Special Manipulator For Injection Molding Machine Based On PLC Control

OFweekrobotNetwork News: At present, the popular special manipulators for injection molding machines in the market are the minimum control systems composed of special microprocessors and interfaces. In terms of mechanical structure, when the positioning accuracy requirement is not high, the time-gauge belt drive is adopted, and the walking part is equipped with a sliding line guide rail, which is controlled by a frequency conversion governor. In this paper, a special manipulator for injection molding machine based on PLC control is proposed, which makes full use of the characteristics of PLC flexible control. The walking part is equipped with sliding line guide rail, and adopts helical gear rack transmission and variable frequency speed control. It is a cost-effective electromechanical integration equipment. This paper makes a more complete discussion on the machine from the mechanical structure and electrical control.

 1 Introduction

In plastic products, the products are classified according to their different processing methods, which can be divided into four categories. One is injection molding products; the second is blow molding products; the third is extrusion molding products; the fourth is calendering molding products. Among them, the most widely used, the most varieties and the highest precision are injection molded products, ranging from pots and bowls and children's toys in daily necessities to parts and components in precision industrial equipment. With the continuous emergence of various new polymer materials, many metal parts are also gradually replaced by these new materials. In order to meet the requirements of automatic production of injection molding products and to ensure the high quality and high efficiency of products, manual intervention must be minimized. Based on the above ideas, many injection molding machine manufacturers include the device of special manipulator for injection molding machine in the scope of customer-assisted selection.

However, for the original injection machines, most of them do not have this device. Therefore, the development of a special auxiliary manipulator suitable for injection molding machines has become an important means and an inevitable choice to enhance the competitiveness of manufacturers' products.

 2 Industry status

Various types of manipulators are essential and important equipment in automatic production. Especially in dangerous situations, in an environment that seriously threatens people's safety and health, it is of great significance to use manipulators instead of people.

the plastic industry in the Pearl River Delta region is very developed and occupies a leading position in China. The Pearl River Delta is also known as the world's factory in the world. At present, most of the special manipulators for injection machines used in this industry are produced in Taiwan, such as the Jinli brand manipulators produced by Taiwan Jinli Company and the special manipulators for "Weideke" W255 series injection machines produced by Taiwan Weideke International Co., Ltd., etc.

analyzing the structure of this kind of manipulator, its electrical control system generally adopts microcomputer minimum system or single chip microcomputer system, and the manipulator drive part adopts pneumatic drive, variable frequency speed control drive and servo drive. In terms of mechanical structure, sliding wire guide rail structure is used with timing belt transmission, or ball gear rack structure is used with sliding wire guide rail. The overall design idea is to use mature control technology and mechanical parts and mechanisms as much as possible.

3 Special Manipulator for Injection Molding Machine Based on PLC Control

the above-mentioned special manipulator for injection molding machine, as far as the manipulator manufacturer is concerned, the price is relatively high because it is a special auxiliary equipment, especially for the equipment transformation of the original injection molding machine, which seems to be "more than the gain" economically. The so-called "high-performance price ratio" special manipulator for injection molding machines has become an important choice and biggest demand for all injection molding manufacturers to improve product quality by using the original injection molding machine equipment.

  3.1 PLC-centered Control System

PLC is a new type of industrial automatic control device developed by taking microprocessor as the core and integrating computer technology, automatic control technology and communication technology. Its biggest feature is small size, strong function, fast response speed and high reliability. The control processes are all programmed in a ladder diagram. It can be randomly modified at any time according to different requirements of the production process, and it is also scalable. Now, because PLC is specialized in research and development and mass production by the world's famous electrical control equipment manufacturers, the price is cheap due to the low production cost. With the acceleration of the process of global economic integration, market competition has led to room for further price reductions, providing favorable conditions for the widespread adoption of such control systems in various industries. The schematic diagram of its control system is shown in Figure 1.

Figure 1PLC control system block diagram

the man-machine interface in the figure also adopts the 5.7 "monochrome touch screen" which is very familiar in technology and technology. It adopts a hand-held structure and is easy to learn through a dialogue operation interface in full Chinese mode. The built-in program can be used in combination at will, and can automatically monitor and record faults. The motion parameters of the three coordinate axes and the parameters of the horizontal axis frequency converter can be modified at any time to meet the product process requirements. PLC through reading the injection molding machine opening and closing signal and thimble signal, through the program to ensure the manipulator and injection molding machine work safety coordination.

3.2 mechatronic mechanical transmission mode

in today's era of faster and faster technological updates, whoever keeps up with the pace of technological development will be able to gain market. At present, all the popular special manipulators for injection molding machines in the market are designed according to the above ideas. This paper extends the above idea into a design pattern: building block structure. The relatively independent components in the system are configured with the highest performance-price ratio on the premise of meeting the system process requirements. According to the structure of this system, the horizontal axis is equipped with a frequency converter motor.reducerdrive; the upper and lower shafts and the pull-out shafts are driven by cylinders. Imported high-rigidity linear slide rails are used on the horizontal, pulling, and up and down walking mechanisms. The upper and lower shafts and the pull-out shaft assembly supports are all made of commercially available high-rigid aluminum alloy profiles, and the horizontal shafts are driven by helical gears and racks. To sum up, the cost-effective mechanical configuration and the cost-effective control system have given birth to a special manipulator for injection molding machines with great market competitiveness.

According to the above design ideas, taking OMRON's CPM2AE as an example, this model is a PLC specially designed for Chinese customers and has extremely high cost performance. The author takes this as the core, is equipped with a touch screen and LG frequency converter, and is supplemented by the above-mentioned mechanical transmission components, which constitutes the hardware part of the special manipulator for injection molding machines. The software programming is written in a ladder diagram language familiar to application engineers. I believe it is not difficult. The special manipulator for injection molding machine has been applied to production. The cost is nearly 20,000 yuan lower than that of similar machines on the market.

  4 Concluding remarks

practice has proved that by using very mature PLC technology, frequency converter speed regulation technology and very mature and advanced mechanical transmission components and adopting building block architecture, application engineers can quickly design and manufacture urgently needed mechatronics equipment for enterprises. It has become a powerful weapon in equipment transformation and upgrading, improving product quality and participating in market competition.

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Created on:2022-08-24