The hydraulic press is a type of machinery widely used in industrial production, whose main function is to perform stamping, shaping, and stretching processes on workpieces through liquid pressure. In the actual operation process, the setting of holding time is one of the important factors affecting product quality and equipment efficiency. Reasonably setting the holding time can not only improve the molding quality of the product but also extend the service life of the equipment and enhance production efficiency.



What is holding time?



The holding time refers to the process of maintaining a certain pressure for a certain period of time after the hydraulic press has completed the pressure application. Its main purpose is to allow the material to flow and fill the mold fully under high pressure, ensuring that the product has a dense internal structure and complete shape, and avoiding defects such as bubbles, cracks, and dimensional deviations caused by premature release of pressure.



2. Importance of holding time



1. Improve product quality: appropriate holding time can ensure that the material is completely filled into the mold cavity, reducing internal defects in the product, thereby improving the compactness and consistency of the product.

2. Enhance molding effect: for parts that require high precision molding, the holding process helps the material to plastic deform under high pressure, achieving better molding quality.

3. Reduce scrap rate: insufficient holding time can easily lead to deformation or cracking of the product when it is demolded, while a reasonable holding time can significantly reduce the scrap rate.

4. Extend equipment life: scientifically setting holding parameters helps to reduce the impact on the hydraulic system, extending the service life of key components such as cylinders, pumps, and valves.



3. How to set the holding time?



# 1. Set according to material characteristics



Different materials have different fluidity, curing speed, and plastic deformation capacity, so the holding time should also be different. For example:



- Metal materials (such as stamping, forging): generally, the holding time is a few seconds to ten or more seconds;

- Plastic or composite materials: due to their longer curing time, they usually require tens of seconds or even minutes;

- Powder metallurgy: to ensure full compaction, the holding time may be longer.



# 2. Set according to product structure



The complexity of the product structure directly affects the time required for the material to fill the mold. The more complex the structure, the longer the required holding time; conversely, it can be appropriately shortened.



# 3. Adjust according to mold temperature and ambient temperature



When the mold temperature is high, the material is more easily flowing, shortening the filling time; while in a low-temperature environment, the material fluidity is poor, and the holding time should be appropriately extended.



# 4. Reference process parameters and experience data



Most hydraulic presses are equipped with PLC control systems, which can set holding time and pressure curves through programming. Enterprises should optimize and adjust according to historical process parameters, product trial molding data, and operating experience, and conduct small-scale trial production verification.



4. Common problems and solutions



- Holding time too short: the product is not fully formed, and it is easy to appear problems such as shrinkage, air holes, and dimensional deviation;

- Holding time too long: increases the production cycle, affects efficiency, and may cause problems such as material overheating and mold wear;

- Solutions:

- Continuously adjust and optimize through trial molding;

- Use sensors to monitor pressure changes and achieve automatic holding pressure;

- Introduce an automatic control system to adjust the holding parameters in real time.



Conclusion



In summary, the setting of the hydraulic press holding time is a technical link that requires comprehensive consideration of various factors. Reasonably setting the holding time can not only improve product quality and consistency but also effectively enhance production efficiency and the stability of equipment operation. With the continuous improvement of industrial automation levels, the control of hydraulic press holding time will tend to be more intelligent and precise, providing more efficient and reliable solutions for modern manufacturing industries.