Drilling fixture

Contents

Introduction

1. Machine Tool Design

1.1. Terms of Reference

1.2. Analysis of the initial data and formulation of the service purpose of the device

2. Selection of the workpiece installation method in the machine tool

2.1 Selection of basing scheme and description of accessory operation

2.2 Location error

3 Power calculation of accessory

3.1. Defining Cutting Forces and Moments

3.2 Drawing up the settlement scheme and the initial equation for calculation of tightening effort of Rz

4 Calculation of clamping device drives

5. Calculation of fixture for accuracy

5.1 Selection of parameters for accuracy calculation

5.2 Calculation of the accessory for accuracy

5.3 Calculation of dimension chain T

6. Calculation of process cost

7. Safety requirements for the designed device

8 Output

9. List of used literature

Introduction

The intensification of production in mechanical engineering is inextricably connected with the technical re-equipment and modernization of production facilities based on the application of the latest achievements in science and technology. Technical re-equipment, preparation of production of new types of mechanical engineering products and modernization of production facilities inevitably include the processes of designing technological equipment and their manufacture.

In the total amount of technological equipment, about 50% are machine tools. The use of machine tools allows:

1. reliably base and secure the machined part with preservation of its stiffness during machining;

2. ensure stable high quality of machined parts with minimum dependence of quality on qualification of the worker;

3. increase productivity and facilitate working conditions as a result of the mechanization of devices;

4. expansion of technological capabilities of used equipment.

Depending on the type of production, the technical level and structure of the machine tools are different. For mass and large-scale production, in most cases special machine tools are used. Special machine tools have a single purpose for performing certain machining operations of a particular part. These devices are most labor intensive and expensive to perform. In the conditions of single and small-scale production, the system of universal prefabricated devices (USS), based on the use of standard parts and assemblies, has become widespread. This type of equipment is more mobile in terms of production preparation and does not require significant costs.

The creation of any type of machine tool that meets the requirements of production inevitably involves the use of skilled labor. Recently, significant successes have been achieved in the field of design, machine tools. Methods for calculating the accuracy of processing parts in machine tools have been developed, precision cartridges and mandrels have been created, clamping mechanisms have been improved and their calculation methods have been improved, various drives have been developed with elements that have increased their operational reliability.

Machine Tool Design

1.1 Terms of Reference

It is necessary to design the machine tool for installation and attachment of part (P1.6) Housing (Fig. 1) during drilling operation on machine 2G125. The initial design data is sufficient. The drawing of this part has sufficient dimensions and specifications for the design of the fixture.

Method of providing specified accuracy by pre-setting of machine. Annual release program Ng = 7000 pcs.

Use of the designed accessory shall solve the following problems:

1. ensure a gain in the forces of securing the blanks, which is achieved by using rational structures of clamping mechanisms;

2. increase the productivity of machine operations by mechanizing and automating the device;

3. improve the working conditions of workers and ensure the convenience of servicing the device.

1.2 Analysis of initial data and formulation of service purpose of the device

As initial data, the accessory shall have: a workpiece drawing and parts with technical requirements for their acceptance; operating drawings for previous and ongoing operations; Operating charts of the processing process of this part.

The analysis of the initial data reveals: the sequence and content of operations; accepted basing; equipment and tool used; cutting modes; designed capacity taking into account the time for installation, fixation and removal of the processed part; dimensions, tolerances, roughness of machined surfaces of parts; material grade and type of heat treatment.

The service purpose of the device is the most refined and clearly formulated task for which it is intended.

When formulating a service assignment, it is necessary to take into account data on the fastened part (quantity, shape, dimensions, surface quality, material, type of heat treatment), manufacturing accuracy, productivity, drive characteristic, environment (temperature, humidity, dust content, type of energy, etc.), appearance, safety, degree of automation, etc.

Selection of the workpiece installation method in the machine tool

2.1 Selection of basing scheme and description of accessory operation

Analyzing the terms of reference, the sketch of the part for the performed operation from GOST 2149576 selects the theoretical basing scheme and from GOST 3.110781 possible practical implementation schemes.

The six-point rule is that each body (part) must be based on six fixed points, and the body is deprived of all six degrees of freedom.

To fulfill this condition, the product is installed on the pin and plane of the bracket, which deprives it of four degrees of freedom (movement relative to the Y and Z axes, as well as rotation around the Z, Y axes).

Basing on the bar deprives the workpiece of the degree of freedom of rotation around the axis X. In order to deprive the product of the sixth degree of freedom - movement along the axis X - it is necessary to press it against the plane of the bracket with a certain force .

Calculation of fixture for accuracy

5.1 Selection of parameters for accuracy calculation

According to the shaft drawing and the part accuracy requirements, you can select the following calculation parameter to calculate the manufacturing accuracy accessory:

In order to ensure a size of 50 ± 0.2 from the machined hole Ǿ14 to the base of the part, it is advisable to select a parameter for calculating the accessory for manufacturing accuracy in the form of a tolerance of the distance of the axis of the conductor bushing to the mounting plane of the bracket.

Safety requirements for the designed device

The developed design of the device complies with all safety requirements: there are no sharp angles, it is easy to remove chips, the hands of the worker do not fall into the processing zone.

Working on milling machines with a pneumatic clamping device is allowed for persons who have completed an introductory training on labor protection, training and certification in the qualification commission, as well as those who have received instructions on safe working methods directly at the workplace.

Before starting of operation there must be no foreign objects on the accessory. Pressure on pressure gauge, condition of pneumatic equipment must be normal. Clamps shall be in retracted condition.

At the end of operation, the clamps must be retracted, the machine and accessory must be cleaned from chips, the rubbing parts must be lubricated..

In compliance with these requirements, as well as other mandatory plant-wide equipment requirements. safety operation on a machine with a pneumatic device will be safe.

Conclusion

Advantages of the developed device:

1. In the design of the device, 79% of standard parts and assemblies are used, which leads to a decrease in the cost of its manufacture.

2. The device is mechanized due to the use of a pneumatic cylinder, which leads to a decrease in the auxiliary time for processing the parts.

3. The accessory will ensure complete basing of the workpiece and eliminate the fixation error due to the stable force of the pneumatic cylinder, which will increase the accuracy of processing.

4. The device according to the design is convenient in operation.

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