In injection molding work, everyone often encounters confusion that mold suddenly cannot be opened after mold is locked. Author combines our own daily maintenance work notes, analyzes and summarizes possible factors of failure to mold opening from setting of process parameters, circuit, oil circuit and mechanical part. I would like to share with you here, if there are any deficiencies, I hope that everyone will correct criticism.

 

1) After new mold change, setting of mold opening parameters is unreasonable. Mold opening position is too small, fault manifests itself that mold can be opened after mold switch is manually turned on, and semi-automatic/automatic mode cannot be normally opened.

Reset first position of mold opening
2) Especially mold products with thin wall and large projection area. Some technicians have insufficient experience. When production is started, injection pressure and position parameters are set unreasonably. One shot is done to the end, injection is too full (upward mold), and a vacuum is formed in the mold. It can't be opened anyway.

Heat mold (mold cooling water path is changed to mold temperature machine), and temperature is as high as possible. Then press mold first and try to open mold again.
3) In order not to let product have flash, cloak, clamping high pressure setting is too high, and mold is locked too dead. Or long-time high-pressure mold-stop, resulting in no mold opening.

Develop good work habits, high pressure is up to 80% of designed maximum pressure. When machine is shut down, mold does not allow high-pressure clamping.

1) There is no open signal output on computer, and computer control board is damaged.

Replace control board.
2) Check mold opening position. If mold opening position is displayed as set value, mold can be locked. When mold cannot be opened, unlocking mold electronic ruler is faulty.

Electronic ruler is damaged and replaced, electronic ruler is disconnected, or electronic ruler fixing screw is loosely displaced and re-repaired.
3) VCA electronic board insurance, triode; i0 board output point and power transistor damage, no DC24v voltage output.

Replace insurance or change iO board
4) Unlocking mold valve coil plug, wiring is damaged, there is no DC24v.

Check plug, signal cable, and replace it with damage.
5) Valve coil is burnt out and resistance is abnormal. Generally, resistance is about 20 ohms.

Replace coil.

1) Mold opening valve is stuck, blocked, and spool cannot move.

Clean oil spool or replace it with a new one.
2) Oil seal in clamping cylinder is aging and damaged, causing leakage and insufficient mold opening force.

Replace oil seal.
3) Hydraulic oil will not be replaced for a long time, use will be discolored, aging, oil viscosity will be reduced, and internal leakage occurs at the gap of seal.

Replace with new oil.
4) Rapid lock valve is stuck. In the performance of fault, only mold can be locked, and mold cannot be opened. In particular, after someone has pressed spool after fault occurs, observe return of spool.

Cleaning express lock spool

 

(Because of mechanical clamping device wear, especially elbow, cross, hinge pin wears, causing mold to be unbalanced)

1) Loosen high pressure termination switch, first press mold lock to move, then press mold open to un-move. It can be determined that clamping piston rod and piston are removed. Remove mold cylinder, tighten piston rod and piston, reinforce.
2) Tap middle end of long hinge with a sledgehammer or a copper rod while opening mold.
3) If above tapping still cannot be opened, finally remove all Corinthian platen screws, loosen large nuts, and try again.
4) With help of jack, open mold at the center of cross.
5) Adjust end of mold clamping to 0, slow mold opening is also adjusted to O, rapid mold opening pressure speed is adjusted to the maximum, position is adjusted to 10-20 mm, and maximum system pressure is adjusted on iO board (commonly known as system pressure) ), try to open mold.
6) Adjust pressure of platform back to the maximum on the computer and return platform to the end. One person presses back button of seat, and the other person presses mold spool first with a small screwdriver, and then presses mold opening. After opening mold, quickly release spool button. More than 90% of open mold failures can be solved. However, it is necessary to only remember that the two people should be skilled; also change position of slow speed of mold opening according to method of 5). Otherwise, it is easy to damage electronic scale due to too much inertia of mold opening force.
7) Loosen piston fastening nut at the center of cross for two or three turns and open it with mold opening inertia.
8) Repair and replace worn elbows, copper sleeves, crosses, and hinges. Equipment active joint lubrication focuses on routine maintenance and can not be used for lack of lubrication.

When robot is connected to injection molding machine and mold is interlocked, if robot cannot return to original position of object due to a certain action failure, injection molding machine cannot open mold because mold opening time is too long.

Troubleshoot robot, reset it, and return to origin.