I. Project Background
A vacuum forming machine, also known as a plastic thermoforming machine, is a machine that uses heated and plasticized thermoplastic plastic rolls such as PVC, PE, PP, PET, and HIPS to form various shapes of high-end packaging boxes, frames, and other products.
II. Customer Needs
At a machinery factory in Wenzhou, Zhejiang, the customer's plastic thermoforming machine integrates functions such as punching, cutting, and stacking discharge, thus creating a higher demand for high-speed and automated production. Therefore, INVT proposed a solution of touch screen + AX70 series programmable controller + DA200 servo motor. The PLC controls the servo drive motor through the CanOpen bus to achieve smooth operation, low noise, and high efficiency.
III. INVT Solutions
Process Flow
The overall process flow of the equipment is as follows:
Heating station: Composed of upper and lower electric furnaces, with Modbus communication-controlled temperature controller and PID temperature control to achieve high-precision heating.
Molding station: Servo-controlled upper and lower guide plates and stretching plates, together with air blowing valve, vacuum valve and back blowing valve, play the role of plastic molding, which is the core part of the machine.
Punching station: Servo-controlled upper and lower punching guides, in conjunction with a waste discharge valve, are used for punching and removing punching waste.
Cutting station: Servo-controlled upper and lower cutting guides and cutters, which are used to cut corners and separate waste materials.
Stacking station: Servo control of five mechanical parts, including pushing, clamping, up and down, forward and backward, and rotation, to achieve four different ways of stacking and conveying finished products.
Invt solution
Based on control requirements, motor response speed, and operating efficiency, the INVT AX70 series programmable controller was selected. Its CANOpen bus-based servo control facilitates equipment operation, making on-site installation and commissioning convenient for customers. Because Modebus TCP communication offers advantages such as high-speed communication and ease of wiring, a touchscreen with a TCP network port was chosen.
Figure 1 System Topology Diagram
IV. Customer Value
1. High-speed production and efficiency improvement
Previously, multi-station thermoforming machines had a maximum capacity of about 32 times per minute for a certain material and mold. Now, the time for each step is divided and calculated within a forming cycle, the connection between forming and sheet conveying is optimized, the step connection is maximized to improve efficiency, the heating temperature is increased and the heating time is reduced. Under the premise of qualified finished products, it can now reach more than 45 times per minute.
2. Automatic adjustment of workstations
The station distance can be automatically adjusted for different sheet lengths. After inputting the actual sheet length or reading the sheet length using the recipe function, the system will automatically calculate the distance interval of each station, ensuring that the mold and cutter positions match and the stacking stations are accurately aligned without fine-tuning.
3. Fast bus control response speed
This solution uses bus control, which greatly improves response speed and simplifies wiring compared to traditional communication methods, making it more convenient for customers.
4. The touchscreen recipe function is easy to operate.
The touchscreen program is powerful, with a simple and easy-to-understand interface similar to WeChat, making it easy to operate. The recipe function is convenient to call up, and recipe data can be imported and exported, simplifying the workload. The molding parameter settings have a timeline navigation chart to avoid collisions caused by improper time settings.
