Manufacturing process of support screw

Contents

CONTENTS

INTRODUCTION

At the present stage of engineering development, the main requirement for production in an emerging market economy is the economic factor, the main condition of which is the production of products to maintain competitiveness and is carried out with the maximum rational use of various types of resources, and this requires the preservation of non-productive costs, reduction of material intensity and labor intensity of production, improved use of financial resources and reduction of the return on investment. All of the above activities should not affect the quality of the products produced and vice versa. The requirement of competitiveness for production sets the task of improving the quality of products, increasing the assortment while reducing its cost.

The specificity of modern tasks for production is also determined by the fact that it is necessary to maintain the timing of updating the production nomenclature, increase its complexity, increase the stability of the main parameters of the machines and their reliability, which leads to a significant increase in production costs.

The real solution to the set of tasks can be automation of production.

The topic of the diploma project is devoted to the development of technical and economic, technological and organizational tasks in order to increase the efficiency of the production of parts for the engineering industry. The specified parts are typical for this industry, are manufactured in large volumes, but the technology for producing such parts is not perfect enough, since the use of outdated equipment and technological equipment does not provide a modern level of machining technology, and therefore the quality of the parts.

The layout of the equipment is also not rational, the main processing equipment is scattered across different sections of the workshop, issues of internal transport are solved using only bridge cranes.

The solution of all these issues involves the topic of the project, since all these issues have been resolved taking into account modern trends in engineering technology.

The parts considered in this project: support screw, flange, ball support - are a classic example of modern products manufactured using the most advanced equipment.

This project is an attempt to modernize the existing technology for the production of basic parts, through an in-depth analysis of bottlenecks in the process, using bar machines and CNC machines at turning operations, and more modern equipment at vertical drilling operations.

All the technological solutions adopted as a result of the analysis in this project meet the modern requirements of engineering production technology.

Analysis of literary and production data development object

Service purpose of support to automobile trailer

The article "Support" is a component of the suspension, installed in the amount of four pieces at the ends of the spar of the frame of the automobile trailer and belongs to the class of "jacks." It consists of the following main parts: shock absorber (1), support screw (pos. 2), bushing (pos. 3), nut (pos. 4), ball support (pos. 5), support plate (pos.6), support pipe (pos. 7) and flange (pos. 8).

The support screw (2) is an integral part of the support, by means of which the trailer frame is hung in a horizontal position to ensure the operability of special equipment installed on the trailer belt, removing loads on the trailer springs and tires. Experiences compression and bending stresses.

Flange (pos.8) serves as housing for bushing (pos.3) contacting with spherical surface of ball support (pos. 5) and support of support plate (pos.6), which serves for stability of support by rotation of sphere in bushing. To reduce friction, an oil cavity is provided in the flange housing, into which oil is supplied through the hole for the connector.

The ball support (pos.5) serves to turn the support plate and performs the function of maintaining it, refers to the components of the suspension that experience maximum loads: the finger tearing force (pos.12) from the ball support body is more than 5 tons, and the extrusion force is 3 tons.

Development of machining process of support parts

Analysis of processability of developed parts

Constructability refers to the property of ensuring the ability to manufacture a part using high-performance technology with minimal allowance, with minimal labor input, production cost without reducing the performance of machines.

The main direction of ensuring the processability of the parts design is as follows:

Standardization and unification of nodes and their elements.

Material and Procurement Selection - The design should ensure that the most economical types of procurement are used.

Reduction of machining:

Using accurate blanks

reduced dimensions of treated surfaces due to minimum allowances.

Simplification of machining due to ease of tool exit and replacement of deep holes with through ones.

Application of production technology in mass and large-scale production.

The part "Support screw" according to the relation belongs to the shaft class. It consists of two parts (support screw and washer), welded into one unit.

The support screw consists of a threaded part of the shank with a trapezoidal thread Tr40 × 68c (the outer diameter of the thread is 40 mm; step - 6 mm; degree of accuracy - 8; the main deviation is (c) ending in a cylinder with a groove with a width to install a finishing washer that prevents the screw from screwing out of the nut.

Thread roughness parameters Ra 2.5 μm. Transverse groove at outlet of threaded part has shape and dimensions providing outlet of threaded-rolling tool.

The second end of the article is made with a radial hole for installation of a wrench that unscrews the screw from the support nut; radial hole for installation of pin fixing ball support paw and central hole for installation of ball support paw. The holes correspond to the 5th accuracy class and have a roughness of 12.5 μm according to the parameter Ra.

The rigidity of the shaft allows for high processing accuracy (the rigidity of the shaft is sufficient, since its ratio). The shape and size of the workpiece are as close as possible to the dimensions and shape of the part. The shape of the axis is straight.

Tolerance of end run-out corresponds to 10 degree of accuracy and is 50 mm. Maximum run-out of washer end face and screw threaded surface is 0.5 mm. Deviations of the shape and location of the surfaces, deviations from the perpendicular of the radial holes and the face of the washer to the shaft axis are within the tolerance for dimensions.

Non-technological is a blind hole on the left side of the screw end and a welded joint. From the point of view of machining, the part has disadvantages with respect to processability. The shaft does not have center holes, which sharply reduces its processability. The axis of the hole is located in another plane from the hole, which does not allow them to be processed in one installation, the treatment of these holes can be carried out only with the permutation of the part in different operations. For these reasons, the part requires refinement for processability.

In general, based on the analysis, the part can be considered technological, since most of the requirements for the processability of the part design are made, it allows the use of high-performance processing modes, quite simple in design.

The part designs provide free access of the cutting tool to all machined surfaces. It is possible to carry out machining with pass-through cutters on universal and special machines with high productivity using standard tools, devices and measuring tools. Specialized tooling is required for individual critical operations to ensure the required accuracy.

From the point of view of accuracy and roughness, the surfaces to be treated are not difficult to process, allow the machining to pass through, and enable the part to be machined in high-performance ways.

The part "Ball support" according to the relation belongs to the class of shafts. The stiffness of the shaft allows for high machining accuracy. The shape of the axis is straight. It consists of a stepped shaft ending in a sphere. At a distance from the end of the stage there is a radial hole for the installation of a pin. The limit deviation of the hole axis from perpendicular to the end of the stage is within the tolerance for size, and is 0.4mm. Parameters of shaft roughness and hole Ra 12.5 mcm, sphere Ra 3.2 mcm.

In general, based on the analysis performed, the Ball Support part can be considered technological, since most of the requirements for the processability of the part design are made, and high-performance processing modes can be used. From the point of view of ensuring accuracy and roughness, the surfaces being treated do not pose technological difficulties, allows processing to be carried out per pass,

The part "Flange" according to the relation belongs to the class of bushing. It has through stepped center hole ending with spherical surface for conjugation with sphere of ball support. In addition, it has a radial cone threaded hole for screwing in the connector. Parameters of shaft roughness and bushing hole Ra 12.5 mcm, spherical surface Ra 3.2 mcm.

Non-technological are the shape and size of the workpiece, which are not close to the dimensions and shape of the part, and therefore do not satisfy the condition of minimum metal consumption, requires refinement for processability.

In general, based on the analysis performed, the Flange part can be considered technological, since most requirements for the processability of the part design are completed, and high-performance processing modes can be used. From the point of view of accuracy and roughness, the surfaces to be treated are not difficult to process.

Conclusion

The developed design version of the process using high-performance equipment, progressive tooling and tools is economically more profitable and, at high capital costs, reduces the cost of processing the part, frees up the equipment for use in the production of other products.

The replacement of universal machines with CNC machines, and the use of a robotic complex led to increased processing accuracy, increased labor productivity, reduced production preparation cycle, and reduced labor input.

The obtained technical and economic parameters of the part processing of the design version of the technological process confirm the economical and progressive development for a particular enterprise.

You can conclude that it is advisable to introduce a new process plan into production.

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