Course tool for cutting tool

Contents

Introduction

1. Design of cutter with NSR

1.1. Initial data

1.2. Cutter material with NSR

1.3. Calculation of cutter with NSR

1.4. Description of cutter structure with NSR

2. Tool Block Design

2.1. Initial data

2.2. First Drill Material

2.3. Tool Block Calculation

2.4. Description of Tool Block Design

3. Disk Modular Cutter Design

3.1. Initial data

3.2. Disk Modular Milling Cutter Material

3.3. Disk Modular Milling Mill Calculation

3.4. Disk Modular Cutter Design Description

4. Flat Pattern Design

4.1. Initial data

4.2. Drilldown Material

4.3. Drilldown Calculation

4.4. Description of the flat pattern design

5. Design of threaded rolling rollers

5.1. Initial data

5.2. Material of threaded rollers

5.3. Calculation of threaded rollers

5.4. Description of the design of threaded rollers

6. Spline Worm Cutter Design

6.1. Initial data

6.2. Spline worm cutter material

6.3. Calculation of splined worm cutter

6.4. Spline Worm Cutter Design Description

Conclusion

List of sources used

Project Description

PP consists of: 47s., 3 Fig., 2 tables, 10 sources.

The objects of the study are metal cutting tools.

The purpose of the work is to master and deepen the knowledge gained in the course "Designing metal cutting tools," and acquire practical skills in calculating and designing tools.

In this course project, according to the initial data, it is necessary to:

design a cutter with mechanical attachment of hard alloy plates;

Select and calculate the positioning accuracy of the tool block

Design and calculate a modular disk cutter

Design a sweep to treat the hole with the specified accuracy

Design the thread rolling rollers to roll the specified thread.

design and calculate a splined worm cutter for processing a given splined shaft;

KEYWORDS:

THE TOOL, CUTTER, MILL, DEVELOPMENT, ROLLER, THE TOOL BLOCK, QUICK CUTTING STEEL, SOLID ALLOY, THE STEEL ALLOYED, DETAIL, MANDREL.

INTRODUCTION

In modern mechanical engineering, cutting is the main technological method that ensures high quality and accuracy of machined surfaces of parts. The most important task for the economic and social development of the country is to accelerate scientific and technological progress through integrated mechanization and automation of production. The efficiency of mechanical engineering should be improved by changing the structure of the metalworking equipment fleet, including automatic lines, CNC machines, robotic, microprocessor and computer equipped flexible automated systems (GAC) and flexible production systems (GPS), which allow you to quickly and efficiently rebuild production for the production of new products.

The efficient operation of said equipment is impossible without the creation of perfect tooling, which has increased reliability, ensuring the economical, labor-saving use of expensive progressive equipment, which makes the metal working tool increasingly important. Therefore, specialists who have to work in metalworking industries should be able to correctly design various types of tools, including tool tools for machine tools, automatic lines, CNC machines, quick-change technological systems, taking into account the requirements for machined parts, equipment features and production efficiency.

Thus, the general line of development of mechanical engineering - comprehensive automation of design and production - requires knowledge and perfect knowledge of design methods that ensure the creation of highly efficient designs of cutting tools.

Design of cutter with cmp

Cutter is the most common tool in the metalworking industry. It is used when working on turning, turret, carousel, boring, strict, long machine tools, turning machines, semi-automatic machines and on many other special-purpose machines. The variety of the use of cutters gave rise to many forms of structures and their geometric parameters, which vary depending on the type of machine and the type of work performed.

Cutters are divided into the following types:

1) according to the type of machine tools: a) lathes; b) strict; c) long; d) cutters for automatic and semi-automatic machines; e) boring for horizontal boring machines; f) special for special machines; g) shaped;

2) by type of processing: a) pass-through; b) undercut; c) cut-off; d) slotted; e) boring; f) shaped; g) threaded;

3) for installation relative to the part: a) radial; b) tangential;

4) by the nature of the treatment: a) defective (draft); b) finished; c) for fine turning;

5) along the cross section of the rod: a) rectangular; b) square; c) round;

6) according to the head design: a) straight; b) bent; c) curved; d) drawn-out;

7) in the direction of supply: a) right; b) left;

8) according to the manufacturing method: a) with a head made integral with the rod; b) with the head welded into the joint; c) with welded or soldered plate; d) with welded strip; e) with built-in head; f) with a replaceable insert head provided with a cutting material plate;

9) by type of material: a) with hard alloy plates; b) made of fast-cutting steel; c) with plates made of mineraloceramics.

1.2. CUTTER MATERIAL WITH NSR

For the treatment of structural quality steel, when finishing, it is recommended to choose a solid alloy of the titanium tungsten group, namely T15K6, T14K8 and T30K4 grades with the following characteristics ([4], vol. 4.9, p.96):

- T15K6: short-term bending strength limit: 1150 MPa; HRA hardness, not less than: 90;

- T14K8: short-term bending strength limit: 1250 MPa; HRA hardness, not less than: 89.5;

- T30K4: short-term bending strength limit: 950 MPa; HRA hardness, not less than: 92;

For this type of treatment, I finally choose the T30K4 hard alloy grade as the most suitable for the specified cutting parameters ("Finishing turn with a small section of the section" - ([4], vol. 4.9, p.96)).

To manufacture the cutter holder, I choose 40X steel GOST 454371 as having good cutting properties and positive mechanical properties after heat treatment.

Tool Block Design

The operational feature of CNC machines is their flexibility, which allows you to automate the production of parts. The efficiency of machine operation requires flexible tool support, which makes it possible to process any surfaces with the minimum possible range of cutting and auxiliary tools, providing its automatic non-stop replacement with a given accuracy. The solution to this problem is achieved by using an auxiliary tool system for CNC machines, which establishes the nomenclature and basic dimensions. The auxiliary tool system is unified and regulated by the technical material and establishes three subsystems of the auxiliary tool:

a) for NC machines of drilling and boring groups;

b) with cylindrical shank for NC machines of turning group;

c) a base prism for lathe NC machines.

Tooling systems are designed for the arrangement of functional units - tool blocks (combinations of cutting and auxiliary tools), each of which is designed to perform a specific technological transition of processing of a given part on a particular machine. The standardization of tool and machine connection surfaces is an important step.

The units are an interchangeable assembly unit, which provides a quick change of it in the boring bar during operation or sharpening of cutting elements.

Tool blocks installed in the spindle shall provide static accuracy resulting in the outflow of cutting edges in accordance with the allowable cutting edge run-out for the tool.

Auxiliary tool is made of 18ChT steel with cementation and hardening up to 53... 57 HRC. Nuts and screws are made of 40X steel with heat treatment to hardness 37... 41.5 HRC.

Tool unit consists of housing with conical seat 7:24 for installation in spindle, and central hole for installation of mandrel with tool in it. Adjustment of tool departure is performed due to change of nut location with trapezoidal thread.

The accuracy of processing depends on the error of the tool blocks. Accuracy of tool blocks is regulated by permissible radial run-out.

Static accuracy can be obtained by correctly selecting the construction and manufacturing accuracy of the auxiliary tool with appropriate manufacturing accuracy of the cutting tool. The beating of the cutting edges of the tool in the coordinate system of the machine is considered as a closing link in a complex dimensional chain formed by deviations in the linear and angular dimensions of the elements of the auxiliary tool.

The use of theoretical and probabilistic methods allows you to calculate the dependence of the beat of the tool on the accuracy of the production of the auxiliary tool. The angular errors of the links (axis misalignments) and vector errors (parallel axis misalignment) of the tool block elements can be summed up by bringing the axis misalignments to a vector view in the plane of the closing link (beating the cutting part) through the gear ratios.

2.4. DESCRIPTION OF TOOL BLOCK DESIGN

The tool block consists of two main parts: a body and a mandrel, into the groove of which a plate of the first drill is inserted. The tool unit is adjusted in such a way: to extend the mandrel forward, the fixing screws are unscrewed, when the nut rotates clockwise, the mandrel moves forward by the required amount, then the fixing screws are twisted; to return the mandrel to the initial position - forward the fixing screws are unscrewed, the nut rotates counterclockwise and moves to the specified value, under pressing of the hand on the end face of the mandrel, it moves inside the body of the tool unit, then the fixing screws are swirled. The tool block is installed in the spindles of machines with a taper of 7:24 No. 40, the torque is transmitted to the unit body through the end keys.

Disk Modular Cutter Design

Disk modular milling cutters are used to cut spur and oblique cylindrical wheels. In the first case, they work by shaped copying, in the second - by the method of cetroid envelopment. In all cases, the process of sequential processing of depressions is carried out by dividing the blank into one circumferential step .

This method of tooth processing is low-performance and low-accuracy. The reasons for the low productivity are the intermittency of the cutting process, the loss of time for dividing the workpiece. Milling teeth in most cases have irrational geometry. Their leading angle is zero, and the trailing angles on the side cutting edges are very small - 1.5... 2.5 °, as a result of this, the cutting properties of the tool and productivity are reduced.

The low accuracy of processing is due to the error of the dividing mechanism, errors in setting the axis of symmetry of the cutter tooth along the axis of symmetry of the recess between the teeth of the wheel, deviations created by a limited number of cutters in the kit. Therefore, disk modular milling cutters are rarely used, mainly in single production and repair shops for processing gears of low accuracy.

Disk cutters are made in the form of sets of 8 or 15 cutters. At the same time, a set of 8 cutters is recommended for cutting wheels with a module of up to 8 mm inclusive, a set of 15 cutters - for wheels with a module of over 8 mm. Each cutter from the set is intended for cutting wheels with a certain number or group of tooth numbers.

3.2. DISK MODULAR CUTTER MATERIAL.

Disk modular cutters are made of tool alloyed steels (9X1F, 9XC, HVG, HVSG) or fast-cutting (P6M5, P6M3, P6M5K5, P18, P9, P12). For this cutter, I choose the fast-cutting steel P6M3, which has better qualities than instrumental alloyed steels and is more economically profitable among fast-cutting steels.

Flat Pattern Design

A sweep is a tool designed to process holes, which rotates about its axis (main motion) during operation and gradually moves along it, carrying out the feed movement.

The deployment of the hole provides it with 6-8 quality accuracy and roughness parameters Ra = 1.253 μm. The unfolding is applied after the holes have been pretreated with a countersink, boring cutter, or drill. According to the general classifier, drilldowns are separated:

- according to the method of application - for manual and machine;

- by the shape of the hole to be treated - by cylindrical and conical ones;

- by design - for solid and prefabricated, of constant diameter and adjustable;

- by the method of fixation - end (tail) and nozzle;

- by the shape of the teeth and the type of cutting material.

The correct operation of the scan depends on the design, the quality of its manufacture and the operating conditions (cutting, cooling modes, the amount of allowance for deployment, the quality of sharpening and refinement of cutting edges, etc.)

Manual deployments are used to manually deploy holes. The screens with a diameter of 340 mm have a cylindrical shank with a square. Small-diameter sweeps are made with cylindrical or conical shank, with the help of which they are fixed on machine.

The nozzle drills are fixed on special mandrels, which are inserted into the spindle of the machine. The simplest designs are single-piece reamers, but they do not provide for diameter adjustment. In this regard, prefabricated reamers with fast-cutting and hard-alloy insert teeth (knives) are widely used, which, after working and overstocking, can be adjusted to the necessary size by increasing the term of their operation.

Unfold assemblies save tool materials, create optimal geometry, increase cutting properties, and increase dimensional resistance.

Main structural elements of reamer are cutting and sizing parts, number of teeth, direction of teeth, cutting angles, non-uniform pitch of teeth, profile of groove, clamping part.

4.4. FLAT PATTERN DESIGN

The designed machine cylindrical deployment is carried out with threaded knives from hard alloy VK3, a body of 40X steel. The deployment is made with an uneven circumferential pitch, which helps to increase processing accuracy. The grooves of this scan are straight, which simplifies their manufacture and control. The scan teeth have a flat front surface coinciding with the axial plane of the tool, that is, the front angle of the scan is taken equal to zero. Working part of reamer consists of cutting and calibrating part of teeth. The cutting tool removes the allowance, and the sizing tool provides a given shape of the hole, its exact dimensions and the necessary purity of the treated surface. The sizing part consists of two sections: cylindrical and conical, the so-called reverse cone. It is made to reduce the friction of the tool against the treated surface. The number of teeth is taken 10. The teeth have a ribbon. The ribbon provides the direction of deployment in the hole, helps to smooth the treated surface and calibrate the hole in size.

Design of threaded rolling rollers

The threaded rolling rollers are cylindrical discs, on the external surface of which a multi-start thread is formed, or annular turns. The features of the threaded rollers and their dimensions depend on the adopted method of thread rolling, the dimensions of the part, the model of the machine used. Rollers are a versatile tool, since they allow you to roll threads of high accuracy, of various lengths with small and large steps, on a wide variety of materials.

Rolling is one of the most progressive methods of thread formation on various parts and primarily on screws, studs and marks. Currently, the thread rolling process has been especially widely used in large-scale and mass production. So, in the production of throwers, he almost supplanted all other methods of producing threads.

At rolling as a result of action of large radial forces, threads of tool thread deform metal of blank and form thread on it. The treated metal surface layer has higher mechanical properties (increased strength and hardness). This is due to the fact that when rolling the fibers are not cut, as is the case with thread cutting by any cutting tool, but are deformed according to the thread configuration. Threaded ticks can be made more resistant by compacting the surface layer. However, with an improperly selected material or process, surface flakiness may occur and the material is threadably peeled off.

There are two types of rolling tools: rams and rollers. Both tools work with a two-piece kit.

Rolling the threads with rollers has the following advantages:

- work with low specific pressures, which allows to obtain threads on hollow or thin-walled parts, as well as on parts with increased hardness (up to HRC 3545);

- Roll-up of rollers ensures higher accuracy of the thread being rolled compared to slips;

- rollers are easier to install and adjust to the size of the thread being rolled;

- possibility of thread rolling on parts from M2 to M60;

- small dimensions of machines, ease of their adjustment and maintenance.

The disadvantage of rolling with rollers is the reduced productivity (6080 pcs per minute) compared to rolling with dies (100120 pcs per minute).

5.2. MATERIAL OF THREADED ROLLERS

The designed rollers are made of 6X6V3MFS alloy steel, this steel is more wear resistant due to the increased content of chromium, so it is advisable to use it for the manufacture of threaded rolling rollers. After hardening and tempering, 6X6V3MFS steel has a hardness of 58... 61 HRC, which is enough to roll threads on pig iron blanks KF 603. Compared to HVSG steel, 6X6V3MFS alloy steel has higher mechanical properties and significantly higher heat resistance - 490... 510 ° C.

5.4. DESCRIPTION OF DESIGN OF THREADED ROLLERS

The threaded rolling rollers are cylindrical discs on the external surface of which a multi-start thread is formed. The main structural elements of the threaded roll are: outer and middle diameters, width, number of starts. The designed threaded roller has an outer diameter of 140.651 mm, a width of 63 mm, a number of starts of 5. Torque is transmitted through a longitudinal key. Roller is installed on mandrel and pressed by end surface. Therefore, the cleanliness of the end face must be at least Ra1.6.

Spline Worm Cutter Design

Worm splines are a tool that works by enveloping the profile of a workpiece. Worm cutters are worm on which grooves forming front surface of teeth and space for chip placement are cut. The turns are capped in order to obtain rear angles. Worm splined cutters are of two types - for cutting splined shafts with an involute profile of splines and splined shafts with a straight profile. These cutters are used for machining shafts with different types of centering - centering on the outer or inner diameter and side faces. Worm cutters with "antennae" are designed for cutting splined shafts with centering along inner diameter and side faces, which provide a rectilinear section along the entire height of the shaft tooth, and the grooves formed by them at the base of the teeth facilitate the grinding process. Worm cutters without antennae are used to cut splined shafts centered on outer diameter and side faces. Worm mills are designed depending on the series of shafts - light, medium or heavy and are made of the following accuracy classes:

- Class A. Applied for the finishing of splined shafts with d9, h9, e9, f9 tooth thickness tolerance fields and e9 inner diameter tolerance fields;

- Class B. Applied for the finishing of splined shafts with tolerance fields for tooth thickness d10 and inner diameter e8 (the tolerance for the outer diameter of the shaft is not limited);

- class C. Designed for rough processing of splined shafts.

By design, worm mills are:

- solid;

- nozzle;

- prefabricated.

By processing type:

- rough (usually multi-start);

- finished and precision.

By the form the worm who is been the basis for a worm mill:

- involute;

- Archimedean;

- convolute.

6.2. SPLINE WORM CUTTER MATERIAL

We select the material of the tool for processing the splined shaft from steel 40X according to the recommendations [], these are steels P6M5, P12, P18. The designed cutter is made of fast-cutting steel P6M5. This steel is a cheaper substitute for P18 steel and, like P18 steel, is intended for all types of cutting tools in the treatment of carbonaceous, alloyed, structural steels (preferably for the manufacture of a threaded tool, as well as a tool working with impact loads) []. Compared to the P6M5F3 steel, the P6M5 fast-cutting steel has slightly lower mechanical properties, however, the P6M5 steel is not prone to overheating and decarbonizing, the P9M4K8 has higher mechanical properties than the P6M5, but it is used to treat high-strength and heat-resistant steels and has a higher cost. I finally accept the material of worm spline cutter quick-cutting steel P6M5 GOST.

6.4. DESCRIPTION OF SPLINE WORM CUTTER DESIGN

The worm cutter is the original worm turned into a cutting tool by cutting chip grooves and napping teeth (double napping in our case). The main structural elements of the worm cutter are: length, number of teeth, parameters of their occipitation, dimensions, shape and direction of grooves. The designed cutter has an outer diameter of 100 mm, the number of teeth 12. Due to the occipitation of the teeth, the diameters of the cutter decrease as they are flipped along the front surface. Chip grooves are inclined relative to the axis of 4 ° 3440.8. " Torque is transmitted through the longitudinal key, the key is made in accordance with GOST 947290. Cutter is installed on mandrel and is pressed by end surface. Therefore, the purity of the end face is relatively high.