MULTIAXIS TOOL PATH GENERATION OF CRANK SHAFT

ABOUT RAMTECH MANUFACTURING INDUSTRIES

Today’s developments of technology in the field of manufacturing sector and the

complexity of the aerospace components demanded the new methodologies in the production

practices and management of the production activities. Global business drivers such as

competition, consumer’s desires, and government regulations continue to influence the

manufacturing applications for product and process development, which leads to reduction in

cost and improvement in quality and productivity by reducing scrap and effective utilization of

man and machines.

At Ramtech Mfg. Industries, components are realized from the conceptual design

to computer aided design (CAD) of the component and then the CAD model of the component is

imported in CAM module and the tool path is generated for the component through simulation

and the generated NC program is fed to 5 axis and 3 axis CNC machines to manufacture the

component with high accuracy and surface finish thus covering the entire Product life cycle.

This project outlines, the generation of NC part program (manually or CAM) and

how the CAD tools are used in the study of product drawings and generation of 3D models using

UG-NX7.5 package. Computer aided design and manufacturing is a technology and application

driven field by utilization of which in industrial environment helps to close the gap between

creating the technology and using it. The work involved in the development of modeling of

components, which are going to be produced using the Part Modeling Module in the UG-NX7.5

software and development of post option files and machine configuration file for the machine

tool on which the component is going to be produced.

ABSTRACT

Process planning is a production organization activity that transforms a product design

into a set of instruction (sequence, machine tool setup etc.) to manufacture machined part

economically and competitively. The information provided in design includes dimensional

specification (geometric shape and its feature) and technical specification (tolerance, surface

finish etc.) The project aims for a detailed study about process planning to manufacture a

crankshaft for a 4 cylinder engine.

Modern power train is currently being faced with a variety of contradictions in terms of

emissions, fuel consumption, and noise as well as vibration level. This has forced to develop

concepts that assure high fuel economy, low exhaust emissions and high specific power that

enhance the mechanical performance of the engine through the development of light weight

engine parts.

The crankshaft, sometimes casually abbreviated to crank, is the part of an engine that

translates reciprocating linear piston motion into rotation. To convert the reciprocating motion

into rotation, the crankshaft has "crank throws" or "crankpins", additional bearing surfaces

whose axis is offset from that of the crank, to which the "big ends" of the connecting rods from

each cylinder attach.

The project aims for a detailed study about process planning to manufacture a crankshaft

for a 4 cylinder engine. Creating 3D model for crank shaft and generating multi axis tool path

and generating NC program for 5-axis DMG milling machine.

This process involves the following steps:

i. Development of 2D drawing

ii. Selection of suitable material with mating parts

iii. 3D model

iv. CAM process

Selection of raw material

Selection of machine

Selection of tool

Fixture design

Sequence of operations

Tool path generation

Process optimization

Post processor

INTRODUCTION

Process planning refers to the product design and decides how to manufacture it within

the resource constraints. Process planning can be seen as an activity which integrates knowledge

about products and resources.

Manufacturing process planning is the process of selecting and sequencing

manufacturing processes such that they achieve one or more goals and satisfy a set of domain

constraints.

Process planning is a production organization activity that transforms a product design

into a set of instruction (sequence, machine tool setup etc.) to manufacture machined part

economically and competitively. The information provided in design includes dimensional

specification (geometric shape and its feature) and technical specification (tolerance, surface

finish etc.)

My project deals with the manufacturing of “Crank Shaft” component using CAM

software (‘UGNX-7.5’ which is a CAD/CAM software used to generate part program by

designing and feeding the geometry of the component) and defining the proper tool path and

thus transferring the generated part program to the required CNC machine with the help of DNC

lines. Then the program is executed with suitable requirements.

The component can be either designed in UG or can be retrieved from any other CAD

software. Then sequence of programs such as modeling the component, selection of tools

according to the sequence of operations and sizes, generating the tool path, at last the generated

NC part program is verified and sent to the required CNC machine to manufacture the particular

component. Finally the required surface finish has been obtained by machining the component at

optimum speeds and feeds and the cost of machining is also optimized by choosing optimal

machining process and machine tools.

COMPUTER AIDED DESIGN

Computer-aided design (CAD), also known as computer-aided design and drafting (CADD),

is the use of computer systems to assist in the creation, modification, or optimization of a

design.

CAD may be used to design curves and figures in two-dimensional (2D) space or curves,

surfaces, and solids in three-dimensional (3D) space.

CAD is an important industrial art extensively used in many applications, including

automotive, shipbuilding, and aerospace industries.

CAD is one part of the whole Digital Product Development (DPD) activity within

the Product Lifecycle Management (PLM) processes, and as such is used together with other

tools, which are either integrated modules or stand-alone products.

Today’s industries cannot survive worldwide competition unless they introduce new

products with better quality, at lower cost, and with shorter lead time. Accordingly, they have

tried to use the computer’s huge memory capacity, fast processing speed, and user-friendly

interactive graphics capabilities to automate and tie together otherwise cumbersome and separate

engineering or production tasks, thus reducing the time and cost of product development and

production. Computer-aided design (CAD), computer-aided manufacturing (CAM), and

computer-aided engineering (CAE) are the technologies used for this purpose during the product

cycle. Thus, to understand the role of CAD, CAM, and CAE, we need to examine the various

activities and functions that must be accomplished in the design and manufacture of a product.

Computer-aided design (CAD) is the use of computer technology for the design of

objects, real or virtual. CAD often involves more than just shape. As in the manual drafting of

technical and engineering drawings, the output of CAD often must convey also symbolic

information such as materials, processes, dimensions, and tolerances, according to application-

specific conventions.

Product life cycle

COMPUTER AIDED MANUFATURING

Computer-aided manufacturing (CAM) is the use of computer-based software tools that

assist engineers and machinists in manufacturing or prototyping product components and tooling.

CAM is a programming tool that makes it possible to manufacture physical models using

computer-aided programs.

Manufacturing as the design stage is a set of activities assigned to the producing of the

designed part. The manufacturing is one of other activities after design stage. The problem

consists in transformation of the CAD data to the manufacturing data. The manufacturing data

are sometimes called as CAM data.

The 10 largest CAM software products are:

Catia

Cimatron

Edgecam

Mastercam

NX

Powermill

Pro/E

Space-E/CAM

Tebis

WorkNC

Applications of CAD/CAM:

AutoCAD is a computer-aided drafting and design system implemenented on a personal

computer. It supports a large number of devices. Device drivers come with the system and

include most of the digitizers, printer/plotters, video display boards, and plotters available on the

market.

AutoCAD supports 2-D drafting and 3-D wire-frame models. The system is designed as a

single-user CAD package. The drawing elements are lines, polylines of any width, arcs, circles,

faces, and solids. There are many ways to define a drawing element. For example, a circle can be

defined by center and its radius, three points, and two end points of its diameter. The system

always prompts the user for all options.

Programming for NC, CNC, and industrial robots;

Design of dies and molds for casting, in which, for example, shrinkage allowances are

preprogrammed;

Design of tools and fixtures and EDM electrodes;

Quality control and inspection----for instance, coordinate-measuring machines

programmed on a CAD/CAM workstation;

Process planning and scheduling.

NUMERICAL CONTROL

The punched tape is the precise input medium used to control moving members of a

machine tool "automatically" as opposed to "manually". Organized numerical information

properly placed on an input medium, usually tape, functions as a series of sequenced machine

tool operating commands. The operating commands are executed automatically with amazing

speed, accuracy, efficiency, and repeatability.

When a command signal is given to the drive unit to perform the motion through certain

distance, the slide moves from the distance desired, which do not have a feedback device and

thus the actual position of the tool slide or worktable is not measured and verified. This system

depends upon the quality of the drive unit.

Open loop system is most often used on large machines that have already retrofitted. This

system offers cost savings for light duty, machinery where problems of instability are absent and

high precision is not required.

In closed loop system, program transmits to the control system, which tells where the tool

slide or table should be positioned. A feedback device transmits a signal back to the control

system including the true position, which creates an unbalanced condition. After the difference is

accurately measured by the electrical control system, the system transmits electrical signals to

the drive mechanism, causing the table tool slide to move in a direction tending to reduce this

difference.

COMPUTER NUMERICAL CONTROL

In CNC Machine tools, the part program punched on tape is run only once and then

stored in the Computer Memory. In recent CNC system the tape reader has been eliminated

altogether by incorporating Manual Data Input (MDI). In MDI consoles are elaborate

alphanumeric keyboards, which allow writing of fairly complex part programs directly into the

computer memory. In off line programming, the part program is written on a personal computer

using the appropriate programming software and is then loaded into the CNC system through a

data communication line.

CNC systems are widely used especially in the metal cut industry. The most common

applications are in milling, turning, drilling, boring, grinding and many other machining

operations. It is also effectively applied to press working, inspection machines, automatic

drafting, riveting, injection moldings etc, and even textile Industry.

Computer Numerical Control (CNC) is one in which the functions and motions of a

machine tool are controlled by means of a prepared program containing coded alphanumeric

data. CNC can control the motions of the work piece or tool, the input parameters such as feed,

depth of cut, speed, and the functions such as turning spindle on/off, turning coolant on/off.

The benefits of CNC are:

(1) High accuracy in manufacturing

(2) Short production time

(3) Greater manufacturing flexibility

(4) Simpler fixturing

(5) Contour machining (2 to 5 –axis machining)

(6) Reduced human error.

INTRODUCTION TO UNIGRAPHICS

NX, also known as NX Unigraphics or usually just U-G, is an advanced CAD/CAM/CAE

software package developed by Siemens PLM Software.

It is used, among other tasks, for:

Design (parametric and direct solid/surface modeling)

Engineering analysis (static, dynamic, electro-magnetic, thermal, using the Finite

Element Method, and fluid using the finite volume method).

Manufacturing finished design by using included machining modules

First release of the new "Next Generation" version of Unigraphics and I-deas, called NX.

This will eventually bring the functionality and capabilities of both Unigraphics and I-DEAS

together into a single consolidated product.

Increasing complexity of products, development processes and design teams is

challenging companies to find new tools and methods to deliver greater innovation and higher

quality at lower cost. Leading-edge technology from Siemens PLM software delivers greater

power for today’s design challenge. From innovative Synchronous Technology that unites

parametric and history-free modeling, to NX Active Mockup for multi-CAD assembly design,

NX delivers breakthrough technology that sets new standards for speed, performance, and ease

of use.

NX automates and simplifies design by leveraging the product and process knowledge

that companies gain from experience and from industry best practices. It includes tools that

designers can use to capture knowledge to automated repetitive tasks. The result is reduced cost

and cycle time and improved quality.

COMMONLY USED BASIC GD&T SYMBOLS

INPUT FOR THE PROJECT

2D Drawing

A 2D drawing is used to design a 3D model for our component using Unigraphics NX 7.5

CAD software.

Below shows the 2D drawings of the CRANK SHAFT with all the required dimensions

and GD&T representations the suits the best for manufacturing the component without any

errors.

Steps involved in 3d modeling

Sketching

Below is the sketch required to obtain the 3D model of the CRANK SHAFT from the

above 2D drawing.

Below image shows the sketch of the crank shaft

Procedure to draw the above sketch

Insert sketch in task environment select plane ok.

insert curve profile.

By using profile curve we will get the 2D design of crank shaft.

Below image shows the revolve option for the crank shaft.

Revolve

By using revolve command we convert sketch from 2D to 3D only for axis

symmetry bodies.

Insert design features revolve.

Select curve specify vector Boolean operation (none) ok.

Below image shows the sketch of the profile required.

Procedure to draw the above sketch

Insert sketch in task environment select plane ok.

insert curve profile.

Below image shows the extrude option .

EXTRUDE

Extrude command is used to create a body by sweeping a 2D or 3D section of curves,

Edges, sketches in a specified Direction.

Insert design features extrude.

Select curve specify vector Boolean operation (none) ok.

Below image shows the instance geometry option.

INSTANCE GEOMETRY

Copies Geometry into various pattern arrays

Here we use mirror

Insert associative copy INSTANCE GEOMETRY

Mirror select object specify plane ok.

Below image shows the instance geometry option.

INSTANCE GEOMETRY

Copies Geometry into various pattern arrays

Here we use translate.

Insert associative copy INSTANCE GEOMETRY

translate select object specify vector specify distance ok.

Below image shows the extrude option at one end of crank shaft.

EXTRUDE

Extrude command is used to create a body by sweeping a 2D or 3D section of curves,

Edges, sketches in a specified Direction.

Insert design features extrude.

Select curve specify vector Boolean operation (unite) ok.

Below image shows the hole option.

HOLE

Generate holes on the body by using Simple, Counter bore and Counter sunk.

insert design features hole.

In form & dimensions specify type of hole required (simple hole) and dimensions of hole (4dia,

15 depth). In Boolean select subtract option then click ok.

Below image shows the entire 3D component of the crank shaft.

MANUFACTURING PROCESS PLAN FOR CRANK SHAFT

CAM PROCESS

COMPUTER AIDED MANUFATURING

Computer-aided manufacturing (CAM) is the use of computer-based software tools

that assist engineers and machinists in manufacturing or prototyping product components and

tooling. CAM is a programming tool that makes it possible to manufacture physical models

using computer-aided programs.

Manufacturing as the design stage is a set of activities assigned to the producing of the

designed part. The manufacturing is one of other activities after design stage. The problem

consists in transformation of the CAD data to the manufacturing data. The manufacturing data

are sometimes called as CAM data.

The 10 largest CAM software products are:

Catia

Cimatron

Edge cam

Master cam

NX Cam

Power mill

Pro/E

Space-E/CAM

Tebis

WorkNC

SELECTION OF MACHINE

Number of different machines is used with an external controller and human or robotic operators

that move the component from machine to machine. In either case, the complex series of steps

needed to produce any part is highly automated and produces a part that closely matches the

original CAD design.

TYPES OF CNC MACHINES:

TYPES OF CNC MACHINE USED IN THIS PROJECT:

DMG 5-axis milling machine is used for manufacturing banjo fitting component. In DMG 5-axis

milling machine X, Y, Z, B, C are 5 vectors, X & Y are tool movement and Z is for table

upwards movement, B for spindle movement, C for table rotation.

High rigidity with Integrated Spindle up to 12000rpm, Spindle is directly coupled with

motor. Vertical Operations, Integrated rotary table of 1200mm X 700mm with rotary dia 700mm.

Horizontal Operations, With head tilting at 90deg.Angular and 5-axes simultaneous machining,

Capable of machining from +30 deg to -120deg head tilting. Machine accuracies, Positional

Accuracy +/- 0.005mm, Repeatability +/- 0.003mm

FOR CRANK SHAFT-axis milling machine is used

SELECTION OF TOOL

Selection of tools plays an important role in manufacturing any component. Proper tools must be

selected otherwise in manufacturing process improper tools results in damage of work piece or

damage to the tools, tool holders.

TOOL DESCRIPTION

END MILL

End mills (middle row in image) are those tools which have cutting teeth at one end, as well as

on the sides. The words end mill is generally used to refer to flat bottomed cutters, but also

include rounded cutters (referred to as ball nosed) and radiuses cutters (referred to as bull nose or

torus). They are usually made from high speed steel (HSS) or carbide, and have one or more

flutes. They are the most common tool used in a vertical mill.

FACE MILL

A face mill consists of a cutter body (with the appropriate machine taper) that is designed to hold

multiple disposable carbide or ceramic tips or inserts, often golden in color. The tips are not

designed to be re sharpened and are selected from a range of types that may be determined by

various criteria, some of which may be: tip shape, cutting action required, and material being cut.

When the tips are blunt, they may be removed, rotated (indexed) and replaced to present a fresh,

sharp face to the work piece. This increases the life of the tip and thus its economical cutting life.

DRILL BITS

Drill bits are cutting tools used to create cylindrical holes, almost always of circular

cross-section. Bits are held in a tool called a drill, which rotates them and provides torque and

axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes.

The shank is the part of the drill bit grasped by the chuck of a drill. The cutting edges of

the drill bit are at one end, and the shank is at the other. Drill bits come in standard sizes.

SETUP 1 TOOLING LIST

We need to select/create a tool for each of the Machining operations. In the Project

Manager, you can create and automatically assign new tools to tool stations in the Tools view.

You can also create tools from the Machining menu.

SHOP FLOOR DOCUMENTATION

TOOLING LIST

MILLING TOOLS

TOOL NAME DESCRIPTION DIAMETER COR RAD FLUTE LEN

ADJ

REG

BALL_MILL Milling Tool-Ball Mill 6.0000 3.0000 125.0000 0

MILL_D20Milling Tool-5

Parameters20.0000 0.0000 50.0000 0

CENTER_DRILL_D2.5 Center Drilling Tool 2.5000 1.2500 50.0000 0

CENTER_DRILL_D8.0 Center Drilling Tool 8.0000 4.0000 50.0000 0

MACHINE SETUP OPERATIONS

Face milling

Vertical multi depth milling

Contour milling

Center drilling

Drilling

TOOLS USED IN MILLING OPERATION

The following is a list of Milling tools and the key dimensions that you can set for each tool foe

deckel cover plate:.

Ball Mill

(D) Diameter

(B) Taper Angle

(FL) Flute Length

(L) Length

Face Mill

(D) Diameter

(R1) Lower Radius

(L) Length

(A) Tip Angle

(B) Taper Angle

(FL) Flute Length

Flutes

TOOLS USED IN DRILLING OPERATION

Spot drill

(D) Diameter

(L) Length

(PA) Point Angle

(FL) Flute Length

Flutes

The following is a list of Turning tools and the key dimensions that you can set for each tool for

deckel cover plate:.

Drilling Tool

(D) Diameter

(L) Length

(PA) Point Angle

(FL) Flute Length

Flutes

FIXTURE DESIGN

A fixture is a work-holding or support device used in the manufacturing industry. Fixtures are

used to securely locate (position in a specific location or orientation) and support the work,

ensuring that all parts produced using the fixture will maintain conformity and

interchangeability. Using a fixture improves the economy of production by allowing smooth

operation and quick transition from part to part, reducing the requirement for skilled labour by

simplifying how workpieces are mounted, and increasing conformity across a production run.

A common type of fixture, used in materials tensile testing

CAM GENERATION

SETUP 1

Below image shows the face milling operation.

Below image shows the verification of face milling operation.

Below image shows the planar milling operation.

Below image shows the planar milling operation.

Below image shows the vertical multi depth milling operation.

Below image shows the verification of vertical multi depth milling operation.

Below image shows the vertical multi depth milling operation.

Below image shows the verification of vertical multi depth milling operation.

Below image shows the planar milling operation.

Below image shows verification of planar milling operation.

Below image shows the planar milling operation

Below image shows verification of planar milling operation.

Below image shows the planar milling operation.

Below image shows the verification of planar milling operation.

Below image shows the planar milling operation.

Below image shows the planar milling operation.

Final component of crank shaft

TOOLING LIST

MILLING TOOLS

TOOL NAME DESCRIPTION DIAMETER COR RAD FLUTE LEN ADJ REG

BALL_MILL Milling Tool-Ball Mill 6.0000 3.0000 125.0000 0

MILL_D20 Milling Tool-5 Parameters 20.0000 0.0000 50.0000 0

CONVERT TO NC CODE

Using the post processor we have to convert CL file data into machine specified NC part

program

1. In the Project Manager, select the first operation on the Operations page, then hold down

the Shift key and select the last operation. All the cutting operations are selected.

2. Press the right mouse button and select NC Code from the menu.

3. Select a Machine Format file from the pull down list (3-Axis/5-Axis).

4. Select Apply.

RESULTS & CONCLUSION

We have generated 3d model by using unigraphics nx7.5 cad software

NC program for crank shaft is generated using cam software.

Generated NC program is given to CNC machines through DNC lines.

As we have optimized Optimum cutting speed, by using 5-axis machine which has high

flexibility in manufacturing by this we can increase Production rate and optimum cost

criteria in manufacturing of crank shaft.