cnc machining report – wheel base

CNC Machining Report - Wheel Centre Abstract: This work involved the formulation and analysis of the machining process plan to complete

the fabrication of a ‘wheel centre’ with Computer Numerical Controlled (CNC) machinery. This is

further augmented with a Numerical Control (NC) program written in ISO G-code, to machine the part

utilising CNC turning techniques.

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Table of Contents

1 INTRODUCTION 12 NC/CNCFUNDAMENTALS 23 PARTANALYSIS 33.1 GeometryFeaturesandDimensions 33.2 RoughnessandAccuracy 43.3 DimensionalTolerances 43.4 MachiningMaterial 43.5 CompatibleMachiningComponents 53.6 StockMaterial(Billet) 54 PROCESSPLANNING 64.1 WorkHoldingStrategy 74.2 DatumPoint 84.3 MachiningOperations 104.4 OperationSequencing 115 CNCISOG‐CODEMACHININGPROGRAM 125.1 CoordinateSystemsChoice 125.2 ChoiceofFixture 135.3 CNCMachineSpecifications 135.4 CuttingToolParametersandAccuracy 146 CONCLUSION 15A. SCHEMATICOFMACHINEDWORK‐PIECE. 17B. G‐CODEMACHININGPROGRAM 18

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Table of Figures Figure1:Suppliedschematicofwheelcentre 1Figure4:Schematicoftheproposedbillet. 5Figure5:Pro/Esketchbeforerevolvingby360ºaroundtheverticaldatumontheleft. 6Figure6:Pro/Emodelofmachinedworkpiece. 6Figure7:Solidandwireframemodeloftheworkholdingstrategy(sideview). 7Figure8:Datumpointofworkpieceshownonthechuckmountedbillet(topdownview).

8Figure9:Datumpoint, shownon imageontheright,onmachiningschematic (topdown

view). 9Figure10:TypicalturningcentreconfigurationwithspindlefaceastheXaxisandspindle

centrelineformingtheZaxis(leftimage,topdownview).Noticethecuttingtoolis

locatedbehindthecentrelineinbothimages. 12Figure11:DefiningcharacteristicsofaCNCmachine. 13

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1 INTRODUCTION

The primary objective of this report is the formulation and analysis of the machining

process plan to complete the fabrication of the wheel centre, shown in Figure 1, with

Numerical Control (NC)/Computer Numerical Controlled (CNC) machinery.

Figure 1: Supplied schematic of wheel centre

Most of the engineering schematics and 3D modelling produced in this report has

been performed utilising Pro/Engineer (Pro/E) Wildfire 4.0 developed by the

Parametric Technology Corporation.

The methodology used in the analysis includes research into the history of NC/CNC

fundamentals, part analysis and process planning and sequencing. Ultimately a NC

program is developed using ISO G-code for the above wheel centre to be machined in

a typical University metal workshop, and is located in Appendix B.

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2 NC/CNC FUNDAMENTALS

The creation of Numeric Control (NC) is credited to John Parsons, who was a

machinist and salesman of Parsons Corporation, which belonged to his father. After

much tribulation, in 1949 the United Stated (US) Air Force funded the development

for the design a machining system to aid in the machining of wings for helicopters

and aircraft (Quesada, 2004)xiii. Parsons decided to contact the Servomechanisms

Laboratory at Massachusetts Institute of Technology (MIT), pioneers in the field of

mechanical computing and motor control systems that implemented feedback so as to

ensure constant driving speed and torque under a load.

On the 14th of August 1952, MIT filed a patent with the US Patent office for a

“Numerical Control Servo-System” – this was the birth of NC. With NC systems, the

commands for experimental metal work had to be performed by hand so as to create

“punch tapes”. A gentleman by the name of John Runyon thought of having a

computer handle all the ‘input’ and this once again resulted in funding from the US

Air Force for the development of a programming language for NC – this was the

creation of Computer Numeric Control (CNC) (Sing, 1996)x.

The metal cutting tasks required were as follows:

1. Determining the location where the machining was to be performed.

2. Controlling the path during the motion of the tool or work-piece.

3. Controlling the rate at which this path was traversed.

4. Controlling the rate at which the tool was fed in into the work-piece.

These are known in NC as: (1) the datum point, a point of reference from which all

Euclidean distances are measured, (2) control is established by the means of linear or

circular interpolation in general, (3) and (4) is known as the feed rate.

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NC blocks are formed of words that are split into 5 categories of commands (with

examples included):

1. Preparatory functions

2. Axis motion commands: X, Y, and Z commands.

3. Feed rate and speed commands: Address words F and S.

4. Identification commands: N or T word.

5. Miscellaneous commands: ‘M’ words (M03, M08)

Linear programming is achieved with the G01 command and referencing the intended

destination location in (X, Y, Z). Contouring is achieved by incorporating G01

commands with the circular interpolation commands G02 (CW direction) and G03

(CCW). It should be noted that rapid control over tool positioning is managed by the

G00 and F commands (Sing, 1996)x.

3 PART ANALYSIS

3.1 GEOMETRY FEATURES AND DIMENSIONS

The part has been described as a ‘wheel centre’ in the supplied schematic, and as such

this geometry is revolute and symmetrical.

The noticeable features of the part in Figure 1 are:

• Base has a thickness of 8 mm and diameter of 240 mm.

• Second layer has a thickness of 8 mm and diameter of 210 mm.

• From the base, along its central symmetrical axis, to its tallest point is 20 mm.

• There is a tapered contour from the second layer to its tallest point at the

forefront of the part; this tapering accounts for a thickness of 4 mm that

follows from the 210 mm diameter of the second layer to the diameter of its

tallest point (90 mm) which is symmetrical about its revolute axis as well.

The centres of the diameters of 240 mm, 210 mm and 90 mm are aligned with the

symmetrical axis.

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The dimensions of the part are significant due to the extremely fine taper. The overall

thickness of the part to its total diameter has a ratio of 1:12, i.e. each increase in

thickness by a mm accounts for an increase in diameter by 12 mm.

3.2 ROUGHNESS AND ACCURACY

Roughness parameters are calculated to describe the granularity in the smoothness of

the surface (or lack thereof). Of most of the roughness parameters in use, Ra, is by far

the most widely encountered (Kalpakjian and Schmid, 2005)iv as it is the arithmetic

mean of absolute values of vertical deviations of the surface, where it is simply

defined (typically in micrometres) as,

€

Ra =1n

yii=1

n

∑ (1)

Although the supplied schematic (Appendix A) specifically states that all dimensions

are in millimetres (mm), it is typical for surface finish (Ra) to be indicated in

micrometres (µm) with a Ra value of 12.5 µm resulting in visible tool marks.

Therefore the value marked in ‘green’ in Figure 1 is understood as 0.8 µm, which

needs to be finished to similar smoothness as that of a bearing surface.

3.3 DIMENSIONAL TOLERANCES

The required tolerances for all dimensions are taken as ± 0.5 mm, although this may

be considered as too conservative. This means that for example the top surface of Ø

90 mm will be machined to 90 ± 0.5 mm and thus the diameter will vary anywhere

between 89.5 mm and 90.5 mm. This liberty has been taken as the supplied

specification (Appendix A) has indicated most of the dimensions accurate to, at most,

1 or 2 significant digits.

3.4 MACHINING MATERIAL

The Vickers hardness of pure aluminium is 167 MPa when compared with that of iron

at 608 MPa, or Tungsten Carbide (the material out of which most cutting tools are

manufactured in) at 22 GPa (Gere and Goodno, 2008)iii. Considering an aluminium

alloy is used as the billet material, the substances it is alloyed with can greatly vary.

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However, it should still the primary characteristic of machine-shop grade aluminium

that is machining friendly.

3.5 COMPATIBLE MACHINING COMPONENTS

As per the analysis above, it is apparent that the machining needs to be performing on

a turning centre as circular and symmetrical part geometries are ideally machined

using lathing operations on turning centres.

Minimum of two tools are required: (i) for profiling the features and (ii) for vertical

slicing through the work-piece material. The accuracy of these tool-tips will

determine the smoothness of the cut (depending on other factors such as spindle

speed, feed rate etc.).

Typical lathing operations will be able to machine the final part from the supplied

billet. These turning operations need to be sequenced carefully to ensure correct

machining of the part, down to the correct level of surface finishing and compensating

for tool radius during profiling and cutting.

3.6 STOCK MATERIAL (BILLET)

The supplied schematic (Appendix A) states that the billet has a diameter of 250 mm

with a length of 25 mm. To satisfy the possibility of machining a one part set and

multiple parts set on the same NC/CNC turning centre, it is proposed that the

aluminium alloy is formed of a rod 500 mm (0.5m) in length.

Figure 2: Schematic of the proposed billet.

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4 PROCESS PLANNING

‘Process Planning, as the name simply implies, is a means for systematically

identifying and specifying the needed machining operations to machine the final part

from the billet. Since the ‘Part Analysis’ has already been completed, it has been

decided to implement lathing operations to machine the final part.

The aid in visualising the particular problem at hand, the supplied schematic was

sketched as a 2D part in Pro/E and was made into a solid part by revolving the sketch

by 360º around the vertical datum on the left (Toogood, 2007)xii.

Figure 3: Pro/E sketch before revolving by 360º around the vertical datum on the left.

‘Rounds’ with a radius of 2 mm were applied (Lamit, 2001)vii to the three edges

shown in the supplied schematic (Appendix A). The modelled wheel centre is shown

below,

Figure 4: Pro/E model of machined work-piece.

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4.1 WORK HOLDING STRATEGY

Since the work-piece is to be machined using lathing operations, the work holding

strategy simply reduces to utilising a chuck, which is a specialized type of clamp used

to hold rotating tools or materials. Lathing centres tend to have three or four-jaw

chucks, however, other types may be encountered (Bray, 2003)i.

To further explain how the work-piece is to be machined, a simple model of a

‘hypothetical’ chuck (Wikipedia, 2009)xiv with billet (held in place by tightening

screws that have not been modelled for the sake of simplicity) was rendered (Kelley,

2008)v in Pro/E and is shown below,

Figure 5: Solid and wireframe model of the work holding strategy (side view).

For the purposes of running the developed G-code, the billet needs to be locked into

place so as to protrude 100 mm (10 cm) from the vertical face of the chuck or jaw-

type chuck. The diameter of the pre-fabricated billet is 250 mm, as defined in the

supplied schematic (Appendix A).

Although there is material wastage working from a larger than necessary diameter,

this allows for the machining process to remove any surface oxidation and ensures

that the entire part is worked out of ‘freshly’ cut metal. This could be important if

there are further stages involving metal treatment, such as anodizing for example.

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4.2 DATUM POINT

In the diagram below, the datum point of the work-piece has been indicated on the

mounted billet, with a Euclidean distance of 75 mm along the Z-axis taken from the

foremost surface of the chuck.

Figure 6: Datum point of work-piece shown on the chuck-mounted billet (top-down view).

This datum point will be referenced as (0, 0) in the developed machining system and

as such great care is needed for any negative motion along the Z-axis to prevent

damaging the tools, and the lathe itself.

As per Figure 7, the datum point is shown placed upon its symmetrical axis flush with

its base, which has a 240 mm diameter. This schematic also clearly depicts all the

dimensions of the final product (apart from the surface roughness attribute of the 90

mm diameter frontal plane).

The developed G-code was based upon the features and dimensions shown in Figure

7.

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Figure 7: Datum point, shown on image on the right, on machining schematic (top-down view).

The X and Z-axes have been indicted above for clarity, as much referencing will be

made to coordinate systems operating in these two orthogonal planes. All lathing

operations are achieved with the cutting tool advancing towards the work-piece along

the X-axis whilst parallel with the Z-axis (Quesada, 2004)xiii.

The datum point on the mounted work-piece has been chosen to be located 75 mm

along the Z-axis (Figure 6), as this allows for 5 mm of excess in finishing the front

profile to the roughness tolerance indicated in the supplied schematic (Appendix A).

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4.3 MACHINING OPERATIONS

Based upon the features of Figure 7, the task of machining the part has been reduced

to a particular sequence of the following three lathing operations (Conover, 2001)ii,

Straight Turning:

Image Source: (Sing, 2000)x

• RECOMMENDED MACHINE TOOL: turning centre.

• CUTTING TOOLS: side-tool (1) with tool-tip radius for

rough profiling and (2) with sharp profile for finishing.

• FIXTURES: turning centre chuck.

• CUTTING PARAMETERS: rough and finishing profiles.

• NC/CNC MACHINE: CNC

Taper turning:



• CUTTING TOOLS: side-tool (1) with tool-tip radius for

rough profiling and (2) with sharp profile for finishing.




Cutting off:



• CUTTING TOOLS: parting-tool (1) with tool-tip radius for

rough cutting and (2) with sharp profile for finish

cutting.




All three operations are to be run on CNC machine (Wikipedia, 2009)xv as it will

ensure the work-pieces can be turned on a single machine-tool, considering the

benefits of CNC. CNC is far more flexible than NC machines due to its inherent

integration with computer control and software to greatly extend the capabilities of

the system past that of simple Microcontroller control (Morton, 2005)ix.

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4.4 OPERATION SEQUENCING

The sequencing of operations to machine the final part, are defined as follows with

the notation of (Z [mm], X [mm]) used with respect to the location of the datum point.

0. Safe tool starting

& resting position

Position the tool tip at a safe distance away from the work-

piece (40, 140). Load the parting-tool into the tool holder.

1. Cutting off

(rough profile)

Cut from (20, 140) along the vertical X-plane to (20, -140)

with TNR compensation for rough profile.

2. Cutting off

(finishing profile)

Finishing cut from (20, 140) along the vertical X-plane to

(20, -140)). Change to the side-tool via manual swap.

3. Straight turning

(rough profile).

Turn first layer; rough profile of r = 120 mm (Ø 240 mm)

with TNR compensation for rough profile.

4. Straight turning

(finishing profile).

Finishing profile of r = 120mm (Ø 240 mm) with TNR

compensation for smooth profile.

5. Straight turning

(rough profile).

Turn second layer to 10 mm thickness; rough profile of r =

107 mm (Ø 214 mm)

6. Straight turning

(finishing profile)

Finish layer with 8 mm thickness and profile of r = 105

mm (Ø 210 mm)

7. Taper turning

(rough profile)

Taper from of r = 47 mm (Ø 94 mm) to r = 107 mm (Ø 214

mm); taper has an excess of 2mm thickness.

8. Taper turning

(finishing profile)

Finish taper from of r = 45 mm (Ø 90 mm) to r = 105 mm

(Ø 210 mm); taper has an excess of 2mm thickness.

10. Straight turning

(finishing profile)

Starting from (20, -105), perform linear interpolation

vertically along the X-plane to finish the foremost face

smoothly to rest at (20, 105).

9. Straight turning

(finishing profile)

Starting from (16, 103) round the three edges located at: (i)

(16, 105), (ii) (8, 105) and (iii) (8, 120) with circular

interpolation (with radius 2 mm for each ‘round’). Change

to the parting-tool via a manual swap.

11. Cutting off

(finishing profile)

Position the tool-tip vertically centred above the datum

point (0, 140). Cut through the vertical X-plane to (0, -

140), with TNR (left) compensation for parting-tool radius.

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It should be noted that after each operation performed in the sequence above (except

for operation No. 10), the tool tip needs to be returned to a safe location away from

the spindle, chuck and work-piece

To ensure the basic profiling of the part is performed to a relatively high degree of

smoothness and finish, the layers and tapering operations have been sequenced in

pairs of rough and finish profiling. The finishing profiles are accompanied by a

higher spindle speed and low tool feed rate (Quesada, 2004)xiii.

5 CNC ISO G-CODE MACHINING PROGRAM

The developed CNC program in ISO G-Code is located in Appendix B.

5.1 COORDINATE SYSTEMS CHOICE

The coordinate system will be based upon operations in the X and Z-planes, as

previously shown, with regard to the datum point of the work-piece. This is ideally

suited for lathing operations, due to their inherent ‘symmetrical’ nature, and this

representation is commonly used in industry (Smid, 2007)xi.

Image Source: (Krar, Gill and Smid, 2000)vi

Image Source: http://www.mmsonline.com,

Date accessed 24 March 2009.

Figure 8: Typical turning centre configuration with spindle face as the X-axis and spindle centre

line forming the Z-axis (left image, top-down view). Notice the cutting tool is located behind the

centre line in both images.

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5.2 CHOICE OF FIXTURE

Although some types of chuck designs tend to offer better work holding

characteristics and quick means for accessing and replacing the work-piece, the

choice of fixture has been chosen to be the standard adjustable chuck that is

commonly found on lathing systems, as discussed earlier during the Process Planning

phase.

5.3 CNC MACHINE SPECIFICATIONS

The three main characteristics of a CNC machine (Krar, Gill and Smid, 2000)vi are: (i)

the number of parts it is able of producing per hour, (ii) the material hardness that can

be machined and (iii) the level of surface finish required. Graphs of all these are

show in Figure 9 below.

Image(s) Source: http://www.mmsonline.com,

Date accessed 24 March 2009. Figure 9: Defining characteristics of a CNC machine.

Based on the design requirements defined in the supplied schematic (Appendix A),

the machine of choice for profiling the part in question would have the following

characteristics:

1. MACHINE THROUGHPUT: 1 to 10 per hour (or less).

2. MATERIAL HARDNESS: standard (approx. Vickers 167 to 400 MPa)

3. SURFACE FINISH: performance

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Further to the previously mentioned characteristics of the system, the following

criteria for selection need to be met as well:

• MACHINE-TOOL TYPE: turning centre.

• AXIS DRIVE: motion in two orthogonal axes.

• ACCURACY: within ± 0.5 mm (as per supplied schematic).

• TOOL HOLDING: manual change, single-tool holder.

• I/O FUNCTIONS: spindle speed and coolant (mist) control

• FEED RATE: minimum 300 mm/min (5 mm/s)

• SPINDLE SPEED: minimum 1000 rev/min (16.67 rev/s)

• MOTOR POWER: minimum of 1.5 hp

Rather than selecting a system with a multiple tool holder, the CNC program has been

designed to work with manual changes of the tool in a single tool holder system.

However, this does not prevent the CNC program from being run on a system with a

multiple tool holder.

5.4 CUTTING TOOL PARAMETERS AND ACCURACY

Particular attention has been paid to the positioning of the cutting tools and especially

the choice of coordinate system. Tool-Nose Radius (TNR) compensation has also

been employed to easily allow for the operator to compensate for variations that may

present themselves during machining without the need for directly modifying the

CNC program (Lynch, 1991)viii, but rather, the associated TNR value for the

particular tool being used.

Due to the class of a particular commercial grade tool, the thickness of a machined

work-piece tends to vary in size. The tool-tip radius largely determines the tool

accuracy and a tool with a .005 tool-tip radius would typically be employed for rough

cuts, whereas a tool-tip of 0.0002 radius would be more suited for finishing cuts.

TNR compensation further plays a vital role in contouring. Without TNR

compensation, much material may not be machined during this motion. It also allows

for the same tool trajectories to be utilised during both rough and finish profiling.

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6 CONCLUSION

The machining quality for a single part set could offer a better finish depending on the

experience of the CNC operator and on his methodology in first testing the NC

program with no work-piece attached, and how well the TNR tolerances are

compensated for.

Multiple part sets are easily produced by repeatedly running the NC program with

constantly re-aligning the billet datum point for the machining to take place. With

sufficiently high spindle speeds and low tool feed rate it would be possible to finish

the work-piece to a very high degree.

The tolerance of the final part could even be taken as ± 0.1 mm as long as the CNC

system supports this. The quality of both the side-tool and parting-tool will also have

an impact on the resulting machined part.

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REFERENCES i Bray, S. (2003) Metalworking Tools and Techniques, Wiltshire, UK: Crowood

Press.

ii Conover, E. (2001) The Lathe Book: A Complete Guide to the Machine and its Accessories, 2nd edition, Newtown, CT: The Taunton Press, Inc.

iii Gere, J.M. and Goodno, B.J. (2008) Mechanics of Materials, 7th edition, Toronto,

Canada: Cengage Learning, Inc.

iv Kalpakjian, S. and Schmid, S. (2005) Manufacturing, Engineering and Technology, 5th edition, Upper Saddle River, NJ: Prentice Hall.

v Kelley, D. (2008) Pro/Engineer Wildfire Instructor, 4th edition, New York, NY: McGraw-Hill

vi Krar, S., Gill, A. and Smid, P. (2000) Computer Numerical Control Simplified, New York, NY: Industrial Press, Inc.

vii Lamit, G. (2001) Pro/ENGINEER Wildfire™ 4.0, Toronto, Canada: Cengage Learning, Inc.

viii Lynch, M. (1991) Computer Numerical Control for Machining, New York, NY: McGraw-Hill.

ix Morton, J. (2005) The PIC Microcontroller: Your Personal Introductory Course, 3rd edition, Oxford, UK: Newnes.

x Singh, N. (1996) Systems Approach to Computer-Integrated Design and

Manufacturing, Somerset, NJ: John Wiley & Sons, Inc.

xi Smid, P. (2007) CNC Programming Handbook, 3rd edition, New York, NY: Industrial Press, Inc.

xii Toogood, R. (2007) Pro/ENGINEER Tutorial Wildfire 4.0, Mission, KS: Schroff

Development Corp. xiii Quesada, R. (2004) Computer Numeric Control: Machining and Turning Centres,

Upper Saddle River, NJ: Prentice Hall. xiv Wikipedia (2009) Lathe (metal), http://en.wikipedia.org/wiki/Lathe_(metal), Date

accessed 24 March 2009.

xv Wikipedia (2009) Numerical Control, http://en.wikipedia.org/wiki/CNC, Date accessed 24 March 2009.

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A. Schematic of Machined Work-piece.

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B. G-Code Machining Program This program relies upon the TNR compensation information stored for tool 1 in

registers #1 and #2 to control rough and finish profiling of many of the surfaces

machined.

%

N000 G90 G21 Absolute programming in metric units

N010 G97 G94 M06 T0101

Constant spindle RPM, feed rate in

mm/min, select tool 1 (parting-tool) and its

TNR value from register #1 for rough

profile.

N020 G00 Z40000 X140000 F0 Rapid move to safe tool start position.

N030 G00 Z20000 X140000 F0 Position above plane of cut.

N040 M03 S300 F250 M08 Start spindle (clockwise) at 300 RPM, tool

feed rate of 250 mm/min and enable

coolant.

N050 G42 Enable TNR compensation (right)

N060 G01 Z20000 X-140000 Utilise parting-tool to rough-cut through

billet.

N070 G40 Disable TNR compensation.


N090 G00 Z20000 X140000 F0 Position above plane of cut.

N100 S500 F120 Spindle speed of 500 RPM and tool feed

rate of 120 mm/min for finishing profile

N110 G42 T0102 Enable TNR compensation (right) and load

TNR value from register #2 for smooth

profile.

N120 G01 Z20000 X-140000 Utilise parting-tool to finish cut through

billet.


N140 G00 Z40000 X140000 F0 M09

M05

Rapid move to safe tool start position for

manual tool change, stop coolant and

spindle.

Replace the parting-tool with the side-tool for straight turning. We now proceed to machine

the first layer.

N150 M06 T0101 Select tool 1 (side-tool) and its TNR value

from register #1 for rough profile.

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N160 G00 Z40000 X140000 F0 Recalibrate safe tool start position.

N170 M03 S300 F250 M08 Start spindle (clockwise) at 300 RPM, tool

feed rate of 250 mm/min and enable

coolant.

N180 G00 Z40000 X120000 F0 Rapid move to align with pending profile

N190 G42 Enable TNR compensation (right)

N200 G01 Z-20000 X120000 Linear interpolate past vertical plane of

datum point (enough clearance to cut-off

part at the end).








profile.

N260 G01 Z-20000 X120000 Linear interpolate past vertical plane of

datum point (finishing profile).



We now proceed to machine the second layer.


rate of 250 mm/min for rough profile




profile.

N320 G01 Z8000 X105000 Linear interpolate the rough profile of the

second layer.








profile.

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N380 G01 Z8000 X105000 Linear interpolate the finishing profile of the

second layer.



We now proceed to machine the tapered feature.


rate of 250 mm/min for rough profile




profile.

N440 G01 Z16000 X105000 Linear interpolate the rough profile of the

tapered feature.








profile.

N500 G01 Z16000 X105000 Linear interpolate the finishing profile of the

tapered feature.



Finish profile the foremost face (Ø 90 mm) with high precision side-tool.

N530 G00 Z40000 X-105000 F0 Rapid move to intermediate location.

N540 G00 Z20000 X-105000 F0 Rapid move to align with pending profile



profile.

N560 G01 Z20000 X105000 Linear interpolate vertically along the X-

plane.

Perform ‘rounding’ the three edges located at: (i) (16, 105), (ii) (8, 105) and (iii) (8, 120)

N570 G01 Z16000 X103000 Arrive at the starting point of first ‘rounding’.

N580 G03 Z14000 X105000 I2000 Circular interpolation (CCW), 1st edge.

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K2000

N590 G01 Z10000 X105000 Linear interpolate to the next starting point.

N600 G02 Z8000 X107000 I2000

K2000 Circular interpolation (CW), 2nd edge.

N610 G01 Z8000 X118000 Linear interpolate to the next starting point.

N620 G03 Z6000 X120000 I2000

K2000 Circular interpolation (CCW), last and final

edge.


N640 G00 Z40000 X140000 F0 M09

M05

Rapid move to safe tool start position for

manual tool change, stop coolant and

spindle.

Replace the side-tool with the parting-tool for separating the part from the reset of the billet.

N650 M06 T0102 Select tool 1 (parting-tool) and its TNR

value from register #2 for smooth profile.

N660 G00 Z40000 X140000 F0 Recalibrate safe tool start position.

N670 M03 S500 F120 M08 Start spindle (clockwise) at 500 RPM, with

tool feed rate of 120 mm/min


N690 G41 Enable TNR compensation (left)

N700 G01 Z00 X-140000 Linear interpolate along vertical plane of

datum point, to cut the machined part off.


N720 G00 Z40000 X140000 F0 M30 Rapid move to safe tool position and turn

off all machine functions.

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QUALITY CONTROL ID: 603001 WORD COUNT: ~3000 (EXCLUDING EQUATIONS, FIGURES, CAPTIONS, DATA, CODE, OUTPUT, TABLE OF CONTENTS, LIST OF FIGURES, LIST OF TABLES, REFERENCES AND APPENDICES.) 15-20 REFERENCES/3K WORDS? 15 REFERENCES (INC. BOOKS, JOURNALS AND WEB) WEB REFERENCES < 15%? 2 WEB REFERENCES DATE COMPLETED: 24TH MARCH 2009 / 1551 HRS GMT NOTES: AMENDED AS PER THE REQUEST OF THE CLIENT TO 15 PAGES IN LENGTH FOR THE MAIN REPORT TEXT. G-CODE LISTING HAS BEEN RELEGATED TO APPENDIX B. DATE COMPLETED: 24TH MARCH 2009 / 1833 HRS GMT NOTE: This document has been created with compatibility for Word 97 – 2004. It is recommended that

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cnc machining report – wheel base

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