What should be paid attention to when installing and debugging the fixture of injection molding manipulator?

The installation and debugging of the fixture of injection molding manipulator directly affects the efficiency of taking parts, product quality and equipment safety, and the principles of "accurate positioning, stable clamping, safe linkage and adaptive technology" should be followed. The specific precautions are as follows:

A, preparation and selection check before installation

Matching verification of fixture, manipulator and mold

Confirm that the size of fixture installation interface is consistent with the end flange of manipulator (such as bolt hole spacing and positioning pin specification) to avoid dislocation after installation;

Check the fixture stroke, clamping force and product adaptation: pneumatic finger gripper is selected for small/thin-walled parts (with adjustable clamping force to prevent clamping injury), vacuum sucker fixture is selected for large/heavy parts (with uniform stress), and special-shaped parts need to be matched with customized copying fixture;

Check the interference area between the fixture and the mold: simulate the picking path of the manipulator to ensure that the fixture does not collide with the mold cavity, guide post, ejector pin and other parts when opening and closing.

Preparation of tooling and accessories

Prepare special installation tools (torque wrenches and Allen wrenches). The bolts shall be made of high-strength carbon steel/stainless steel and tightened with specified torque to prevent loosening during operation.

Vacuum fixture needs to check whether the suction cup material (silica gel suction cup is suitable for smooth plastic parts, sponge suction cup is suitable for rough surface) and the negative pressure value of vacuum generator are up to standard;

Pneumatic fixture should be equipped with pressure regulating valve and throttle valve to adjust air pressure and opening and closing speed, and magnetic switch should be installed to detect the opening and closing signal of fixture.

Second, the key points in the installation process

Precise positioning and fixing

The flange at the end of the manipulator should be closely attached to the connecting plate of the fixture without gap, and the positioning pin should be completely inserted into the positioning hole to prevent the fixture from rotating and deviating;

After installation, use a dial indicator to detect the parallelism and verticality of the fixture, and the error should be controlled within 0.1mm to avoid the product from being skewed and falling when taking the parts;

Long-stroke fixture needs to be equipped with supporting or guiding structure to prevent the cantilever end from sagging and deformation, which will affect the positioning accuracy.

Specification for gas path/circuit connection

Pressure-resistant gas pipe should be used for gas path connection, and raw material belt should be wound at the joint or sealing ring should be installed to avoid air leakage; Vacuum pipeline needs to be equipped with a filter to prevent plastic debris from blocking the suction cup;

The wiring of the circuit needs to distinguish between the signal line and the power line, and the wiring of the magnetic switch and the sensor needs to correspond to the manipulator control system to ensure accurate signal feedback (such as the signal of "the gripper is closed in place" and "the suction cup vacuum reaches the standard");

After wiring, arrange the wiring and fix it with tie straps to avoid the pipeline/cable from winding the motion shaft of the manipulator or being damaged by high-temperature baking of the mold.

Third, the core operation in the debugging stage

No-load debugging: safety before movement

Before debugging, turn off the clamping signal of the injection molding machine, only start the single-axis movement of the manipulator, and test whether the opening and closing action of the fixture is smooth, without jamming or abnormal sound;

Adjust the opening and closing speed and stroke of the fixture: control the opening and closing speed of the pneumatic gripper through the throttle valve to avoid the impact deformation of the gripper caused by too fast speed; The clamping stroke is limited by the limit screw to ensure the same clamping position every time;

Test the negative pressure stability of the vacuum fixture: start the vacuum generator, use a negative pressure meter to detect the negative pressure value of the suction cup (usually ≥-0.06MPa), and observe the negative pressure holding time after turning off the gas source to prevent the product from falling during the transfer.

Debugging with material: matching injection molding process parameters.

For the first time, it is necessary to manually operate the manipulator and run at a low speed, so as to confirm that the stress point of clamping the product by the fixture is reasonable: the clamping claw should clamp the non-appearance surface and non-thin-walled area of the product, and the vacuum sucker should cover more than 60% of the effective adsorption area of the product;

Adjust the picking time of the manipulator: it needs to be linked with the opening stroke of the injection molding machine. After the mold is completely opened and the product ejected by the ejector pin is stable, the fixture will go down to take the part to avoid scratching the product by taking the part too early;

Test the stability of product transfer: simulate the whole process of product transfer to conveyor belt/material box by manipulator, check whether the product slips or deforms, and adjust the clamping force of fixture or the number of suction cups if necessary.

Commissioning of linkage signal (core safety link)

Set interlock protection signal: Only when the fixture is clamped in place (the vacuum reaches the standard/the gripper is closed), the manipulator can rise and move; Only when the manipulator completely withdraws from the mold area can the injection molding machine close the mold to prevent the manipulator from being crushed by the mold;

Debugging abnormal alarm mechanism: when the fixture fails to clamp (such as lack of vacuum and the gripper is not in place), the system needs to stop immediately and give an alarm to prevent defective products from flowing into the next process, or the manipulator collides with the mold in idle operation;

Test the emergency stop function: after pressing the emergency stop button, the manipulator and fixture should stop moving immediately to prevent accidents.

Fourth, trial production and optimization adjustment

Batch trial production verification

Continuously produce 50~100 molds, and check whether there are clamping marks and scratches on the surface of the product. If there are, it is necessary to reduce the clamping force or replace the soft fixture accessories (such as adding rubber pads);

Count the success rate of picking, if the product falls, it is necessary to investigate the vacuum leakage, insufficient gripper stroke or deviation of picking path;

Monitor the operation noise and temperature of the fixture. If the abnormal sound of the pneumatic gripper is serious, check whether the cylinder is worn and replace the sealing ring in time.

Parameter curing and recording

After the debugging is qualified, the parameters such as the pressure value of the fixture, the opening and closing stroke, the movement speed of the manipulator and so on are recorded and stored in the manipulator control system to avoid the loss of parameters caused by misoperation;

Make a fixture check list, and specify the routine maintenance items (such as gas path leak detection, sucker wear inspection and bolt fastening).

V. Matters needing attention in safety and maintenance

During debugging, the operator should wear safety helmet and cut-proof gloves, and it is forbidden to stand or reach out within the motion range of the manipulator to prevent pinch injury;

Avoid the fixture being in the clamping state for a long time, and loosen the clamping jaw when it is idle to prevent the cylinder sealing ring from aging;

Regularly clean the plastic chips and oil stains on the surface of the fixture, and replace the vacuum sucker in time if it cracks and hardens.