Increase of productivity and quality, reduction of labour intensity and cost of assembly and welding of the amplifier for attachment of the safety belt regulator assembly VAZ 21236 - diploma

Contents

Introduction

1. Status of the question

1.1. Product Design Description

1.2. Product Material Description

1.3. Basic welding technology

1.4. Selection of compression drive to provide welding force

1.5. Wording of thesis project tasks

2. Choosing the Basic Technology Automation Tool

3. Development of special welding machine

3.1. Device for automatic feeding of welded nuts

3.2. Design of electrodes for contact relief welding

3.3. Electrode Group Design

3.4. Electrical schematic diagram of welding machine

3.5. Calculation of the secondary circuit of the welding machine

3.6. Selection of standard transformer

3.7. Cooling system

3.8. Pneumatic compression drive

3.9. Selecting the Contact Weld Adjuster

3.10. Welding Machine Description

4. Robotic process complex for assembly-welding

5. Project safety and environmental friendliness

6. Cost-effectiveness of the project

7. Patent research

Conclusions on the diploma project

List of literature

Applications

Summary

In the course of the diploma project, the goal was set - to increase productivity and quality, reduce the labor intensity and cost of assembling and welding the amplifier for the attachment of the safety belt regulator assembly of the VAZ 21236 car. The goal was achieved by sequentially solving a number of technical problems, during which the technological process of robotic assembly and welding was developed. To implement the proposed process, industrial robots FANUK AM 120 and A520 iB were chosen as automation means. Special welding equipment was also developed - a welding machine with a mechanism for supplying welded nuts to the welding zone.

The economic efficiency of the project, which is about 270 thousand rubles. per year. Patent studies were carried out, during which an application was made for a useful model - an automatic device for supplying parts to the contact welding zone.

Diploma project contains

Graphic part sheets - pcs.

Pages of explanatory note - pcs.

Introduction

Currently, contact spot welding in the automotive industry is almost completely (90%) automated. In this case, multi-electrode welding machines and industrial robots act as automation means. However, such a relatively high percentage of automation applies only to parts of a certain type - sheet metal parts with dimensions of the order of 1 meter, connected by contact spot welding in several places located in the local area and one plane. This type, although one of the most common among the body parts of a modern car, is far from the only one.

In production, contact relief welding is very common, by which bolts and nuts are welded to sheet blanks. In most cases, the mass and dimensions of such parts are measured in several tens of grams and centimeters. At the same time, the number of welded nuts or bolts on such parts is one, less often two. This does not make it difficult to use the manual labor of a welder working on a universal welding machine, which, among other advantages, has another - high versatility of the process.

In 2007, it is planned to establish mass production of the VAZ 21236 NivaChevrole, equipped with the Opel FAM1 engine. This car is assembled on the basis of the famous VAZ 2123 Niva-Chevrolet model and has all its positive qualities. The Niva FAM 1 is equipped with a modern power unit and transmission. It has improved dynamic properties, meets modern safety requirements. The body is equipped with additional elements that increase passive safety, has enhanced noise insulation. In addition to the steering power, immobilizer with central lock, the standard configuration includes new options: anti-lock system, air conditioning, two airbags. The SUV is equipped with new front seats of increased comfort, and the driver's seat is adjustable in height. As on the usual ChevroleNiva, the FAM 1 15 "" disks and radio training are included in the configuration.

However, a number of parts, which include an amplifier for fastening the seat belt in the assembly of the VAZ 21236 car (on the new Niva there are safety belts with a pre-tensioner) are difficult to weld on a universal welding machine using manual labor. This is primarily due to the fact that the part is quite responsible and combines two welding methods - contact relief and semi-automatic in the environment of protective gases. Such design features dramatically reduce the quality and productivity of manual welding, as well as worsen the working conditions of the welder.

Therefore, the purpose of this diploma project is to increase productivity and quality, reduce the labor intensity and cost of assembling and welding the amplifier for fastening the safety belt regulator assembly of the VAZ 21236 car is relevant.

Protection against mechanical injuries

The operation of automated production is associated with injuries, which most often occurs during the repair and maintenance of lines. Therefore, in order to avoid the possibility of injuries at the workplace, a number of additional, specific labor protection requirements have been developed.

Blocking systems shall be used everywhere to prevent the automatic line from being switched to commissioning or automatic mode in a sequence that does not meet the requirements of the process. Signal devices should be widely used here. They are designed to inform about the progress of the process, the presence of malfunctions and breakdowns of both the main equipment and ventilation systems, pneumatic transport, etc.

The layout of robotic process areas should ensure convenient and safe access of maintenance personnel to the main and auxiliary technological equipment, industrial robots and emergency shutdown and control bodies of industrial robots. During the planning of robotic sections, it is necessary to exclude the intersection of the routes of the operator and actuators of industrial robots and ensure the freedom of movement of maintenance personnel, minimizing the possibility of appearance of third parties.

The industrial robot control panel shall be located outside the working space of the industrial robot; there shall be sufficient space around it for the operator to have unhindered access to the emergency shutdown button and good visibility. Robotic process areas shall be protected and marked with signal colors and safety signs in accordance with the requirements of GOST 12.4.02676 *.

The entrance to the fence area should be blocked with the control system. The interlock should be disabled by an industrial robot operating in automatic mode when a person enters the fence area.

When the industrial robot moves the blanks and parts on your cell above the passages, driveways and workplaces in order to prevent accidents, it is necessary to provide protective nets or other devices under the movement zone of the manipulator of the industrial robot to prevent the fall of the moved parts.

Protection against electromagnetic radiation when working on contact machines

Devices generating electromagnetic fields caused a number of problems in protecting personnel from their effects.

The most effective and often used of all methods of protection against electromagnetic radiation is the installation of screens. Radiation source or workplace is shielded. Screens are reflective and absorbing. Reflective screens are made of well-conducting metals - copper, brass, aluminum, steel. Protective means made of absorbing materials are made in the form of thin rubber mats, flexible and rigid sheets of foam or fibrous wood impregnated with appropriate composition, ferromagnetic plates.

Noise protection

To reduce noise, the method of reducing noise in the source is used, as well as reducing noise in the path of its propagation.

Combating noise by reducing it at the source is the most rational. To do this, it is recommended to replace the pneumatic cylinders in the contact machines with hydraulic cylinders or electric presses, which work much quieter.

To reduce noise in the path of its propagation, sound-insulating fences, casings, screens are used that protect workers from medium and high-frequency noise.

If it is not economical or impossible to reduce noise to acceptable values ​ ​ by general technical measures, then personal protective equipment is the main measures that prevent occupational diseases of workers.

Personal protective equipment includes inserts, headphones.

Conclusions on the environmental section

During the implementation of this section of the diploma project, hazardous and harmful production factors were identified (electric current, electromagnetic radiation and splashes from splashes, harmful emissions during welding, fire risk), which are a standard set of factors accompanying contact relief welding. An analysis of the possibility of their elimination and reduction was made, which showed that the use of standard means of ensuring production safety and sanitation will ensure the employee's safety when implementing the technology proposed in the diploma project. Development of special and additional tools is not required.

Construct a useful model formula

In this case, the ITR contains only typical device features. Analysis of these features shows that they are all interconnected, they do not have independent significance, therefore, only one new object is specified - the device.

There are no alternative and negative features in the object description. Embodiments of the device are not shown in the description. Therefore, it is necessary to compose a single-link formula.

We select all known features from the table of comparative analysis and make up the limiting part of the formula.

Device for automatic feeding of nuts into zone of contact welding consists of cylinder fitted on lower electrode of contact machine with hole made along its axis and fixed on electrode holder of ring resting on cylinder when electrode moves upwards.

We choose unknown features and form a distinctive part of the formula of the useful model.

Across the cylinder axis there is a rectangular hole in section, the size of which corresponds to the size of the nut, connected to the nut supply channel made of flexible material, the cylinder is fixed in the sleeve with the possibility of longitudinal movement and is spring-loaded, the diameter of the longitudinal hole in the cylinder corresponds to the diameter of the contact machine electrode.

Utility model formula as a whole

Device for automatic feeding of nuts into contact welding zone is co-standing from cylinder fitted on lower electrode of contact machine with hole made along its axis, a ring fixed to the electrode holder, abutting against the cylinder when the electrode moves upwards, characterized in that: that in order to improve working conditions and increase productivity, a rectangular hole is made across the cylinder axis; the size of which corresponds to the size of the nut connected to the nut feed channel, made of flexible material, the cylinder is fixed in the sleeve with the possibility of longitudinal movement and is spring-loaded; Note here that diameter of cylinder lengthwise hole corresponds to contact machine electrode diameter.

7.12. Peculiarities of preparation of documents of application for issuance of certificate for utility model

Documents of patent application for utility model:

1. Patent Application

2. Description of the utility model

3. Drawings illustrating the description of the utility model

4. Utility Model Formula

5. Abstract of Useful Model

Since this work is an official assignment, the right to submit a patent for a useful model belongs to Togliatti State University represented by its rector Zhilkin S.F., that is, the applicant and patent owner - Togliatti State University.

The author of the present invention is * * *

7.13. Utility Model Patent Application

IN 23 K 37/04

Device for automatic feeding of nuts into contact welding zone

Useful model relates mainly to machine building and can be used for assembly for welding of thin-sheet articles with nuts.

A bench is known for assembling products for welding mainly from two elements, (A.s. 1073059 of the USSR), containing an inclined slab mounted on the base, a mechanism for stopping, fixing and assembling products, characterized in that, in order to increase productivity by simultaneously releasing the articles and transferring the articles from the bench to a subsequent processing position, mechanism for stopping, fixing and assembling articles is made in the form of a power cylinder fixed on a rod; a spring-loaded cylinder with a longitudinal hole fixed in the sleeve, a bar with slots freely mounted on the rod and pivotally connected to the double-arm gripper plate for one item element and mounted on the bayonet clip bracket for the other item element; Note here that one of grips arms is fitted in appropriate slots of said bar. However, the assembly quality on such a stand is poor.

A device for assembling and embossing welding of plates and rods is also known. (A.s. 946870 of the USSR), taken as a prototype, containing a cylinder with a longitudinal hole worn on the lower electrode of the welding machine, made on the diameter of the welded rod, scissor-like grips with fixing prisms installed on their ends; device for movement of scissor-shaped grips, which is a pneumatic cylinder rigidly fixed on the hull of a welding machine; double-arm levers, on which grips are fixed, with the possibility of changing the angle of inclination to the horizon; guides, characterized in that, in order to improve the assembly quality, the cylinder is spring-loaded and is longitudinally movable along the lower electrode; on the electrode holder there is a fixing ring resting against the lower end of the cylinder when the electrode moves upwards; and the length of the free part of the cylinder is taken on the basis of 0.9... 0.6 from the length of the rod. Due to a certain ratio of rod lengths and hole length in the cylinder, the assembly quality is improved, however, the labor productivity on such a device is low and working conditions are poor.

The purpose of the utility model is to increase productivity and improve working conditions.

Proposed device consists of cylinder, in which holes are made, cylinder is fitted on lower electrode of contact machine with possibility of longitudinal movement, fixed and spring-loaded in sleeve. A ring is fixed on the electrode holder, which rests against the cylinder when the electrode moves upwards. Due to that, in the cylinder the under-river hole is made in its dimensions corresponding to the dimensions of the nut to be welded and is connected to the nut supply channel made of flexible material, we improve the quality of the assembly for welding and improve the working conditions of the operator, since the nut loading can occur on the side with the corresponding length of the nut supply channel.

Proposed device represents hollow cylinder 3, through inlet transverse hole of which nuts 1 connected with flexible channel are fed by force of nut 2 supply, and lower electrode 5 is fed through longitudinal hole and performs longitudinal movements there. Electrode is fitted on electrode holder, which has lower ring, which rests against supply union when electrode moves upwards. The cylinder is spring-loaded in the sleeve 4 and can make longitudinal movements in it. At the same time, the transverse hole is made in the form of an 8x18 rectangle, so that only one nut can pass into it, oriented in a certain way, and the longitudinal hole is made with a diameter of 17.6 mm, so that the nut can move in it, the axis of which at the same time retains a vertical position.

The operation of the apparatus according to the invention is as follows. A part is supplied to the upper electrode, and one welded nut 2 is supplied to the cylinder 3 through the supply channel of nuts 1, which is laid on the lower electrode 5, while access of other nuts is impossible, since the entire volume is occupied by a per nut. Under the action of the compression drive, the lower electrode 5 starts to move upwards, at the same time the electrode closes the nut supply channel in the cylinder 3, and the ring rests against the cylinder. Under ring stop cylinder 3 moves upwards together with lower electrode, at that welded nut 2 is pressed to part. Welding current is passed and welding is carried out, after which the lower electrode 5 is lowered to the extreme lower position, and the next welded nut enters the cylinder through the channel, at the same time the welded nut is released from the grip, and the welded part is removed from the welding zone. Due to the fact that the nuts are supplied through a flexible channel to the assembly zone and are automatically supplied to the welding zone, we increase productivity and improve working conditions.

An example of the application of the device is the assembly and welding of the amplifier for the attachment of the safety belt of the VAZ 21236 car. The welding machine is of the standard MTK type. Ring made of copper M0 is installed on lower electrode holder. Standard electrode is inserted into electrode holder. Cylinder with longitudinal hole corresponding to electrode diameter and with transverse hole made corresponding to size of nut to be welded is installed on electrode. The cylinder is turned out of steel 40 on a lathe. Longitudinal hole is made on drilling machine. The transverse hole is made at first on a drilling machine, then it is reworked to a rectangular shape on a long machine. A standard spring is installed on the cylinder, and then a sleeve made of steel 40 is worn. After that, a channel made of fluoroplastic was connected to the cylinder for supplying nuts, and on the other side the channel was connected to a standard hopper .

The amplifier was welded to attach the safety belt of the VAZ 21236 car. Nuts were loaded into the hopper. Turned it on. The hopper automatically sorted the nuts and fed them into the channel. One nut fell on the lower electrode. Then the operator supplied the part to the upper electrode and pressed the "START" button. The control system of the welding machine sent a signal for the operation of the pneumatic cylinder of the compression of the machine. The lower electrode began to move upward, while it blocked the channel for supplying nuts in the cylinder, and the ring rested on the cylinder. Under the stop of the ring, the cylinder moved up together with the lower electrode, while the welded nut was pressed to the part. The control system of the machine was activated and welding current was passed. The welding current was received 15,000 amperes, the pulse time of the welding current was 0.1 seconds, the compression pressure was 250 kilograms, and the voltage on the secondary winding of the transformer was 5 volts. Welding was carried out, after which, according to the command of the control system, the lower electrode drops to the extreme lower position, and the next welded nut came into the cylinder through the channel, at the same time the nut welded to the part was released from the grip, and the operator removed the welded part from the welding zone.

After welding, quality control of the welded joint was carried out.

It can be seen from the application example that the device according to the invention does not require special materials, can be manufactured using known technical means and provides a technical result. Therefore, the object has industrial applicability.