Mechh311 Manual Summer 2011

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MECH311MANUFACTURINGPROCESSES

LABMANUAL

CONCORDIAUNIVERSITY

SUMMER2011

COURSEINSTRUCTORS:

DR.JOHNCHEUNG

LABINSTRUCTORS:

DANIELELIZOV

MICHAELREMBACZ

WRITTENBY: R.KUNANEC,D.MORGAN,D.ELIZOV


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MECH

311

LAB

CHECKLIST

(Students MUSTcomply with all items listed below before entering each lab session. Students

must supply their own glasses / shoes / clothing for this lab.)

Safety glasses

Closed toe shoes (No sandals, flip-flops, etc.)

Old clothes / Lab coat / Coveralls (you will get dirty!)

No loose clothing

No dangl ing jewellery / rings

No cell phones

Tie back long hair

Completed material from previous classes (if applicable)

No food or drink allowed in the lab


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Lab Outl ine & Requirements

Arrive on time as late people wi ll not be admitted to the lab.

Before Lab 1 Before entering the EDML, the student must have successfully passed the

EDML mandatory safety quiz. A successful pass is considered a mark of no less than 100%.

Should the student fail on the first attempt, they will have two other chances to complete the

test; however there is a time delay of 30 minutes between tries. Failure to have successfully

completed the quiz before entering the students first scheduled lab will result in a deduction

of 10% from the final lab mark. See the lab instructor if you fail the test 3 times. Please print

out pages 10, 13 & 27- 29 of this manual and bring it to lab #1.

Lab 1 The student will learn different metrology operations and techniques. The student will

be required to measure an existing gyroscope in the lab and note all of the dimensions on a

sheet which the student must print from the lab manual. Once the measurements have been

taken, the instructor will give a brief introduction to all the machines in the EDML followed by

an introduction to use the mill and lathe for a basic material removal operation. Before leaving

Lab 1, have your sheets initialed by either the lab instructor or TA. With the duly completed

sheets from the lab manual, the student will be required to create three detailed CAD

drawings for their next lab session, as well as submitting the initialed data sheets. The use of

2D AutoCAD is prohibited.Suggested platforms are Solidworks and Catia.

Lab 2 The student will be required to hand in the completed detailed drawings and data

sheets at the beginning of their lab session. These drawings will be corrected and returned.

No marks will be given for the drawings, however failure to hand them in, or a drawing that

has little or no effort put in to it will result in a deduction of 10% from the final lab mark. The

students will be required to correct their mistakes and resubmit their drawings in the final

report.


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The student will also witness a demonstration of either a gyroscope frame or gyroscope rotor

being fabricated. The students will be required to note all the steps in a process sheet

template which can be found at the end of this manual or on the EDML Moodle site. Care

must be taken when filling out this sheet as students will have to follow it to fabricate their

own part. After the demonstration, the student will be placed on his or her own machine and

will complete either half of the frame or the entire rotor. Please print out and bring at least 2

copies of the process sheet template.

Lab 3 The student will continue to complete all the machining operations on the part they

started in Lab 2. The students on the milling machine will continue machining their frame,

while the students that are on the lathe will be able to machine the shaft and fabricate the ring

for the gyroscope. Students must be sure to receive their corrected detailed drawings.

Lab 4 The student will witness a demonstration of either a gyroscope frame or gyroscope

rotor being fabricated (whichever they did not witness in Lab 2). The students will be required

to note all the steps in a process sheet template which can be found at the end of this manual

or on the EDML Moodle site. Again care must be taken when witnessing the demonstration

and filling out the process sheet as students will be required to machine the part individually

on their own machine. Please print out and bring at least 2 copies of the process sheet

template.

Lab 5 The student will continue to complete all the machining operations on the parts they

started in Lab 4. The students on the milling machine will continue machining their frame,

while the students that are on the lathe will be able to machine the shaft and fabricate the ring

for the gyroscope.

Before Lab 6 After all machining steps are completed, the student will proceed to fill out an

inspection report for the frame, rotor, shaft and ring. A template can be found at the end of

this manual or on the EDML Moodle site. The student must complete this on their own time

and before lab 6. The EDML will be open every weekday from 9am till 5pm (Closed from

noon till 1pm). 2 calipers are available in H0024-1, if the student requires measuring

equipment.


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Lab 6 The student will be able to engrave writing on their gyroscope by using the CNC

milling machine in the EDML A. Students will next be able to polish their gyroscope frame. At

last, students will also be able to fabricate a stand for the gyroscope using a GMAW welding

process. Once the welding / engraving / polishing procedures are completed, the student will

be able to proceed with assembly followed by testing.

Af ter Lab 6 A final report will be required. The deadline will be determined by the

manufacturing instructor. Please see the following pages for the report content.


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Final Report:

The report must be formatted as follows:

1.0 ENCS Lab Expectation of Originality Form

2.0 Title Page (name, section, date, ID#)

3.0 Table of Contents

4.0 Introduction

4.1 Brief introduction to the project and machines used and the parts being fabricated

5.0 Frame

5.1 Detailed Drawing (Proper drawing, landscape format, title block, CAD only)

5.2 Process plan

5.3 Inspection report

5.4 Conclusion (Comment on how well (or not) your frame turned out)

6.0 Rotor


6.2 Process plan


6.4 Conclusion (Comment on how well (or not) your rotor turned out)

7.0 Shaft


7.2 Process plan

7.3 Inspection report7.4 Conclusion (Comment on how well (or not) your shaft turned out)

8.0 Ring

8.1 Process plan


8.3 Conclusion (Comment on how well (or not) your ring turned out)

9.0 Assembly Drawing + Assembly Procedure + Bill of Materials

9.1 Assembly drawing is a view of the gyroscope with all the components shown as they

go together. (ie. fully assembled) Each component should be labeled with a number

which corresponds to the same number on the bill of materials. Assembly drawings

typically only have the overall dimensions of the assembly and do not have all the

dimensions from the working drawings. See pages 71 and 72 (not the Acrobat page

numbers, the ones that appear on the bottom right of the page) in the lab manual for

an example. Although dimensions are not always required on assembly drawings.


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9.2 Assembly Procedure is a detailed step by step guide for workers on how to assemble

the product. Imagine you are writing these steps for someone that has never seen

this type of gyroscope.

9.3 Bill of Materials (BOM) is a list of all components required to assemble the final

product. Include: quantity, was part purchased or fabricated, drawing number of

fabricated parts, description of parts, etc. The BOM can be included on the assembly

drawing if it fits.

10.0 Overall conclusion

10.1 How did your gyroscope turn out? Any problems?

10.2 Any comments on how the lab should be improved for next year

Marking:

Final repor t 70

Format + Content 10

Drawings (3) 27

Process sheets (4) 34

Inspection sheets (4) 14

Assembly Drawing 8

Assembly Procedure 2

BOM 5

Manufactur ing Evaluation 30

Final lab Mark (10% of Grade) 100

Bonus Question: 5

Empirically determine if your rotor and frame are balanced (static only) based on your

dimensions. Show how the mass of the frame can provide a balanced motion, and if not, what

percent error exists.

Deductions:

As noted above in the lab outline, deductions of up to 30% of the final lab mark may be applied

for incomplete or not submitted items or missed labs. In addition, a deduction of 15% may be

applied for students that fail to abide by the EDML safety rules or show insubordination toward

the instructor, technician, POD or any other authority figure in the EDML. Failure to properly clean

ones machine at the end of the lab period will result a 5% penalty per infraction. Lastly, a final

report submitted after the date set by the Manufacturing Instructor will result in a 2% per day

deduction.


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LAB 1METROLOGY AND THE EDML

1. Introduction to EDML

The Concordia Engineering Design and Manufacturing Laboratory (EDML), located in H-0024, isa valuable resource of the Mechanical and Industrial Engineering Department. The EDML

provides support to the entire Faculty of Engineering and Computer Science for all the staff and

students needs. The EDML staff is able to provide helpful suggestions and ideas for designs,

from their varied and extensive experience.

The student side of the EDML, located in H-0026, is open to students from within the faculty,

working on course related design projects, as well as extra-curricular projects, such as

Concordias student built Formula SAE race car (Figure 1).

FIGURE 1. PHOTO COURTESY OF CONCORDIAS SOCIETY OF AUTOMOTIVE ENGINEERS (CONCORDIA SAE)

It is important to understand the manufacturing processes involved in the design and fabrication

of a part because an improperly designed part results in increased costs, wasted material and

wasted time. By understanding these processes, the engineer can make choices in his or her

design to reduce costs, reduce waste, and facilitate the fabrication of a part.

For example, an engineer is tasked with designing a sealed box. The engineer decides to make

it out of steel, and to weld it from the inside. He or she takes it to the machine shop, where the

designs are rejected because it is impossible to weld inside a sealed box. Had the engineer

understood the process of welding, he or she would have been able to avoid this costly mistake,in terms of downtime and resources.


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1.1. SAFETY REGULATIONS

The use of the EDML, while open to all students, is regulated by a set of strict safety rules and

procedures, to be obeyed at all times. Compliance with the regulations are mandatory; those in

contravention of the rules will be given a warning. A subsequent infraction will result in the

immediate expulsion of that person from the EDML, and further access can be denied.

A summary of the safety rules found within CON-EDML-004 are found below. For the complete

EDML policy, please visit http://users.encs.concordia.ca/~dng

Personal

Always wear safety glasses

Wear appropriate footwear and clothing

o No loose clothing

o Roll up sleeves

o Take off ties, scarves, etc.

o No open toe shoes

Wear hearing protection (if required)

Remove wristwatches, rings, bracelets, etc.

Never wear gloves when operating machines

Long hair must be tied up

Report all accidents or injuries immediately

Safe Work Practices

Understand how the machine works and how to stop it quickly before operating it

Be sure all guards and safety devices are in place and in working order

Keep hands away from moving parts

Stop machine before measuring, cleaning or making adjustments

Only one person operates a machine at one time

o Do not talk to or distract a person while they are operating a machine

Keep work area clean and tidy

Chips, oils, heat, and sharp tools are hazards

Be alert, be aware


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Safety at the Machine

Be sure cutting tools and work piece are properly mounted

Remove all burrs and sharp edges from work piece

Be sure work is clamped securely

Before starting a machine, ensure cutting tool and machine parts clear work piece and

clamping

Use proper tools for the job

Wear any safety equipment specific to equipment being used

Be careful when lifting heavy objects

Be familiar with the posted Concordia Standard Lab Safety Rules. There must be a qualified

technical staff member present when you work in the EDML.


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2. INTRODUCTIONTOMETROLOGY

Metrology is a very important part of the design and manufacturing process. Unless numerical

values are specified and measured, one cannot ensure proper fitting between parts. This is very

impractical and inefficient; in reality no part can be made without some form of measurement. In

the next section of this lab, you will be introduced to a scale of measurement used throughout

machine shops around the world.

Note: While measuring instruments are available in both Imperial and SI units, we will be using

Imperial measurements for this course.

2.1.INTRODUCTIONTOVERNIERSCALE

Pierre Vernier (1580-1637) in 1631 invented the linear scale. This scale is one of the simplest to

use for measurement, and offers a fine discrimination. The Vernier scale is used in all modernmeasuring devices. Two instruments we will be covering are the Vernier caliper and Micrometer,

both of which use a form of the Vernier scale.

2.1.1. INTRODUCTIONTOVERNIERCALIPER

FIGURE 2. VERNIER CALIPER (PICTURE COURTESY OF TECHNOLOGYSTUDENT.COM)

The modern Vernier caliper, as shown in Figure 2, was invented by Joseph R. Browning and his

father (Fundamentals of Dimensional Metrology 3rd Ed p. 106). Browning went on to form Brown

& Sharp Manufacturing Co., which today is one of the major manufacturers of measuring

instruments and tooling. The Vernier caliper is one of the most versatile measuring tools used by

engineers and machinists. The caliper can be used to measure the following features: linear

distances / outside diameters, internal diameters, and depth.


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FIGURE 5. READING A MICROMETER CALIPER (FUNDAMENTALS OF DIMENSIONAL METROLOGY 3RD ED., P.

135)

In addition, if your micrometer is equipped with a Vernier scale, meaning you can measure to 4decimal places (i.e. one ten thousandth of an inch), see Figure 6 below.


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3. SURFACETEXTUREMEASUREMENTS

3.1. Introduction

Although the term surface finish is frequently used to denote the general quality of a surface, it is

not a technically accepted term. In fact, surface finish is a colloquial term widely used for

qualitative assessment of a surface and is generally not quantified. Surface texture is the

technically accepted term which is used to describe the repetitive or random deviations from the

nominal surface which forms the three dimensional surface topography. Consider a surface as

shown magnified in Figure 7. The predominant direction of the surface patter is called the lay and

is usually determined by the production method. Occasionally an unintentional irregularity can

occur in one spot or infrequent locations on the surface, this is called a flaw. Flaws can include

such defects as cracks, inclusions, and scratches.

FIGURE 7. MAGNIFIED SURFACE

3.2. Texture Parameters

3.2.1. Curve Types

Currently there are over fifty parameters defined by various standards organizations, such as

DIN, ISO, and JIS, to quantify the surface texture, they are based on curves derived from surface

texture. Some of the most common parameters are described here.


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3.2.1.1. P-Curve (Unfiltered profile)

Consider the intersection of a surface and a plane normal to the surface and oriented such that

the surface roughness Ra (to be explained later) is maximum. This is usually in a direction normal

to the lay. The resulting profile shown in Figure 8 is called the P-Curve or unfiltered profile.

FIGURE 8. P-CURVE

3.2.1.2. R-Curve (Roughness profile)

Observations of the P-Curve often reveal the existence of low frequency component, If one

removes all the low frequency components lees that a specified wavelength c from the P-Curve

the resulting curve shown in Figure 9 is called the R-Curve or the Roughness Profile. The

wavelength c is called the cutoff value.

FIGURE 9. R-CURVE

3.2.1.3. WC-Curve (Filtered waviness curve)

To obtain the R-curve the low frequency components were removed from the P-curve. If one

does the opposite and removes the higher frequency components from the P-curve then the WC-curve or Filtered waviness curve is obtained as shown in Figure 10. The wavelength limit above

which components are removed is called the high-band cutoff value (fh).


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FIGURE 10: WC-CURVE

These represent the basic types of curves; there are several others less commonly used.

3.2.2. Definition of Parameters

From the different curves one can obtain the parameters which are used to define the surface

texture. As mentioned earlier there are many parameters to quantify the surface texture. Some

of the most common ones will be explained in this lab as defined by the ISO and DIN.

3.2.2.1. Arithmetic Mean Deviation of the Profile (Ra)

Consider the roughness profile and place a straight line through it as shown in Figure 11 such

that for some evaluation length lm the sum of the area above this line is equal to the sum of the

area below the line. This line is called the center line.

FIGURE 11: ARITHMETIC MEAN DEVIATION OF PROFILE (RA)

If one considers the center line as the X-axis then let the roughness curve (R-curve) de defined

by some function f(x). The arithmetic mean deviation is the mean of the absolute value of f(x)

over the evaluation length lm as shown in Figure 12. It is sometimes called the Center Line

Average (CLA) or the Arithmetic Average (AA Rating). It is given by the equation:


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FIGURE 12. FUNCTION F(X) OVER EVALUATION LENGTH LM

The evaluation length lm for calculating Ra is typically five times the cutoff value c.

3.2.2.2. Average Peak-to-Valley Height (Rz (DIN))

Consider again the roughness profile. Taking a sampling length lm of five times the cutoff value

c, divide the roughness profile into five sections of equal sampling lengths (le) equal to the cutoff

value c as shown in Figure 13. Let Zi be defined as the difference between the highest peak

and lowest valley in the ith sampling length. The Average Peak-to-Valley Height Rz (DIN) isdefined as the average value of Zi for the five sampling lengths.

FIGURE 13. AVERAGE PEAK-TO-VALLEY HEIGHT RZ (DIN)

If there is not sufficient length on the surface for an evaluation length five times the cutoff value

then an evaluation length of three times the cutoff value may be used but the sampling length

must always be equal to the cutoff value.

3.2.2.3. Maximum Peak-to-Valley Height (Ry (DIN))

The Maximum Peak-to-Valley Height Ry (DIN) is defined as the maximum value of Zi used when

calculating the Average Peak-to-Valley Height: RyDIN= ZiMAX

3.2.2.4. Average Peak-to-Valley Height (Rz (ISO))


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The ISO defines the Average Peak-to-Valley Height Rz (ISO) differently than DIN. Using the

unfiltered profile (P-curve), place a line through it as shown in Figure 14, such that within the

evaluation length the sum of the squares of the profile departures from this line is minimized.

FIGURE 14. AVERAGE PEAK-TO-VALLEY HEIGHT RZ (ISO)

Using the mean line the ISO defines the Average Peak-to-Valley Height Rz (ISO) and the

difference between the average of the five highest peaks and the five lowest valleys measured

from a reference line parallel to the mean line as shown in Figure 15.

FIGURE 15. AVERAGE PEAK-TO-VALLEY HEIGHT RZ (ISO)

3.2.2.5. Maximum Peak-to-Valley Height (Ry (ISO))

The ISO defines the Maximum Peak-to-Valley Height Ry (ISO)) as the distance between a line

parallel to the mean line of the unfiltered profile (P-curve) passing though the highest peak and a

line parallel to the mean line of the unfiltered profile (P-curve) passing through the lowest valley

as shown in Figure 16.


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FIGURE 16. MAXIMUM PEAK-TO-VALLEY HEIGHT RY (ISO)

3.3. Standard Sampling and Evaluation Lengths

It should by now make sense that the sampling and evaluation lengths would vary depending on

the magnitude of the parameters being measured. A rough surface would have longer sampling

and evaluation lengths than a smooth surface. The following tables represent some standards

used by the ISO and DIN.


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3.4. Specifying Surface Texture on a Drawing

On a technical drawing, when surface finish is important, it must be clearly indicated. The

parameters presented to this point represent some of the most commonly used standards todescribe surface texture. There are however some parameters which are not recognised by the

ISO but are in common use such as the Waviness Width and the Waviness Height. Figure 17

describes the use of the surface finish symbols. The Roughness Height can also be expressed

as a Roughness Grade. Figure 18 gives the Roughness Height associated with different

Roughness Grades and typical applications. Figure 19 describes the machining processes which

could be used to obtain different surface textures. Figure 20 describes how to represent the

direction of the lay.

FIGURE 17. USE OF SURFACE FINISH SYMBOLS


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FIGURE 18. ROUGHNESS HEIGHT ASSOCIATED WITH DIFFERENT ROUGHNESS GRADES


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Figure 18 (contd) Roughness Height associated with different Roughness Grades


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FIGURE 19. SUR ACE FINISHES OF DIFFERENT MACHINING ROCESSES

3


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FIGURE 20. LAY DESIGNATION SYMBOLS

3.5. Demonstration of Surface Texture Measurement

The student will observe the operation of the surface texture measurement machine by one of the

EDML staff.


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Measure Existing Gyroscope

Figure 22) you will be measuring has been manufactured by the EDML on numerical controlled

machines. Now that you have been exposed to basic measuring principles, you are required to

fill in the missing dimensions indicated on the attached sketches (Figure 24,

Figure 25 Figure 26). Be sure not to omit any dimensions, as you will be using your data to

manufacture your own gyroscopes.


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FIGURE 23. DIGITAL CALIPER (PICTURE COURTESY OF MACHINE MART)

For the next lab session, you will be required to make three detailed drawings of the frame, rotor,

and shaft.

3.6.1. DOS

AND

DONTS

OF

USING

A

DIGITAL

CALIPER

Do:

Treat your caliper with respect, as it is a delicate instrument

Turn off caliper after use to preserve battery

Place caliper in its protective case / box after use

Unlock the set screw before opening the jaws

Dont:

Use your caliper as a scriber (i.e. to scratch or mark a surface)

Drop or mistreat / abuse your caliper

Force the jaws of the Vernier caliper open (check the set screw prior to use)

Lay your caliper in a dangerous position, where it could fall

Set it down in a dirty environment, as any foreign object debris (FOD) could damage the

instrument, and subsequently your measurements.

Lay your caliper in coolant as this will distort the measurements.


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FIGURE 24. SKETCH OF GYROSCOPE FRAME

Table 1. Dimensions for Gyroscope Frame

Dimension Value Dimension Value

1 16

2 17

3 18

4 19

5 20

6 21

7 22

8 23

9 24

10 2511 26

12 27

13 28

14 29

15


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FIGURE 25. SKETCH OF GYROSCOPE ROTOR

Table 2. Dimensions for Gyroscope Rotor

Dimension Value

1

2

3

4

5

6

7

8


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FIGURE 26. SKETCH OF GYROSCOPE SHAFT

TABLE 3. DIMENSIONS FOR GYROSCOPE SHAFT

Dimension Value

1

2

3

4


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LAB 2 5 MACHINE TOOLS / GYROSCOPE

MANUFACTURING

The following information is general information about all the machines and cutting tools used in the fabrication

of the gyroscope. The procedure / steps on how to use the machine / fabricate the gyroscope will be

demonstrated by the lab instructors. It is up to the students to take detailednotes and fill out their process

sheets during each demonstration.

1. Process Plan for Machine Demonstration

The process plan of a work piece must be followed in order to machine a part. This plan has been determined

by an engineer (in most cases there is a dedicated process planner), and is the most efficient order of

operations. For further information on process plans, consult your course textbook.

A process sheet is to be filled out by the students during the demonstration for each part of the gyroscope (the

frame, rotor, and shaft, and ring). The filled out process sheet will be used as a guide for students to follow

while they machine their own parts. The EDML process sheet template can be found at:

http://users.encs.concordia.ca/~dng

The formulas for the material removal rate (MRR), cutting time (CT), speeds and feeds are available in the

course textbook. Be sure to record the material of the cutting tool and the workpiece as the material types

affect the formulas / values to be used.

Note: The student will be required to make copies of this sheet, as only 1 part is to be listed per process sheet.


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2. The Engine Lathe

The engine lathe is one of the most common machines found in machine shops around the world. It can be

used for turning, facing, drilling, boring, tapering, screw cutting, grinding, etc. The workpiece is held in place

and rotated about its axis, while the cutting tool is fed along it. The engine lathe is usually found in schools or

custom shops, where there is not a high volume production. For higher volume productions, shops would eitheruse CNC lathes or turret lathes.

2.1. Safety on the Engine Lathe

ALWAYS WEAR SAFETY GLASSES

Do not operate a lathe unless you fully understand its controls and safety mechanisms. Be sure you

can stop the machine quickly in case something happens.

Only one person operates the machine at a time

Never leave the chuck key in the chuck (If the key is in the chuck, your hand is on the key)

Dont wear any clothes or jewelry that may become entangled with the machine

Make one full revolution of the workpiece to ensure it clears the cutting tools and the bed of the lathe

Always use the brake (if applicable) to stop the rotating workpiece

Never grab a rotating workpiece

Do not leave rags in proximity to a lathe that is in operation they may become snagged by the rotating

parts

Make sure the workpiece has come to a complete rest before attempting to approach the workpiece (tomeasure or to remove chips, etc.)

Never remove chips by hand (very sharp) use either a brush or pliers

Keep work area tidy


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34

.


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35

Metal Removal On The Engine Lathe

It should be noted that in order for metal cutting to occur, the workpiece must come in contact with the cutting

surface of the tool. The figure below shows the convention used in the vast majority of cases: the workpiece

rotates in a counterclockwise direction, when viewed from the tailstock. Two examples of when the convention

does not apply (i.e. the workpiece must be rotated clockwise): if the tool is attached upside down, or if the tool is

fed from the right side of the workpiece, as seen from the tailstock. If the workpiece is rotated in the wrong

direction and the tool is fed into it, a loud squealing noise will occur, followed by the breaking of the tool bit.

FIGURE 30. METAL REMOVAL ON LATHE (TECHNOLOGY OF MACHINE TOOLS 5TH ED.)

2.1.3. Cutting Speed And Feed Calculations On The Engine Lathe

TABLE 4. LATHE CUTTING SPEEDS USING HSS CUTTING TOOL (TECHNOLOGY OF MACHINE TOOLS 5TH

ED.)

Material Turning and Boring Threading

Rough Cut Finish Cut

ft/min m/min ft/min m/min ft/min m/min

Machine Steel 90 27 100 30 35 11Tool Steel 70 21 90 27 30 9

Cast Iron 60 18 80 24 25 8

Bronze 90 27 100 30 25 8

Aluminum 200 61 400 93 60 18

TABLE 5. FEEDS FOR VARIOUS MATERIALS USING HSS CUTTING TOOL (TECHNOLOGY OF MACHINE TOOLS 5TH

ED.)

Material Rough Cuts Finish Cuts

in / rev mm /rev in / rev mm /rev

Machine Steel .010-.020 0.25-0.5 .003-.010 0.07-0.25

Tool Steel .010-.020 0.25-0.5 .003-.010 0.07-0.25

Cast Iron .015-.025 0.4-0.65 .005-.012 0.13-0.3

Bronze .015-.025 0.4-0.65 .003-.010 0.07-0.25

Aluminum .015-.030 0.4-0.75 .005-.010 0.13-0.25


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The feed is directly selected on the headstock of the engine lathe and is expressed in units of distance per

revolution.

To determine the spindle speed (in r/min), the cutting speed, diameter of the workpiece, the material of the tool

bit and the workpiece, and the type of operation (roughing, finishing, or threading) must be known. These

parameters can be in either Imperial or SI units; however the formulas for calculating the spindle speed variesslightly for each system of units.

2.1.3.1. Inch Calculations

The formula to calculate the spindle speed using Imperial units is:

1

12

D

VN

= or r/min= (CS*12) / (*D)

where V, CS = cutting speed (ft/min)

D, D1= diameter of work to be turned (in)

A simpler formula is commonly used because many lathes offer a limited choice of speed settings. It is also

used for ease of calculation. This formula is:

1

4

D

VN = or r/min= (CS*4) / (D) or RPM=

D

CS 4*

2.1.3.2. Metric Calculations

The formula to calculate the spindle speed using Metric units is:

1

320

D

VN = or r/min= (CS*320) / (D)

where V,CS = cutting speed (m/min)

D, D1= diameter of work to be turned (mm)

2.1.4. Types Of Cutting Tools You Will Use On The Engine Lathe

Turning tool bits

These are typical high speed steel (HSS) tool bits used on the engine lathe. Note that each one below has

different features related to its intended purpose.


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FIGURE 31. TURNING TOOL BITS (WWW.VARMINTAL.COM)

Twist drill

Twist drills are end cutting tools used to produce holes in many materials. Drills are categorized in foursystems: fractional, number, letter, and metric.

Fractional size drills range from 1/64 to 4 in diameter

Number size drills range from #1 (.228) to #97 (.0059)

Letter size drills range from A (.234) to Z (.413)

Metric drills range from 0.04 mm to 80 mm.

FIGURE 32. TWIST DRILL (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)


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Center drill

The center drill is defined by its length (l1), and the two diameters (d1and d2). It is used to spot the location for

a hole as it is very rigid and has a small web. A center drill must be used before using a twist drill; else the drill

will wander across the surface, resulting in a misshapen hole.

FIGURE 33. CENTER DRILL (WWW.GREENWOOD-TOOLS.CO.UK)

Reamer

Reamers are used to finish pre-existing holes to an accurate dimension. They remove only a very small

amount of material. The following are guidelines for material removal for reamers:

Nominal Size Suggested Depth of Cut

1/4 .010

1/2 .016

1 .020

FIGURE 34. REAMER (EFUNDA.COM)


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2.1.5. Types Of Work Piece Holders

3-Jaw chuck

The 3-jaw chuck is the most versatile workholding device used on the engine lathe. It has the ability to center

the workpiece automatically, and all 3 jaws can be actuated by using the key in one of the three key holes.

FIGURE 35. 3-JAW CHUCK (WWW.MICROMEX.COM.MX)

Spring collet

Collets are used to hold smooth workpieces with greater centering accuracy than conventional chucks. Also,

there are no clamping marks left on the surface of the workpiece, as it is uniformly held in place by the collet.

FIGURE 36. SPRING COLLET (WWW.JJJTRAIN.COM)


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FIGURE 37. COLLET ATTACHED IN HEADSTOCK (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)

2.1.6. Processes To Be Performed by the Student on The Engine Lathe

Facing

Facing is accomplished by turning the cross-slide handle so that the cutting tool moves to cut and level the end

of the work piece.

FIGURE 38. FACING (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)


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Turning

Turning is the process whereby metal is removed from the surface parallel to the axis of rotation, while the tool

bit is fed along the work piece.

FIGURE 39. TURNING (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)

Drilling

Twist drills are end cutting tools used to produce holes in many materials. They are attached in the tailstock by

means of a taper or a chuck, and held stationary. The operator advances the drill into the workpiece via the

tailstock handwheel.

FIGURE 40. TURNING (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)


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43

3. The Vertical Milling Machine

3.1. Safety on the Vertical Mill

ALWAYS WEAR SAFETY GLASSES

Do not operate a mill unless you fully understand its controls and safety mechanisms. Be sure you

can stop the machine quickly in case something happens.

Only one person operates that machine at a time

Dont wear any clothes or jewelry that may become entangled with the machine

Ensure the wrench is never left on the top of the machine when changing chucks

Before starting machine, ensure that the High / Low gear selector is properly engaged

Always use the brake to slow down the rotating cutter

Never grab a rotating cutter

Make sure the cutter has come to a complete rest before removing chips

Never remove chips by hand (very sharp) use either a brush or pliers

Keep work area tidy

3.2. Nomenclature of the Vertical Mill

FIGURE 42. VERTICAL MILL NOMENCLATURE (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)


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3.2.1. How Vertical Mills Are Specified

Work piece envelope: Maximum size of piece that can fit on the machine. Expressed in three

coordinates (X, Y, Z).

Horsepower: This dictates basically how much material you can remove in a given time. Higher the HP,

the larger the Material Removal Rate (MRR).

3.2.2. Axes of Vertical Mill

FIGURE 43. AXES OF A VERTICAL MILL

3.2.3. Metal Removal On The Vertical Mill

3.2.3.1. Climb Milling

In climb milling (down milling), the cutter rotation is in the same direction as the feed rate. The main difference

in the two types of milling is the chip formation more detail will be provided in the class lectures.


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FIGURE 44. CLIMB MILLING (TECHNOLOGY OF MACHINE TOOLS 5TH

ED.)

3.2.3.2. Conventional Milling

In conventional milling (up milling), the cutter rotates against the direction of feed of the workpiece. Due to

limitations of the machine, you must take care to ensure that you only use conventional milling.

FIGURE 45. CONVENTIONAL MILLING (TECHNOLOGY OF MACHINE TOOLS 5TH

ED.)

3.2.4. Cutting Speed Calculations on the Vertical Mill

To determine the spindle speed (in r/min), the cutting speed and circumference of the cutter must be known.

These parameters can be in either Imperial or SI units; however the formulas for calculating the spindle speed

varies slightly for each system of units.


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TABLE 6. MILLING MACHINE CUTTING SPEEDS (TECHNOLOGY OF MACHINE TOOLS 5TH

ED.)

4001000


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47


The formula to calculate the spindle speed using Imperial units is:

D

VN

= or r/min= (CS) / (circumference)

where V,CS = cutting speed (ft)

circumference = circumference of cutter (in)

D = diameter of cutter (in)

N = RPM of cutting tool

D

VN

12= or r/min= (12 * CS) / (* D)

A simpler formula is commonly used because 12 / 4. This formula approximates to:

D

VN

4= or r/min= (CS*4) / (D)


The formula to calculate the spindle speed using Metric units is:

D

VN

1000= or r/min= (CS * 1000) / (* D)

where V,CS = cutting speed (m)

D = diameter of cutter (mm)

N = RPM of cutting tool

This reduces to:

D

VN

320= or r/min= (CS*320) / (D)


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3.2.5. Feed Calculations on the Vertical Mill

The milling feed is the rate at which the work is fed into the milling cutter.

TABLE 7. RECOMMENDED FEED PER TOOTH FOR HSS CUTTERS (TECHNOLOGY OF MACHINE TOOLS 5TH

ED.)


The formula to calculate the feed using Imperial units is:

Feed = n * CPT * r/min or Nnff tm =

Where

Feed, fm= feed of workpiece (in/min)

n= number of teeth in the milling cutter

ft, CPT = chip per tooth for a particular cutter and metal (found in tables)

N, r/min = revolutions per minute of the milling cutter


The formula to calculate the feed using Metric units is:

Nnff tm = or Feed = N * CPT * r/min

where fm= feed of workpiece (mm/min)

n= chip per tooth for a particular cutter and metal (found in tables)

N, r/min = revolutions per minute of the milling cutter


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50

FIGURE 47. TWIST DRILL (MATERIALS AND PROCESSES IN MANUFACTURING 9TH

ED.)

Center drill

The center drill is defined by its length (l1), and the two diameters (d1and d2). It is used to spot the location for

a hole as it is very rigid and has a small web. A center drill must be used before using a twist drill; else the drill

will wander across the surface, resulting in a misshapen hole.

Figure 48. Center Drill (www.greenwood-tools.co.uk)

3.2.7. Types of Work Piece Holders

Vise

Vises are used to clamp workpieces securely while milling. The vises are attached to the table of the mill.


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54/77

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53

4. General Machine Shop Machines

Drill Press

Drill presses are commonly used in machine shops. The drill bit is held in place by the chuck, and is lowered

into the workpiece (being held stationary on the table with a vise) by means of the capstan wheel. The table

can be raised or lowered, depending on the height of the part to be drilled.

4.1.1. Drill Press Nomenclature

FIGURE 51. DRILL PRESS (MATERIALS AND PROCESSES IN MANUFACTURING 9THED.)

4.2. Hand Tools

In addition to the many machines used in the EDML, a variety of hand tools are used as well.

4.2.1. Taps

Taps are used to make internal threads on a part. They can be done either by hand or on a machine, but for

the purpose of this lab we will deal only with hand taps.

A hole of diameter slightly larger than the minor diameter of the thread must already exist. The thread profile iscreated by the cutting edges of the flutes; the flutes also provide space for lubrication and chip removal. Tap oil

must be used, as taps create a lot of friction and are prone to breaking.

The table below, called a Tap / Drill Size Chart, is a very useful tool when designing interior threaded parts. It

tells the user that in order to tap threads of a certain size, the pre-existing hole of a corresponding diameter


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54

must already exist. For example, to tap internal threads of -28 NF, the #3 drill must be used, which

corresponds to 7/32.

TABLE 8. TAP / DRILL SIZE CHART

To Tap This Size Screw Or Bolt: Use This Drill Bit: (Closest Fractional:) Decimal Inches

0-80 NF 3/64" 3/64" .0469

1-64 NC #53 - .05951-72 NF #53 1/16" .0595

2-56 NC #50 - .0700

2-64 NF #50 - .0700

3-48 NC #47 5/64" .0785

3-56 NF #45 - .0820

4-36 NS #44 - .0860

4-40 NC #43 3/32" .0890

4-48 NF #42 3/32" .0935

3mm-.060mm 2.5mm - .0984

1/8-40 NS #38 - .1015

5-40 NC #38 - .1015

5-44 NF #37 - .1040

6-32 NC #35 7/64" .11006-36 NS #34 - .1110

6-40 NF #33 - .1130

6-48 NS #31 - .1200

4mm-0.70mm 3.4mm - .1338

4mm-.075mm 3.4mm - .1338

8-32 NC #29 - .1360

8-36 NF #29 9/64" .1360

8-40 NS #28 - .1405

3/16-24 NS #26 - .1470

10-24 NC #25 5/32" .1495

3/16-32 NS #22 - .1570

10-32 NF #21 5/32" .1590

5mm-.090mm 4.2mm - .16535mm-.080mm 4.3mm - .1693

12-24 NC #16 11/64" .1770

12-28 NF #14 3/16" .1820

12-32 NEF #13 - .1850

14-20 NS #10 - .1935

1/4-20 NC #7 13/64" .2010

14-24 NS #7 - .2010

6mm-1.00mm 5.2mm - .2047

1/4-24 NS #4 - .2090

1/4-28 NF #3 7/32" .2130

1/4-32 NEF 7/32" 7/32" .2188

1/4-40 NS #1 - .2280

7mm-1.00mm 6.1mm 15/64" .2401

5/16-18 NC Ltr. F 17/64" .2570

8mm-1.25mm 6.9mm 17/64" .2716

5/16-24 NF Ltr. I - .2720

8mm-1.00mm 7.1mm - .2795

5/16-32 NEF 9/32" 9/32" .2812

9mm-1.25mm 7.9mm - .3110

3/8-16 NC 5/16" 5/16" .3125

9mm-1.00mm 8.1mm - .3189


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9mm-0.75mm 8.3mm - .3268

3/8-24 NF Ltr. Q 21/64" .3320

10mm-1.50mm 8.7mm - .3425

10mm-1.25mm 8.9mm 11/32" .3503

10mm-1.00mm* 9.1mm - .3583

7/16-14 NC Ltr. U 23/64" .3680

11mm-1.50mm 9.7mm - .3818

7/16-20 NF 25/64" 25/64" .390612mm-1.75mm 10.5mm - .4133

12mm-1.50mm 10.7mm 27/64" .4212

1/2-13 NC 27/64" 27/64" .4219

12mm-1.25mm* 10.9mm 27/64" .4291

1/2-20 NF 29/64" 29/64" .4531

1/2-24 NS 29/64" 29/64" .4531

14mm-2.00mm 12.2mm - .4803

9/16-12 NC 31/64" 31/64" .4844

14mm-1.50mm 12.7mm - .4999

14mm-1.25mm* 12.8mm - .5039

9/16-18 NF 33/64" 33/64" .5156

5/8-11 NC 17/32" 17/32" .5312

16mm-2.00mm 14.2mm 35/64" .55905/8-18 NF 37/64" 37/64" .5781

16mm-1.50mm 14.7mm - .5787

11/16-11 NS 19/32" 19/32" .5938

18mm-2.50mm 15.8mm 39/64" .5220

11/16-16 NS 5/8" 5/8" .6250

3/4-10 NC 21/32" 21/32" .6562

18mm-1.50mm* 16.8mm - .6614

3/4-16 NF 11/16" 11/16" .6875

20mm-2.50mm 17.8mm 11/16" .7008

7/8-9 NC 49/64" 49/64" .7656

7/8-14 NF 13/16" 13/16" .8125

22mm-1.50mm 20.9mm - .8228

7/8-18 NS* 53/64" 53/64" .8281

24mm-3.00mm 21.4mm 53/64" .8425

1.8 NC 7/8" 7/8" .8750

24mm-2.00mm 22.3mm - .8779

1.12 NF 59/64" 59/64" .9219

1-14 NS 15/16" 15/16" .9375

1 1/8-7 NC 63/64" 63/64" .9844

1 1/8-12 NF 1 3/64" 1 3/64" 1.0469

1 1/4-7 NC 1 7/64" 1 7/64" 1.1094

1 1/4-12 NF 1 11/64" 1 11/64" 1.1719

1 3/8-6 NC 1 7/32" 1 7/32" 1.2188

1 3/8-12 NF 1 19/64" 1 19/64" 1.2969

1 1/2-6 NC 1 11/32" 1 11/32" 1.34381 1/2"-12 NF 1 27/64" 1 27/64" 1.4219


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5. How to Fill Out an Inspection Report

Once you have completed manufacturing a component of the gyroscope, you must now verify your work and fill

out an inspection report for that part.

5.1. Description of Inspection Report

No.: Feature number of each part (corresponds to numbers on the sketches).

Dwg. Dimension: Dimension of feature (from detailed drawing)

Tolerance: Tolerance of feature if applicable (from detailed drawing)

Actual Measurement: Measured value of the feature on the machined part

Accept: Either yes or no, depending if the feature is within specification

Reject (OHL or ULL): If the feature is rejected, indicated either how much over the high limit it is (OHL)

or how much under the low limit it is (ULL)

Comments: Why the part was rejected, what caused error, etc.

Use the attached sketches for reference in filling out the inspection reports.

FIGURE 52. SKETCH OF GYROSCOPE FRAME


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FIGURE53.SKETCHOFGYROSCOPEROTOR

FIGURE 54. SKETCH OF GYROSCOPE SHAFT


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LAB 6GYROSCOPEASSEMBLY /CNCENGRAVING /

WELDING GYROSCOPE STAND /POLISHING

1. Computer Numerical Controlled (CNC) Engraving of Gyroscope Frame

The student will be able to engrave writing on their gyroscope by using the CNC milling machine in the EDML A

area. The current semester and the year will be engraved on the gyroscope frame. Students will be able to see

how a CNC program is made from a CAD drawing and watch the code being executed by the machine on their

frame.

1.1. CNC Vertical Center

Figure 55 is a picture of a CNC vertical center or a CNC milling machine. This machine has all the same axes

of a conventional vertical milling machine. Most CNC machines are enclosed to prevent the operator from

being injured, as well as to enable coolant to be sprayed over the entire work area. Notice the computer screen

attached to the machine. This is known in industry as the controller. The programmer would program the partrequired in the controller and monitor the status of the part during machining operations. Some CNC machines,

like the one pictured below have automatic tool changers. This eliminates the need for an operator during the

machining cycle as the machine can change to the required tool itself.

FIGURE 55. CNC VERTICAL CENTER (MILL)


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A tool changer like the one in Figure 56 below consists of a carousel (or two) of various tools ready to be

installed in the spindle of the machine upon request from the program. The tools that are loaded in the carousel

are determined by the technician operating the machine and vary from job to job. When the program requests a

tool change, the spindle stops, orientates and locks, then the tool carousel is rotated to a location where there is

currently no tool. The current tool in the spindle is removed and placed into the empty space. The carousel is

then rotated to the designated tool position and the new tool is installed in the spindle. This usually happens in a

period of no more that 10 seconds.

FIGURE 56. AUTOMATIC TOOL CHANGER (WWW.HARDINGE.COM)

Another nice feature of CNC machines is that you can control all three axes at a given time. This means you

can create accurate radii, curves, ramped surfaces or complex 3-dimensional surfaces. All of the above would

not be able to be created on a conventional machine tool. Some more expensive CNC machines can control up

to five axes simultaneously. Figure 57 below illustrates the five different axes which can be controlled at the

same time.

FIGURE 57. AXES OF A MACHINING CENTER (MILL)

Figure 58 is a Computer Aided Manufacturing example of how controlling all five axes at the same time may be

useful. This manufacturing simulation is of an impeller. Note the complex end mill path.


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FIGURE 58. TURBINE IMPELLER (WEST-GMBH.DE)


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1.2. CNC Lathe

The CNC lathe is similar to all other CNC equipment where all the axes can be controlled at the same time. The

CNC lathe has also the ability to change tools on its own. The CNC lathe can make very complex parts that are

not able to be made on conventional machines. A typical CNC machine is pictured below (Figure 59).

FIGURE 59. CNC LATHE

A very nice feature which some CNC lathes have is the ability to control a third or fourth axis. The part can be

stopped from rotating and live tooling can be used to radially and axially machine pockets. An example of a

CNC three axis lathe operation is pictured below (Figure 60).

FIGURE 60. THIRD AXIS CNC LATHE MACHINING OPERATION


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1.3. CNC Programming Language

The program language used by CNC machines has been fairly standardized. It is known as G and M code

programming. Some companies however have built in software in the controllers of the CNC machines which

works based on a graphical interface. Basically this means that you can draw the part on the controller and the

controller will convert your drawing into G and M code and subsequently machine your part. Within the past ten

years, Computer Aided Manufacturing has been playing a huge role in manufacturing. Computer Aided

Manufacturing software can analyze a part drawn in AutoCAD or CATIA, etc. and generate the proper G and Mcodes for the part. You can even simulate the whole machining process on your screen where you see the

movement of each cutting tool in relation to the workpiece. A standard G and M code description is provided

below. Note that these are standard codes and some machines have codes specific to themselves.

1.3.1. G&MCODE COMMANDSUMMARY

Preparatory Command (G-Codes) Miscellaneous Functions (M-Codes)

G00 Rapid positioning move M00 Temporary stop

G01 Linear cutting move M02 End of program stop

G02 Clockwise circular cutting move M03 Spindle CW (output #1)

G03Counterclockwise circular cutting

moveM04

Spindle CCW (output #5)

G28Set system or user defined

variable to valueM05

Spindle (output#1, output#5)

G81 Canned threading cycle M06 Tool change

G70 Set inch programming (default) M08 Coolant (output #2)

G71 Set metric programming M09 Coolant (output #2)

G90 Set absolute programming mode M30 End program

G91Set incremental programming

mode (default)M39

Chuck (output #6)

M40 Chuck (output #6)

Special Codes M99 Restart part program from beginning

* Multiplies two variables

F Feed rate

S Spindle speed

T Tool number

FIGURE 61. G AND M CODE FUNCTIONS (WWW.MICROKINETICS.COM/ TMPRO.HTM)


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With the above codes one could write their own CNC program control. An example of one such program is as

pictured below. Note the N5, N10, N15, etc. are used to denote the lines of the program. Each line of the

program is called a block.

N5 G0 X0.5 Y0.5

(THE CUTTER MOVES FROM THE ZERO POSITION TO THE BOTTOM

LEFT CORNER OF THE SQUARE)

N10 G1 Z-.125 F20(THE CUTTER PLUNGES 1/8" INTO THE MATERIAL AT 20 INCHES PER

MINUTE)

N15 Y1.0 (THE CUTTER TRAVELS TO Y 1.0)

N20 X1.0 (TO X 1.0)

N25 Y0.5 (TO Y 0.5)

N30 X0.5 (TO X 0.5)

N35 Z.125 (RAISES UP TO 1/8" ABOVE THE MATERIAL)

N40 G0 X0.0 Y0.0 (RETURNS BACK TO THE START POINT)

FIGURE 62. BASIC CNC PROGRAM


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2. Welding Gyroscope Stand

Students will also be able to fabricate a stand for the gyroscope using a GMAW welding process. The stand

will consist of three parts that will be held in a welding fixture to assure consistency and repeatability. See

figure 65 below for the welding drawing of the gyroscope stand.

Figure63 GyroscopeStand


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2.1. Welding Safety

Welding and brazing causes harmful ultraviolet light, radiation and high heat. Do not look at the light

from welding or brazing without wearing the proper welding mask. You willcause damage to your eyes

even if you catch a flash of light from welding.

Welding and brazing causes harmful fumes, only weld or brazing with proper ventilation turned on.

Welding and brazing causes sparks of molten metal; ensure that you have the proper clothing if you are

near someone welding.

Welding and brazing cause large amounts of heat build-up which last a long time in the workpiece,

table, welding gun, etc. Make sure you handle all the parts and tools with proper gloves and take care

not to lean, step on or pick-up any hot parts

Welding uses high voltage! Ensure that you are not touching any part of the electrode before you start

welding.

Proper safety equipment is needed when welding, which includes:

o Apron

o Helmet (with proper shade of lens)

o Safety glasses

o Gloves

o Proper ventilation

Time permitting; you will receive a demonstration of the following joining processes:

- Brazing

- Gas Tungsten Arc Welding

- Gas Metal Arc Welding

- Shielded Metal Arc Welding


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2.2. Gas Metal Arc Welding (GMAW)

Gas Metal Arc Welding (GMAW) is also commonly referred to as Metal Inert Gas Welding. (MIG). GMAW is

known for its extremely high metal deposition rates, and is used in high production environments. The fillermaterial is fed through the torch or gun and also acts as the electrode (consumable). The electrode, like

GTAW, is shielded by an inert gas, usually CO2or Argon. The filler material depends on the application and

varies widely.

FIGURE 64. GMAW PROCESS (WELDINGENGINEER.COM)


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2.3. Brazing

Brazing is a process where unlike welding, the base metals are not melted and fused together. Brazing uses a

filler metal which when heated with the base metal is sucked into the base metal through capillary action.

These filler metals are typically an aluminium silicon copper alloy or a silver alloy, but it should be noted that

there are many other filler materials depending upon the application.

FIGURE 65. BRAZING (LUCASMILHAUPT.COM)


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Gas Tungsten Arc Welding (GTAW)

Gas Tungsten Arc Welding (GTAW) is also commonly referred to as Tungsten Inert Gas Welding (TIG). GTAW

is frequently used when high quality, high precision, low volume welds are needed. The reason for this is

because GTAW requires skill and the process itself if not conducive to high volume production (GTAW has a

low metal deposition rate). In GTAW, an electric arc is formed between a tungsten electrode (non-consumable)and the workpiece. Inert gas (Argon or Argon-Helium) is fed from the welding torch around the electrode to

prevent air from coming in contact with the molten metal, which would cause oxidation and thus resulting in

poor quality welds.

FIGURE 66. GTAW PROCESS (WELDINGENGINEER.COM)


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2.4. Shielded Metal Arc Welding (SMAW)

Shielded Metal Arc Welding (SMAW) is also commonly referred to as stick or arc welding. This welding process

is the most widely used of all the welding processes. This is due to the fact that it requires minimal investmentfor a machine; as well, the consumables are not very expensive. SMAW uses a rod covered with a flux; this is

the consumable electrode. Once the electrode comes in contact with the workpiece, the filler metal, flux, and

base metal (workpiece) are all melted together. The flux, being lighter than the base or filler metal floats to the

top of the molten metal and creates a slag which shields the molten metal from the surrounding air (to prevent

oxidization). Once the weld has cooled, the welder must chip off the slag.

FIGURE67.SMAWPROCESS(WELDINGENGINEER


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3. Polishing of Gyroscope Frame

Students will also be able to decrease the surface roughness of their frame while being able to achieve a mirror

like finish. It is recommended that the student first measure the surface roughness of their frame before they

start polishing as to have a starting surface roughness value to compare the final result to. The polishing

procedure starts with wet sanding on a pane of glass over a sink. Various grits of sand paper are used inincreasing order to sand away any imperfections on the frames surface. The student will start at 120 grit, then

240, and at last 600 grit sandpaper. The longer the students sands at each step, the better the overall surface

finish will be achieved. Once the sanding step is done, the student will proceed to polish their frame using an

aluminum billet polish compound. The compound will be rubbed into the surface of the frame using a piece of

rubber until a black haze appears. Once the haze is uniform on both side of the frame, the student will use a

terry cloth and buff the haze off the frame resulting in a mirror like finish. The final step is to verify the surface

roughness by using one of the Mitutoyo surface measurement machines and compare it to the initial value.

4. Gyroscope Assembly

Now that you have completed machining the gyroscope components, you must now assemble the components.

You will be given a drawing of the assembled Gyroscope (Figure 69 below).

Assembly drawings vary greatly in the amount and type of information they give, depending on the type of

mechanism they describe. The main functions of the assembly drawing are to show the product in its

completed shape, to show the relationship between its various components, and to designate these

components by a part or detail number. Other information that might be given includes overall dimensions,

relationship dimensions between parts (necessary information for assembly), operating instructions, and data

on design characteristics. The weight can also be included, and this information can be useful when calculating

packaging or shipping requirements. Assembly drawings never have detailed dimensions unless it is requiredfor an assembly. For example, if during assembly you have to press a bearing onto a shaft without a shoulder,

the distance that the bearing must be pressed onto the shaft will be noted.

Usually on assembly drawings there is a table. This table is known as the bill of materials. A bill of materials is

a must for every assembly and is either on the assembly drawing or attached as a separate sheet. The bill of

materials is used to determine how many parts the assembly is made up of and the name, description and

drawing number of those parts (if the parts are manufactured in house) or name, description and supplier name

and catalogue number (if the parts are purchased).

For example, Company X places an order for 500 Gyroscopes, they would look at the assembly drawing and

figure out how many of each components they would need (1000 #8-32 nuts, 500 rotors, etc). They would also

be able to determine which detailed drawings we would need to start production and pull them from filing or the

computer (D-01, D-05, etc.). Any purchased parts as indicated in the bill of materials can be sent out for quote.

Once all the information is gathered from the assembly drawing, the production engineer can give an estimated

cost and manufacturing time to the customer.


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Figure 68 below is an example of a more complex assembly, something that you might be more likely to see in

industry. Note that this assembly has several views including an isometric and a section view due to its

complexity. In our case, as the gyroscope is a relatively simple assembly, we will only need one view.

FIGURE 68. DETAILED ASSEMBLY DRAWING (HTTP://WWW.PROFILESMAGAZINE.COM/P19/TIPS-DESKTOP-PG1.HTML)

Figure69is the assembly drawing of the gyroscope. Note that in the upper left hand side of the drawing all the

components required are listed, as well as their respective quantities. A full page landscape drawing will be

provided for you at the end of this manual.


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FIGURE 69. ASSEMBLED GYROSCOPE SAMPLE DRAWING


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6. Rapid Prototype Demonstration

With increasing costs of manufacturing, engineering departments are being forced to use less machining

resources to develop their projects. They want to machine their prototype once and know that it will all fit

together and work as designed. This is where rapid prototyping comes into play. Most major engineering

design companies have these machines located on their premises. There are many different process used to

create rapid prototypes. Some of these processes are:

- Stereolithography

- Selective Laser Sintering

- Paper Lamination Technology

- Fused Deposition Method

- 3D Printing

We will focus on the starch deposition method as this is the type of machine that Concordia University owns.

FIGURE 70. 3D PRINTER (Z-CORPORATION)

With the machine pictured in Figure 70 engineers are able to turn complex CAD drawings into real life three

dimensional objects within hours. All rapid prototype machines recognize a standard solid model extension

format. These models have a .stl file name and are used for rapid prototyping. An example of a complex rapidprototyped assembly is shown below (Figure 71).


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FIGURE 71. COMPLEX RAPID PROTOTYPED PART

If the above part was sent to a machine shop to be made out of metal, this would be very costly and require a

lot of time to make. This would be even more costly if there was an error in the design and a revision of the part

was required. Within a short period of time an engineer can have his or her part made from a polymer. The

part is the actual size, and can be used for actual size mock-up and assembly. The rapid prototyped part would

have cost a fraction of the cost if it were to be machined. If a revision of the design is required, the new part

can be rapid prototyped without the costs and delays of having it machined.

The 3D printing method works as follows. A thin layer of starch is placed and rolled flat on a moving platform.

An inkjet print head then moves over the profile of the part and dispenses a liquid which solidifies the starch.

The moving platform is then lowered by a small increment and a new layer of starch is placed on the moving

platform. The inkjet print head then moves over the profile again building the part by a thin slice of starch at

time. Once the part is finished, it is removed leaving the unhardened starch behind.

FIGURE 72. HOW THE 3D PRINTER WORKS (CADCAM.NET)


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For a process sheet template, title block template, inspection sheet templateand examples of how to fill them out, please refer to the following webpage:

http://users.encs.concordia.ca/~dng/edml/

Mechh311 Manual Summer 2011

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Transcript of Mechh311 Manual Summer 2011