The concept of achieving automated process control in a HPHT Hydraulic Cubic Press is proposed to adapt to the rapid development of large-tonnage presses, improve the quality grade of synthetic diamond, and fully leverage the performance and advantages of industrial computers. Currently, the control systems for HPHT Hydraulic Cubic Presses still rely on manual experience to adjust the synthesis process, making human factors a primary reason affecting synthesis quality, and control precision remains relatively low.
Here is a detailed explanation of how to achieve automated process control:
1. Selection and Configuration of Industrial Control Computer
    To achieve automated process control, it is necessary to increase multiple analog input and output controls and introduce a large amount of data calculation, processing, and judgment.
    Industrial PCs are superior to PLC programmable controllers because they can use software platforms like DOS and Windows, offer various control program development software, and provide flexible and diverse programming methods.
    Industrial PCs can easily implement these complex control contents and apply advanced control methods such as self-learning control, adaptive control, and self-optimizing intelligent control.
2. Introduction of Other Characterization Parameters, Improvement of Control Accuracy, and Establishment of an Automated Process Control Model
    Currently, the control parameters for the synthesis process on presses usually only include pressure parameters and power adjustment parameters.
    To achieve automated process control, it is essential to introduce other characterization parameters to enable automatic adjustment of pressure and power parameters.
    Key parameters to be introduced include:
        Six-cylinder compression displacement: If the compression displacement of the six cylinders is introduced as a condition participating in the control of the synthesis process, it will require a higher control precision for the hydraulic system, with detection and control of six-cylinder displacement needing to reach micron-level accuracy. Since the single ram compression stroke of a HPHT Hydraulic Cubic Press is one-third of that of a two-ram press, its displacement control precision may need to be higher than that of a two-ram press.
        Electric heating system parameters: The control precision of the electric heating system should be less than 0.5% (five per thousand). It is advisable to appropriately increase the current and voltage detection points of the electric heating system as part of the automated process control conditions to achieve more precise and detailed control.
    Establishment of an automated process control model: During the synthesis process, the action of synthesis pressure and heating power on the synthetic block will inevitably cause changes in compression displacement, heating voltage, heating current parameters, and other characterization quantities. These parameter and characterization quantity changes can be used as control bases to establish an automated process control model, and control software can be programmed according to this model.
    Addressing assembly errors: Raw materials forming the synthetic block can still have assembly errors within permissible quality ranges, affecting the consistency and stability of synthesis quality. An automated control system can automatically minimize the impact of assembly errors on synthesis.
• 3. Path and Difficulties in Achieving Automated Process Control
    The true difficulty in achieving automated process control lies in establishing an automated control model based on the performance characteristics of the HPHT Hydraulic Cubic Press and the detectable and given characterization parameters during the synthesis process, such as pressure, voltage, current, six-cylinder displacement, and other parameters.
    This process is described as solving a multivariate equation system where each variable is an unknown.
    Establishing the automated control model requires a thorough understanding of the synthesis process, extensive practical experience accumulation, and the ability to distinguish true from false to identify the relationship between key variables and characterization parameters with synthesis pressure and heating power, using scientific methods to build the model.
    Once the control model is established, programming software to achieve automated process control becomes relatively much easier.
    This is a gradual process that should follow a "simple to complex, low-level to high-level" development approach. After initial establishment and implementation, the model needs to be further refined in experimental production, and control content gradually expanded to ultimately achieve practical and perfect results.
By implementing automated process control, the performance of the HPHT Hydraulic Cubic Press will be significantly improved, promoting the advancement and development of industrial technology and equipment. Although the cost of the control system will increase due to hardware configuration (host, peripheral boards, functional components), software development, and extensive testing expenses, the yield and crystal grade of synthetic products will improve once the press achieves automated process control. This will lead to better economic benefits for enterprises, thus giving automated process control HPHT Hydraulic Cubic Press systems their due value positioning.