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Course No.: Student No.：
Course Project :
Manufacturing Technology Design
Title Machining process specification and technological equipment of bearing
Student Name 邱菲菲
Class Mechanical Design 、Engineering and Automation (English)151
Student No. 201535510107
Department/College Engineering Institute
Advisor Dr. Wang
Date
II
Course Project: Manufacturing Technology Design
Design Instruction on
Course Project:
Manufacturing Technology Design
Design Assignment
Title：Machining Process Specification of Shell Parts and Special Clamp for Milling Two Milling inner small end face
Content：
1) Manufacturing process planning sheet 1
2) Assembly drawing of Fixture or jig 1
3) Detail drawing 1 / part
4) Design Instruction 1
5) Assembly animation 1
Student Name 邱菲菲
Class Mechanical Design 、Engineering and Automation (English)151
Student No. 201535510107
Department/College Engineering Institute
Advisor Professor Wang
Date
Course Project: Manufacturing Technology Design
Contents
Abstract 5
Chapter 1 Preface 5
Chapter 2 Process analysis of workpiece 6
2.1 Function of workpiece 6
2.2 Process analysis of parts 7
2.3 Processing requirements 8
Chapter 3 Blank part determination 9
3.1 Blank design 9
3.2 Determination of blank allowance 10
Chapter 4 Manufacturing process planning 10
4.1 Process planning 10
4.2 Selection of processing equipment and process equipment 12
Chapter 5 Cutting parameters and labor-hour 13
5.1 Determination cutting parameters 13
5.2 Time quota calculation 14
Chapter 6 Fixture design and usage of equipment 15
6.1 Jig/Fixture design 15
6.1.1 locating and clamping of the workpiece 15
6.1.2 Analysis of location errors and clamping error 16
6.1.3 Analysis and calculation of cutting force and clamping force 17
6.3 Summary 19
Chapter 7 Conclusion 20
References 21
Thanks 22
Abstract
The design course is a teaching link on the basis of finishing the course Technology of Mechanical Manufacture(including machine tool fixture design)and most of the specialized courses. It is a design of special fixture mainly for the processing technic of parts and some procedure processing of parts. From the process of the parts,it mainly analyses what problems should pay attention in the processing,and what methods and process should be adopted to ensure the accuracy and raise labour productivity. As far as special clamp is concerned, good fixture design can improve product productivity, accuracy, reduce costs and so on, and can also expand the scope of use of machine tools, so that improve the production efficiency and reduce the costs under the premise of ensuring accuracy.This design enables us to apply the basic theory of manufacturing technology, combining with practical knowledge gained from production practice,and analyze and solve process problems independently.Besides,it enables us to master the ability to design a process specification for a moderately complex part (shell) and the knowledge of the basic principles and methods of fixture design.This design is also a practice shot of drawing up jig design plan, completing jig structure design ability,being familiar with and using relevant manuals, charts and other technical data and writing technical documents and other basic skills,which lays a good foundation for future graduate design and future work.
Due to limited capacity, lack of experience, there are many inadequacies in the design, I hope the teacher will be more advice.
Key words: process planning, design, special fixture
Chapter 1 Preface
The bearing seat, as the name implies, ACTS as a support bearing, which holds the bearing's outer ring in place.Only the inner ring is allowed to rotate, but the outer ring does not rotate. It always rotates in the direction of the drive (for example, the motor is in a positive rotation, the inner ring is in a positive rotation, and vice versa), actually is a kind of bearing parts, is composed of bearing and housing, convenient for application in the field of various industries, advantage lies in between the parts and have to cooperate with more harmonious, easy to use, direct help manufacturer to cost control. In terms of shape, it has many kinds of diversity, often just a box body, the bearing can be installed in.As China's mechanical technology becomes more and more developed, it becomes even more important in production and develops well, especially in the fields related to automobile and electronics and electrical appliances, which have witnessed rapid development.
This subject is the mechanical processing technology and fixture design of bearing seat, which is an important task after learning automobile manufacturing technology.
Under the guidance of the teacher, this design will require the students' union to make a comprehensive application of all the lessons learned before, and complete a basic engineering training independently.
Chapter 2 Process analysis of workpiece
2.1 Function of workpiece
The parts for bearing seat, according to the shape of the parts to see the big hole and the corresponding shaft connection between, among the big hole and shaft connection need to guarantee a certain tolerance matching, to ensure the bearing on the shaft bearing can make can make smooth shaft rotation, and the bearing seat need to connect with the corresponding shaft and bearing, so to play a role in connecting the center hole and connecting face right certain accuracy and the behavior of tolerance size requirements.
2.2 Process analysis of parts
Figure 2-2
As can be seen from the part diagram of the bearing housing, preliminary technical requirements are analyzed according to the basic features, which are divided into machining features of surface and hole:
(1) on the end face, wide groove on the surface of the upper and the lower right side end face, wide groove on the lower right side of the face, on his men along the surface, lower left along the surface, phi before and after the end of 250, the surface characteristics of phi 250 before and after the end of the surface roughness request for Ra6.3, two parts of the wide groove is 50 h11 Ra6.3, in addition to the rest of the state that the surface roughness of the requirements are Ra12.5 did not indicate the surface roughness were not processed.
(2) the characteristics of the hole include: the large circular hole of the central datum is with a mean value of 180H7; the surface roughness of the hole is required to be Ra1.6; the surface roughness of the upper and lower right holes is required to be Ra12.5; the surface roughness of the upper and lower right holes is required to be Ra12.5; and the surface roughness of the big end face is required to be Ra12.5.
(3) tolerance demands between upper end and lower end verticality 0.12 mm, phi 180 center circle hole roundness requirement of 0.008 mm, big face phi 250 as a benchmark, B center circle hole phi 180 as a benchmark C, two wide groove relative to B benchmark position degrees 0.4 mm requirement, before and after the big end faces for C benchmark center has vertical degree is the requirement of 0.1 mm, upper wide groove center line parallelism and phi 250 face right after the requirements of 0.12 mm, 6-13 holes compared with B and C datum axis position requirement of 0.6 mm.
2.3 Processing requirements
When selecting the processing methods of surfaces and holes,
① Considering the accuracy of the machined surfaces and surface roughness requirement.According to the technical requirements of the processing surface,select the processing methods and process several times.Equipment should be selected according to the type of production,and in the mass production,efficient equipments can be used,however in single piece small batch production, common equipments and general processing methods are often used.Such as diesel engine connecting rod small hole processing,in small batch production, using drilling, reaming, reaming processing method.
② Considering the property of the material to be processed. For example, hardened steel must be grinding or electrical processing, but due to easy to plug the grinding wheel when grinding,non-ferrous metal generally use fine turning and high-speed finish milling.
③ Considering the actual situation in a factory or workshop.
④ Considering improving existing processing methods and equipments, popularizing new technology and improving process level.
In addition, considering other factors,such as special requirements for the physical and mechanical properties of the machined surface,the shape and weight of the workpiece and so on.
Chapter 3 Blank part determination
3.1 Blank design
We can know from the bearing pedestal diagram that the materials for the bearing pedestal parts are HT200 materials, and HT200 materials are pearlite gray cast iron type materials.
This kind of material's strength will be relatively high, in wear-resistant performance aspect also is better, but the tendency of white mouth is bigger, in casting aspect's performance will be relatively poor so, generally speaking must first carry on the artificial aging to carry on the processing processing.
Because the production requirements of the bearing seat parts are batch processing, we choose the materials of the parts to prevent the casting, and achieve the forging of the blank.
This time, ordinary sand casting blank is selected. After casting, the surface stress is removed by annealing and the residue is cleaned. In the casting process, casting defects such as pores, cracks and shrinkage should also be avoided.
The part of the integral part is selected as the parting surface, and the position of the pouring riser is selected on both sides of the main reference hole.
Whether the selection of blank is reasonable or not has a key influence on our subsequent processing, especially the selection of blank materials, as well as the processing mode of the blank and the precision of the blank can deeply affect our subsequent processing.
So make sure good manufacture of blank form is very important, the bearing considering for mass production, according to the shape of parts, determine the blank for casting can be integral parts of the basic cavity can be cast out, some don't processing surface can be directly cast molding, which is convenient, the choice of casting method for sand mold casting, casting way can to a great extent to reduce the costs of our technical personnel of the production.
3.2 Determination of blank allowance
According to the mechanical manufacturing technology foundation course design guidance tutorial on casting blank, choose the parts of the surface of the basic characteristics of the casting blank and machining of the net size relative to consider machining allowance, query the book table 2 to 25, draw a plane machining allowance, the thickness of surface is greater than 50 mm, width is between 200 and 400 mm, so rough machining allowance of 2.5 mm, half finishing allowance of 1.5 mm, on end face and lower end face similarly also according to the rough machining allowance of 2.5 mm.
When the center hole is roughmachined to 3mm, the semi-finishing to 2mm and the finishing to 1.0mm, it is concluded that the size of the blank of the center hole which is join180-3-2-2-1=168.
The thickness of the blank is 100+2.5+1.5+2.5+1.5=108mm.
Chapter 4 Manufacturing process planning
4.1 Process planning
The main process arrangement of this shape basically adopts the processing of big features first and then small features, first of all, the easier processing and positioning areas are processed, and then the more difficult areas are processed, especially the more difficult ones.
The principle of first face, second hole, first big hole and small hole is basically suitable for the process arrangement of bearing cover parts. This time, the process arrangement of bearing seat is just following the principle of such process arrangement.
After the casting of the workpiece is completed, the foundry residue of the workpiece shall be cleaned.
Cleaning is done at high temperature with a certain component of soda and a certain volume of sodium nitrite solution.
After finishing, the surface of each part is cleaned with sufficient compressed air to get rid of the residue.
In this way, the impurities, iron shavings, burrs and sand particles in the cast parts will be reduced or even disappeared accordingly.
For the bearings used in this batch production, concluded processing technology program.
4.2 Selection of processing equipment and process equipment
Because the production type is batch production, this USES in the numerical control milling machine to carry on the processing.
When milling each surface feature, because the processed object is the integral plane surface.
Considering the positioning clamping scheme of workpiece and the structural design of jig, vertical milling machine X52K is adopted.
In the process of milling each surface, since the workpiece is a certain irregular object, special clamps are needed to be used for mounting and clamping.
The assembly and clamping of the parts is relatively standard, and the universal clamping device is basically adopted. This time, the underside of the workpiece is added with a pad iron, so as to bore or bore the workpiece without damaging the worktable of the machine tool.
Milling cutters are used in the process of milling each surface.
The selected measuring tools include the vernier caliper 0-300mm, vernier depth gauge 0-150mm, etc.
When boring the middle hole, the tool selected is the special boring cutter. Since the diameter of the inner hole is 180, the inner diameter micrometer selected is 50-575m.
When drilling various holes, select the method of first drilling the underhole and then reaming according to the need of drilling. The hole of the "25" shall first adopt the standard twist drill bit of the "20", and then select the "25" reaming bit.
The measuring tool can be selected with a vernier caliper of 0-150mm.
Drill the hole of the bit with the same bore diameter.
Chapter 5 Cutting parameters and labor-hour
5.1 Determination cutting parameters
Operatinon 90 Milling the inner small end surface
Material of parts processed: HT200
Machine selection: vertical milling machine X53K
Tool selection: shell face milling cutter, diameterφ50mm, number of teeth Z=8
The milling depth ：
Feed per tooth ：
Cutting speed V:
Machine spindle speed ：
Feed ：
Table feed per minute ： ==1.8mm/s=108mm/min
5.2 Time quota calculation
The milling length of the workpiece
Cutter cut length ：
Is the nominal width of milling, It is concluded that the width of the cylindrical milling cutter with a diameter of 50mm is 3mm
：The diameter of the milling cutter is 50mm
， so
The cutter cut out the length ：，this choice 3mm.
：Bench level feed
The number of cuts is 1.
Time
Chapter 6 Fixture design and usage of equipment
6.1 Jig/Fixture design
The fixture is as followed.
6.1.1 locating and clamping of the workpiece
On the bearing seat selection for men to concave and left on the right side of the concave milling special fixture, according to the features of parts, the two parts can be done on the same special fixture, to operation is a feature in finish machining, after the workpiece is removed and rotate on a feature after processing.
According to its technological process, the basic shape of the workpiece is relatively large, and the datum of each positioning is easy to be selected. Therefore, the positioning method basically selects the basic features of the appearance for positioning.
Processing concave up and down again to choose the right side of the workpiece end face can be as a positioning base, to the right side of the face as a locating datum can limit the three degrees of freedom of workpiece, when I was in the same way and then to the left lower concave processing more than face for locating datum, part after flip feature are exactly the same, in addition to the workpiece under the small side end face positioning in order to prevent the workpiece move, from the whole positioning way basically artifact will not flip and mobile, in order to guarantee the stability of the artifacts as a whole and strength, choose the auxiliary positioning end face for an activity, the auxiliary positioning does not restrict freedom, just in order to enhance strength.
Then the large end surface can be used as a reference to limit one degree of freedom, until the entire workpiece is fully positioned.
6.1.2 Analysis of location errors and clamping error
(1) location error
According to this positioning method, the positioning method is based on the plane of the bottom surface of the workpiece. The positioning method of the plane is based on the positioning of two vertical planes (the bottom plane and the side of the bottom plane).
Figure 5 1Vertical plane localization example
Through the tolerance analysis of two vertical plane positioning, the following formula is calculated:
In this case, α=90°，=64，=35，
So
The positioning error accounts for the machining tolerance is , which can guarantee the processing requirements.
(2) clamping error
Common notation
According to the design manual of machine tool fixture [1] table 17-9,
=2（H-h）tan
The positioning method in this case is the positioning pad on the bottom surface and two support pins on the side of the bottom surface.
Then，H=98mm，h=51mm，=0.1o，so
=2×（98-51）×tan0.1o
=0.16mm
According to the jig design manual of the machine tool [1], machining accuracy grade IT=8. According to geometric tolerance and detection [8] attached table 3-2, the tolerance is 0.54mm, within the allowable range.
6.1.3 Analysis and calculation of cutting force and clamping force
(1) calculation of cutting force
The cutting force is milling two small end faces, then the cutting force is milling force
Formula is as follows
Among them,
F: cutting force N
: consider the type coefficient of workpiece material milling cutter when milling HSS milling cutter, and check the table
: milling depth mm
D: diameter of milling cutter is mm
: mm feed per tooth
B: milling width mm
Z: the number of teeth of the milling cutter
: the correction coefficients of different mechanical properties of workpiece materials are taken into account when milling HSS
The diameter of the mill according to the cylindrical milling cutter φ50mm,The feed amount of each tooth of the milling cutter is =0.1mm The?width?of?the?milling?is?the?length?and?the?size?is?170,?so?B=170mm,the?tooth?number?of?millin?is?8,?so?Z=8,?the?milling?depth?is=?1.5mm?,according?to?the?rough?milling?specification and?the?milling?cutter?milling?bearing?seat?material?is?carbon?steel?material,?the?index?is?=294,?=1.
SO
=1595N
(2)?calculation?of?clamping?force
：Prime movers
：Actual clamping force required
：Equivalent friction radius between screw end and workpiece
：Half the diameter of the thread
：Thread Angle
：Angle of friction between screw end and workpiece
：The equivalent friction Angle of the screw pair
：Mechanical efficiencyThen,
Wk =1946N, r' = 3, φ1 = 3.2, rz = 6.9, α = 2.5, φ'2 = 9.83, L = 43, η0 = 0.88, l = 21
So,
= 1830.68N
6.3 Summary
The clamp is milling surface, due