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Course Project :
Manufacturing Technology Design
Title Design of special fixture for coarse and fine boring of bearing block___
Student Name ___________CHICK ARTHUR NICK FUSI____
Class Mechanical Design 、Engineering and Automation (English)151_________
Student No. _______201535510132________
Department/College ___ Engineering Institute________
Advisor Dr. Wang____________
Date _______2018 年 11 月 07日____
II
Course Project: Manufacturing Technology Design
Design Instruction on
Course Project:
Manufacturing Technology Design
Design Assignment
Title：Design of special fixture for coarse and fine boring of bearing block
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
Course Project: Manufacturing Technology Design
Contents
Contents 3
Abstract 4
Chapter 1 Part Analysis 5
1.1 Part role 5
1.2 Process Analysis of Parts 5
Chapter 2 Process Design 6
2.1 Determination of the manufacturing form of the blank 6
2.2 Datum selection 6
2.3 Formulating the route 6
2.5 Determine the cutting amount and basic working hours 8
2.5.1 Thick and fine milling front and rear end faces of φ250 8
2.5.2 coarse and fine boring φ180H7 10
2.5.3 drilling reaming φ25 12
2.5.4 Milling groove 10mm 14
2.5.5 drilling expansion 6-φ13 14
Chapter 3 Fixture Design 17
3.1 Proposal of the problem 17
3.2 Selection of positioning criteria 17
3.3 Analysis of positioning error 18
Operation List Sheet 22
Conclusion 24
References 25
Thanks 26
Abstract
The mechanical manufacturing process curriculum is designed after completing all the basic courses, professional basic courses and most of the main courses of the university. This is an in-depth and comprehensive review of the courses that students have taken before graduation design. It is also a theoretical and practical training. Therefore, the design of mechanical manufacturing technology courses is very important.
I hope that I can adapt the mechanical manufacturing process design through this course design, from which I can get exercise, and consciously analyze the problem and solve the problem, and lay a good foundation for future work.
Due to limited capacity, there are many deficiencies in the design process, so please ask the teachers to enlighten me.
Key words: process planning, design, special fixture
Chapter 1 Part Analysis
1.1 Part role
The bearing housing parts are generally the components that connect the bearings. Of course, if there are connecting bearings, there will be shaft holes, and the central shaft hole will have high precision. The center hole is connected with the corresponding shaft and bearing. The center hole of the bearing housing this time. It is connected with the bearing on the corresponding shaft. The center hole of the bearing connection needs to have a certain surface precision, and the cylindricity and other geometrical tolerance requirements must be ensured. Therefore, the bearing seat can ensure the rotation of the transmission shaft smoothly. The role.
1.2 Process Analysis of Parts
Some of the surfaces to be machined in this housing part mainly include a wide groove on the upper end surface and the upper end surface, a wide groove on the lower right side end surface and the lower right side end surface, and a lower end surface on the upper wide groove opposite side, The opposite end faces of the wide groove on the right side, the front and rear end faces of φ250, etc., the surface roughness of the front and rear end faces of φ250 in these surface features is Ra6.3, and the width of 50h11 of the two parts is also Ra6.3, and the others are The specified surface roughness requirements are Ra12.5, and the surface roughness is not indicated.
The characteristics of the hole include a large circular hole φ180H7 on the center reference, the surface roughness of the hole is required to be Ra1.6, and the surface roughness of the 2-φ25 hole on the upper wide groove and the lower right wide groove is required to be Ra12.5, on the large end face. The 6-φ13 through hole requirement is also Ra12.5.
The geometrical tolerance requires 0.12mm between the upper middle end and the lower right end. The center large round hole φ180 requires a roundness of 0.008mm, the large end surface φ250 is the reference B, and the center large round hole φ180 is the reference C. The two wide slots are relative to The B-reference has a positionality of 0.4 mm, and the front and rear large end faces have a verticality of 0.1 mm with respect to the C-reference center.
Chapter 2 Process Design
2.1 Determination of the manufacturing form of the blank
The material of the bearing housing is HT200. The material is gray cast iron. The material of gray cast iron is usually made in the form of casting. This part is of course also used in the form of casting. The casting adopts the common sand type. The way of casting is fine.
2.2 Datum selection
(1) Rough reference selection
The basic rough reference of this bearing housing part can select the shape of the workpiece. At the beginning, the front and rear end faces of the φ250 large outer circle are used as the rough reference for processing the front and rear end faces. Of course, the upper end face and the lower right end face of the part can also be used as a rough reference.
(2) fine benchmark selection
If the precision of the bearing housing parts is selected, the center hole is used as the subsequent fine reference. For example, the machining of the small hole and the wide groove can be used as the subsequent machining precision reference.
2.3 Formulating the route
For this time, the two parts of the process plan are determined and compared. as follows
(1) Process plan one
Process 1: Casting blank
Process 2: rough and finish milling φ250 front end face
Process 3: After roughing and finishing φ250, the end face is guaranteed to have a size of 100mm.
Process 4: coarse and fine center hole φ180H7 in place
Step 5: Milling the upper end face and the right end face
Step 6: Milling upper lower end surface and right lower end surface to ensure size 50mm
Step 7: Milling the upper end and the right end of the wide groove 50mm
Process 8: Drilling and expanding 2-φ25 holes
Process 9: Drill 6-φ13 hole
Process 10: Deburring chamfering
Process 11: Inspection and storage
(2) Process plan 2
Process 1: Casting blanks
Step 2: Thick and fine center hole to φ180H7
Process 3: coarse and fine milling φ250 front and rear end faces to ensure thickness dimension 100mm
Step 4: Milling the end face and the right end face
Step 5: The lower end surface and the lower right end surface corresponding to the upper part of the milling machine are guaranteed to have a size of 50 mm.
Step 6: Wide groove 50mm on the upper and right end faces of the milling
Step 7: Drilling and expanding 2-φ25 holes
Process 8: 6-φ13 hole on the large end face
Step 9: Deburring the chamfer
Process 10: Inspection into the warehouse
(3) Comparative analysis of process plans
Let us analyze the comparative analysis of the two process schemes for the parts of the housing as above.
In the second scheme, the large hole is processed first, and then the front and back end faces and the remaining surface features are processed. This obviously violates the basic principle of the front face back hole, so it is not used, so this processing plan selection The first processing solution.
2.4 Determination of machining allowance, process size and blank size
According to the material blank of the bearing seat, the HT200 gray cast iron blank is used to determine the machining allowance, process size and blank size of each machined surface.
1, front and rear end faces of φ250
For the plane machining allowance of Table 2-24 of the "Guidelines for the Design of Mechanical Manufacturing Technology Basic Courses", the surface roughness of the planes of the front and rear end faces of the bearing housing φ250 is Ra6.3, which must be completed after roughing and semi-finishing. The thickness range is 50~100mm. It is known that the roughing allowance is 1.7mm on one side and the semi-finishing allowance is 1.3mm on one side. Thus, the blank size of the front and rear end faces of φ250 is 100+3+3=106 mm.
2, hole ( )
Query Table 2-20 The diameter of the hole φ180 of the bearing housing before the roughing can be φ170mm at the maximum. This time, it is manufactured according to the blank size of φ170 hole.
2.5 Determine the cutting amount and basic working hours
? 2.5.1 Thick and fine milling front and rear end faces of φ250
(1) rough milling
Material to be processed: HT200
Machine tool selection: vertical milling machine X53K
Tool selection: Select sleeve end mill, diameter φ100mm, number of teeth is Z=10
Milling depth :
Feed per tooth : According to Table 5-5 of “Guidelines for the Design of Mechanical Manufacturing Technology Basic Courses”
?Milling speed : refer to Table 5-11 of "Machinery Manufacturing Technology Basic Course Design Guide"
Machine tool spindle speed :
Feed rate :
Feed per minute of the workbench:
According to the basic time calculation of milling in Table 5-47 of the "Machinery Manufacturing Technology Basic Course Design Guide", this is the sleeve face milling cutter. The basic working hour calculation formula of milling is as follows
?In the middle
Milling length of the workpiece
Tool cut length :
In the middle
? For the nominal width of the milling, look up Table 5-11 to find that the face milling cutter with a milling width of 100 mm has a milling width of 48 mm.
? : Milling cutter diameter is 100mm
Substituting the above formula
,inferred
Cut length of the cutter : Take , select 3mm this time
? : Workbench horizontal feed
The number of passes is 1
Mobility time
(2) Finishing φ250 end face
Material to be processed: HT200
Machine tool selection: vertical milling machine X53K
Tool selection: Select sleeve end mill, diameter φ100mm, number of teeth is Z=10
Milling depth :
Feed per tooth : According to Table 5-5 of “Guidelines for the Design of Mechanical Manufacturing Technology Basic Courses”
?Milling speed: refer to Table 5-11 of "Machinery Manufacturing Technology Basic Course Design Guide"
Machine tool spindle speed :
Feed rate :
Feed per minute of the workbench:
According to the basic time calculation of milling in Table 5-47 of the "Machinery Manufacturing Technology Basic Course Design Guide", this is the sleeve face milling cutter. The basic working hour calculation formula of milling is as follows
?
In the middle
Milling length of the work piece
Tool cut length :
In the middle
? For the nominal width of the milling, look up Table 5-11 to find that the face milling cutter with a milling width of 100 mm has a milling width of 48 mm.
? : Milling cutter diameter is 100mm
Substituting the above formula
? ,inferred
Cut length of the cutter : Take , select 3mm this time
? : Workbench horizontal feed
The number of passes is 1
Mobility time
2.5.2 coarse and fine boring φ180H7
(1) Rough hole to φ179
Choose high speed steel file
The roughing tool is selected as
For the feed amount query, refer to Table 5-36 of the Mechanical Engineering Technology Basic Course Design Guide.
The cutting speed is shown in Table 5-1.
Machine tool spindle speed :
The cutting time is calculated according to the following formula
?
In the middle
L: The length of the cutting is 179mm according to the aperture
?: The actual length of the workpiece is 179mm
: roughing selection is 2mm
Leading angle , then
? , this time select 4mm
The number of feeds is
?
(2) fine
Choose high speed steel file
For the feed amount query, refer to Table 5-1 of the "Machine Manufacturing Technology Basic Course Design Guide".
The cutting speed is shown in Table 5-1,
Machine tool spindle speed :
The cutting time is calculated according to the following formula
?In the middle
L: the length of the cutting is 180mm according to the aperture
: The actual length of the workpiece is 180mm
?Leading angle , then
?, this time select 4mm
The number of feeds is
2.5.3 drilling reaming φ25
(1) Drilling to φ20
Feed rate : According to Table 5-22 of "Machine Manufacturing Technology Basic Course Design Guide"
Cutting speed: refer to Table 5-22 of "Technical Manufacturing Technology Basic Course Design Guide"
Machine tool spindle speed : ,
The cutting time of the drilling hole is calculated as follows
?In the middle
Length of the layer to be cut: this time according to the depth of the cutting
Tool cut length :
?: The front angle of the taper shank twist drill is generally 118 degrees. This time is calculated according to 120 degrees.
?Tool cutting length : , this time is drilling through hole, according to 3mm
The number of passes is 1
Maneuver time :
(2) Reaming to φ25
Feed amount : According to Table 5-25 of "Machine Manufacturing Technology Basic Course Design Guide"
Cutting speed: Refer to Table 5-26 of the "Guidelines for the Design of Mechanical Manufacturing Technology Basic Courses".
Machine tool spindle speed : ,
The cutting time of the reaming is calculated as follows
?In the middle
Length of the layer to be cut : this time according to the depth of the cutting
Tool cut length :
? : The front angle of the taper shank twist drill is generally 118 degrees. This time is calculated according to 120 degrees.
?Tool cutting length : , this time is drilling through hole, according to 3mm
The number of passes is 1
Maneuver time :
2.5.4 Milling groove 10mm
Machine tool: Milling machine X53K
Tool: high speed steel keyway milling cutter
Number of teeth
Feed amount : According to Table 5-15 of "Machine Manufacturing Technology Basic Course Design Guide"
Cutting speed : refer to Table 5-15 of "Machine Manufacturing Technology Basic Course Design Guide"
Machine tool spindle speed : ,
The method of milling the keyway is used to calculate the basic working hour calculation formula of milling as follows
?In the middle
Cutting length of the workpiece
Tool cutting length : , calculated according to 25mm,
Cutting length of the cutter : Take , this time select 2mm
? : Workbench horizontal feed
?Mobility time
2.5.5 drilling expansion 6-φ13
(1) Drilling to φ10
Feed rate : According to Table 5-22 of "Machine Manufacturing Technology Basic Course Design Guide"
Cutting speed: refer to Table 5-22 of "Technical Manufacturing Technology Basic Course Design Guide"
Machine tool spindle speed : ,
The cutting time of the drilling hole is calculated as follows
?In the middle
Length of the layer to be cut : this time according to the depth of the cutting
Tool cut length :
? : The front angle of the taper shank twist drill is generally 118 degrees. This time is calculated according to 120 degrees.
?Tool cutting length : , this time is drilling through hole, according to 3mm
The number of passes is 1
Maneuver time :
(2) Reaming to φ13
Feed amount : According to Table 5-25 of "Machine Manufacturing Technology Basic Course Design Guide"
Cutting speed : Refer to Table 5-26 of the "Guidelines for the Design of Mechanical Manufacturing Technology Basic Courses".
Machine tool spindle speed : ,
The cutting time of the reaming is calculated as follows
?In the middle
Length of the layer to be cut : this time according to the depth of the cutting
Tool cut length :
?: The front angle of the taper shank twist drill is generally 118 degrees. This time is calculated according to 120 degrees.
?Tool cutting length : , this time is drilling through hole, according to 3mm
The number of passes is 1
Maneuver time :
Chapter 3 Fixture Design
3.1 Proposal of the problem
This time, the housing block process selects the special clamp for the hole in the middle of the large hole φ180H7. Since the center hole is very large, it is necessary to select a larger area as the positioning place when considering the positioning. The first thing to consider is its φ250. The large end face is additionally considered as an auxiliary positioning reference considering the front and rear end faces and the upper end face.
3.2 Selection of positioning criteria
In this time, the large hole of the bearing seat center needs to place the workpiece horizontally, and the three end points φ250 are used as the main positioning reference to limit the three degrees of freedom. This time, four support plates are used, and three of the support plates are positioned and restricted. The other supporting plate only serves to strengthen the strength. The upper end surface or the right end surface limits the two degrees of freedom for a positioning reference, and the lower end surface limits one degree of freedom, so that the entire workpiece is completely positioned, and the positioning is adopted. Support elements are used for the components.
3.3 Analysis of positioning error
One positioning of this time is that the right end surface and the lower end surface are two planes perpendicular to each other, and the positioning error can be analyzed as follows.
?
Figure 3-1 Two vertical plane positioning
The tolerance analysis of two vertical plane positioning is calculated as follows:
?The choice of this time is 90 degrees, and the two sides of the positioning are 30 and 35 respectively.
The positioning error accounts for the machining tolerance and can guarantee the processing requirements.
The positioning scheme can meet the processing precision requirements, and the positioning scheme is reasonable.
3.4 Calculation of cutting force and clamping force
(1) Cutting force calculation
This material is gray cast iron, the tool is made of high-speed steel bore boring tool, turning force according to its longitudinal and transverse turning and boring.
? (Cutting gray cast iron)
? :Circumferential cutting force component N
?: The amount of back-to-back knives refers to the length of the cutting edge during cutting, grooving and forming turning
? : feed per revolution
?: Cutting speed
?: Correction factor , when the thread is threaded
? : coefficient of mechanical properties of workpiece materials
?: coefficient of tool geometry parameters
?(2) Calculation of clamping force
Since the clamping of the workpiece is to clamp the upper portion of the workpiece, the cutting force is the drilling force from top to bottom, so that the clamping force is consistent with the direction of the cutting force. According to the "Machine Tool Clamp Design Manual, Third Edition", when the other mid-range cutting force is small, only a small clamping force is required to prevent the workpiece from vibrating and rotating during the machining process.
In the middle
? : prime mover
?: Actual clamping force required
?: equivalent friction radius between the end of the screw and the workpiece
?: half of the thread diameter
? : Thread angle
?: friction angle between the end of the screw and the workpiece
?: equivalent friction angle of the helical pair
?:Mechanical efficiency
The motive force in this clamping device is 1072N
The thread diameter of the bolt part of the selected pressing part is 16, that is, the bolt of M16 drives the movable top pin. According to the third edition of the "Machine Tool Design Manual" (the same below), the spiral in Table 1-2-20 The equivalen