Injection Molding Machine Safety Mechanism Maintenance Guidelines

Electrical Safety Protection mechanism

The front and rear safety doors of the injection molding machine are equipped with limit switches for protection. Before injection starts, the safety doors must be closed. Typically, the rear door remains closed permanently, while the front door has two interlocked limit switches. Injection can only begin after the rear door is closed, the front door's front limit switch is engaged, and its rear limit switch is released. Daily checks and maintenance should be performed by injection molding operators and specialized maintenance personnel, with regular safety inspections conducted by mechanics. Key maintenance points are as follows:

① Check if the front and rear door pulleys are functioning normally. Look for derailment or fallen pulleys.
② Ensure the pulleys operate smoothly, the spacing is appropriate, and the bearings are in good condition.
③ Inspect the door frame for cracked welds, detachment, or other damage.
④ Verify that the door brackets are secure, screws are tight, and protective frames are undamaged.
⑤ Confirm the limit switches are reliable, with no loosening, broken wires, short circuits, or open circuits. When replacing a limit switch, note that the front and rear switch wiring differs: the front switch engages when pressed, while the rear switch engages when released. Injection can only proceed after the doors are securely closed.

Mechanical Safety Protection mechanism

The mechanical safety mechanism, located above the safety door, serves as a fail-safe to prevent injury in case of mechanical or electrical failure. Key maintenance points include:

① Check if the base of the mechanical safety mechanism is secure, with no detached welds or loosening.
② Ensure the safety bar is not loose and its mounting bracket is firm.
③ Verify that the safety block operates flexibly, reliably, and is securely fixed.
④ Confirm the spacing of the safety bars is appropriate. This is generally set based on the molded product—e.g., a 120mm gap for box-shaped products.
⑤ Inspect the rear safety cover mesh for integrity and damage.