Process Tooling Course Project

Contents

1 INTRODUCTION

2 TERMS OF REFERENCE

3 ANALYSIS OF BASELINES

4 POWER CALCULATION

4.1 Determination of components of cutting force

4.2 Selection of clamping mechanism

5 ADJUSTMENT OF ACCESSORY TO SIZE

6 ACCURACY CALCULATION

7 DETERMINING THE ECONOMIC IMPACT

8 DESCRIPTION OF THE PRINCIPLE OF OPERATION OF THE DEVICE

9 CONCLUSIONS

10 LIST OF LITERATURE USED

Introduction

Accessories in mechanical engineering are the accessories to process equipment used in machining, assembly and inspection operations.

According to the target purpose, devices are divided into devices for metal cutting machines (turning, milling, drilling, etc.), for assembly, control and testing processes.

Depending on the degree of mechanization and automation, manual, mechanized, semi-automatic and automatic devices are distinguished.

According to the degree of specialization, machine tools are divided into universal, special and specialized (readjustable).

The design of the devices is carried out in three stages:

1) first make a schematic diagram of installation and fixation of the workpiece to be treated or the assembled assembly unit in the appliance;

2) then calculation of accessory elements is performed;

3) constructively design the assembly drawing in the form of a project.

The main calculations in the design of the devices are as follows:

1) calculation of clamping forces;

2) calculation of ensuring accuracy;

3) economic feasibility of manufacturing the device.

Machine tools have the greatest specific weight in the total weight of the tooling, with the help of which 3 main tasks are solved:

1. basing the machined parts on a machine with verification bases reconciliation is replaced by basing without reconciliation, which accelerates the basing process and provides the possibility of automatic sizing on tuned machines;

2. increased productivity, and easier working conditions of workers through mechanization of devices, as well as through the use of multi-seat, positional and continuous processing;

3. expanded technological capabilities of machines, which allows to perform such processing on conventional machines or to obtain such accuracy for which machines are not intended.

Recently, the level of mechanization and automation of devices has increased significantly, as well as a lot of work has been done to standardize their parts, assemblies and individual structures. Extensive mechanization of devices in serial and small-scale production has become possible on the basis of the application of 2 modern principles in design:

1. creation of readjustable (group, universal) devices with individual mechanized drive (pneumatic, hydraulic, electromechanical, etc.);

2. creation of universal (aggregated) power units for sequential maintenance of a number of universal devices.

At the same time, in single and small-scale production, a system of universal prefabricated devices was widely used, based on the principle of repeated use of a certain set of standard parts and assemblies, from which a variety of devices are assembled over several hours

Use of the readjusted and universal and combined devices and also universal drives sharply reduces expenses of means and time for production preparation.

Adjust fixture to size

Adjustment of the accessory to the resulting dimensions is necessary to automatically obtain machined surfaces, excluding the process of monotone measurements and passes. Adjustment is performed after replacement of cutting tool, removal of accessory from machine, after repair of accessory.

The accessory is adjusted using the installation.

During rearrangement of the accessory (after each installation of the accessory on the machine), it is necessary to set the accessory to the received times-measures (in our case, to the size of 29 ± 0.1 mm.

At the same time, this process is subject to certain requirements:

1) the time for adjustment of the device should be insignificant;

2) adjustment shall ensure the necessary accuracy of the accessory;

3) the tuning scheme should be convenient and, if possible, exclude complex and painstaking measurements.

First, it is necessary to install the accessory on the machine. The accessory is installed on the machine by means of locating keys. The keys are inserted into the central precise slot of the table, thereby ensuring parallelism between the central axis of the device and the longitudinal axis of the table.

The accessory is fixed along the interfacial slots of the table due to bolts and nuts.

When the workpiece is removed and the spindle is off, the table rises until the cutter touches the lower surface of the installation (this achieves the height position of the cutter relative to the tool). The cutter is then removed from the fixture area. The cutter is retracted by means of longitudinal feeding of the table. The accessory is considered tuned.

When machining parts, use only longitudinal feed. The use of transverse and vertical feeding is prohibited, since this will inevitably lead to the appearance of marriage.

Description of the principle of the device operation

The accessory is designed to mill the plane onto the passage with width 35 at length 38 mm, maintaining size 29 ± 0, 1 mm relative to the pro-longitudinal axis of the part. Milling is carried out by end cutter, machining is carried out by means of longitudinal feeding of machine table. When processing parts, the use of transverse and vertical feeding of the machine table is not allowed.

Before operation it is necessary to adjust the accessory to the received dimensions. This is done using the installation (see 5. Adjust fixture to receive dimensions).

After the fixture has been set up, you can start working.

Installation and fixing of the workpiece. The blank is installed along two holes with a diameter of 22mm and a diameter of 6.8mm on two pins with a diameter of 22mm and cut with a diameter of 6.8 mm. Blank is secured by displacement of spring cone by means of screw clamp. The purpose of the spring cone in the additional centering of the post-preform and in the creation of the second guide base, which significantly increases the accuracy of the device. For convenience and increase of fixing speed, wheel is attached to shaft-screw on key, nut and spring washer. By turning the wheel one way or the other, the blank is clamped and squeezed. After fixing at the end of the part, the billet plane is milled. Setting to size is performed by installation.

Conclusions

The designed accessory satisfies the required working conditions. It is convenient to use, provides the necessary accuracy parameters, easily and quickly re-set, repairable.

This device can be classified as unified, changing the mounting and clamping elements on it, it is possible to process various parts having cylindrical holes.

The device made it possible to reduce the mass of time compared to standard universal devices (due to basing and back-up).

In part processing, only one longitudinal feed is used, which reduces the processing of parts to an elementary process, and allows you to service the process of processing by low-skill workers.

To secure the blank, a low physical force of the machine tool is used, which increases the ergonomics of the designed device.

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