Adjust injection molding machine tie bar need by heating, mechanical adjustment and sensor feedback 4 main steps.
We will talk about how to adjust tie bar for injection molding machine from below 4 main parts:
- Preparation work before adjusting the tie bar
- Specific steps for adjusting the tie bar
- Common tie bar faults and adjustment measures
- Preventive maintenance recommendations
The tie bar are rod-shaped components installed on the injection molding machine.
It’s principle is to balance the sliding of the template, to withstand the tension brought about by the clamping mold. It is a crucial component of the injection molding machine industry. In the clamping mechanism, the performance of the tie bar directly affects the rigidity and stability of the system. Moreover, it will improve the structural characteristics of the Column, in order to effectively improve the rigidity and stability of the system.
Preparation work before adjusting the tie bar
This has 4 steps as following
Cleaning and Inspection
- Remove oil stains, rust, and foreign objects from the threads, nuts, and contact surfaces of the pull rod.
- Check the integrity of the threads, repair scratched or deformed threads, and ensure smooth thread engagement.
- Verify the compatibility between the pull rod and nut to avoid mixing parts from different batches.
Lubrication treatment
Apply nickel based anti bite compound evenly on the threads and contact surfaces to reduce friction and sticking.
Equipment calibration
- Check the calibration status of hydraulic systems (such as jacks and oil pumps) to ensure accurate readings on the oil gauge.
- Prepare strain gauges or pressure sensors for real-time monitoring of the force on the tension rod.
Parameter calculation
Obtain parameters for example (Haichen 360ton injection molding machine parameter)such as tie bar diameter based on the machine model, and calculate the theoretical elongation and tension values.
Haichen injection-molding machine tie bar parameter
Specific steps for adjusting the tie bar
It basically has below 3 steps:
Stepwise tensioning with torque cycling
- Initial pre tensioning: Use a hydraulic jack to apply tension in stages, and tighten the nut after each tensioning.
- Multi cycle tightening: Perform 4 torque cycles
- The first two cycles: gradually narrowing the template to avoid overload
- Third cycle: Ensure that the seal is in place
- Fourth cycle: evenly distribute the load of the four tension rods
Closed loop feedback control
- Real time monitoring of the stress of each tension rod through strain gauges, and servo motor driven gear adjustment of the front nut position to achieve dynamic balance.
- Compare the measured stress with the design value (such as reducing the maximum stress of the unloading groove by 52% after optimization), and adjust it within the error range.
Symmetry and uniformity verification
- The consistency of measuring the elongation of the tie rod should have a deviation of less than 5% (refer to the bridge tie rod construction standard)
- Check the parallelism of the four pull rods after mold installation (tolerance ± 0.05mm/m).
Common tie bar faults and adjustment measures
Tie bar fracture
Reason: The rounded corner at the root of the thread is too small, the unloading groove design is unreasonable, and non-metallic inclusions accumulate.
Solution: Optimize the thread root rolling process and use elastic nuts to reduce stress concentration.
Deformation caused by unbalanced load
Reason: Template deformation transmits additional bending moment.
Solution: Optimize the unloading slot parameters through finite element analysis to ensure uniform stress distribution.
Thread biting
Reason: Insufficient lubrication or foreign object jamming.
solution: Thoroughly clean and reapply anti bite compound.
Preventive maintenance recommendations
- Regular inspection: Check the surface cracks (magnetic particle inspection), thread wear, and elongation of the pull rod every quarter.
- Load monitoring: Install an online stress monitoring system to provide real-time warning of abnormal loads.
- Design optimization: Based on the finite element analysis results, improve the design of the unloading groove and thread profile.
Regularly check the wear of the connecting rod and its connecting parts, and perform necessary maintenance.
If the connecting rod finds to be obviously worn or damaged, you should replace tie bar in time to prevent failure during production.
Thus through the above steps and precautions, these injection molding machine tie bar can be effectively adjusted. That can ensure the correct clamping of the mold and high-quality molding effect.
