Flexible automatic assembly module of pneumatic cylinder assembly

Introduction

Modern flexible automated assembly production (GASP) is a complex system with a multi-component and hierarchically subordinate structure containing two large components: information and technological, called flexible process complex of assembly production, which includes transport-storage and loading subsystem, which performs functions of storage, transportation, accumulation, loading, unloading, shifting and basing of assembly objects, assembled products, tools and equipment, i.e. organization of all material flows in the system. The peculiarity of automated assembly systems is the number of assembly components included in the manufactured products, for the delivery of which a large number of converging material flows must be organized into the technological zone. The above operations of storage, transportation, accumulation, loading, unloading, shifting and basing in the general set of tasks of automated assembly are characterized by considerable complexity, which is caused by the variety of the assembly processes themselves, the shapes and sizes of the assembly objects, as well as the labor intensity of these operations. The purpose of the operation of transport-storage and loading devices (TNZU) is not only to automate the listed operations, but also to increase the efficiency of using assembly equipment, and therefore the entire assembly system as a whole. Thus, TNZUs are considered effective if they contribute to increasing the productivity of assembly equipment, increase its utilization rate, do not affect the quality of the material objects with which they operate, have a simple design, built in a modular manner and containing standardized parts and assemblies, are convenient and reliable in operation and repair, and are flexible in transfer.

In recent years, work has been widespread in the processes of inspection and assembly, the creation of control and assembly machines and automatic lines for assembly. Automation of these processes allows, first of all, to improve the quality of manufactured products, especially in industries with large production scales (bearings, vacuum instruments, radio elements, etc.). In addition, automation of control and assembly allows to eliminate the resulting imbalance, when more workers are employed in the control and assembly of finished products than in their manufacture.

Therefore, in recent years, automation has increasingly gone beyond the automation of processing processes, covering all parts of the production process, which allows you to solve automation problems in the complex, to increase the efficiency of funds invested in automation.

1. Study the status of the issue and set the design task

1.1 Process Automation Philosophy and Provisions

A key role in accelerating scientific and technological progress belongs to mechanical engineering, the task of which is to ensure a rapid transition in industrial production from individual units of technological equipment to automated complexes (sites, lines and workshops), and in the future to automatic plants. The most important feature of such automated production is their flexibility, which provides for the possibility of easy reconfiguration of equipment for the production of a wide range of products in conditions of labor-saving (deserted) technology.

The creation and wide introduction of flexible automated production is currently determined by the acceleration of the development of machine tools, robotics, computing, microelectronics and instrument making, which are the catalyst for scientific and technological progress. Industrial robots (RVs) are a universal means of automating production processes in conditions of great variety and frequent change of products. In mechanical engineering, PR are effectively used to perform both basic and auxiliary operations for the maintenance of process equipment. From traditional automation tools, PR is distinguished primarily by the versatility and flexibility of redirection to various production functions. Industrial robots are widely used for servicing CNC machines, forge-press and casting machines, warehouse equipment, transportation, assembly and other operations. Together with the main process equipment, accessories and control devices, the PR form various types of robotic complexes.

The main direction of the development of mechanical engineering is to increase the output of products and increase its quality while reducing labor costs. This is ensured by improving existing and introducing new types of equipment and technological processes, means of their mechanization and automation, as well as improving the organization and management of production.

Work on the creation and improvement of automation tools should develop in two directions: the creation of automation tools for the equipment produced and currently operating in order to increase its efficiency; creation of new automated technological complexes, which link the issues of improvement of productivity, reliability, accuracy of works execution, as well as level of automation of operations with necessary and economically justified flexibility for quick re-adjustment in order to adapt to changing production conditions.

The level and methods of automation depend on the type of production, its seriality, equipment.

The efficiency of automation due to the use of robotics can be achieved only with a comprehensive approach to the creation and implementation of industrial robots, processing equipment, controls, auxiliary mechanisms and devices, etc. Only the expanded use of PR in complex robotic systems will be justified technically, economically and socially. Compared to traditional automation tools, the use of industrial robots provides more flexibility in technical and organizational solutions, reducing the time required to complete and launch flexible automated systems. Providing automatic installation and removal of parts on machines with the help of PR allows the worker to service from four to eight metal cutting machines. Thus, industrial robots must be considered as an important factor in ensuring multi-site maintenance, and therefore labor saving. The greatest economic effect can be achieved when the robot maintains several machines, while ensuring two- and three-shift operation of the equipment.

The social aspect of their use is also closely related to economic issues arising in the use of industrial robots. In determining the feasibility of using robots in one case or another (especially if it is necessary to replace a worker to perform work in areas with dangerous, harmful working conditions), the interests of a person, their safety and convenience of work should come first.

Industrial robots must free a person from mechanical mindless work, compensate for the increasing need for low-skilled labor.

Expanding the areas of application of PR in various branches of mechanical engineering requires solving the following main tasks when designing them:

1) increase technological flexibility in order to best meet specific use conditions;

2) simplification of structures in order to reduce the cost of production and operation.

The use of a unified system of aggregate module construction of the PR, containing structural modules of manipulators, gripping mechanisms, unified units of cycle and numerical program control, as well as components (electro, hydraulic and pneumatic drives, transducers and automation means), makes it possible to develop a general type of automation equipment in mechanical engineering. The creation of such a type, which in addition to the main technological equipment includes PR, transport and loading devices, automated warehouses and other auxiliary technical means, helps to reduce the time for the design, manufacture and implementation of various flexible automated production systems: sections, lines, and later - workshops and automatic plants based on them.

The structural element in the aggregate construction of flexible automated production systems is a robotic complex consisting of one or more units of equipment (machines, presses, etc.) together with the PR serving them.

Robotic systems shall meet the following requirements:

1) provide technological flexibility and adaptation to changes in production conditions;

2) to connect equipment of different purposes with wide variation of loading and other accessories;

3) have high operability and reliability in operation;

4) provide for the possibility of further development and improvement.

The creation of a single type of robotic complexes and automation of auxiliary operations that combine these complexes in general automated production is the basis for the further development of flexible production systems. At the same time, the labor intensity of creating, debugging and implementing flexible production systems, differentiated by purpose, composition and level of automation, can be significantly reduced.

From newly created modules, as well as from modules built on the basis of CNC machines, you can build flexible production systems with centralized computer control. Rotary and rotary conveyer lines are widely used. At the same time, it should be borne in mind that any typical solution, no matter how perfect, needs creative thinking and refinement when "linking" to container production conditions.

Automated production systems are referred to as large systems, which are characterized by the interaction of objects, complex communication of information and material flows, the presence of random influences.

With an increase in the degree of automation, the requirements for formalizing production processes, for the unambiguity and optimality of control algorithms increase, the number of random factors taken into account increases, since on the way to complete automation of production, direct human participation in the production process decreases.

1.2 Overview of existing methods and tools for automation of assembly process

Let's consider the peculiarities of application of various methods of assembly in conditions of its automation.

In most cases, automatic assembly is carried out according to the method of complete interchangeability. At the established tolerances for the dimensions of the parts, compliance with the assembly specifications for all assembled products is ensured. This build method provides relatively simple designs for automatic devices. Other methods of assembly in automation are fundamentally possible, but their implementation is associated with great technical difficulties. To ensure uninterrupted operation, they often go to 100% control of parts, which is carried out manually or using control machines. Selective inspection of parts does not guarantee uninterrupted operation of assembly equipment. This monitoring system can, however, be adopted if the possible idle time of the automatic line is small.

Assembly according to the method of group interchangeability with preliminary sorting of parts into dimensional groups (selective assembly) is found much less often in automated production. It is used with increased requirements for the accuracy of the closing links, as well as with narrow tolerances for clearances or interference of conjugations. Assembly machines in this case are more complex, since separate silos or magazines are required for each dimension group of parts.

Assembly by selection method is used in automatic production of rolling bearings. External and internal rings of bearings come from separate hoppers, where they are loaded without preliminary sorting. At one of the positions of the automatic line, their treadmill diameters are measured. The measurement results give the required number of rolling bodies of the corresponding dimension group. It is also fundamentally possible to assemble by the control method using rigid or movable (adjustable) compensators. Its use is advisable in the presence of complex ladder dimensional chains. The assembly machine is somewhat complicated by means of a device for checking the withstand size of the closing link of the dimension chain and a device for appropriate installation of an adjustable (or rigid) compensator.

Assembly with racing on an assembly machine is impractical. Racing work on an automated assembly disrupts the pace of work, complicates actuators and should be excluded. If by the nature of the connection, the mating parts should be rubbed, then the fitting should be made separately, outside the automatic line. Parts must be supplied to the assembly in a paired view.

The development of automatic assembly has led to the creation of a certain type of assembly equipment. The following types of automatic and semi-automatic equipment are currently used in assembly production.

1. Special assembly units and devices for intermediate assembly during machining. Assembly plants are used as self-operating equipment between adjacent processing operations of the basic part of this product, and special assembly devices are embedded in machines or semi-machines for mechanical processing.

2. Single-position assembly semiautomata used to assemble relatively uncomplicated products and their elements consisting of a small number of parts (usually 3-5). The basic part of the product is manually installed on the assembly position. The remaining parts of the product are installed automatically in a certain order or simultaneously. The assembled product is removed automatically by the pushing device into the container, as well as manually. Thus, this equipment not only facilitates assembly conditions, but also improves its performance often several times. However, the release of collectors from servicing semiautomata usually does not occur. Assembly single-position semi-machines are often made on the basis of universal equipment (eccentric presses for riveting operations, single-spindle vertical-drilling machines for flaring operations, etc.) with or without a slight change in its design.

3. Single-position assembly machines are used to assemble relatively simple products with automatic feeding of precisely oriented parts from bunkers, magazines or cassettes to the assembly position. After completion of one working cycle, the assembled article is automatically removed by the ejector in the container or removed by the mechanical hand without losing orientation for transfer to the conveying device for the next assembly operation. A new work cycle begins without human involvement. Similar to aggregate machines, single-position assembly machines (and semi-automatic machines), depending on the design of the product, can be of the same and multilateral types with sequential or parallel assembly transitions.

4. Multi-position assembly semi-machines are used for more complex products with a relatively large number of assembly transitions. They are usually of the carousel type. The round table, on which the mounting devices for articles are fixed, is periodically rotated by means of a dividing device through a certain angle depending on the number of positions. The base part, as well as some other parts, which are difficult to dispense from the hoppers (coil springs, complex parts, wire parts), are installed manually. Finished products are usually removed manually, only in some cases automatically.

5. Multi-position assembly machines are of the same type for the same products as previous carousel semi-machines. All parts of the assembled product are supplied from the silos or magazines automatically. The number of assembly positions, including the base part installation and removal positions of the assembled product. It usually ranges from 6 to 12. With a large number of positions, first, the diameter of the table increases, and at the same time the area occupied by it (the growth of the area is proportional to the square of the diameter of the table; with a large table diameter, its central part is not used, since the work positions are located around the periphery); secondly, the reliability of the machine, and at the same time its performance, is reduced.

6. Semi-automatic (automatic) lines are used to assemble more complex products. The total number of manual and automatic assemblies is several tens. Manual positions perform assembly transitions that are difficult to automate. The location of work positions in the plan can be linear, in the form of a closed rectangle or oval. In most cases, the basic part of the assembled article is fixed in satellite devices and moved from one position to another, where mating parts are attached to it. Satellite devices are mounted on rigid plates moving along guides; the entire satellite system is a closed circuit.

7. Automatic assembly lines are used less often in practice. Than semi-automatic lines. They have fewer work and support positions for the same reasons. As for multi-position assembly machines. Their device is more difficult. In addition to assembly, other works are performed on automatic lines (mechanical processing, control, testing, preservation, packaging). Automatic and semi-automatic assembly lines have a wide variety of designs. Assembly lines are in most cases made with satellite devices for fixing the basic part of the assembled product. The problem of returning satellite devices to their original position is most simply solved in closed-type lines.

8. A relatively new direction in the automation of assembly work is the use of assembly manipulators (industrial robots, mechanical hands) equipped with a permanent or replaceable control program. This makes it possible for them to be easily "trained" and "retrained," as a result of which a fairly flexible universal system of assembly equipment is obtained. It is advisable to use assembly rebalable robots on the assembly of simple products in mass production. They can work as individual installations or be built into a production line. Assembly robots can install the basic part of the product on an automatic line and remove the assembled product from it, change the position of the assembled object, perform basic and auxiliary transitions of the assembly. Perform connection with clearance of mating parts, perform point and contact welding and painting by dipping or pulverization method and other works. Use of robots of the type both readjusted, and not readjusted promotes automation of assembly works in serial and mass productions and to release of a significant amount of collectors.

9. Of interest are attempts to automate the assembly processes of small, simple rotary drum articles, shaking and vacuum-pneumatic type, magnetic and other devices. In these installations, a large number of products are simultaneously assembled, the parts of which, while in random motion, are connected to each other. This method collects products with a guaranteed gap. To accelerate assembly, compressed air is supplied or vacuum is created in working space.

The listed means of automation of assembly works perform a complex set of technological and auxiliary functions, which take place in a certain sequence.

2. Process Section

2.1 Analysis of the assigned task

This project discusses the flexible automatic assembly module of the air distributor assembly. It is necessary to develop the process route of assembly of the main unit of pneumatic distributor, which consists of housing, slide valve and two sealing gaskets. Calculate the unit time of the product assembly, select the necessary process equipment, develop a process control scheme for the product assembly. Provide economic justification of the presented process for the product assembly.