Creo parametric basic turning by jouni ahola

It is derived based on the cutting speed and the work diameter cut in case ofturning/ boring or tool diameter in case of drilling/ milling etc.... Tool geometry: For the tool to effectiv

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2.4 FIXTURE

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2.5 WORKCELL

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LATHE MACHINE TOOL

SIMULATION………

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2.7 CUTTING TOOLS

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FACE AREA OPERATION 2

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CREATING CL DATA FILE FOR OPERATION

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1.2

This book consists of several chapters each dealing with a primary theme of CreoParametric and are meant to be used alongside the running Creo Parametric

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1.3

ating NC steps The reference model can be also imported from the other CAD-software You must assemble a reference model before creating NC steps

edges are selected from the reference model and are used as references when cre-

3 Workpiece model – This represents the unmachined stock material It is an op-tional element and is not required to create NC steps However, using a

workpiece enables you to simulate the machining of the stock material

Workpieces can be standard stock billets or you can configure them to representmodels such as castings

4 You can assemble or create a workpiece in a manufacturing model A number

gular or round workpiece depending on your requirements

of options are available An automatic workpiece enables you to create a rectan-5 Fixtures are parts or assemblies that can be used to hold the component being

tures

and simulation have been completed, you can create ASCII format cutter location(CL) data files for operations or selected NC steps This CL data file will thenhave to be postprocessed to generate an MCD file, containing the proper CNCcodes

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Default settings:

Save settings:

Open Configuration Editor Select Find

Type keyword: pro_mf – Find Now

These all settings are for directories

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box, you get the New File Options window Here you can select or browse template.

Sometimes may happen, that you can´t open templates or there is no template whatyou need You can create customized templates that can be used to create new partsand assemblies

Creo Parametric Basic Turning

tem locates

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Below is the picture of 5 axis mill/turn machine:

You have to create the coordinate system of the template match to the machine axis.Usually in lathes, Z-axis is horizontal and pointing away from the chuck and it iscollinear with turning axis

You can define the plane as XZ-plane and create view for it Rotate the template sothat you can see coordinate system as below:

Icon - Select Working Directory:

From the Folder Tree or Web browser- Right click the folder and select: Set

Working Directory.

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From the File menu:

Click (File), Open – Right click the folder:

hide tags:

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Creating of the coordinate system for turning.

In the Ribbon - Select Model – Coordinate System:

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1.9

Model properties

analyses File - Prepare - Model Properties:

Note! If you use templates for start modeling or importing, the units comes from thetemplate Material can also be defined in the template However, you can changethem from Model Properties

Task 1.9: Material – change:

Select material from the list and move it to the Materials in Model window.

1.10 Cutting parameters

You should know the Basics about Metal Cutting Parameters before creatingtoolpaths

1 Material machinability: The machinability of a material decides how easy

or difficult it is to cut The material’s hardness is one factor that has a stronginfluence on the machinability

4 Spindle speed: Spindle speed is expressed in RPM (revolutions per minute).

It is derived based on the cutting speed and the work diameter cut (in case ofturning/ boring) or tool diameter (in case of drilling/ milling etc.) If V is thecutting speed and D is the diameter of cutting, then Spindle speed N = V /(Pi

7 Tool geometry: For the tool to effectively dig into the component to remove

material most efficiently without rubbing, the cutting tool tip is normally

gle, approach angle, etc.) The role played by these angles in tool geometry is

cant in cutting to reduce tool wear, coolants are used in metal-cutting Cool-on

9 Machine/ Spindle Power: In the metal-cutting machine, adequate power

should be available to provide the drives to the spindles and also to providefeed movement to the tool to remove the material The power required for

cutting is based on the metal removal rate – the rate of metal removed in a

pends on work material, tool material, the cutting speed, depth of cut, and

given time, generally expressed in cubic centimeters per minute, which de-feed rate

10 Rigidity of machine: The rigidity of the machine is based on the design and

construction of the machine, the age and extent of usage of the machine, thetypes of bearings used, the type of construction of slide ways, and the type ofdrive provided to the slides All play a role in the machining of componentsand getting the desired accuracy, finish, and speed of production

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1.10.1 Cutting Speed Formulas

dle Cutting speeds are usually given in feet or meters per minute and these speedsmust be converted to spindle speeds, in revolutions per minute, to operate the ma-chine Conversion is accomplished by use of the following formulas:

Most machining operations are conducted on machine tools having a rotating spin-Where N is the spindle speed in revolutions per minute (rpm); V is the cutting speed

in feet per minute (fpm) for U.S units and meters per minute (m/min) for metricunits In turning, D is the diameter of the workpiece; in milling, drilling, reaming,and other operations that use a rotating tool, D is the cutter diameter in inches forU.S units and in millimeters for metric units π = 3.1417

Example: The cutting speed for turning a 4-inch (102-mm) diameter bar has beenfound to be 575 fpm (175.3 m/min) Using both the inch and metric formulas, calcu-

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More formulas for Turning:

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1.10.2 Feed and Depth of Cut

The axial (or in face turning the radial) tool movement is called feed, fn, and ismeasured in mm/r When feeding radially towards the centre of the workpiece, therpm will increase, until it reaches the rpm limit of the machine spindle When thislimitation is passed, the cutting speed, vc, will decrease until it reaches 0 m/min atthe component centre The feed (f) in mm/rev is the movement of the tool in relation

The cutting depth (ap) in mm is the difference between un-cut and cut surface It is

ting depth is always measured at right angles to the feed direction of the tool

half of the difference between the un-cut and cut diameter of the workpiece The cut-The cutting edge approach to the workpiece is expressed through the entering angle

(κr) This is the angle between the cutting edge and the direction of feed and is an

important angle in the basic selection of a turning tool for an operation The enteringangle usually varies between 45 to 95 degrees but for profiling operations, even larg-

er entering angles are useful The entering angle can be selected for accessibility and

ing the number of tools needed

to enable the tool to machine in several feed directions, giving versatility and reduc-Feed and depth of the cut are chosen together The ratio (f : ap) is important factor aswell as the cross-sectional area of the chip (A= f x ap)

Recommended ratio for the feed and depth of the cut in turning is:

f: ap = 1:6 – 1:10

For example if the depth of the cut is 3mm, the feed can be 0.5 – 0.3mm Guidingvalue for roughing feed is 0.2-1.0mm and for finishing 0.1-0.3mm

The perfect surface quality in turning would not be achieved even in the absence of

irregularities and deficiencies of the cutting process, as well as environmental ef-face roughness

In turning operations, the generated surface finish will be directly influenced by thecombination of nose radius and feed rate

The nose radius also affects the chip formation Generally, chip breaking improveswith a smaller radius

As a general rule of thumb, the depth of cut should be greater than or equal to 2/3 ofthe nose radius, or 1/2 of the nose radius in the feed direction

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1.10.4 Constant Surface Speed

To maintain a constant rate of material removal as the cutting diameter decreases,most CNC machines automatically speed up the spindle, based on how far the toolmoves towards center This constantly variable spindle control is called ConstantSurface Speed (CSS) mode It is commanded on most machines using G96 to acti-vate, and G97 to de-activate

When the tool moves down the face of the part, the diameter where the cutting edgecontacts the part gets smaller

ple, don’t use CSS mode for drilling or tapping on part centerline

CSS does not apply where the tool does not change its position along X For exam-Creo Parametric Basic Turning

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1.11 Camshaft cutting parameters

ers choose to make the camshaft from steel billet In this case the material of thecamshaft is EN40B It is a chromium-molybdenum nitriding steel and usually sup-plied in the hardened and tempered condition, which offers high wear resistance to-gether with good toughness and ductility It is characterized by its suitability for ni-triding, which can give a hard wear resistant core in the range of 61-65Rc The rela-tively low temperature of the nitriding process produces components with a scalefree surface, and minimum distortion

Cutting speed (V) for Carbide tools is 300 foot per minute (ft/min) = 90m/min

rameters.

Note! Keep in mind previously mentioned the Basics about Metal Cutting Pa-For example: The diameter of the bar is 50mm and when using carbide inserts thecutting speed is 90m/min

The spindle speed is 573 rev/min

tial manufacturing model configuration You can also make user-defined templatemanufacturing models Using a template manufacturing model is recommended

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fault datum planes and a default coordinate system

The new manufacturing model is created by using template You can see three de-2.2

Reference model

You must assemble a reference model before creating NC sequences The referencemodel represents the final machined component Surfaces and edges and the otherfeatures are selected from the reference model and are used as references when creat-ing NC sequences

Task 2.2: Select Working directory Start New – Manufacturing.

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NC Assembly is ready – Fully Constrained - Accept.

You can hide the other coordinate systems from model tree so that only visible isfrom the reference model

workpieces – for example default Automatic This enables you to create simple rec-tangular or round workpiece You can also create workpieces using the InheritedFeatures option As well you can select the model as workpiece Picture below the

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You can change Overall Dimensions from Options Page:

Now the reference model is inside the workpiece All green color means the materialwhat is needed to remove Save the manufacturing model

Task 2.3 is ready.

Select Components and Add a fixture component Browse to the folder where the

fixture locates:

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Select Datum Plane from the reference model:

Give value 0 for Offset and Flip The orientation should be as below CoordinateSystem X-axis positive pointing to the jaw number 1

Accept Component Placement.

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Fixture setup is almost ready Give the name for the fixture setup Select Propertiespage:

Give the name and Accept

Adjust the jaws Select jaw number 1.from the fixture Select Edit Definition, Give

value 25 for Distance as below Accept

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Fixture setup is ready

Now you can see the Fixture Setup and in this case it will be better if you add morelength to workpiece and fix it more than 30mm

Select Workpiece from the model tree and Edit Definition:

Add 50mm more length and accept:

2.5

Workcell

The workcell specifies the type of machine used when creating NC sequences, forexample, mill, lathe, or mill/turn You must specify a workcell before you can create

NC sequences

Workcells consist of a number of different elements that describe the capabilities ofthe machine tool, including post-processor options, multiple axis output options, siteparameter file options, and the ability to configure a PPRINT table

Mill/Turn, or Wire EDM The number of axes you can specify is dependent on theworkcell type.

LOADTL, COOLNT/OFF, and SPINDL/OFF statements are output in CL data files.– Cutter Compensation – When you expand this field, the following output cutterposition options become available:

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Task 2.5: Create Lathe Work Center using previous information:

After needed information, you should have work center in the Model Tree and youcan change or add information if wanted

Task 2.5 is ready.

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2.5.1 Lathe Machine Tool Simulation

Within Creo Parametric you can simulate the CNC machine running the various NCsequences you created The Lathe machine assembly is selected within the Assemblytab of the Lathe Work Center dialog box This machine assembly can be edited torepresent your CNC machine You must specify a reference coordinate system for

the machine assembly (MACH_ZERO) This reference coordinate system should be

the same location as the machine zero coordinate system for the operation

Once the machine has been properly defined, the simulation of the operation with themachine can be reviewed The system displays the machine tool simulation in a newwindow You can then use typical play commands from the Animate dialog box.Some commands include controlling the speed of the simulation, stopping the simu-lation, and capturing the simulation to an MPEG file As the machine simulationplays you can zoom and rotate the machine to any desired view When you close themachine tool simulation display, the system returns you to the manufacturing model

An operation consists of a number of configured elements such as:

o The machine coordinate system (specified by the machine zero position)

This also specifies the direction of the X- and Z-axes on the machine tool

o An optional fixture setup

When these items have been specified, you can create NC steps to machinecomponents assembled into the manufacturing model These NC steps refer-ence the machine tool and the machine zero position You cannot create NCsteps until you configure the manufacturing operation and configure a ma-chine tool

Creo Parametric Basic Turning

</MfgWpMaterialList>

quired This enables you to select from more than one workpiece material

Once you configure a tool, you can store the information and use it again There are

three different tool types: standard, solid, and sketched Each type of tool is created

stand the differences between each type of tool and when you should use them

in a different way and is designed for a specific purpose It is important to under-2.7.1 Standard Turning tools

When you start configure a tool, the default is standard tool:

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log box The type of tool, for example turning or drilling, determines the tool cross-section and therefore which parameters are available for configuration The tool pa-rameter values control the tool shape, for example:

You create standard tools by configuring tool parameters within the Tools Setup dia- Length

Nose_Radius

Note, when playing a toolpath, the tool is displayed based on the parameter values

A number of tabs are available within the dialog box that enables you to configuredifferent types of tool information

General – In the General tab, a graphic image of the tool appears during configura-tion You can configure the tool name and tool type Many different standard tooltypes are available for selection The selected tool type determines the displayed toolshape