The control system of the HPHT Hydraulic Cubic Press has an extremely important impact on the grade of synthetic diamonds. As industrial technology continuously advances, the demands for diamond grade are also increasing. The development and perfection of the control system are crucial factors for improving diamond quality.
Here is a detailed explanation of how the HPHT Hydraulic Cubic Press control system affects diamond grade:
1. Overcoming Limitations of Traditional Control Systems
Traditional electrical control systems for diamond presses used a logic control circuit composed of a large number of low-voltage electrical appliances, such as intermediate relays, time relays, and contactors. These traditional systems had several limitations that restricted the development of diamond grade to higher levels:
Low Control Precision: The control over pressure and temperature was imprecise.
Outdated Technology: The control effect was undesirable, hindering the development of high-level diamond grades.
Maintenance Issues: They also suffered from a high failure rate and were inconvenient to repair.
The severity of market competition demands that companies rely on advanced automated control systems to improve grade.
2. Achieving Precise Control of Process Parameters
Precise pressure control and temperature control are the two crucial elements that guarantee the accurate implementation of the synthesis process and thus ensure the quality of diamond synthesis. Advanced automated control systems, such as those adopting industrial computers and advanced PID control, have greatly improved the grade of synthetic diamonds.
Temperature Control (Current Control):
HPHT Hydraulic Cubic Presses (like those used at Henan Jinqu Gold Limited Company Super Hard Material Sub-Company) use current control. This is considered the most ideal control method because it directly reflects the heat within the cavity.
The system utilizes closed-loop PID control to effectively and automatically control the heating power.
By controlling the conduction angle ($\alpha$) of the SCR phase shift trigger, the system ensures that the current magnitude strictly follows the preset current curve.
Pressure Control:
Pressure control mainly uses a switch control mode, which involves setting a pressure lower limit and a pressure compensation upper limit.
The system achieves dynamic pressure compensation (dynamic补压) using a small pump. This mechanism ensures the stability of the pressure environment during the diamond generation process to the maximum extent.
Parameter Matching:
The decisive condition for obtaining ideal diamonds is the reasonable matching of temperature (T), pressure (P), and time (t).
Achieving precise control of temperature and pressure through industrial computer automation, alongside research into reasonable T, P, t matching processes, is necessary to meet the stringent requirements for growing high-grade diamonds.
3. Enhancing System Stability and Safety
Advanced control systems increase protection parameters, allowing the press to operate more stably. The system continuously monitors the changes in various parameters during operation.
Protection Parameters: Industrial computer control systems can set numerous absolute protection parameters (e.g., maximum pressure protection, maximum current protection) and relative protection parameters (e.g., pressure sudden change protection, voltage sudden change protection, current sudden change protection).
Stable Operation: When a parameter exceeds the set protection value, the system can promptly trigger an alarm and stop the machine. This stability reduces the occurrence of accidents and has a highly important impact on diamond grade. The alarm system also helps avoid carbide anvil consumption caused by equipment faults (like SCR breakdown, burnout, or hydraulic issues).