manufacturing process

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11. Material Removal Energy requirements

11.1 Specific energy requirements for different materials

1. What is a specific energy requirement (E1)?

- Required energy to remove mm3 material (W.s/mm3) or (hp.min/in3) Table 16-1 page 632

11.2 Machining fluids (coolants) for different material removal processes

1. Why need use Machining fluids?

i) Reduce cutting temperature,

ii) Reduce cutting force and increase production rate,

iii) Reduce tool wearing and elongate tool life,

iv) Flush out cutting chips,

v) Improve surface finish and product quality. Table 16-2 page 637

11.3 Tap Chart - UNC/UNF Threads

Tap size NF/NC

UNF/UNC Threads per inch

Basic major dia (inches)

Basic effective dia

(inches)

Basic minor dia of ext. threads

(inches)

Basic minor dia of int. threads

(inches) Drill size

0-80 UNF 80 .0600 .0519 .0447 .0465 3/64

1-64 UNC 64 .0730 .0629 .0538 .0561 #54

2-56 UNC 56 .0860 .0744 .0641 .0667 #50

2-64 UNF 64 .0860 .0759 .0668 .0691 #50

4-40 UNC 40 .1120 .0958 .0813 .0849 #43

4-48 UNF 48 .1120 .0985 .0864 .0894 #42

5-40 UNC 40 .1250 .1088 .0943 .0979 #38

5-44 UNF 44 .1250 .1102 .0971 .1004 #37

6-32 UNC 32 .1360 .1177 .0997 .1042 #36

6-40 UNF 40 .1360 .1218 .1073 .1109 #33

8-32 UNC 32 .1640 .1437 .1257 .1302 #29

8-36 UNF 36 .1640 .1460 .1299 .1339 #29

10-24 UNC 24 .1900 .1629 .1389 .1449 #25

10-32 UNF 32 .1900 .1697 .1517 .1562 #21

1/4-20 UNC 20 .2500 .2175 .1887 .1959 #7

1/4-28 UNF 28 .2500 .2268 .2062 .2113 #3

5/16-18 UNC 18 .3125 .2764 .2443 .2524 F

5/16-24 UNF 24 .3125 .2854 .2614 .2674 I

3/8-16 UNC 16 .3750 .3344 .2983 .3073 5/16

3/8-24 UNF 24 .3750 .3479 .3239 .3299 Q

7/16-14 UNC 14 .4375 .3911 .3499 .3602 U

EX 2. The drawings of a part are given below. All dimensions are in inches. The part will be made from a

solid steel rod of 4” diameter. Based on your knowledge of processes to produce round shapes, select the

appropriate manufacturing equipment and processes to make the part. Describe the manufacturing processes

and list them in the sequence of operations.

Equip

ment

Description Tools In your assignment and

exams, draw hand

sketches for each

process step to illustrate:

10 Saw 1. Saw 4” steel rod into 5” length. a) wp position,

b) wp holding method,

c) wp motion direction

(→must touch the

WP),

d) cutter shape and

position,

e) cutter holding

method,

f) cutter motion

direction (→ must

touch the tool).

20 Lathe 1. Clamp WP in three-jaw chuck with 4” extend to right side;

2. Face the open end to clear up;

3. Turn OD  3.50” to 1.7” length;

4. Turn OD  2.50” to 1.00” length;

5. Groove 0.125x0.062 relief;

6. Drill ID  1.50” hole to 2.5” length;

7. Bore  1.50” hole to  1.666” to 2” length;

8. Bore  1.666’ hole to  1.750” starting 0.125” from the right end;

9. Chamfer to remove sharp edges;

10. Cut off at 1.500” from the right end.

Facing cutter

OD cutter

Groove cutter

1.50 drill bit

Boring cutter

45 chamfer

Parting cutter

30 Drill 1. Drill 4 holes  0.1959” centered on 3.00” 0.196 drill

Note: 0.25-20 UNC =

Unified coarse threads,

nominal diameter 0.25”,

20 threads/inch.

40 Work

Bench 1. Tap four 0.25-20UNC holes; 2. Debur, clean and final inspection.

Tap 0.25-20 UNC

File

Note: If you re-clamp workpieces in the chuck jaws, you will lose the workpieces’ concentricity. Thus, design your

processes well and DO NOT re-clamp workpieces in the chuck jaws. If you have to re-clamp workpieces, you

much first drill a center hole on each end, then hold the workpiece on the lathe using two center pins as shown in

Topic 4 (Part 1) page 7-9.

Assignments

P1. The drawings of a part are given below. All final dimensions are in inches. The part will be made from a solid

steel of your chosen original dimensions. Based on your knowledge of material removal processes, design the

manufacturing processes by filling the process route table with: 1) the correct manufacturing equipment, 2) the

correct material removal processes, and 3) the correct the process sequence to make this part. Follow the format as

shown in EX 2. For each operation step, you are required to draw hand sketches to show: a) Work Piece (WP)

position; b) WP holding method; c) wp motion direction (your arrow →must touch the WP); d) cutter shape and

position; e) cutter holding method; f) cutter motion direction (your arrow→ must touch the tool). Create the

process design table as shown in EX 2.

P2. The drawings of a part are given below. All dimensions are in inches. The part will be made from a solid steel of

your chosen original dimensions. Based on your knowledge of material removal processes, design the

manufacturing processes by filling the process route table with: 1) the correct manufacturing equipment, 2) the

correct material removal processes, and 3) the correct the process sequence to make this part. Follow the format as

shown in EX 2. For each operation step, you are required to draw hand sketches to show: a) WP (work piece)

position; b) WP holding method; c) wp motion direction (your arrow →must touch the WP); d) cutter position; e)

cutter shape and holding method; f) cutter motion direction (arrow→ must touch the tool). Create the process

design table as shown in EX 2.

Reminder: First you must face the WP to 6” length. Second you must drill a center hole at each end. Third you

must support the WP with two center pins using two center holes. Then you are able to 1) offset the tail stock, and

taper the 0.788” to 0.948” taper, 2) rotate the WP ends without loss the concentricity.

Note: Internal thread ¾-16-UNF-3B = Unified Fine

threads, nominal diameter 3/4”, 16 threads/inch, 3B

tolerance, which is tighter tolerance than 1B and 2B.

 0 .7

8 8

 0 .9

4 8

 1 .0

0 0