Designing the technological process of mechanical processing of the gear and the choice of machine tool - coursework

Contents

Introduction

Process Section

Part Assignment and Design

Constructability Analysis

Define Production Type

Procurement Selection

Selection of process bases and evaluation of constructability

Process Route Design

Calculation of processing allowances

Calculation of cutting modes

Calculation of time standards

Design Section

2.1 Calculation and design of machine tool

2.1.1 Machine tool design

2.1.2 Description of device and operation of accessory

2.1.3 Calculation of accessory capacity

2.2 Calculation of cutting forces, part clamping forces in the accessory

2.3 Calculation of the accessory for accuracy

3. Economic justification of the accepted process version

Conclusion

Literature

Appendix 1. Set of documents for processing process

Appendix 2. Accessory on the machine

Introduction

Recently, agricultural engineering has begun to pay great attention. It is necessary to study the regularities of processes to ensure the production of machines of a given quality in the amount established by the production program and at the lowest national economic costs. Engineering technology covers all stages of the manufacturing process of machine-building products: casting technology, pressure treatment technology, mechanical and physicochemical processing technology. It is rational to consider the selection of metal cutting machines and cutting tools, with cutting edges made of materials of increased strength, which allows increasing cutting speeds and other parameters, thereby increasing the economic effect of the part. Of great importance is the competent design of devices, which can greatly increase the economic effect in the manufacture of a part. Agricultural engineering technologists have their own requirements for wear resistance and fatigue strength of working surfaces of parts experiencing high loads. How the engineering industry faces the challenges of agricultural engineering technology:

higher efficiency, higher quality of products, higher accuracy. Achieving the above objectives leads to competitive products.

Selection of technological bases and assessment of location accuracy

Based on the data in the drawing in which the beats are specified, we select the center axis as the base. The principle of alignment and constancy of bases is observed.

When selecting bases, we take into account the basic basing principles, therefore, a complete cycle of part processing from a rough operation to a finishing one in order to reduce errors and increase the processing efficiency of the part is carried out with the least number of rearrangements of the workpiece during processing.

Selection of bases for roughing: When machining a part as a process base in order to increase the accuracy of basing the workpiece in the appliance, we accept surfaces that have higher accuracy and low roughness, have no defects and with the smallest allowance. The base for the first operation is also selected to ensure better surface conditions. Since the first operation is a lathe, the base is the outer cylindrical surface of the workpiece.

Selection of bases for finishing: Considering that the highest accuracy is achieved by using the same bases in all machining operations, as well as the possibility of combining the process and measuring bases, the basing surfaces will be the center holes of the gear. At the same time, it is necessary to ensure that they do not deform under the influence of cutting forces, clamping and own weight of the workpiece.

Evaluation of the accuracy of the basing during each operation: We establish whether the principle of base alignment is respected when maintaining the specified dimensions. To do this, we consider axial dimensions and radial run-out of surfaces. During the turning and grinding operation, the gear is based in a cylindrical mandrel (GOST 1825972), while the radial run-out of the working cone surface relative to the shank cone at normal accuracy is 0.01 mm, which meets technological requirements. Measuring base is aligned with process base in axial direction. Since all the principles of base alignment are observed, the basing error is zero.

Conclusions

In the course design, the technological process of machining a part of the gear type is developed, which is designed to transmit rotation. The workpiece for this part is forging since the cost of the workpiece obtained by stamping 647 rubles. which is much more profitable compared to rolling, where the price of the part is 1104 rubles. The gear is made of 25HGT 454371 alloy steel.

During the course project, the piece calculation time was reduced and the cutting speed for the turning operation was increased due to the use of newer and more productive equipment. The designed single-seat tool for milling operation allows you to significantly accelerate the process of milling the teeth of the part.

The circumferential component of the cutting force (20 N) and the clamping force Q (33.3) were determined.

Based on calculations of the reduced costs for the designed process (2397 RUR).

The new equipment made it possible to increase the performance, ensure the convenience of adjusting the cutting tool to size.

All calculations in the project were made in 2009 prices.