Research, design improvement and manufacture tailstock of CNC gear bobbing machine

OVERVIEW

INTRODUCTION

Vietnam's government aimed to transform the nation into a modern industrialized country by 2020, with a key focus on advancing mechanical engineering This sector is crucial for the country's industrial landscape and serves as a foundation for economic growth As mechanical engineering progresses, it fosters the development of supporting industries, including automotive and machinery manufacturing Consequently, this growth plays a significant role in the industrialization and modernization of Vietnam, positively impacting the nation's economy.

To enhance engineering education in Vietnam, it is crucial to focus on workforce training and preparation Recent statistics reveal a significant number of mechanical training facilities across the country; however, the availability of CNC gear hobbing machines for educational purposes falls short of expectations, creating challenges for both educators and students Additionally, local gear manufacturers express a strong demand for domestically produced gear hobbing machines, which would offer more affordable pricing and reduced maintenance costs compared to imported options Emphasizing the development of CNC gear hobbing machine manufacturing technology is essential for establishing a solid foundation, paving the way for advancements in high-accuracy industries and maximizing the potential of Vietnam's workforce.

The rapid advancement of science and technology has intensified global competition, with each country striving to enhance its competitiveness Vietnam must stay abreast of these developments; otherwise, it risks falling behind and becoming reliant on more advanced nations This could hinder Vietnam's ability to integrate into global value chains, particularly in supporting industries.

Gears are rotating machine components with cut teeth that interlock with other toothed parts to transmit torque effectively The teeth of meshing gears are uniformly shaped, allowing for smooth operation When multiple gears work together in a sequence, they form a gear train or transmission system Additionally, gears can engage with a linear toothed element known as a rack, which converts rotational motion into linear movement.

- Based on the geometry and function properties, gear can be devided into many types as follows

- Gears for parallel shafts: spur gear, helical gear, double helical (herringbone) gear, rack and pinion a) Spur gear b) Helical gear c) Double helical gear

Fig 1.1: Types of gear for prallel shaft

Straight bevel gears and spiral bevel gears have a shape resembling a right circular cone with the tip truncated When these bevel gears engage, their theoretical vertices must align at a common point where their shaft axes intersect, creating an arbitrary angle that is neither zero nor 180 degrees.

- Gears for skew shafts driving: Hypoid gears, worm gears a) Bevel gear b) Spiral bevel gear

Fig 1.3: Gears for sknew shaft

- Spur gear – rack rail transmission movement operate rotary motion to progressive motion or opposite ( Fig 1.4)

Fig 1.4: spur gear – rack rail transmission

- Transmission ratio: i = - Circular pitch: t (mm)

A hob is a cylindrical cutting tool designed to create teeth in a workpiece, featuring helical cutting teeth along its length The grooves on these teeth facilitate effective cutting and efficient chip removal during the machining process.

The cross-sectional shape of hob teeth closely resembles that of rack gear teeth, which are used in the finished product To enhance performance, the shape is slightly modified, including an extended tooth length to ensure proper clearance at the gear's roots Additionally, each hob tooth features a relieved backside to minimize friction during operation.

- Hobbing cutter is operation tool gear used popularity, It’s used operation spur gear, helical gear, spur bevel gear double helical gear and spiral bevel gear

 The hob cutter with one start

 The hob cutter with multi-start

 Based on the structure of hob cutter:

 The hob with cutter bar

 The hob with inserted cutter bars

Fig 1.7: Generating cutter of composition

 t' 1 - depth of chase by standard (mm)

ELEMENTARY THEORY OF GEAR HOBBING

Hobbing is a specialized machining process used for gear cutting, where the teeth or splines of a workpiece are progressively shaped through a series of cuts made by a cutting tool known as a hob This process is carried out on a hobbing machine designed specifically for efficient gear formation.

Gear hobbing is a cost-effective and precise gear forming process, making it suitable for producing a wide variety of parts and quantities It is the most commonly used method for manufacturing spur and helical gears, as more gears are cut using hobbing than any other technique due to its speed and affordability.

The intermeshing between hob and workpiece must be ensured in line of action by equation:

The pressure angle between hob and workpiece should be at

The rotation speed fraction can be determined by equation:

- Alternatively is rotation speed, a number of revolutions and a number of teeth on hob

- Alternatively is rotation speed, a number of revolutions and a number of teeth on workpiece

The hobbing process involves three essential motions that work in unison to shape gear teeth: the rotary motion of both the workpiece and the hob, along with the reciprocating motion of the hob to achieve the desired gear width.

Once the hob rotates 1/k revolutions, the workpiece also rotates 1/Z revolutions, which means:

K: a number of start on hob cutter

Z: a number of desired teeth on machining workpiece

The gear hobbing process requires three essential motions: the rotary motion of both the hob cutter and the workpiece, along with the reciprocating motion of the hob cutter (S1) to effectively cut through the width of the gear.

Note: The rate of S 1 depends on the feeding rate of the hob cutter

A hob cutter is a specialized worm tool featuring a lead angle that requires an adjustment angle, known as α, between the hob cutter and the workpiece face This adjustment angle, α, is influenced by the helix angle of the hob cutter, which can be oriented to the left or right.

Fig 1.9: Left-handed Fig 1.10: Right-handed

The principle of hobbing helical gear is the same with hobbing spur gear, but there has a required in the setting angle of the hob cutter – it called ω:

 : setting angle of the gear

 : lead angle of the hob cutter

 Mark (-) applied when workpiece and hob cutter have same inclined direction

 Mark (+) applied when workpiece and hob cutter have different inclined direction

The transmission chain plays a crucial role in the machining process, requiring a differential to properly adjust the mesh between the hob cutter and the workpiece If the differential is not utilized, recalculated change gears, also known as a set of change wheels, must be used as a substitute to ensure effective machining.

Fig 1.11: Left - handed Fig 1.12: Right-handed

ELEMANTARY THEORY OF HOBBING MACHINE

Hobbing is a cost-effective and precise machining process used for cutting gears, splines, and sprockets on a specialized milling machine known as a hobbing machine This method involves progressively cutting teeth or splines into the workpiece using a cutting tool called a hob, making it suitable for a wide variety of parts and production quantities.

Hobbing is the most commonly employed gear cutting method for producing spur and helical gears, as it is both efficient and cost-effective, resulting in a higher volume of gears being manufactured through this process compared to others.

Hobbing is a machining process that employs a hobbing machine featuring two skew spindles; one holds the blank workpiece while the other is equipped with the hob The angle between the hob's spindle and the workpiece's spindle is adjustable, depending on the specific product being manufactured.

When cutting gear teeth, there are two main types of hobs: custom-made hobs and general-purpose hobs Custom-made hobs are specifically designed for creating gears with modified tooth profiles, which enhance strength, minimize size, and reduce gear noise.

When evaluating a gear hobbing machine, the most critical factor is the tolerance grade of the finished gears, as precision is essential for effective transmission Accurate design and manufacturing are vital, necessitating thorough calculations and inspections for each component The tolerance grade of gears largely relies on the machine's accuracy, with common standards typically ranging from IT07 to IT08.

CNC GEAR HOBBING MACHINE

- Thanks to the development of researching in science and engineering field, which contributes to the success in manufacturing CNC gear hobbing machine

- Hobbing machines are characterized by the largest module or pitch diameter it can generate For example, a 10 in (250 mm) capacity machine can generate gears with a

Most hobbing machines are vertical, featuring a pitch diameter of 10 inches and a maximum face width of 10 inches, with the blank mounted vertically In contrast, horizontal hobbing machines are typically employed for cutting longer workpieces, such as creating splines on the ends of shafts.

The machine tool is equipped with essential components, including a bed, column, hob head, tailstock, worktable, and counter column It operates through a technological program that enables continuous cutting without the need for a complex index table, making it highly efficient for manufacturing various types of gears, such as spur gears, helical gears, small cone gears, crown gears, and sprockets.

- There are two operation principles:

Operation principle 1: Fixed hob head and movable tailtock to cut out the length of gear.

Operation Principle 2: Movable hob head and fixed tailstock Operation principle of our designed machine

When assessing a gear hobbing machine, the tolerance grade of the finished gears is crucial, as it directly impacts their performance as transmission components Accurate design and manufacturing are essential, requiring precise calculations and thorough inspections The tolerance grade for gears typically ranges from IT07 to IT08, reflecting the machine's overall accuracy.

RESEARCH SITUATION

EVALUATION CRITERIA FOR GEAR

The tolerance grade of gear depends on these criteria as follows:

THE FACTORS AFFECTS TO THE PRECISION OF CNC MACHINE

- The machine with a large table, large working space, which brings an ability in machining kinds of gear in different parameters

- Enusure the transmission accuracy: ball screw – screw nut, linear guider, servo motor,…

- The continuously cutting process of the hob that brings an ability in machining a number of gears at the same time.

FOREIGN RESEARCH

In developed countries, the advancement of manufacturing mechanical parts and gears is driven by automation, where robots and automated systems enhance production efficiency This innovation not only accelerates line performance but also minimizes labor costs and reduces wasted time.

Gear blanks can be shaped through various cutting and finishing processes, including gear forming, forming milling, broaching, and gear hobbing Leading manufacturers in this field include RicharDon and Schiess-Brighton from Germany, Ronson Gears from Australia, Bourn & Koc from the U.S., and S&T from Korea, known for their GHO-200 model.

DOMESTIC RESEARCH

In Vietnam, there is a notable lack of research on the manufacturing of gear hobbing machines, particularly CNC gear hobbing machines Surveys indicate that no research centers or scientific departments have conducted investigations into this type of machinery.

A CNC gear hobbing machine has been developed and introduced by a research team at HCMC University of Technology and Education, showcasing significant advancements in this field.

- Built up a control programme for a forming process in machining spur gear and helical gear

- Design a model of CNC gear hobbing machine in 3D

- Simulating the operation principle and applying the strength verification for the machine

- Able to machine plastic or copper gears

- The operation rigid-plastic material

Fig 2.1: CNC GHO-200 MACHINE Fid 2.2: CNC HERA-200 MACHINE

SUBJECT OF URGENCY AND SUBJECT DETERMINE

SUBJECT OF URGENCY

In recent years, the rise of industrialization and modernization has led to significant investments in automation and mechanization within schools This includes the enhancement of educational programs, the introduction of new courses in automation, mechanization, and mechatronics at universities and colleges, as well as the nationwide upgrade of laboratory equipment, all of which collectively amount to millions of dollars annually.

In HCMC and the south area, there are not less than 10 universities or colleges investing more than 10 billions of VND in this field Generally speaking, the process includes 3 periods:

- The first period: The equipment of basic practice

- The second period: The equipment of advanced practice

- The third period: The equipment of CNC outsourcing machine

After conducting online research, I discovered numerous organizations and companies that have successfully developed CNC machines; however, these are primarily just models The images below illustrate that the production and use of gear hobbers remain uncommon in our country.

The CNC gear hobbing machine on sale domestic from foreigner as : ( Japan, Korea, Germany, …) with:

 Having many problems by the mainternance

 We are dependented on foreign supplier

After conducting online research, I discovered numerous organizations and companies that have successfully developed CNC machines However, these are primarily just models, and the actual manufacturing and application of these machines remain uncommon in our country.

Fig 3.1: Search keywords result “Chế tạo thành công máy phay lăn răng CNC Công nghiệp 5 trục”

Fig 3.2: Search keywords result “Chế tạo thành công máy phay lăn răng CNC Công nghiệp ở Việt Nam”.

OBJECTIVES

- Be proactive in high-tech manufacturing, aming to boost up the localization of our products many possible

The product scale offers a comprehensive modular system, including remote controls and flexible software for safe operation, designed to facilitate the transfer of the entire system or specific components based on customer requirements.

- The product has high level of localization (90%) and low cost They can replace imported devices and can be exported

- Manufacturing Vietnamese products with high-tech quality that can meet the need of automation and mechanization in our country, contributing in the development of national industrialization and modernization

- The manufacturing scale after the trial will be the larger scale that can meet the requirement of domestic and international market.

OBJECTS AND SCOPE OF THE RESEARCH

- The tailstock of CNC gear hobbing machine

- Designing, calculating and simulating by using Autodesk Inventor 2015

- Designing and suggesting the alternative designs

- Calculating strength of the taistock structure

- Designing and improvement portfolio: detail drawings and assembly drawings

- Combining with 2 other groups in order to complete the CNC gear hobbing machine.

SUBJECT DETERMINE

- The successful in researching and manufacturing a CNC gear hobbing machine require the time, human resource and the large budget

- Because of the limited time and the students has low specialization level and restricted wage expense then we just research and design and calculation, emulation machine.

OVERVIEW OF TAILSTOCK OF CNC GEAR HOBBING MACHINE19 I STRUCTURE

FUNCTION

- Induce rotary axis C and details clamping force, concentricity insurance and stiffness, accuracy effect of the gear

- Colunm tailstock: fixing, clamping force, concentricity insurance,accuracy effect of the gear

- Rotary table: rotary transmission from motor to tailstock and under load and concentricity

- Fixture: locate and clamp the workpiece.

THE TAILSTOCK DEVELOPMENT PROCESS

 The tailstock withdevelop period: from machine tool to CNC model machine

 The tailstock modification design phase and enhanced, arrange plans, fixing, clamping difference

 The tailstock survey, The team display design survey tailstock modern level and specialization of the tailstock:

1 Manual alternative design ( Conventional machine)

There are many clamp and unclamp machenism, they also have a general location, clamped by hand, center tailstock go down and it’s usually used rack bar and gear interlock mechanism

 There are two alternative design to manufacture loose shaft gears:

 Using loose shaft: we apply this alternative design when we use chuck for one head and tailstock one head for clamping the part by the bolt

 Using linear shaft: workpiece was fit up shaft linear on rotary table, clamping the part by bolt

 Strength’s alternative design is stability than chuck, but gear shaft is hard manufacture

 Manufacturing gears shaft: tailstocking two head and using clamping stirrup transmit rotational motion

Figure 4.1: Shaft linear Figure 4.2: Shaft losse

2 Semi-automatic alternative design (the machines manufactured big gear, big conventional machine or NC, CNC machine)

 The general all of them is workpiece jig, location by hand but auto clamping by hydraulic (quick-release fastener), centering by hydraulic

 Location in the hole of gear and front-end, combining with tailstock

 In the alternative design depend on the type of manufacture gear research firm having many fixtures For per gear profile having type of fixtures different

Figure 4.3: Fixture for gear hobbing CNC

3 Automatic alternative design (Auto supply workpiece and clamping by hydraulic)

Figure 4.4: Gear hobbing auto supply workpiece

This innovative design features a semi-automatic option with an enhanced structure, specialized components, and an automatic workpiece supply system It also includes integrated abrasive gear and a quality measurement system to evaluate the gear after manufacturing.

 This alternative design with high specialized, requesting high level and researching in a long time.

ANALYSING TO SELECT THE IDEAL ALTERNATIVE DESIGN

SELECTION OF THE ROTARY TABLE STRUCTURE

1 Alternative design 1: Electromagnetic rotary table

Figure 5.1: Structaral rotary table electromagneitc

Cleaning mechanical transmission components such as gearboxes, worm gears, cogged belts, and couplings is essential for maintenance Unlike brush motors, these components do not have a direct connection between the rotor and stator, which enhances the reliability and extends the lifespan of electromagnetic rotary tables.

The market offers a wide range of motor sizes, with diameters ranging from 140mm to 1290mm, featuring customizable shaft hole locations and T-slot designs to accommodate various components These motors come with a large hollow shaft that can easily integrate cables, cooling tubes, hydraulic mechanisms, and other equipment This flexibility in design allows for adaptable motor placement, facilitating efficient feedback and load management.

Improving kinetic efficiency is achieved through the use of a direct disk, which operates under tightly controlled bandwidth This approach allows for comprehensive system execution while reducing elasticity and vibration, ultimately enhancing the overall efficiency and lifespan of the machine.

 Disadvantages: Hard to manufacture, high price

The rotary motor is an excellent choice for CNC gear hobbing machines, offering high performance; however, its cost may be prohibitive for graduation projects.

2 Alternative design 2: Rotary table use worm and worm gear

Figure 5.4: Worm and worm gear rotary table

 Worm gear transmission is more compact than others

 This alternative design is widely used for an index dial, which is uncontinously rotary motion or rotate at low speed caused by the corrosion of transmission system

3 Alternative design 3: Rotary table use cogged belt (servo motor)

Figure 5.5: Vogged belt rotary table

 Trasmit the torque in large center distance

 Smooth operation thanks to the ductility of belt lace even runing at high speed, avoiding the oscillation of mechanisms caused by loads based on the elasticity of belt lace

 Decrease the effect of slippage between belt and pulley

 High load places on pivot and bearing

 According to the transmission in CNC gear hobbing machine, the cogged belt is widely used thanks to its advantages

Table 5.1: Evaluation table for tailstock transmission

In conclusion, we strongly recommend adopting alternative design 3, which features a cogged belt for the tailstock transmission This design enhances the flexibility of the tailstock, aligns with industrial production standards, and offers a cost-effective solution.

SELECTION OF THE CENTER TAIL STOCK STRUCTURE

1 Alternative design 1: Fixed center tailstock

 This design is being used in the HCMUTE CNC gear hobbing machine, aiming to serve for students and lecturers in studying

2 Alternative design 2: Applying rack and pinion for the transmission of center tailstock

Figure 5.7: Center tailstock use rack and pinion

- V-slot: limitd five degrees of freedom, giving a vertical motion for the center tailstock

- Easy to machine and replace once failure

- Move down and up of tailstock by hand so spend a lot of time, non-automatic

 It usually uses in small machine

3 Alternative design 3: Center tailstock uses hydraulic mechanism

Figure 5.8: Center tailstock uses hydraulic cylinder

- Tailstock column: integral casting with a hollow design, it thickness is 30mm

- Linear guide square: ensure the precision in motion, smooth operation

- Hydraulic cylinder: it helps in the motion of the center tailstock and creates the necessary clamping force

The tailstock is a crucial component that directly interacts with the gear, facilitating both the locating and clamping processes Equipped with ball bearings, it ensures smooth rotational motion at the center Additionally, the tailstock offers flexibility in adjusting the center to accommodate various types of gears during machining.

- Hydraulic mechanism creates large clamping force, stability and fast manipulation

 It uses in the large machine such as CNC industrial machine

Table 5.2: : Evaluation table for alternatives

In conclusion, we strongly recommend Alternative Design 3, which features a hydraulic mechanism for the center tailstock This design offers enhanced flexibility, aligns well with industrial production standards, and is cost-effective, making it a superior choice for modern manufacturing needs.

SELECTION OF THE FIXTURE

Jigs and fixtures for gears come in various types, tailored to specific requirements, tolerance grades, and gear profile designs Based on our extensive research and visits to Tam Binh Phuong gear manufacturer and VIKYNO, we confidently propose three alternative designs to meet diverse manufacturing needs.

1 Alternative design 1: Three-jaw chuck:

Figure 5.9: Three-jaw chuck on the rotary table

Figure 5.10: Gears are jiged on shaft, chuck

 This alternative design is used on gear hobbing machine

1.2 Location: located five degrees of freedom on the hole and the end surface, clamping by the bolt

- Flexible fixtures, it able to use for machining gear shaft or shaft loose

- Damage the workpiece caused by large cutting force

- Require time for locating and clamping

1.1 Structure: including the parts have linear profile, which is tighten by by bolt

1.2 Locating: on the hole and end face, clamping by the bolt

- Linnear profile help boost rigidity for the tailstock

- Easy to locate the workpiece

- Specified usage, it is unchangeable for multi-purpose of locating to machine gear in different diameter

- Only using for machining gears loose

 It usually use on small the conventional machine

1.1 Structure: hydraulic cylinder and collet chuck

1.2 Locating: on the hole and end face Clamping by hydraulic

- Easy and convenient in locating

- Deduct concentricity tolerance between workpiece and fixture, which increases the tolerance grade of the finished products (gears)

- Create large clamping force thanks to the aperture of a collet

- Well elasticity of the used material properties

- Hard to machine, high price

 The alternative design three is widely used for the fixture mechanism on CNC gear hobbing machine, creating the clamping force thanks to the collect chuck

4 Alternative design 4: Clamp and unclamp mechanism

Figure 5.13: Clamp and unclamp mechanism in machine GHO 200

1.2 Locating: on the hole and end face of the workpiece Clamping by hydraulic

- Easy to change the fixture

- Easy and convenient for locating

- It’s can manufacture simultaneous many parts thanks to the created large clamping force thanks to long shaft and hydraulic mechanism

Table 5.3: : Evaluation table for the alternative design of fixture:

 Conclusion : As the evaluating is shown above, we suggest selecting the alternative design 4, it is ideal for a CNC gear hobbing machine.

DESIGN

DESIGN THE ROTARY TABLE

This is the part impart a rotary motion form motor to tail stock and hold up tail stock but still warranty concentric rotary Warranty capacity supporting power axial when cut

1 Alternative design 1: Rotary table structure cylinder a) Operation principle

The servo motor delivers torque to the rotary shaft through a cogged belt, utilizing a stepped linear shaft supported by two rows of roller bearings This system includes a thrust block and a blind flange that facilitate rotary motion while managing axial loads, with the housing securely mounted on the machine table.

Figure 6.3: Structure rotary table cylinder

Housing draw-off roll Shaft

Cap of housing blank flange cowl

2 rows roller bearing sand bearing sand bearing

2 rows roller bearing following roller b) Advantages:

- Stability, ball bearings supporting axial load

- Hard to replace and repair caused by a large number of parts

2 Alternative design 2: Box-shaped a) Operation principle:

The motor transmits torque to the rotary table via a cogged belt, supported by two tapered roller bearings that stabilize the shaft, thrust block, and blank flange Additionally, a bed-plate is installed on the machine bed for enhanced stability and performance.

Figure 6.5: Rotaty table structure box-shaped

Figure 6.6: Separation rotaty table structure box-like b) Advantages:

- Easy to replace and repair thanks to a few number of parts for the installation c) Disadvantages:

- Hard to machine the housing

- Less aesthetics in industrial design

- Local load placed on the shaft.

DESIGNING THE FIXTURES FOR CLAM AND UNCLAMP MECHANISM

Based on the jigs and fixtures on GHO 200 and the research, the requirements for the fixture on gear hobbing machine are shown as follows:

- Quick clamp and unclamp mechanism

- Easy to locate and assembly with the rotary table

1 Structure: (As shown in Figure 6.7)

To properly locate the workpiece, ensure that its end surface is aligned with the fixture's body plane Next, position bush C above the workpiece When the shaft is removed, bush C generates the necessary clamping force to securely hold the workpiece in place After the machining process is completed, the shaft is automatically elevated to release the workpiece.

Figure 6.7:Jigs and fixtures designed Figure 6.8: Jigs and fixtures machine GHO 200

DESIGN ROTARY CYLINDER FOR CLAMP AND UNCLAMP MECHANISM

 Hydraulic cylinder for clamp and unclamp is special cylinder:

- Cylinder have stroke equal to stroke jigs and fixtures clamp and unclamp

The cylinder is mounted on the rotary table's shaft, allowing both to rotate simultaneously This design ensures that the connected oil galleries maintain oil flow to the cylinder, enabling the piston to function effectively while the cylinder spins, thereby facilitating the clamping and unclamping operations.

C bushing workpiece Housing Hexagona M10 bushing

Bushing of push-out collet connector

 Based on the resreaching on the internet and related documents, we have sucessful in selecting the cylinder to meet all the critera as listed

- Redesign the model based on the dimension shown in catalog

- This is single-purpose cylinder, complex, highly require in precision, we recommends to order the cylinder of SEOAM, No.YSM-120-20 (it is used in GHO

200), SMW Autolok product of Sin-S

Figure 6.9: Assembly drawing of clamp and unclamp cylinder

Figure 6.10: Photo realistic Figure 6.11: Photo design hexagon bolt

Figure 6.12: Unpack assembly cylinder clamp and unclam

DESIGN HEAD OF TAILSTOCK

The head of the tailstock, known as the tailstock center, operates on ball bearings and exerts a clamping force on the arbor when lowered, ensuring that it remains concentric with the rotary table This setup prevents horizontal bending of the support arbor during cutting, which is crucial for maintaining stability and accuracy in gear manufacturing.

Figure 6.13: Rotaty table worm and worm gear

DESIGN STRUCTURE BODY OF TAILSTOCK

- Tailstock brings the head of the tailstock move up and down in order to clamping shaft

- Structure make sure stability and antishock

- Make sure dimention of the stoke move center

- Directive part for the head of the tailstock

Figure 6.14: Structure welding Figure 6.15: Structure casting

4 Select the alternative design column:

According to structure column after consulting reality machines and document on the structure of machine tool, my team selected the option for design a) The alternative design casting

- Continuously and completely mixed of casting material

- Avoiding the locked-up stress of workpiece

- High rigidity, less vibration during operation time

- High manufacturing cost caused by one-off production

- Spending a large amount of time making a completely molded part b) The alternative design welding

- Reducing the manufacturing time as possible

- Flexible structure, easy to form as the desired shape

- Material layout often heterogeneous and discontinuous

- Workpiece warping detection caused by created heat during the welding process

- Low load withstands compared to the casting c) Conclusion:

To meet the high precision and low vibration demands of CNC machines, casting is typically an ideal method for manufacturing the column's body However, due to project time constraints, we have opted to use welding instead of casting.

5 Select alternative design guide for the head of the tailstock a) Alternative design 1: Using V - slot groove

- Hard to machined b) Alternative design 2: Using linear guide square

- High cost c) Alternative design 3: Using linear guide circulary

- Low normal force withstand capacity

- Each alternative design has different advantages and disadvantages Therefore, for easy selection we have the following table:

Alternative design V - slot groove Linear guide square Linear guide circulary

The CNC gear hobbing machine requires smooth transmission, minimal friction, and a high load capacity To meet these transmission requirements, we utilize metal slide squares for the head and tailstock.

CALCULATE

CALCULATE SHEAR FORCE OF THE KNIFE ON WORKPIECE

Accurate calculation of force and load in machine transmission is crucial to prevent mechanical failures and inefficiencies An under-calculated load can lead to part breakage, while an over-calculated load results in oversized components, causing unnecessary waste Therefore, precise load calculations are essential, particularly for specialized machines, where the load must correspond to the most demanding processing details The forces involved are illustrated in Figure 6.1.

P x - The cutting force acts in the direction of the knife run

 Calculates the forces to be applied when milling

- According to the formula 5.4 page 82 (book “Cong nghe che tao banh rang” of Assoc Prof Ph.D Tran Van Dich), shear force is:

= 15 – Coefficient effect to many factors fix to shear force when gear hobbing by worm milling cutter

= 1 – Coefficient refers to the number of milling cutter (the number of milling cutter is 1)

= 1 – Coefficient refers to the hardness the material of workpiece (thép C45)

- The amount of running knife: S = (0,8 ÷ 1,8) (mm/round) (According to page 81, the book “Cong Nghe Che Tao Banh Rang’ Choose S = 1 (mm/round)

- Cutting depth (According to book ‘Che do cat gia cong co khi, page 177)

- When manufacturing 2 cut: t 1 = 1,5mm t 2 = 0,75mm

The cutting speed (V) for module milling cutters can be calculated using the formula provided in the book "Che do cat gia cong co khi" on page 178.

S = 1 (mm/round) – The amount of running knife m – Module of gear

- Look at table 11.8 page 185, book ‘Che do cat gia cong co khi, We have the following values:

M = 0,33 According to tables 12.8 and 13.8, page 186, the book ‘Che do cat gia cong co khi’, we have:

K mv = 1 – Correction factor considering the mechanical properties of steel affects V

Cut once 1st cut 2nd cut

Table 0.1 The suggestion of cutting times based on the module

According to Table 3.2, for gears with a module m ≤ 3.5, only one cut is required, with the depth of cut equal to the height of the tooth However, for gears with a module m ≥ 3, two cuts are necessary In this evaluation, we will focus on machining a gear with a module m = 4, which will involve two cuts, with the depth of cut specified for each operation.

 t2 = 0,75.m = 0,75*4 = 3 (mm) o Module m = 3,5 the depth of cut: t = 2,25.m = 2,25*3,5 = 7,875 (mm)

- Due to the economical, we have to select the depth of cut is t = 7.875 (mm) and the module m = 3.5 to get the largest cutting force as follows

 So the largest cutting force put in the part is Pz = 5268 N

According to the formula page 178, the book “Che do gia cong co khi” of HCM City University of Technology and Education, we have:

 Cuttingcapacity: N c = 10 -3 C N S yN m xN D uN Z qN V.K n

= 2,274(Kw) Recalculate machine capacity (according to formula 5.6, page 83, book ' Cong nghe che tao banh rang) N m = =

 Speed of knife round when cutting for this case: n d = 9550 4,8.9550

CALCULATION OF CAPACITY FOR CONVEYING AND SELECT MOTOR FOR

1 CALCULATION OF POWER CAPACITY AND TORQUE IN THE ROTARY TABLE

 The relationship between the rotation of the knife and the workpiece when manufature:

- K: a number of start on hob cutter

- Z: a number of desired teeth on machining workpiece

 To determine the enclosure capacity, consider the case that is when the helical gear is cut:

- There is the largest processing module: m = 4 (mm)

- The largest angle of inclination of the gears:  = 45 o

- Milling cutter with helical screw angle  = 2 o So  +  = 47 o

Picture 7.2 Analyzes the force when cutting the tilting teeth

 The torque on the shaft rotating trays is required when milling: n f = n d K/Z = 400.1/48 = 8,3 (round/min)

 The maximum speed of the shaft : n = 400 (round/min) (According to calculations choose the engine of the knife assembly)

 Power on the rotary axis is:

 Power and torque on the motor shaft are:

2 Choose servo motor for rotary

 To ensure a sufficient working torque for machining the gear module with the largest diameter and diameter of the servomotor, the maximum torque is greater than the

To achieve effective synchronization of control, pulse, and motor functions, it is essential to select a motor with power closely matching that of the engine cluster, ensuring alignment between the workpiece axis and the knife axis.

 Based on the Mitsubishi servo motor catalog selected motor has the same parameters :

- Large capacity servo type Low inertia Electromagnetic braking brake

- Rated speed (Max): 1000(1200) revolution per minute (RPM)

- Applied: compressor control, compressor semiconductor equipment production line

CALCULATE THE BELT CONVEYOR FOR ROTARY

(based on curiculum ‘ Calculation – Design of mechanical drive system ’ volume 1 of Authors Trinh Chat and Le Van Uyen from page 68 – 72)

1 Determine the module and belt width :

In order to transmit the desired power and torque, we choose the transmission ratio u = 2,8 Module of transmitter : m = 35*√

+ = P đc = 8 (kw) – power on the belt is active

+ – is largest number of revolutions ofthe belt is active:

= 6,59 (mm) according to the table 4.27 page 68 I choose :

 The distance from the bottom to the average of the load: δ = 0,8 (mm)

Inside : = (6…9) – Is the belt width coefficient, choose = 9

According to the table 4.28 page 69, choose b = 63 (mm)

2 Determine the parameters of the transmitter

- Number of teeth the small belt is selected by the board 4.29 (page 70) To ensure the longevity of the belt, choose = 20 (teeth )

- Number of teeth of the belt:

= 129,66 According to the table 4.30 (page 70), choose :

- External diameter of the belt:

- Number of teeth at the same time on the small belt:

In it, is the hug angle on the small belt:

3 Test the belt for its own strength q = + < [q]

- = 0,009 (Kg/mm) (Select table 4.31 page 71)

- = 1,25 (Choose from table 4.7 on page 55)

+ [ ] = 45 (Select table 4.31 page 71) + = 1 – The coefficient refers to the effect of the number of concurrent teeth

+ = 1 – The coefficient refers to the effect of acceleration

From (*) and (**) we find: q satisfies the condition

4 Determine the initial tension and force acting on the axis

5 Data of the belt conveyor

Figure 7.4: Parameters of dental belts

 According to Table 4.27 page 68, we have the parameters of the belt as follows:

- Number of teeth of the belt : = 125 (răng)

- The smallest tooth thickness: S = 8 (mm)

- The distance from the bottom of the tooth to the average of the load: δ = 0,8 (mm)

- Corner profin: γ - Corner radius of the teeth : = 1,5 (mm)

Figure 7.5: Parameters of the toothed belt

 According to table 4.32 page 72, we have the parameters of the gear belt as follows:

- Number of teeth of the belt :

- Split ring diameter of the belt :

- The smallest width of the groove: s = 11,5 (mm)

- Groove profile angle: γ - Corner radius: = 1,5(mm)

- Number of teeth at the same time on the small gear: = 9 (teeth )

CALCULATE THE SELECTION OF THE SLIDER FOR THE CENTER COLUMN

( Based on the Book of General Machine Design of Tran Thien Phuc - HCMC University of Technology HCM Page 313 Song Lan)

Figure 7.6: Analysis of the force acting on the slide rail

W: Is the weight of the nose against the moving center h: The distance from the center of the trunk is fixed to the center of the head

F The clamping force of the anti-center head acts on the shaft

L: Is the arm from the fixed part to the moving nose

Figure 7.7: The moment efect on the ball slide

 Because the slip rail bear the maximum Mp momentum So we have:

 Equation of moment equation in 1:

- Choose rail according to parameters Mp= 0,52 kN.m

- Choose the coeficient of safety = 2,5

Should be selected in the following table Mp=1.4 kN.m

We choose the slider type code HGH35HA.

CALCULATE REQUIRED CLAMPING FORCE

1) Roller milling of straight teeth

The hobbing process involves three essential motions that work together to shape gear teeth accurately These include the rotary motion of both the workpiece and the hob, along with the reciprocating motion of the hob, which enables it to cut through the width of the gear.

The gear hobbing process relies on three essential motions: the rotary motion of both the hob cutter and the workpiece, along with the reciprocating motion of the hob cutter (S1) to effectively cut through the width of the gear.

- Note: The rate of S1 depends on the feeding rate of the hob cutter

The hob cutter, a specialized type of worm, features a lead angle that requires an adjustment angle (α) between the cutter and the workpiece surface This adjustment angle is influenced by the helix angle of the hob cutter, which can be oriented to the left or right.

Tool layout when machining straight teeth:

Figure 7.8: Right-handed Figure 7.9: Left-handed

Where: β : setting angle of the gear α : lead angle of the hob cutter

Mark (-) applied when workpiece and hob cutter have same inclined direction

Mark (+) applied when workpiece and hob cutter have different inclined direction

The transmission chain plays a crucial role in the machining process, requiring a differential to properly adjust the mesh between the hob cutter and the workpiece If the differential is not used, recalculated change gears, or a set of change wheels, must be implemented to ensure effective machining.

Figure 7.10: a) Left-handed Figure 7.11: Right-handed

 Calculate the inclination of the sprocket with the angle β = 20

- Analyzes the force acting on the gear:

The Pzx force is larger so we calculate the momentum equation according to Pzx

Figure 7.12: Analysis of force required

- Pzx force causes torque to spin around O:

- Equation of moment equation in O: KM c = M ms

+ M ms = R ms2 F ms2 + R ms1 F ms1

VI CALCULATING AND SELECTING HYDRAULIC CYLINDER:

1 Calculating and selecting the diameter for cylinder:

- Diameter of cylinder includes two parameter as:

The diameters of cylinders are determined by the work surface area that is affected by hydraulic oil pressure, which is essential for overcoming resistance forces This includes the work surface areas of both the cylinder-tail and the rod cylinder, where the thrust force acts on the rod cylinder and the tension force is also applied to it.

Figure: Mass of center tailstock

- Mass of center tailstock is 68.9kg So

 Because the pressure acts work surface areas of rod cylinder very smaller than the pressure acts work surface areas of cylinder-tail, so we select d = 36mm

2 Velocity and needed flow bomb to cylinder:

- According to the study, in most cases, the speed of the cylinder should not exceed v

= 0.5 m/s to safety So we select v = 0.3 m/s

- The Q flow needs to be bomb into the cylinder so that the cylinder goes through the required travel time

3 Hydraulic motor and pump: a) Hydraulic motor

- Transmission capacity of hydraulic motor: p: Pressure of pump

- Torque of hydraulic motor: p: Pressure of pump

10 : Coefficient conversion of units b) Pump:

- Number of revolutions of motor pulling pump:

VII CALCULATING AND SELECTING RORATY CYLINDER:

 Arcoding to the caculation is shown above we suggest calculating and selecting, buying the rotary cylinder, with the catalog

 Arcoding to the caculation is shown above we suggest selecting and buying the SIN – S 125 rotary cylinder.

TESTING WITH INVENTOR PROFESSIONAL SOFTWARE 2015 71 I SUSTAINABILITY FOR GLASS

CHECKING FOR ROTARY TABLE

- In assemblies there are many details with different materials But most of the load bearing parts, made of carbon steel material, only get carbon steel material

Mass Density 7.85 g/cm^3 Yield Strength 350 MPa Ultimate Tensile Strength 420 MPa

Young's Modulus 200 GPa Poisson's Ratio 0.29 ul Shear Modulus 77.5194 GPa

Table 8.4 Material parameters b) Set the load

- Force F1 is according to the y direction put in:

- Force M1 is due to the moment of rotation acting on the axis:

- M1A0000 N mm (Refer to the GHO 200)

Magnitude 410000.000 N mm Vector X -0.000 N mm Vector Y 410000.000 N mm Vector Z -0.000 N mm

Table 8.5 Load parameters c) The results after the durable:

Von Mises Stress 0.00000000275557 MPa 88.0268 MPa 1st Principal Stress -19.9414 MPa 31.9297 MPa 3rd Principal Stress -100.497 MPa 6.09699 MPa

- There are many results after software testing, but just focus on the application and system-wide details to ensure the safety of your data

- The maximum stress caused is less than the allowable stress of the material

CHAPTER IX : MAKE PLANS TO BUILD CLUSTERS

PURCHASE FOR STANDARD DETAILS AND HARD TO PROCESS, FABRICATE

After considering to the economy and the ability to manufacture with parts, parts in the cluster The group decided to order the standard parts and hard to make as:

Single row ball bearings Bearings block a range

Symbol: JIS B 1522 7005 25 x 47 x 12 Symbol : SO 104 (Single Direction)

Symbol: DIN 5412 SKF- type NNU with Tapered Bore SKF NNU 4938 BK/SPW33

Mitsubishi servo motors with the following parameters:

Maximum number of revolutions n max (v/p)

PROCESSING THE REMAINING DETAILS

The majority of components in the embankment assembly are cylindrical and will undergo machining through turning Due to the large size and high precision requirements of certain details, specialized machinery is essential to meet these demands.

CONCLUSION AND SUGGESTION

COMMENT

Throughout the duration of this graduation project, the team has engaged in extensive research and exploration, acquiring significant knowledge about gear milling utilizing rolling milling technology.

 Learn a lot of structure or from the machine to the CNC rolling milling machine

 When designing, we always learn more about the method of machining so that when the design is finished, it can be machined

 More knowledge about using 3D Inventor Profesional 2015 design software, publishing drawings, simulations

During our project, my team faced significant challenges in comprehending the intricate structure of the CNC gear hobbing machine due to the limited availability of design documents, which were mostly organized uniformly To overcome this hurdle, we sought out catalogs from foreign manufacturers and conducted a site visit to observe the actual machine in Vietnam.

 In addition, because of limited foreign language ability, it is possible to search for material that has ignored important content.

CONCLUSION

The team initially faced challenges due to their limited expertise and understanding of the subject, which led to overlooked shortcomings It is essential for the council's teachers to share their insights, enabling the team to leverage their experience and gain a clearer perspective on this research topic.

[1] Assoc Prof Tran Van Dich - "Technology of manufacturing gears"; Scientific and technical publishing house; 329 pages

[2] Assoc Prof Dr Trinh Duong - PhD Le Van Uyen - "Calculating, Designing the Drive System" Volume 1, Education Publishing House, 272 pages

[3] Nguyen Ngoc Dao - Ho Viet Binh - Tran The Sang - "mechanical cutting mode";

University of Technical Education Ho Chi Minh City, Da Nang Publishing House, 256 pages

[4] Tran Quoc Hung - "Design of metal cutting machine", University of Technical

Education Ho Chi Minh City

[5] Prof Vo Tran Khuc Nha (translation) - "Mechanics Handbook" volume 1; Hai Phong Publisher, 621 pages

[6] Prof Vo Tran Khuc Nha (translation) - "Mechanic Handbook" volume 2; Hai Phong Publisher, 598 pages

[7] Tran Quoc Hung - "Tolerance - Measurement Techniques"; University of Technical Education TP HCM; Publisher of Vietnam National University

[8] Ho Viet Binh - Nguyen Ngoc Dao - "Machine building technology"; University of Technical Education TP HCM; 267 pages

[9] Nguyen Hoc Anh - "Metal Technology"; University of Teachnology and Education TP.HCM

Analyzes the force when cutting the tilting teeth

 The torque on the shaft rotating trays is required when milling: n f = n d K/Z = 400.1/48 = 8,3 (round/min)

 The maximum speed of the shaft : n = 400 (round/min) (According to calculations choose the engine of the knife assembly)

 Power on the rotary axis is:

 Power and torque on the motor shaft are:

2 Choose servo motor for rotary

 To ensure a sufficient working torque for machining the gear module with the largest diameter and diameter of the servomotor, the maximum torque is greater than the

To achieve effective synchronization of control, pulse, and motor systems, it is essential to select a motor with power that closely matches that of the engine cluster, ensuring alignment between the workpiece axis and the knife axis.

 Based on the Mitsubishi servo motor catalog selected motor has the same parameters :

- Large capacity servo type Low inertia Electromagnetic braking brake

- Rated speed (Max): 1000(1200) revolution per minute (RPM)

- Applied: compressor control, compressor semiconductor equipment production line

III CALCULATE THE BELT CONVEYOR FOR ROTARY

(based on curiculum ‘ Calculation – Design of mechanical drive system ’ volume 1 of Authors Trinh Chat and Le Van Uyen from page 68 – 72)

1 Determine the module and belt width :

In order to transmit the desired power and torque, we choose the transmission ratio u = 2,8 Module of transmitter : m = 35*√

+ = P đc = 8 (kw) – power on the belt is active

+ – is largest number of revolutions ofthe belt is active:

= 6,59 (mm) according to the table 4.27 page 68 I choose :

 The distance from the bottom to the average of the load: δ = 0,8 (mm)

Inside : = (6…9) – Is the belt width coefficient, choose = 9

According to the table 4.28 page 69, choose b = 63 (mm)

2 Determine the parameters of the transmitter

- Number of teeth the small belt is selected by the board 4.29 (page 70) To ensure the longevity of the belt, choose = 20 (teeth )

- Number of teeth of the belt:

= 129,66 According to the table 4.30 (page 70), choose :

- Number of teeth at the same time on the small belt:

In it, is the hug angle on the small belt:

3 Test the belt for its own strength q = + < [q]

- = 0,009 (Kg/mm) (Select table 4.31 page 71)

- = 1,25 (Choose from table 4.7 on page 55)

+ [ ] = 45 (Select table 4.31 page 71) + = 1 – The coefficient refers to the effect of the number of concurrent teeth

+ = 1 – The coefficient refers to the effect of acceleration

From (*) and (**) we find: q satisfies the condition

4 Determine the initial tension and force acting on the axis

5 Data of the belt conveyor

Figure 7.4: Parameters of dental belts

 According to Table 4.27 page 68, we have the parameters of the belt as follows:

- Number of teeth of the belt : = 125 (răng)

- The smallest tooth thickness: S = 8 (mm)

- The distance from the bottom of the tooth to the average of the load: δ = 0,8 (mm)

- Corner profin: γ - Corner radius of the teeth : = 1,5 (mm)

Figure 7.5: Parameters of the toothed belt

 According to table 4.32 page 72, we have the parameters of the gear belt as follows:

- Number of teeth of the belt :

- Split ring diameter of the belt :

- The smallest width of the groove: s = 11,5 (mm)

- Groove profile angle: γ - Corner radius: = 1,5(mm)

- Number of teeth at the same time on the small gear: = 9 (teeth )

IV CALCULATE THE SELECTION OF THE SLIDER FOR THE CENTER

( Based on the Book of General Machine Design of Tran Thien Phuc - HCMC University of Technology HCM Page 313 Song Lan)

Figure 7.6: Analysis of the force acting on the slide rail

W: Is the weight of the nose against the moving center h: The distance from the center of the trunk is fixed to the center of the head

F The clamping force of the anti-center head acts on the shaft

L: Is the arm from the fixed part to the moving nose

Figure 7.7: The moment efect on the ball slide

 Because the slip rail bear the maximum Mp momentum So we have:

 Equation of moment equation in 1:

- Choose rail according to parameters Mp= 0,52 kN.m

- Choose the coeficient of safety = 2,5

Should be selected in the following table Mp=1.4 kN.m

We choose the slider type code HGH35HA

1) Roller milling of straight teeth

The hobbing process involves three essential motions that work together to shape gear teeth: the rotary motion of both the workpiece and the hob, along with the reciprocating motion of the hob to cut through the gear's width.

The gear hobbing process relies on three essential motions: the rotary motion of both the hob cutter and the workpiece, along with the reciprocating motion of the hob cutter (S1), which enables it to effectively cut through the width of the gear.

- Note: The rate of S1 depends on the feeding rate of the hob cutter

The hob cutter, a type of worm, features a lead angle that requires an adjustment angle (denoted as α) between the hob cutter and the workpiece face This adjustment angle α is influenced by the helix angle of the hob cutter, which can be oriented to the left or right.

Tool layout when machining straight teeth:

Figure 7.8: Right-handed Figure 7.9: Left-handed

Where: β : setting angle of the gear α : lead angle of the hob cutter

Mark (-) applied when workpiece and hob cutter have same inclined direction

Mark (+) applied when workpiece and hob cutter have different inclined direction

A crucial aspect of this process is the transmission chain, which requires a differential to properly align the mesh between the hob cutter and the workpiece If a differential is not available, recalculated change gears must be used to replace it, enabling the machining process to proceed effectively.

Figure 7.10: a) Left-handed Figure 7.11: Right-handed

 Calculate the inclination of the sprocket with the angle β = 20

- Analyzes the force acting on the gear:

The Pzx force is larger so we calculate the momentum equation according to Pzx

Figure 7.12: Analysis of force required

- Pzx force causes torque to spin around O:

- Equation of moment equation in O: KM c = M ms

+ M ms = R ms2 F ms2 + R ms1 F ms1

VI CALCULATING AND SELECTING HYDRAULIC CYLINDER:

- Diameter of cylinder includes two parameter as:

The diameters of a cylinder are determined by the work surface area affected by hydraulic oil pressure, which is essential for overcoming resistance forces This includes the work surface areas of both the cylinder-tail and the rod cylinder, as well as the thrust force acting on the rod cylinder and the tension force that also influences the rod cylinder.

Figure: Mass of center tailstock

- Mass of center tailstock is 68.9kg So

 Because the pressure acts work surface areas of rod cylinder very smaller than the pressure acts work surface areas of cylinder-tail, so we select d = 36mm

2 Velocity and needed flow bomb to cylinder:

- According to the study, in most cases, the speed of the cylinder should not exceed v

= 0.5 m/s to safety So we select v = 0.3 m/s

- The Q flow needs to be bomb into the cylinder so that the cylinder goes through the required travel time

3 Hydraulic motor and pump: a) Hydraulic motor

- Transmission capacity of hydraulic motor: p: Pressure of pump

- Torque of hydraulic motor: p: Pressure of pump

10 : Coefficient conversion of units b) Pump:

- Number of revolutions of motor pulling pump:

VII CALCULATING AND SELECTING RORATY CYLINDER:

 Arcoding to the caculation is shown above we suggest calculating and selecting, buying the rotary cylinder, with the catalog

 Arcoding to the caculation is shown above we suggest selecting and buying the SIN – S 125 rotary cylinder.

CHAPTER VIII: TESTING WITH INVENTOR PROFESSIONAL SOFTWARE 2015

 The spinning wheel section is the largest load in the embryo clamp so it will only last for the rotation of the clutch

I SUSTAINABILITY FOR GLASS a) Material and parameters of the material:

- In assembly assemblies are many details with different materials But most of the load bearing parts, made of carbon steel material, only get carbon steel material

Table 8.1: Parameters of Steel, Carbon material from Inventor Profestional 2015 b) Set the load

- F1 force is the cutting force of the knife set in the detail:

- Force F2 is the pressure against the hydraulic cylinder:

- Take F200 N (Refer to the GHO 200)

Load Type Force Manitude 8400.000 N Vector X 0.000 N Vector Y -8400.000 N Vector Z 0.000 N

Table 8.2: Load parameter c) The results after the durable:

Von Mises Stress 0 MPa 122.513 MPa 1st Principal Stress -24.6493 MPa 27.2683 MPa 3rd Principal Stress -130.957 MPa 2.24503 MPa

The software durability test yields various output parameters, including durable stresses and positional displacement; however, the primary focus remains on the stress levels and safety factors of the components in relation to the material's safety stress.

II CHECKING FOR ROTARY TABLE a) Material and material parameters:

- In assemblies there are many details with different materials But most of the load bearing parts, made of carbon steel material, only get carbon steel material

Table 8.4 Material parameters b) Set the load

- Force F1 is according to the y direction put in:

- Force M1 is due to the moment of rotation acting on the axis:

- M1A0000 N mm (Refer to the GHO 200)

Magnitude 410000.000 N mm Vector X -0.000 N mm Vector Y 410000.000 N mm Vector Z -0.000 N mm

Table 8.5 Load parameters c) The results after the durable:

Von Mises Stress 0.00000000275557 MPa 88.0268 MPa 1st Principal Stress -19.9414 MPa 31.9297 MPa 3rd Principal Stress -100.497 MPa 6.09699 MPa

- There are many results after software testing, but just focus on the application and system-wide details to ensure the safety of your data

CHAPTER IX : MAKE PLANS TO BUILD CLUSTERS

I PURCHASE FOR STANDARD DETAILS AND HARD TO PROCESS,

After considering to the economy and the ability to manufacture with parts, parts in the cluster The group decided to order the standard parts and hard to make as:

Single row ball bearings Bearings block a range

Symbol: JIS B 1522 7005 25 x 47 x 12 Symbol : SO 104 (Single Direction)

Mitsubishi servo motors with the following parameters:

Maximum number of revolutions n max (v/p)

II PROCESSING THE REMAINING DETAILS:

The embankment assembly primarily consists of cylindrical components that undergo machining through turning Given the large size and high accuracy requirements of certain details, specialized machines are essential to meet these demands effectively.

Throughout the course of this graduation project, the team has engaged in extensive research and exploration, gaining valuable insights into gear milling using rolling milling technology.

 Learn a lot of structure or from the machine to the CNC rolling milling machine

 When designing, we always learn more about the method of machining so that when the design is finished, it can be machined

 More knowledge about using 3D Inventor Profesional 2015 design software, publishing drawings, simulations

My team faced significant challenges in understanding the intricate structure of the CNC gear hobbing machine due to limited documentation, as most design materials were uniformly categorized To overcome this, we sought catalogs from foreign manufacturers and visited an actual machine in Vietnam for hands-on experience.

 In addition, because of limited foreign language ability, it is possible to search for material that has ignored important content

The team's initial encounter with a vast subject, coupled with limited expertise, led to overlooked shortcomings It is essential for council teachers to share their insights, enabling the team to leverage their experience and gain a more comprehensive understanding of the research topic.

[1] Assoc Prof Tran Van Dich - "Technology of manufacturing gears"; Scientific and technical publishing house; 329 pages

[2] Assoc Prof Dr Trinh Duong - PhD Le Van Uyen - "Calculating, Designing the Drive System" Volume 1, Education Publishing House, 272 pages

[3] Nguyen Ngoc Dao - Ho Viet Binh - Tran The Sang - "mechanical cutting mode";

University of Technical Education Ho Chi Minh City, Da Nang Publishing House, 256 pages

[4] Tran Quoc Hung - "Design of metal cutting machine", University of Technical

Education Ho Chi Minh City

[5] Prof Vo Tran Khuc Nha (translation) - "Mechanics Handbook" volume 1; Hai Phong Publisher, 621 pages

[6] Prof Vo Tran Khuc Nha (translation) - "Mechanic Handbook" volume 2; Hai Phong Publisher, 598 pages

[7] Tran Quoc Hung - "Tolerance - Measurement Techniques"; University of Technical Education TP HCM; Publisher of Vietnam National University

[8] Ho Viet Binh - Nguyen Ngoc Dao - "Machine building technology"; University of Technical Education TP HCM; 267 pages

[9] Nguyen Hoc Anh - "Metal Technology"; University of Teachnology and Education TP.HCM

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