It can more accurately control the processing and production of multilayer plastic products, accurately control the wall thickness of each layer of the parison and the degree of adhesion between each layer, and ensure the quality of multilayer products.

Hollow plastic barrel products have special requirements for strength, that is, the wall thickness of the product is specified. The plastic barrel blow molding machine used in the early days does not have a parison wall thickness control system, in order to make the thin part of the product meet the requirements of small wall thickness, It is necessary to thicken other parts of the product correspondingly, which makes it difficult to cut with scissors. The parison wall thickness control system uses a closed-loop feedback design, which mainly consists of a wall thickness controller, an electro-hydraulic servo valve, an action actuator, and an electronic ruler as a signal feedback device. The user can set the axial change curve of the parison wall thickness through the wall thickness controller panel. The controller will output the voltage or current signal of the size change to the electro-hydraulic servo valve according to the curve, and then the hydraulic servo of the electric blow molding machine The valve drives the actuator to control the mold core to move up and down to form the change of the mold core gap. The electronic ruler obtains the corresponding voltage signal through the measurement of the gap size, and then feeds it back to the wall thickness controller, thus forming a closed-loop wall thickness control system.

The above content is the reason and solution for the plastic barrel blow molding machine’s scissors not cutting.

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