Analysis and solution of insufficient mold opening force of injection molding machine


In this article, Qingdao Sainuo pe wax manufacturer takes you to understand the analysis and solution of the insufficient mold opening force of the injection molding machine.

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1. The area of die opening oil pressure ring is too small
Die opening force = die opening oil pressure ring area × Die opening oil pressure
If you want to increase the opening force when the maximum pressure is determined, you can only increase the opening oil pressure ring area by increasing the cylinder diameter or reducing the piston rod diameter.
2. Too small oil clearance during mold opening
In the first stage of mold opening, because the fit clearance between the hydraulic buffer sleeve and the inner hole of the front cover of the oil cylinder is too small, the pressure oil is slow and even difficult to enter the mold opening cavity of the oil cylinder, so the maximum mold opening force cannot be provided. Increase the fit clearance between the hydraulic buffer sleeve and the inner hole of the front cover of the oil cylinder, so that the pressure oil can quickly enter the die opening cavity of the oil cylinder and form a die opening force with a certain impulse, which may have a certain impact during die opening.
3. After high voltage mode locking θ Reverse hinge caused by angle exceeding 90 °
The design of mechanical hinge parameters and the stroke and installation position of die locking cylinder determine the termination position of small hinge during the last high-pressure die locking, and form a θ Angle, designed θ The angle must ensure that the machine installed within the cumulative machining tolerance of each part θ The angle should be absolutely less than 90 ° θ When the angle exceeds 90 °, the small hinge has a reverse hinge. At this time, the opening moment is actually to lean the hook hinge and the long hinge towards the straight line to produce greater mold locking force. Finally, the small opening force is not enough to overcome the deformation force generated by increasing the mold locking force, so the opening moment can not be completed.
4. Excessive mold locking pressure and flow lead to overload of mold locking force, excessive deformation force of machine hinge, and excessive deformation force can not be overcome by mold opening force
After the mechanical hinge of the mechanical hinge machine is designed, the mechanical hinge amplification ratio when it produces the established clamping force to be achieved has also been determined. Therefore, the thrust of the required clamping cylinder can be designed to determine the diameter of the clamping cylinder. The cylinder also needs to ensure sufficient mold opening force. If sufficient mold opening force is required, the larger the cylinder diameter is, the better, However, if the cylinder diameter is too large, the cylinder thrust during mold locking is too large and the mold locking force is overloaded (when the mold adjustment is not good), the deformation force of the mechanical hinge is too large, and the mold opening force cannot overcome the excessive deformation force, resulting in the inability to open the mold.
5. Low die opening pressure and small flow, resulting in small die opening impulse
Due to the low die opening pressure and small flow, the die opening impulse is small, which can not overcome the deformation force of the mechanical hinge. In particular, the flow of the first die opening provided by the servo control system is small, the die opening impulse is smaller, and it is more difficult to open the die. This problem can increase the die opening impulse by modifying the PID and die opening slope of the controller.
6. The temperature rise after mold loading and pressure test leads to difficulty in mold opening
After the mold is installed and pressure tested for a period of time, the mold will heat up and expand, and the mold locking force will increase, resulting in difficult mold opening. Pay attention to timely adjust the cosmetic modulus to make the mold locking force return to the original value and avoid mold opening failure.
7. The shutdown time after mold locking is too long, resulting in failure to open the mold
The shutdown time after mold locking is too long, resulting in the complete disappearance of the lubricating oil film of the machine hinge and the further increase of the deformation of the machine hinge, resulting in the inability to open the mold. Therefore, the shutdown time of mold locking shall be reduced as much as possible. Remember to open the mold before shutdown, and do not shut down when the mold is locked.
8. Die opening back pressure, resulting in insufficient die opening impulse
Setting die opening back pressure in the first section of the oil circuit also leads to insufficient die opening impulse. If this situation is found, the die opening back pressure will be cancelled.
9. The excessive friction resistance in the machine hinge leads to mold opening resistance. The excessive friction resistance of the large pin shaft and steel sleeve in the machine hinge leads to the need for greater mold opening force to overcome its friction resistance:
(1) There is no deburring at the edge of the oil groove in the steel sleeve, which causes the burrs to wear into particles and enter the mating surface of the large pin shaft and the steel sleeve, so that the mating surface is worn or burned. In order to avoid this problem, it is required to deburr and smooth these parts after processing. During installation, check again and clean all surfaces, and then install after applying grease.
(2) If insufficient lubrication or lubrication failure will also lead to excessive friction resistance, check whether each lubricating oil circuit and lubricating pump are normal.
Qingdao Sainuo Chemical Co.,Ltd. We are manufacturer for PE wax, PP wax, OPE wax, EVA wax, PEMA, EBS,Zinc/Calcium Stearate…. Our products have passed the REACH, ROHS, PAHS, FDA testing. Sainuo rest assured wax, welcome your inquiry! Website:https://www.sanowax.com
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