Process Tooling Design

Contents

Introduction

1.Specific Features of Milling Machine Tool Designs

2. Information about the process operation

2.1 General part

2.2 Characteristics of the machine

3 Installation of the workpiece in the accessory

3.1 Selection of bases

3.2 Layout and fixing diagram

3.3 Installation method. Basing error

3.3 Calculation scheme, equilibrium equation and clamping force calculation

Selection of clamping device

Defining the Initial Force

3.4 Calculation of the drive

4 Elements for tool coordination

4.1 Design Features

Errors

5 Installation of accessory on the machine

5.1 Installation Method

Errors

6 Dividing device. Design features. Division errors

7 General error of accessory

8 Structure of the accessory

8.1Hull Features

8.2 Strength calculations

8.4 Justification of the developed accessory

8.5 Description of the structure and operation of the accessory

Literature

Graphic part:

Part Drawing

Specification (of accessory components)

Assembly drawing

Drawings of parts from accessory structure

Introduction.

Processing productivity largely depends on: the degree of equipment of production with technological equipment. The more process equipment is used, and the higher its technical level, the higher the productivity. The degree of equipment of different industries varies. In large-scale and mass production, equipment is much higher than in individual and small-scale production. This mainly explains the fact that the labor intensity of manufacturing such parts in large-scale and mass production is 2-3 times, and sometimes 5 times less than in small-scale and individual.

The cost of tooling is high - it accounts for about 30% of all production preparation costs, so in the conditions of individual and small-scale production, where the nomenclature of products is often replaced, it is not possible to have a high degree of equipment.

Naturally, the task of reducing the cost of tooling and reducing the time of its manufacture, and therefore the preparation of production, is one of the most important tasks of modern production.

Design features of milling machine tools.

In connection with the design of milling machines and the specifics of the work performed, the devices for them must meet the following requirements: the parts must be located on the machine table so that the surfaces we need can be treated so that the elements for fastening the workpiece do not interfere. Typically, the milling machine tools consist of a body which is in the form of a plate or box on which the clamping devices, the actuator, the mounting elements, the coordinating elements on the machine table and the coordinating elements of the cutting tool relative to the part are mounted.

As a drive, depending on the type of production and the qualities of the part, both manual and pneumatic, hydraulic and pneumohydraulic can be used.

Process Operation Details

In this operation, the pipe ski is milled. The size of 62.5mm shall be maintained within the tolerance of 0.3mm. Roughness Ra 6.3 is required.

Milling is performed by end cutter GOST 2435980 with hard alloy cutters T15K6:

Mill height from teeth tops L = 50mm.

The largest diameter of the cutter D = 100mm.

Diameter of cutter mounting hole d = 32mm.

Number of cutting teeth z = 10.

Install the workpiece in the accessory.

When designing a machining process, the technician selects the machining installation bases on which the machining accuracy of the part depends. Installation of the machined part with basic surfaces in the tool determines its position relative to the cutting tool.

There are three main methods of mounting a machining part:

1) with individual reconciliation of its position according to compliance

surfaces;

2) with reconciliation of its position on markup risks;

3) with its direct installation in the accessory.

The first two methods are very laborious and are used when installing parts on machines in single and small-scale types of production. The third method of mounting parts in the device is the best, since it ensures the exact position of the part in the working area of the machine, requires a minimum of auxiliary time; used in mass, large-scale types of production.

Select databases.

Process bases are the surfaces used to determine the position of a workpiece or article in the manufacturing process (GOST 21495-76). When the part is installed in the accessory, real surfaces directly contacting the fixture mounting elements are taken as process bases.

Position of part in accessory is determined by its basing surfaces. Parts installed in machine tools have different basing surfaces in shape and appearance.

Design bases are the bases (surfaces) used to determine the position of a part in a product or subassembly. These bases must first be used to install the workpiece in the appliance, since less processing errors are obtained. The design bases of parts by purpose are basic and auxiliary.

When machining surface (end face) - A

The original base of the surface is B, because the original dimension H is set from it.

The installation base of the surface is B because it is most developed and with the help of it it is easy to coordinate the part in space.

The measuring base of the surface (end) is B, since the initial dimension H is set from it.

Initial (structural) dimension - H.

Design features and errors.

In this case, we apply the standard high-altitude installation (GOST 409157) of Fig. 4a. The milling cutters are oriented by standard probes.

Errors in the location of the cutters in the device with the installation. The error δP N is expressed by the error ± γ of size from the setting element to the working surface of the installation. The maximum value of this sinfulness is δP H = 2 γ.

The adjustment error δH in this case is: the result of the combined effect of two errors of the probe manufacturing error in thickness (by diameter) and the error of the milling cutter installation in the probe.

The maximum error value of the probe is equal to the tolerance for manufacturing the probe by thickness (diameter). For probes with a thickness (rum diameter) of 1-3 mm, the absolute deviation will be 0.006 mm, and with a thickness of 5 mm - 0.008 mm.

The accuracy of installation of the cutter on the probe depends on the qualification of the worker. You can't calculate it. It can be about 0.01-0.02 mm.

Installation of the accessory on the machine.

Devices can be installed on the machine (depending on its type) on the spindle, on the table or on some other of its working bodies. For installation of accessories on each machine seat is provided.

As a rule, machine seats are standardized. In revolving machines, seats according to OST 428 and GOST 257058 are also used.

In order to quickly and accurately install the device on the machine, special surfaces are made on it that are consistent with the seats of the machine. These are the so-called mounting surfaces of the device. The designer designing the device must know which machine it is intended for and have all the necessary data about it. landing place. Only then does he choose how to install the fixture on the machine and design the landing surfaces.

Divider. Design features. Division errors.

Dividing devices are designed so that in one installation of the part it is possible to give it several positions in order to treat a number of surfaces located at a given step relative to each other.

In multiposition machining, a part often has to be rotated by an angular pitch rather than moved by a linear pitch. Therefore, only rotary units would be considered in the future.

Dividing device can be made in the form of separate independent unit used for fixation of various devices for their rotation by angular pitch together with processed part. Such units include universal dividing heads, rotary dividing tables and posts. Their designs are very diverse, some of them are normalized.

The dividing device may also be part of the device itself, usually a special one.

In both cases, the divider should have the following main parts and assemblies: fixed and rotating parts, divider disk, retainer and mechanism for fastening the turning part to the fixed part after division.

Fixed part in dividing device is its body. In dividing units - heads, tables and posts - the fixed part is the unit housing. In special devices with a dividing device, the fixed part is the body of the device itself).

The fixed part, like each housing of the device, has mounting surfaces and centering elements for the rotating part.

The pivoting part is usually mounted on some shaft mounted in the centering elements of the fixed part. Depending on the weight of the rotating part together with the workpiece, it can be mounted on sliding or rolling bearings. At vertical axis of rotation rotary parts of large weight rest on rolling bearings. In some designs, the rotatable part with a vertical axis rests on the rolling bearing only at the moment of rotation (division). To do this, before turning, it is slightly lifted from smooth ring guides using a special lifting device, and after turning, it is lowered.

On the rotary part there are mounting elements for installation of the processed part and clamping devices for its fixation.

In dividing heads, tables and posts on the turning part there are provided seats for installation of devices.

Dividing disk is the main part of dividing device. It is usually mounted on a rotary part and with it turns at the time of division. Dividing discs have sockets into which retainer enters. The sockets are arranged circumferentially at such an angular step (from each other) that it is necessary to withstand the workpiece. In universal dividing units, the sockets are arranged in such a way as to ensure division of the circle into several equal parts with one disk.

Dividing disks are divided into two groups in the shape of sockets: with holes and with slots.

Discs are made raw. In order to reduce the wear of the walls of the holes, heat-treated bushings 2, which have been cleaned to high hardness, are pressed into them.

Structure of the accessory and features of the housing.

This body is much functional and has a complex shape.

At the same time, it is a guiding element for the part, a prismatic surface, and at the same time it is a body of a power device (hydraulic cylinder). Also, a lever for strengthening the clamping force is mounted on it .

On the surface of the table in contact with the slots, keys are attached to coordinate the device on the machine.

Also mounted on it is a machine for adjusting the cutter to size.

Justification of the developed device.

This device is designed for milling the end face of the PTO 2002 - 4026 DT part. It allows you to process two parts at once, unlike standard universal devices.

The accessory allows to secure the blank quickly and reliably with the help of hydraulic cylinder. Using the installation, you can easily set the mill to the desired size .

Description of the structure and operation of the accessory.

This device consists of position spirit for fixation of blanks made in the form of prisms and pin. Clamping is performed by levers by means of two-piston hydraulic cylinder by means of oil supply to working cavity under pressure of 6 mPa.

пружина.cdw

Сборочный чертеж.cdw

Труба.cdw