CONTENS

CONTENTS...1

ABSTRACT.. 2

Contents. 3

I. Analyze Mechanical part and determine type of production. 7

I.1. Analyzing mechanical part: 7

I.1.1. Analyzing function of the mechanical part: 7

I.1.2. Analyzing material of the mechanical part: 7

I.1.3. Analyzing technical properties of the mechanical part: 8

I.2. Determine type of production: 8

II. Determine the workpiece manufacture:. 12

II.1. Determine the workpiece manufacture process: 12

II.1.1. Sand casting. 12

II.1.2. Permanent mold casting. 12

II.1.3. Centrifugal casting. 12

II.1.4. Die casting. 12

II.1.5. Investment casting (Lost wax casting) 13

II.2. Determine redundant metal in workpiece: 13

III. Determine machining process. 15

III.1. Selection of machining method for surfaces. 15

III.2. Machining time for each surface: 15

III.3. Design manufacturing step: 19

III.3.1. Task 1: 19

III.3.2. Task 2: 26

III.3.3. Task 3: 29

III.3.4. Task 4: 33

III.3.5.    Task 5: 36

IV. Determine intermediate surplus stock:. 40

IV.1.Determine intermediate surplus stock by analysis method: 40

IV.1.1. The machining step order: 40

IV.1.2. Calculate intermediate minimum surplus stock for machining steps: 41

IV.2. Determine the surplus stock bu table method: 42

V. Determine cutting condition:. 44

V.1. Determine cutting condition by analysis method: 44

V.2. Determine cutting condition by analysis method: 45

V.2.1. Step 1: rough milling surface 8. 46

V.2.2. Step 2: Thin milling for surface 8. 46

V.2.3. Step 3: Drilling hole 2. 46

V.2.4. Step 4: Thin reaming for hole 2. 47

V.2.5. Step 5: Rough boring for hole 5. 47

V.2.6. Step 6: Thin reaming for hole 5: 48

V.2.7. Step 7: Rough milling for surface 4. 48

V.2.8. Step 8: Thin milling for surface 4. 49

V.2.9. Step 9: rough milling for surface 1. 49

V.2.10. Step 10: Rough milling for surface 7. 50

V.2.11. Step 11: Drilling for hole 6: 50

V.2.12. Step 12: Thin reaming hole 6. 50

V.2.13. Step 13: Rough milling surface 9. 51

V.2.14. Step 14: Drilling hole 10. 51

V.2.15. Step 15: Thin reaming hole 10. 52

V.2.16. Step 16: Rough milling surface 11. 52

VI. Design of jig and fixture:. 54

VI.1. Requirement in designing the specialized jig and fixture: 54

VI.2. Select the fixture mechanism.. 54

VI.3. Calculate the work holding tolerance: 54

VI.3.1. Nominal tolerance: 55

VI.3.2. Holding tolerance. 55

VI.3.3. Wearing tolerance. 55

VI.3.4. Adjustment tolerance. 55

VI.3.5.Setting tolerance. 55

VI.3.6. Manufacture tolerance. 56

VI.4. Calculate the safety coefficient: 56

VI.5. Calculate the required clamping force: 56

VII. CNC Coding. 58

VII.1. Task 1: 58

VII.2. Task 2: 61

References. 62

ABSTRACT

Manufacturing project is the result after studying many related subjects such as: Manufacturing Engineering 1, 2, 3, Manufacturing process, … This project will help students get used to reality manufacturing engineering and play an important role in graduate thesis.

Our country now is in the development stage. Therefore, demands on mechanical manufacturing is very important. However, the old-dated technology which is the main problem led to consequences of ineffective production, so the modern technologies should be applied in order to increase not only in quality but also efficiency. The weakness of this project is that all the calculation is not fully implemented due to lack of time and learning material. Therefore, this project might have several mistakes. It would be my pleasure to learn more knowledge from teachers, lecturers and professors

I. Analyze Mechanical part and determine type of production

I.1. Analyzing mechanical part:

I1.1. Analyzing function of the mechanical part:

This mechanical part is claw type (dạng càng) which usually transfer linear motion into rotating motion.

The part has 3 holes with diameter ,  and  respectively on 3 axes of 3 - dimensional coordinate.

I.1.2. Analyzing material of the mechanical part:

The material of the part is gray cast iron GX 15-32. Grey cast iron is made by remelting iron. It is an alloy of Carbon and Iron. Small amounts of silicon, Phosphorus, Manganese and Sulfur are also present in it. The reasons behind its popularities are: ability to make complex structures and low cost. Its properties are as follows:

- High Compressive Strength: This strength is defined by the endurance of any material or alloy to withstand its compressive force. The compressive strength of cast iron is.

- Tensile Strength: There are different varieties of grey cast iron and their tensile strength varies accordingly. Some varieties show the tensile strength of some show 19 but on an average their strength is 7 .

- Holes allow to manufacture simultaneously

- Able to control cutting tool to manufacture surfaces and holes easily

- Hardness of the part can ensure good manufacture

I.2. Determine type of production:

The topic said that production rate is 10.000 part/year and part’s weight is 5426.46 gram.

After that, referring to table 2.1 the type of production for this product is mass production – medium.

The purpose of the determining the type is to determine the necessary number of machine or production line for manufacturing, balancing the producing time and managing the production or organization.

II. Determine the workpiece manufacture:

II.1. Determine the workpiece manufacture process:

According to mechanical part’s structure, working condition and type of production, I choose the workpiece manufacture is casting workpiece. Below is list of type of casting process with their pros and cons. After that, I will choose the type of casting which is appropriate with condition of my part most.

II.1.1. Sand casting

The advantages of sand casting are that they are design flexibility which products can range from few millimeters to meters. Besides that, they can make high complexity shapes. This is a low-cost tooling, which is suitable for medium and large mass production, which does not need a fine finish surface of products. However, the product which is made by sand casting has less accuracy than the product made by other processes. In addition, due to internal sand mold wall surface texture, the finish surface of part will be poor.

II.1.3. Centrifugal casting

This process is applied for casting round or cylinder shape products, so the melted metal is poured into a rotating mold. The structure of part is tighter but less uniformed from inside to outside.

II.1.5. Investment casting (Lost wax casting)

In investment casting, the product will have closer dimensional tolerance and both ferrous metal and non-ferrous metal can be used in this type of casting. It delivers a good as-cast finish. With investment casting, complex shapes, intricate core sections, finer details and thinner walls are possible. However, investment casting has a higher cost associated with it. In fact, it is more expensive than sand casting and permanent casting. When compared to other type of casting processes, investment casting needs a longer product cycle time.

II.2. Determine redundant metal in workpiece:

Referring to the table 3.3 to 3.5 in the reference (3).

- Degree of accuracy in dimension which need to machining

Follow by specification requirements: dimensions without tolerance will follow Js12.

III. Determine machining process

III.1. Selection of machining method for surfaces

According to [1], because it’s the mass production – medium, the type of processing method is machining in one position by using 1 tool for each surface respectively.

III.2. Machining time for each surface:

For surface, although planning method have a shorter basic machining time, milling process still be chosen because of some reason:

- The characteristic of part:         

- For planning method, surface (2) needs 2 tasks, which also increase the incidental time.         

- It’s unable to unique the designing standard and machining standard, which increase the error on machining process.

Using planning machine requires clamping many times on different clamper and increase rapidly machining time and error on machining process.

The total basic machining time is:9,68 mm/pht

III.3. Design manufacturing step:

Since the products type is house types with complicated form, which has many surface and hole need to be machine, CNC machining was chosen due to many advantages:

- Increase the productivity

- Reduces to number of labors → reduces labor cost and machining cost

- Save clamping time …

III.3.1. Task 1:

For orientation: Using surface 3, 1

For clamping: Using surface 12

Step 1: Rough milling surface 8 to acquire the surfaces roughness Ra 12.5

- These surfaces have most redundant metal, and these surfaces will be the base surfaces for all later task.

- Cutting tool:

- According to Seco Rotating Tool 2020.2

- Select face milling cutter: Quattro mill R220.53-0125-12-8A

Step 2: Finishing milling surface 8

- For cutting tool: Quattro mill R220.53-0125-12-8A (same as step 1)

- The insert for the tool: SEEX1204AFTN-D16-LF CBN200 (same as step 1)

- Workpiece dimension:

*  For surface 8:

- Requirement dimension:

- For surface 8:

- Lubricant – Coolant Fluid: Trisodium phosphate

Step 6: Finishing reaming hole 5 with diameter

- For cutting tool:

+ Select CoroBoreⓇ 825 fine boring tool: 825-45TC09-C3

- For insert:

+ Select: CoroTurnⓇ 107 insert for turning: TCMT 09 02 04-KF 3210

III.3.2. Task 2:

For orientation: Using surface 3, 1

For clamping: Using surface 12

Step 7: Rough milling surface 4

- Cutting tool:

-  Select CoroMillⓇ 345 face milling cutter: 345-050A32-13M.

- And insert for the tool:

+ Select CoroMillⓇ 345 insert for milling: 345R-1305M-PH 4330

Step 8: Finishing milling surface 4

- Cutting tool:

+ Select CoroMillⓇ 345 face milling cutter: 345-050A32-13M (same as step 7).

- And insert for the tool:

+  Select CoroMillⓇ 345 insert for milling: 345R-1305M-PH 4330 (same as step 7).

- Requirement dimension:

+  For surface 8:

- Lubricant – Coolant Fluid: Trisodium phosphate

Step 9: Rough milling surface 1

- Cutting tool:

+ Select CoroMillⓇ 490 square shoulder milling cutter: 490-040B32-08H

III.3.3. Task 3:

For orientation: Using surface 3, 1

For clamping: Using surface 12

In this task, to optimize the CNC machine, a rotating table was used.

For easy to illustrate the principle of this task, the table’s rotating angle of first step will be chosen as 0.

III.3.4 Task 4:

For orientation: Using surface 3, 1

For clamping: Using surface 12

In this task, to optimize the CNC machine, a rotating table was used.

The table’s rotating angle: .

Step 13: Rough milling surface 9

- Cutting tool:

- Select CoroMillⓇ 419 face milling cutter: 419-052Q22-14H

- And insert for the tool:

+ Select CoroMillⓇ 490 insert for milling: 490R-08T308M-KM 3220 (same as step 10)

+ Workpiece dimension for surface 9:

- Requirement dimension:

+ For surface 9:

+ Lubricant – Coolant Fluid: Trisodium phosphate

Step15: Finishing reaming hole 10 with diameter

- Cutting tool:

- Select CoroBoreⓇ 825 fine boring tool: 825-36TC06-EH25

Step 16: Rough milling surface 10

- Cutting tool:

+ Select CoroMillⓇ 419 face milling cutter: 419-052Q22-14H (same as step 13)

+ And insert for the tool:

+ Select CoroMillⓇ 490 insert for milling: 490R-08T308M-KM 3220 (same as step 10).

- Workpiece dimension for surface 4:

+ Requirement dimension:

IV. Determine intermediate surplus stock:

IV.1. Determine intermediate surplus stock by analysis method:

I will I will determine the intermediate surplus stock for hole 10 (step 14, 15). The hole (11) has the dimeter  with the surface roughness Ra 3.2

IV.1.1. The machining step order:

First, the hole 10 will be drilled with diameter

Then, it will be finishing reaming to acquire the diameter  and surface roughness Ra 3.2

IV.1.2. Calculate intermediate minimum surplus stock for machining steps:

Step 14:

- Drilling hole

- We have the workpiece is made by casting process with material is gray cast – iron, with accuracy rate II.

Therefore, we choose the drill bit with diameter 13.8mm

IV.2. Determine the surplus stock by table method:

Table for surplus stock [1], table 3.95, page 252

Table for tolerance [1], table 3.91, page 248

Table IV‑2: All surplus stock by table method

V. Determine cutting condition:

V.1. Determine cutting condition by analysis method:

In this method, i will analyze the cutting condition for rough milling for surface 7

Initial data:

- The width of machine surface: 48 mm

- The intermediate surplus stock: 4 mm

- Cutting tool: Square shoulder milling cutter: 490-050Q22-08H

- Machine: Quelling CNC machine

- Workpiece material: Gray cast – iron.

Determine depth of cut:

- Due to no restrain in the tool and machine. Therefore, the depth of cut will be equal to the surplus stock, t=4.0mm

Determine the feed rate:

- According to the reference [1], page 29, book II, the feed rate for machining gray cast – iron can be referred at the table 5.33, we select 0.15 mm/teeth. Therefore, the feedrate is:

V.2. Determine cutting condition by analysis method:

Initial data for all surface:

- Machine: Quelling CNC machine

- Workpiece material: Gray cast – iron.

V.2.1.Step 1: rough milling surface 8

Initial data:

- The width of machine surface: 196 mm

- The intermediate surplus stock: 3.5 mm

- Cutting tool: Quattro mill R220.53-0125-12-8A

V.2.2. Step 2: Thin milling for surface 8

Initial data:

- The width of machine surface: 196 mm

- The intermediate surplus stock: 4.0 mm

- Cutting tool: Quattro mill R220.53-0125-12-8A

V.2.5. Step 5: Rough boring for hole 5

Initial data:

- The depth of hole: 114 mm

- The depth of cut for hole: 2.75mm

- Cutting tool Twin-edge rough boring tool: BR20-45CC09F-C3

V.2.7. Step 7: Rough milling for surface 4

Initial data:

- The width of machine surface: 70 mm

- The intermediate surplus stock: 3.5 mm

- Cutting tool CoroMillⓇ 345 face milling cutter: 345-050A32-13M

V.2.10. Step 10: Rough milling for surface 7

V.2.11. Step 11: Drilling for hole 6:

Initial data:

- The depth of hole: 60 mm

- The diameter of hole: 24.5 mm

- Cutting tool CoroDrillⓇ 870 drill tip: 870-2450-24-KM 3334

V.2.13. Step 13: Rough milling surface 9

Initial data:

- The width of machine surface: 56 mm

- The intermediate surplus stock: 3.5 mm

- Cutting tool CoroMillⓇ 419 face milling cutter: 419-052Q22-14H

V.2.16. Step 16: Rough milling surface 11

Initial data:

- The width of machine surface: 56 mm

- The intermediate surplus stock: 3.5 mm

- Cutting tool CoroMillⓇ 419 face milling cutter: 419-052Q22-14H

VI. Design of jig and fixture:

VI.1. Requirement in designing the specialized jig and fixture:

In this method, i will analyze the cutting condition for rough milling for surface 7

- The jig and fixture must ensure to gain quick clamping process and short machining time

- The jig and fixture must increase the accuracy rate for machining process

- The jig and fixture need to acquire these features: inexpensive, easy to assembly common material, easy to replace and convenient

- In this chapter, the jig and fixture which is used in machining step 1.

VI.2. Select the fixture mechanism

The part fixed by the mechanical vice with the orientation surface 3 and clamp with surface 12.

The surface 1 is placed on 3 location pins.

V.5. Calculate the required clamping force:

Because this part is clamping by mechanical vice with 2 side surfaces used for orientation a milling by surface milling cutter. Therefore, clamping force can be calculated by formula:

In order to simplify the clamping force, I assume that only Ps applies on the workpiece. In this case the clamping devise must create a friction force which is greater than : W=10.7KN.

REFERENCES

[1]. GS. TS. Nguyễn Đắc Lộc, Sổ Tay Công Nghệ Chế Tạo Máy, NXB Khoa học và kỹ thuật.

[2]. Lê Trung Trực, Đặng Văn Nghìn, Hướng dẫn đồ án môn học Công nghệ chế tạo máy, Hồ Chí Minh: NXB Đại học Quốc gia, 2012.

[3]. Ninh Đức Tốn, Dung sai và lắp ghép, NXB Giáo dục Việt Nam, 2019.

[4]. T. V. Địch, "Thiết kế quy trình công nghệ gia công chi tiết" in Thiết kế đồ án công nghệ chế tạo máy, Hà Nội, NXB Khoa học và công nghệ, 2008, p. 19.

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