Milling Workpiece (Intermediate)

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )

6. Having selected a suitable cutting speed from the table, this must be converted into revolutions per
minute (RPM) of the machine spindle. This can be done using the chart shown here.

7. Example: a cutter of 80mm diameter is to cut at 90 m/min.
What spindle speed should be selected?

Answer: The two broken lines --------- on the chart show that the spindle speed
should be 355rpm.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 4

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )

Feed

8. Cutter feed in milling is the amount of
material removed by each tooth of the cutter.

9. Feed is express as millimetres per tooth (mm/tooth)

10. The feed rate has an effect on the life of the cutter,
that is the length of the time the cutter can be used
before it needs to be resharpened.

11. Feed depends on the same factors as those that effect
cutting speeds.

- Workpiece material, type of cutter, strength and rigidity
of the machine .

12. Always use the maximum feed that conditions will allow:
If possible, avoid using a feed of less than 0.025 mm/tooth
because this will reduce the life of the cutter.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 5

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
13. When milling hard materials using small diameter
end mills such a small feed may be necessary, but
otherwise use as much feed as possible.
14. The rate of feed has an effect of the cutter
an increase in feed, using the same cutting
cutting speed and depth of cut will reduce
the amount of wear on the cutter.

15. We can say, in general the following:
Cutting speed should be reduced when
feed is increased

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

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Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
Cutting speed should be increased when feed
Is reduced

16. The table below shows the feed in millimetres per tooth (mm/tooth) for various
materials using High Speed Steel (HSS) cutters. As with cutting speeds, these feeds must
be considered as average values which may vary according to actual working condditons.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 7

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
17. Carbide cutters can be used with much higher feeds than HSS cutters. If you are going

To use a carbide cutter, ask your instructor what feed you use, as this will depend on what grade
Of carbide is used in the cutter, the condition of the machine and its power.

18. Having selected a cutter feed in mm/tooth, this must be
converted into a table feed in mm/min, which is what the
milling machine gear box will provide.

19. To find the table feed in mm/min. We use the following formula:
mm/tooth x number of teeth

Feed (mm/min)= in cutter x rpm of spindle
Example:
20. A cutter having 8 teeth is to have a feed of 0.04mm/tooth.

the spindle speed is to be 200 rpm. What feed, in mm/min
should be set on the machine?

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 8

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
21. For rough milling, when the objective is to remove

surplus metal as quickly as possible and finish is not
important, a heavy feed and low cutting speed are used.
we should not, however, reduce cutting speed too much
as the cutter would then be operating under very heavy
cutting forces.

22. For finish milling, quality of the surface finish is of course
Important. Therefore a light feed and a high cutting speed are used.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 9

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
Depth of Cut
23. The depth of cut is the depth to which the cutter penetrates the

Workpiece surface during a given cut.

24. It depends on :
(i) the machining allowance- that is the amount of material to be
removed during a given milling operation.

(ii) whether it is rough or finish milling

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

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Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
(iii) The material of the cutter

- carbide cutters can be at higher cutting speed (HSS) cutters

(iv) The type of milling cutter
- Cylindrical and form cutters generally are used at lower cutting
speeds than other milling cutters.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

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Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
25. For rough milling we can say that a depth of 3-6 mm is suitable.

26. For finish milling a depth of 0.5 mm will ensure a good cutting action and
a good finish.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

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Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )

Worksheet 1.1.3: Calculate Speed and Feeds for milling

L.O.
1. Determine job requirements:

Learning activity:
1.2. Set cutting speeds and feeds in a machine

Read the instruction carefully, be sure to answer the question fully before going to the next
activity.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 13

Information Sheet 4.1.1 : Milling Workpiece ( Intermediate )
1. Using the spindle speed chart at the front page you are going to compute and point the arrow in the
chart with the following given condition:

Material: Brass

Cutter: End mill cemented carbide, diameter 15mm.

 Explain the importance of setting correct speed in a machine
 What will be the probable cause if you set spindle speed at high RPM or low.

Code No. Date: Developed Date: Revised Page #
ALT723307
Milling Workpiece (Intermediate)

June 10,2010 14

O38 mm drill 2 holes, O11 mm drill

TESDA Tolerance u
Linear + 0.2

ROUGHNE

3.2

radii and fillets – 3 mm

unless otherwise stated PROJECTION UNIT TIME
2 Angles + 30 CHECKED
mm
ESS SCALE
DRAWN DATE
1:2
C.L.Y June 18, 2010

RTC PROJECT TITLE REMARKS

Jig Block

Tolerance u
Linear + 0.2

DRG NO.

T – T 01

unless otherwise stated PROJECTION UNIT TIME
2 Angles + 30 mm

TESDA ROUGHNE
RTC
3.2

PROJECT TITLE REMARKS

Tapered Shaft Guide

ESS SCALE DRAWN DATE CHECKED

1:2 C.L.Y June 18, 2010

DRG NO.

M2 - 04

TESDA PROJECT TITLE Tolerance u
RTC Linear + 0.2
Sliding V Block
ROUGHNE

3.2

REMARKS

unless otherwise stated PROJECTION UNIT TIME
2 Angles + 30 mm CHECKED

ESS SCALE DRAWN DATE

1:2 C.L.Y June 18, 2010

DRG NO.

T2 - 11

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)
Learning outcomes:
1 Check/ Measure Workpiece
Learning Activity:
1.2 Read properly measuring instrument using vernier caliper

01 234 567 8
0 2 4 6 8 10

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
1

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

15

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
2

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

Sliding Jaw
Fixed Jaw

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
3

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

0 01 23 4 56 78
0 2 4 6 8 10
01 23 4 56 78 1
0 2 4 6 8 10
2

3

4

5

6

0 2 4 6 8 10 7
8

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
4

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

01 23 4 56 78
0 2 4 6 8 10

1 Note the number of whole centimetres to Working

the left of the zero on the vernier scale.

Multiply the number by 10. 3 x 10 mm = 30.00 mm

2 Note the number of whole millimetres 6 mm = 6.00 mm
Between the figure noted in (1) and
the zero on the vernier scale.

3 Find the line on the vernier scale that 28 divisions
coincides with the line on the main scale.
28 x 0.02 mm = 0.56 mm

Multiply the number by 0.02. Reading 36.56 mm

3456 78

1 Main Scale
50 Vernier Scale

01234 5 6 7 8 9 10

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
5

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

1 Note the number of whole centimetres Working
to the left of the zero on the vernier scale.
8 x 10 mm = 80.00 mm
Multiply the number by 10.

2 Note the number of whole millimetres 6 mm = 6.00mm
between the figure noted in (1) and the

zero on the vernier scale.

3 Find the line on the vernier scale that

coincides with the line on the main scale. 18 divisions

Multiply the number by 0.05. 18 x 0.05 mm = 0.90 mm

8 9 10 11 12 13 Reading 86.90 mm

Main Scale

0 2 4 6 8 10 1 Vernier Scale
20

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
6

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

Learning Outcome:
1. Check / Measure workpiece

Learning Activity:
1.3 Reading measuring instrument properly using outside micrometer

__________________________________________________________________

Thimble Ratchet Stop
Thread Thread
Spindle
5 25
Anvil 0
45 10
5
Sleeve or
0 Barrel

0 - 25 mm Lock Clamp
Frame

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
7

Operation Sheet 1.2.1 : Mill Workpiece ( Intermediate)

Index With Zero Error
Line
05
0
45

Without Zero Error

05
0
45

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
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Worksheet 1.2.1 : Milling Workpiece (Intermediate )

Learning outcomes:
1 Determine Job Requirement
Learning Activity:
1.2 Blue Print Reading

Read the instructions carefully, be sure to answer the questions fully before going to the next
activity.

Exercise 1

Match the pictures on the left with the orthographic views on the right.
Write the answers in the spaces provided.

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
ALT723307
June 10,2010 1

Worksheet 1.2.1 : Milling Workpiece (Intermediate )
Example on Filling in the Missing Views in the First Angle Projection

Exercise 2

Fill in the missing views in the First Angle Projection

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
ALT723307
June 10,2010 2

Worksheet 1.2.1 : Milling Workpiece (Intermediate )
Blueprint Reading

Exercise 3 (Refer to the blueprint on page 7)

1. What is the name of the project? ______________________
2. What is the scale used in drawing? ______________________
3. What is the angle of projection used? ______________________
4. What is the Drawing Number? ______________________
5. What is the overall length of Jig Block? ______________________
6. What is the overall width of Jig Block? ______________________
7. How many holes are to be drilled? ______________________
8. What does the line ____ _ ____ _ ____
______________________
Represent? ______________________
9. What is the size of A? ______________________
10. What is the size of B?

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
ALT723307
June 10,2010 3

Worksheet 1.2.1 : Milling Workpiece (Intermediate )
Exercise 4
Refer to the blueprint on page 85 and answer the question below.

1. What is the name of the project? ______________________
______________________
2. What is the scale used in the drawing? ______________________

3. What is the angle of projection used? ______________________
______________________
4. What is the overall length of the Tapered ______________________
Shaft Guide? ______________________

5. What is the overall width of the Tapered ______________________
Shaft Guide? ______________________
______________________
6. How many 0 11 mm holes are be drilled? ______________________

7. What is the depth of the spotface?

8. What is the difference in size between the large
between the large and the small diameter of the
tapered hole?

9. What does the symbol represent?

10. What is the size of H?

11. What is the size used for the radii and files?

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
ALT723307
June 10,2010 4

Worksheet 1.2.1 : Milling Workpiece (Intermediate )
Exercise 5
Refer to the blue print on page 87 and answer the questions below.

1. What is the name of the project? ______________________
2. What is the scale used in the drawing? ______________________
3. What is the angle of projection used? ______________________
4. What is the Drawing Number? ______________________
5. What is the overall length of the Sliding Block? ______________________
6. What is the overall width of Sliding Block? ______________________
7. What is the overall height of the Sliding Block? ______________________
8. What is the size of angle A? ______________________
9. Calculate the sizes of the following
i. B _______________
dimensions: ii. C _______________
iii. D _______________
iv. E _______________
v. F _______________

Code No. Milling Workpiece (Intermediate) Date: Developed Date: Revised Page #
ALT723307
June 10,2010 5