Introduce: What causes the instability of the injection molding manipulator?

Common causes of unstable picking of injection molding manipulator

The unstable picking of parts by injection molding manipulator is mainly manifested in the following six reasons: unable to clamp, unstable clamping, product dropping, dislocation, grasping deviation, grasping the ejector pin before returning, unstable placing after picking up the parts, etc., which are generally caused by machinery, air pressure, signal, mold, technology and fixture.

1. Fixture/fixture problems (most common)

Wear and aging of chuck/sucker

Hardening, air leakage and insufficient adsorption force of the sucker; Claw rubber pad is worn and skidded.

Wrong fixture selection

The common gripper for deep cavity, thin wall and special-shaped parts is easy to grasp and deviate; Small suction cups for large-area smooth parts are easy to fall off.

The clamping position is unreasonable

Clamped in the weak position of the glue, the rib position and the front, uneven stress leads to deformation and falling off.

Improper clamping force

If the air pressure is too small, the clamp will not be tight, and if it is too large, the clamp will deform and rebound.

Second, the air pressure/gas path problem

The air pressure is insufficient and fluctuates greatly.

The main air pressure is low, and the suction/clamping force at the moment of snatch is not enough.

Air leakage and blocked throttle valve.

The aging of trachea, loose joint and water accumulation in filter lead to slow movement and weakness.

Abnormal vacuum system (sucker type)

Failure of vacuum generator, insufficient vacuum pressure, and incorrect air-breaking delay lead to unstable suction or failure to release.

Third, the problem of the manipulator itself

Mechanical looseness

The screws of the arm, clamp seat and telescopic shaft are loose, and the operation is shaking and the positioning is not accurate.

Servo/cylinder accuracy drops.

Bad buffer of cylinder, servo out of step and loose belt lead to position drift.

Move too fast

Run wild, pull out, vertical speed is too fast, and inertia causes the product to fall off and catch off.

Incorrect descent depth/position

Grab the position on the high side or low side, and grab it if it is not fully in place.

Fourth, the mold and product problems

Sticking mould, coating glue and sticking slide block.

Poor demoulding, dislocation or falling caused by hard pulling of manipulator.

Ejection instability

The ejector pin is unbalanced, the ejector pin is not in place, the ejector pin is bent, and the product is skewed.

Nozzle/handle interference

The nozzle is not broken, wire drawing, upside down, and the product is pulled, which leads to the failure of picking.

There is residue and oil stain in the mold.

Product placement position is not uniform.

Five, injection molding process problems

Insufficient cooling time

The product is too soft and unshaped, and it will deform and fall off when it is clipped.

Unreasonable pressure holding/firing rate

The size of the product is unstable and deformed, and the inconsistent shape leads to unstable grasping every time.

Unstable mold opening position

The end position of mold opening drifts, and the relative position of manipulator and mold changes.

Six, signal and linkage problems

Wrong signal timing

The thimble is not completely returned to reset, and the manipulator descends ahead of time to grasp the piece.

Detect signal abnormality

The in-mold monitor is not installed/adjusted, and the parts are forcibly taken if there are residual materials and dislocation.

The manipulator and the injection molding machine are not synchronized.

Mold opening is in place, and the picking signal is allowed to be delayed or triggered by mistake.

VII. Environment and Operation

Large workshop vibration and fan blowing lead to light and small products deviation.

Grabbing coordinates were not recalibrated after die changing.

Quick judgment train of thought

Missing parts but accurate position → mostly due to fixture, air pressure and vacuum problems.

Incorrect position, grasping deviation → mostly mechanical looseness, too fast speed and coordinate drift.

Occasionally successful and occasionally failed → mostly unstable ejection, die sticking and signal timing.

All products are unstable → mostly due to air source, main engine parameters and mechanical looseness.