Coursework on mechanical engineering technology - Topic Flange

Contents

Introduction                           

1 General section                        

1.1 Description and processability of part design    

1.2 Part material, its chemical composition and mechanical      properties                    

1.3 Part processability analysis             

2 Process section                  

2.1 Definition of production type             

2.2 Justification of selected procurement variant      

2.3 Analysis of the basic and proposed process     

2.4 Selection of process                bases

2.5 Calculation and design of the workpiece          .

2.6 Development of RTC for CNC machine.           

2.7 Calculation of cutting modes and time standards.        

3. Design section.                 

3.1. Device and operating principle of designed device.                       26  

3.2. Base selection and base error calculation     

3.3. Calculation of clamping force                 .

3.4. Calculation of the main parameters of the clamping  mechanism.

3.5. Strength calculation of accessory parts     

Literature                         

Appendix  A Graphic part (2 A1)

Introduction

The leading role in accelerating scientific and technological progress is to play mechanical engineering, which as soon as possible needs to be raised to the highest technical level. In this regard, the development and mass production of modern electronic computing equipment is a primary task.

The immediate goal of machine builders is to change the structure of production, increase the quality characteristics of machines and equipment. New approaches will be required in investment and structural policies, in the development of science and technology.

Many economic experiments are aimed at overcoming the shortage of labor resources and increasing labor productivity, which are based on organizational, scientific, technical and economic solutions. Other scientific and technical programs are operating in the same direction. According to experts, they will not only create new devices, machines and mechanisms, progressive technological processes, but also save the labor of about 3 million people.

The word "technology" means the science systematizing set of methods and ways of processing of raw materials, materials, semi-finished products the corresponding instruments of production for receiving finished goods. The technology includes technical control of production. The most important indicators characterizing the technical and economic efficiency of the technological process: consumption of raw materials, semi-finished products and energy per unit of production; quantity and quality of finished products and products; productivity; process intensity; production costs; cost of products and products.

The subject of research and development in mechanical engineering technology are types of processing, selection of blanks, quality of machined surfaces, accuracy of processing and allowance for it, basing of blanks; methods of machining surfaces - flat, cylindrical, complex-profile, etc.; methods of manufacturing typical parts - housings, shafts, gears, etc.; assembly processes (nature of connection of parts and assemblies, principles of mechanization and automation of assembly works); design of devices.

The technology of mechanical engineering is constantly updated and changes as the technology develops. Improving technology is an important condition for accelerating technological progress.

General Section

1.1 Description and processability of the design of the specified part

The flange part belongs to the class of flanges.

The main surfaces are: external F900,022 Ra1,6, h6

internal F80 + 0.019 Ra0.63, H6

These surfaces are made with higher accuracy than others and have lower roughness than the others. Surfaces are linked between

a tolerance for mutual location    (flange drawing  40 3562). Other surfaces are made with lower accuracy and higher roughness

external F840.54 Ra3.2; Ra6.3 F960.54,

internal F72 + 0.46 Ra6.3

In addition, the part has a shaped flange on which 4 holes are located. F6.5 + 0.22 Ra6.3 for fastener passage

The part is made of 20X3MVFSH (tungsten chromium) structural material.

According to the process, thermal treatment is provided:

-numbering operation 1020 to increase workability of the workpiece in machining operations.

-cementation and hardening operation 1320 for surface hardness HRC≥59, core HRC 33... 45,5.

Conclusion: Thus, the design of the part provides the accuracy of its dimensions and the roughness of its surface, the material of the part and the heat treatment ensure satisfactory workability of the workpiece and reliable work of the part during the entire service life of the product.

.  1.2 Part material, its chemical composition and mechanical properties

Steel 20H3MVFSh. Purpose-fasteners and other parts operating at temperature up to 54005600 С.

Mechanical properties of bars (GOST 2007274): hardening 1030010600 С oil, tempering 66007000 С air = 880 MPa

Process Properties:

 Forging temperature 0C beginning 1240 end 780 section 50 mm cooled in boxes 51700mm are annealed with one supercooling.

Weldability is a limited weldability method. Welding methods: RDS requires heating and subsequent heat treatment, CTS.

Machinability by cutting in annealed state at HB157 and = 530 MPa Kv, b st = 1.1; Kv, b split = 1.5

1.3 Part processability analysis.

The part processability analysis is carried out by 2 methods (quantitative and qualitative).

a) Qualitative method:

Surfaces to be ground: internal F79,050.05 operation 1300,

exterior F90.50.05 operation 1400, F84.50.4 operation 1410

Conclusion: the part has not been refined process surfaces: they are not ground on the pass and do not have a groove for the exit of the grinding wheel.

outer diameters increase from the end to the middle of the part

  F840,54 F117 – F900.022

internal diameters decrease F800.019 - F720.46

Output: part is technological

There is no variety under the fastener 4 otv. F6.5 + 0.22 Ra6.3 for fastener passage

Output: part is technological

b) Quantitative method

Process Section

2.1 Definitions of production type

The production type is determined by the consolidation factor of the operations

Serial production is characterized by the following features: equipment is arranged along the process, in groups of interchangeable equipment, parts are produced in repeated batches (series). The process describes in detail the order and content of the operation, indicates the tooling processing modes and the order of transitions. Workers on the site of medium and high qualification. Medium-skilled workers perform rough and semi-simple transitions to operations, and high-skilled workers perform finishing passes at operations.

Conclusion: mass production is high-performance, ensures high quality of products reduces scrap, as a result of which cost is reduced.

2.2 Justification of selected procurement variant

When selecting the procurement method, the following factors are taken into account: part design, part material, production type, product type.

In this work: detail material steel 20H3MVFSh production type serial for the specified conditions we choose a way of receiving preparation hot volume stamping of the increased accuracy. This provides minimal processing allowance. Due to this, the stamping slope of 2 to 30 minutes is the die resistance less than that of hot bulk stamping. Due to a decrease in processing allowances, the time required to manufacture a part is reduced.

Conclusion: The chosen method of manufacturing the workpiece provides minimal allowances for the mechanical processing of the workpiece and saving material due to this.

2.3 Analysis of the basic and proposed process.

CNC machines are not used in the basic process, a one-dimensional measuring tool is not used enough.

Operation 1010 (procurement) was transferred from stamping to GKM (high-precision hot volume stamping).

In the basic process, steps 1100, 1110, 1120, 1130 are performed on lathe 1K62 in the proposed process of steps 1100 and 1200; 1110 and 1130 are combined and converted to a machine with CNC 16K20F3 more high-performance and accurate.

Operations 1150, 1155 were performed on the machine 12H125 combined with operation 1190which is performed on the vertical milling machine 6K11 and transferred to the CNC machine 2254VMF4 for this operation, a conductor has been developed in which it is possible to carry out all operations without changing the conductor on this machine: vertical drilling 4 holes, vertical milling 4 holes.

Operation 1170 (shell milling along the flange contour) was removed due to a change in operation 1010 (billet) hot volume stamping of increased accuracy on which the flange contour is stamped with the necessary size F96, R7.

Conclusion: the proposed changes in the process reduce the time required to manufacture the part. Improve the quality of products and working conditions of workers. Due to the introduction of hot bulk stamping of increased accuracy, the mass of the workpiece decreased the coefficient of material use, which in the conditions of mass production made it possible to save material, as a result of which the cost of the workpiece decreased.

2.4 Selection of process bases.

When selecting bases, the constancy rules of bases and the principle of combining design and technological bases are observed. In the first operation of the process, the base is the outer F87 mm and the adjacent end 20 mm. This base is also used in other process operations. In the operation of drilling and milling of slots, the blank is centered according to F84.50.05 stop on the end 2.5 clamp by the opposite end. To provide the tolerance specified by the drawing for mutual arrangement of surfaces, run-out of ends

relative to internal F80 + 0,019 and external F900.022 diameters not more than 0.02 mm.

At grinding operations No. 1300, 1400, 1410, 1450, the same bases are adopted as at turning operations, which ensures the constancy of the bases.

Conclusion: this principle of selection of technological bases ensures the specified accuracy at all operations of the technological process and reliable fixation of the workpiece.

Design Section

3.1. Device and operating principle of designed device.

The accessory is designed to perform operation No. 1150 vertical-drilling drill 4 holes. F6.5 + 0.22, vertical -

drilling removal of chamfers 4 0, 51mm, vertical-milling milling of 2 slots with width 15 + 0.43 depth 3 on the machine with CNC 2254VMF4.

Part pos.7 (refer to drawing conductor B1KP151.001.003.005) is installed as per external diameter F84.5 + 0,019 until stop against flange end on mounting element pos.4 which is fixed on plate pos.1 using screws pos.2. in the amount of 8 pcs. For coaxial arrangement of the axis of holes and projections of the flange, the blank is fixed along the flange projection with prism pos. 12 devices. Reliable workpiece is provided by 2 nuts, pos. 8 through clamp pos. 3.