Drip plastic technology is the use of thermoplastic polymer materials with variable state characteristics, that is, under certain conditions have viscous flow, and can be restored to solid state at room temperature, and the use of appropriate methods and special tools ink-jet, in its viscous flow state according to the requirements of the shape of the design, and then solidified at room temperature. Drip plastic process has been widely used in a variety of trademark nameplates, cards, daily hardware products, travel commemorative badges, exquisite crafts and senior book cover decoration. STEP operation control relies on numerical control processing technology, the manual dispensing process of plastic drop process is changed to the automatic dispensing machine, greatly improving the efficiency of production.

Key words: drop plastic; Curing molding; Numerical control machining; STEP; Motor control; Servo system

The dropper adopts gantry type design, which is mainly composed of bed, operation and control system, X/Y/Z three-axis motion system (servo system drives ball screw drive), feeding module and dispensing module.

Figure 1. Drip molding machine

Operation and control system mainly provides G code map processing, motion trajectory planning, dispensing valve plastic drop process control, HMI handheld touch control and button control graphic processing flow.

The AC servo system of X/Y/Z three-axis motion system receives the command information from the control system, and after power amplification and shaping processing, it is converted into the linear displacement motion of the executing parts of the drip molding machine. Its performance will directly affect the technical indicators such as the precision and speed of the drip molding machine. It is required to have good rapid response performance and accurately and sensitively track the digital command signal issued by the controller. And can faithfully execute the instructions from the upper controller, improve the dynamic following characteristics and static tracking accuracy of the system.

The drip molding machine relies on X/Y/Z three-axis motion system to reach the PVC paste dispensing needle to the specified position of the drip plastic mold, and controls the amount of dispensing by controlling the time of extrusion resin and the speed of needle movement, so as to achieve a certain dispensing effect.

The relevant operation process is as follows:

Figure 2 Starting process of drip molding machine

STEP operation control drip molding machine system is mainly composed of motion controller, servo driver, servo motor, HMI, expansion IO, etc.

The system topology is as follows:

FIG. 3 STEP Topology of drip plastic scheme of operation control

The control core of this scheme is composed of AMC1600 motion controller and Sigriner Ω6s-APR series pulse AC servo system. This scheme supports G code track mapping processing, supports 18-way dispensing valve drop plastic process, and 36 processes of external buttons control fast switching processing.

The system configuration list is shown in Table 1:

Table 1 System configuration

STEP operation control plastic machine program application advantages are as follows:

(1) More dispensing valve control, supporting a maximum of 18 dispensing valves, to complete the multi-formula function, the maximum support of 36 groups of product processing.

(2) Add the upper computer to set parameters of networked devices online and upload or download files, and support the upper computer to collect operating data of devices.

Figure 4 Debugging interface of upper computer

(3) Support handheld touch screen adjustment and full button operation, processing G code and parameters support U disk import and export. Maximize the convenience of the operator debugging.

Figure 5 HMI control interface

(4) Larger parsing cache support, a single processing file maximum 30000 lines of G code instruction. (5) Powerful acceleration and speed curve planning of CNC ensures high-speed and stable operation of the equipment, improving the efficiency by 8%-10% compared with traditional models.

Figure 6 CNC speed planning

(6) After long-term testing and summary, Sigriner customizes a set of servo system parameters matching plastic molding process. The newly developed automatic setting function of Ω6s-ARR servo series saves 90% of equipment debugging time. Processing results as shown in the figure below, to meet the customer's ideal demand.

FIG. 7 Drip plastic processing  FIG. 8 Finished products

Scheme summary:

STEP operation control Ω6 series AC servo system and AMC1600C motion controller products are serialized products jointly developed by STEP Group Central Research Institute and Sigriner team. The products are widely used in general industrial control occasions. In addition to the application effect of drip plastic machine solution shared by the customer, Also in the industrial robot, engraving machine, laser cutting, packaging and other fields have been a good application effect and consistent user praise.

It can successfully help users solve many problems with complex solutions and high maintenance costs, which reflects the high performance and high reliability of STEP products, and is the value presentation of STEP's insistence on innovation-driven and high-quality development. With motion control as the core, STEP Motion Control Division integrates related interface equipment and provides overall automation control solutions to meet the needs of customers in various industry segments to improve quality, expand production capacity and reduce costs.