I want a thesis about "CNC Graduation"

Part One: Survey on CNC Machine Tool Application

1. Appearance and Introduction of Pinzheng CNC Deep Hole Drilling Machine

The appearance of Pinzheng CNC Deep Hole Drilling Machine is as shown in the figure 1-1

Figure 1-1

Introduction to Pinzheng CNC deep hole drilling machine:

Deep hole drill: Since its production in 1982, it has always occupied the largest share of production. important location. The current market has an urgent demand for mold production and delivery. Deep hole processing machines are fast and convenient. They do not require reaming and can be completed in one step, making them an indispensable tool. It also has fast investment recovery cost and is a powerful tool to seize the market.

2. Advantages of deep hole drilling in design

It can process deep holes such as water channels, hot runner, ejector holes, oil pump deep holes, and roll holes. The design of our deep hole drill has the following advantages:

1. The workbench, base body, column, and lifting platform are all made of FC30 cast iron to achieve the best shock-absorbing effect during processing.

2. The base of the bed and workbench is formed in one piece, with a consistent structure and strong muscles. There is no design that separates the columns from the workbench.

3. The slide rails and workbench guide rails adopt V-shaped guide rails to ensure accurate guidance and no side gaps between square rails. There is no snaking phenomenon when sliding, and smooth sliding can be maintained. Under strong pressure, the bearing seat and the sliding seat are more closely combined. The two are in contact and can bear the force evenly. Long-term motion can maintain stable dynamic and static accuracy, thereby extending the life of machine parts and improving processing quality.

4. The slide rails are heat treated and ground to ensure durability and rigidity.

5. Use good hydraulic pump design to control flow and pressure to ensure service life.

6. In addition, a CNC tool changing system device is adopted. Just press the control button lightly to lock the tool system pneumatically. Tool replacement is easy.

7. The paper tape and magnet filter device can filter the trace elements discarded from iron filings and cutting oil during steel processing and recycle them.

3. Pinzheng deep hole drill specification table

Deep hole drill specification table

Model MGD-813 MGD-1015 MGD-1520 MGD-1525

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Table (unit mm)

Workbench size 400x1500 600x2000 800x2300 800x2800

Working area 1300x600x800(z1)x400(z2) 1500x600x1000 2000x1000x1500 2500x 1000x1500

T-slot 18mmx63mmx5 22x34x5 22x34x7 22x34x7

Spindle

Spindle feed stroke 800 1000 1250 1500

Spindle feed speed (mm/min) 20-5000mm

Spindle diameter Φ120

The distance from the spindle end to the table is 70 mm

Motor

Spindle (kw) 7.5kw

Magnetic separator (W) 25W

Paper tape filter 25W

Iron chip removal machine (W) 0.375

Hydraulic pump 10HPx6P

Lubrication oil pump 150Wx2

Processing capacity

Processing depth 800 1000 1250 1500

Drilling capacity Φ3-25mm (32)

Hydraulic system

Cutting oil barrel (L) 1800LT

High-pressure pump pressure (kg/cm2) 0-120

High-pressure pump discharge volume (L /min) 5-70

Maximum load (kg) 1000 3000 5000 7000

Net weight of machinery (kg) App.9000 App.10500 App.14500 App.16500

Occupied area App.3125x2046 App.5000x5000 App.5500x5500 App.6000x6000

Part 2: CNC machining process analysis

Requirements: Able to analyze the geometric characteristics and technology of drawings Requirements: use CNC machining technology knowledge to select processing methods, clamping and positioning methods, reasonably select cutting tools and geometric parameters used for processing, divide processing processes and steps, arrange processing routes, and determine cutting parameters. On this basis, you can complete the preparation of CNC machining process files for moderately complex parts (process analysis of at least two parts). 1. Process the slots and holes on the flat cam parts. The outer contour has been processed and the part material is HT200. Figure 2.1

1. Parts drawing process analysis

The inner and outer contours of the cam groove are composed of straight lines and arcs. The relationship between the geometric elements is clearly and completely described. The sides of the cam groove and The surface roughness of the two inner holes is required to be relatively high, which is Ra1.6. There are perpendicularity requirements between the inner and outer contour surfaces of the cam groove and the hole and the bottom surface. The material of the parts is HT200, which has good cutting performance.

Based on the above analysis, the processing of the inner and outer contours of the cam groove and the two holes should be divided into two stages: roughing and finishing to ensure the surface roughness requirements. At the same time, the bottom surface A is positioned to increase the clamping stiffness to meet the verticality requirements.

2. Determine the clamping plan

According to the structural characteristics of the part, when processing two holes, position them with bottom A (process holes can be set if necessary), and use a spiral plate mechanism. Clamp.

When processing the inner and outer contours of the cam groove, the "two holes on one side" method is used for positioning, with the bottom surface A and the two holes as the positioning reference.

3. Determine the processing sequence and tool path

The processing sequence is determined according to the principle of base surface first, rough first and fine later. Therefore, the two holes used as positioning reference should be machined first, and then the inner and outer contour surfaces of the cam groove should be machined. In order to ensure the machining accuracy, roughing and finishing are separated, and the two holes are processed using the drilling-rough reaming-fine reaming scheme. The tool path includes two parts: plane feed and depth feed. During plane feed, the convex contour is cut from the tangent direction, and the concave contour is cut from the transition arc. In order to make the cam groove surface have better surface quality, the down milling method is used. There are two methods of depth feed: one is to mill back and forth on the XOY plane (or YOX ??plane) and gradually advance to a predetermined depth; the other method is to first drill a process hole, and then advance from the process hole to the predetermined depth.

4. Tool selection

Select 8 tools according to the characteristics of the part, as shown in the following table:

Serial number tool number tool processing surface remarks

Specification Name Quantity Tool Length/mm

1 T01 ￠5 Center Drill 1 Drill ￠5mm Center Hole

2 T02 ￠19.6 Drill 1 45 ￠20 Hole Roughing

3 T03 ￠11.6 drill bit 1 30 ￠12 hole roughing

4 T04 ￠20 reamer 1 45 ￠20 hole finishing

5 T05 ￠12 reamer 1 30 ￠ 12 hole finishing

6 T06 90° chamfering milling cutter 1 ￠20 hole chamfering 1.5×45°

7 T07 ￠6 high speed steel end mill 1 20 roughing cam The bottom fillet of the inner and outer contours of the groove is R0.5

8 T08 ￠6 carbide end mill 1 20 Finishing the inner and outer contours of the cam groove

5. Cutting amount selection

Leave a milling allowance of 0.1mm when finishing the inner and outer contours of the cam groove, and leave a reaming allowance of 0.1mm when finishing the two holes. The spindle rotation speed is 1000r/min. 2. Processing technology analysis and examples of shaft parts

A carburized spindle (as shown in Figure 2-2), 40 pieces per batch, material 20Cr, S0.9~C59 except for internal and external threads. The process of carburized parts is relatively complex, and a process sketch must be drawn for the rough machining process (as shown in the figure).

Spindle machining process

Process types, process steps, process content and requirements, machine tools and equipment (omitted), fixtures, tools and measuring tools

1. Carry everything to size according to the process sketch.

Process requirements: (1) Drill a center hole φ2 on one end. (2) 1:5 taper and Mohs 3# inner cone coloring inspection, contact surface >60. (3) The radial runout of each outer circle to be ground relative to the center hole shall not be greater than 0.1

CA6140 Mohs No. 3 reamer Mohs No. 3 plug gauge 1:5 ring gauge

Inspection

2 Quenching heat treatment S0.9-C59

3 Car removal of carbon.

Clamp one end firmly, and set the center frame on the other end

lt; 1gt; Turn the end face, ensuring that the length from the right end face step to the shaft end of φ36 is 40

lt; 2gt; Drill the center hole φ5B type

lt; 3gt; U-turn

Turn the end face, take the total length 340 to the size, continue drilling to a depth of 85, chamfer 60°

Check

4 Cart one clamp and one CA6140

lt; 1gt; Car M30×1.5–6g left thread major diameter and ф30JS5 to

Φ30

lt; 2gt; Turning φ25 to φ25, length 43

lt; 3gt; Turning φ35 to φ35

lt; 4gt; Turning grinding wheel over-travel groove

5 Turn the car around, one clamp and one top

lt; 1gt; Car M30×1.5–6g thread major diameter and φ30 JS5 to φ30

lt; 2gt; Car φ40 to φ40

lt; 3gt; turning grinding wheel over-travel groove

6 Milling 19 Two planes to size

7 Thermal heat treatment HRC59

8 Grinding 2 End center hole

9 Externally grind the two top points, (the other end is plugged with a cone) M1430A

lt; 1gt; Rough grind φ40 outer circle, leaving 0.1~0.15 margin

lt; 2gt; Coarsely grind φ30js outer circle to φ30t (two places) and grind out the steps

lt; 3gt; Coarsely grind 1:5 taper, leaving a grinding allowance

10 V-shaped clamp for internal grinding (ф30js5 positioning on the second outer circle) M1432A

Grinding Morse 3# inner cone (refitting Morse 3# cone plug) fine grinding allowance

0.2～0.25

11 Heat and low temperature aging treatment (baking) to eliminate internal stress

12 Clamp one end of the car and set up the center frame on the other end

lt; 1gt; Drill φ10.5 hole, use guide sleeve to position, do not tap the thread Z-2027

lt; 2gt; U-turn, drill φ5 hole and tap M6-6H internal thread

lt; 3gt; 60° center hole with countersink opening

lt; 4gt; U-turn drill sleeve drilling hole ф10.5×25 (the thread is not changed)

lt; 5gt; Countersink 60° center hole, surface roughness 0.8 60° countersinking

Inspection

13 pliers lt; 1gt; insert a tapping sleeve into the tapered hole

lt; 2gt; Tap the M12–6H internal thread to size

14 Grind the center hole Ra0.8

15 Clamp the externally ground workpiece between the two centers

lt; 1gt; Precision grinding of φ40 and φ35φ25 outer circles to size

lt; 2gt; Grinding of M30×1.5 M30×1.5 left thread major diameter to 30

lt; 3gt; Half Precision grinding ф30js5 two places to ф30

lt; 4gt; Fine grinding 1:5 taper to size, use coloring method to check the contact surface is greater than 85 1:5 ring gauge

16 Grind the workpiece between two centers and grind the thread

lt; 1gt; Grind M30×1.5–6g left thread to size M33×1.5 left ring gauge

lt; 2gt; Grind M30×1.5–6g thread to size M33×1.5 ring gauge

17 Grind the center hole Ra0.4

18 Outside Fine grinding, the workpiece is clamped between the two centers M1432A

Fine grinding 2-φ30 to size, pay attention to the shape and position tolerance

19 The internally ground workpiece is installed in the V-shaped fixture to 1-ф30 outer circle as the benchmark, fine grind Mohs No. 3 inner tapered hole (remove plugging, position with 2-ф30js5 outer circle), color and check that the contact surface is greater than 80, pay attention to the technical requirements "1" "2" MG1432A

Inspection

20 Clean and apply anti-rust oil, and hang the workpiece vertically when it is put into storage. Some instructions during the processing of shaft parts:

1. Two central holes are used as the positioning datum, which conforms to the aforementioned principles of datum coincidence and datum unification.

2. For this part, the outer circle is first used as a rough reference, the end face is turned and the center hole is drilled, then the outer circle is roughly turned using the two center holes as the positioning reference, and the tapered hole is machined using the rough turning outer circle as the positioning reference. This is the principle of mutual reference. This enables processing to have a positioning reference surface with higher accuracy every time. No. 3 Morse cone requires very high accuracy. Therefore, a V-shaped fixture is required to use the 2-ф30js5 outer circle as the positioning reference to meet the geometric tolerance requirements. When coning in the car, one end is clamped with a claw, and the other end is set on a center frame, and the outer circle is also used as the precision reference.

3. When semi-finishing and finishing the outer circle, a cone plug is used, and the center hole of the cone plug is used as the positioning reference for finishing the outer circle surface of the shaft.

Requirements for the cone plug:

① The cone plug has high precision, ensuring that the cone surface of the cone plug and its tip hole have high coaxiality.

② The cone plug should not be replaced after installation to reduce installation errors caused by repeated installation.

③ The outer diameter of the cone plug must be made with external threads near the shaft end to facilitate the removal of the cone plug.

4． The spindle is carburized and hardened with 20Cr low carbon alloy steel, and the workpiece does not need to be hardened or distributed (M30×1.5-6g left, M30×1.5-6g, M12-6H, M6-6H), leaving a 2.5-3mm decarburized layer on the surface. .

5. The thread cannot be processed on a lathe after being quenched. If the thread is turned first and then quenched, the thread will be deformed. Therefore, threads are generally not allowed to be hardened, so the carbon layer must be left on the diameter and length of the threaded part in the workpiece. For internal threads, a 3mm carbon removal layer should also be left at the hole.

6. In order to ensure the accuracy of the center hole, the center hole of the workpiece is not allowed to be hardened. For this reason, the total length of the blank is increased by 6mm.

7. In order to ensure the grinding accuracy of the outer circle of the workpiece, the process of grinding the center hole must be arranged after heat treatment, and a fine surface roughness is required. During cylindrical grinding, the roundness of the workpiece is mainly affected by the coaxiality of the two center holes and the roundness error of the center hole.

8. In order to eliminate grinding stress, a low-temperature aging process (baking) is arranged after rough grinding.

9. To obtain a high-precision outer circle, grinding should be divided into rough grinding, semi-fine grinding and fine grinding processes. Precision grinding is performed on a high-precision grinder. Part 3: Preparation of CNC machining programs

Requirements: Able to correctly prepare machining programs for moderately complex typical parts according to the technical requirements of the drawings and the instruction format and programming methods specified by the CNC machine tool, or use CAD/CAM Automatic programming software prepares processing programs for more complex parts. (at least two parts).

1. Compile CNC machining program for shaft parts (1)

The parts shown in Figure 3.1.

The blank is a 42mm bar, which is cut axially from the right end to the left end; the feed depth for roughing is 1.5mm each time, and the feed amount is 0.15mm/r; the finishing allowance is in the X direction 0.5mm, Z direction 0.1mm, cutting blade width 4mm. The origin of the workpiece program is shown in Figure 3.1.

The structure of this part is relatively simple. It is a typical shaft part with an axial size of 80mm. It can be clamped by a three-jaw chuck. The intersection of the workpiece rotation axis and the right side is selected as the origin of the processing coordinate system. .

1. Select the tool number and determine the tool change point

Select 3 packages of tools according to the processing requirements: No. 1 is a left-side rough turning tool for the outer circle, No. 2 is a left-side fine turning tool for the outer circle, and No. 3 is a left-side fine turning tool for the outer circle. For circular cutting tools, the tool changing point coincides with the tool setting point

2. Determine the processing route

1) Rough turning of the outer circle. Cut the outer contour from right to left using a rough turning cycle.

2) Fine turning of the outer circle. Left end chamfer → 20㎜ outer circle → chamfer → 30㎜ outer circle → chamfer → 40㎜ outer circle.

(3) Cutting

3 Select cutting amount

See Table 3.1 for selecting cutting amount parameters.

Table 3.1 Select cutting amount parameters Revolution command feed speed (mm/r) Tool

Rough turning outer circle M43 0.15 No. 1

Finish turning outer circle M44 0.1 No. 2

Cutting off M43 0.1 Program No. 2

O0001

M03T0101 M43 F0.15

G00 X43.Z0.

G01X0.

G00X42.Z0.

G71 U2.R0.3

G71 P1 Q2 U0.25 W0.1 F0.15

N1 G01 X18 .

X20.Z-1.

Z-20.

X28.

X30.Z-21.

Z-50.

X38.

X40.Z-51.

Z-82.

N2 X44 .

G00Z0

M00

M03 M44 T0202

G70 P1 Q2

G00Z5.

M00

M03 M43 T0303

G00 Z-44.

G01X0.

X44.

G00Z5.

M30 2. Compile the CNC machining program for shaft parts (2)

Process the parts as shown in Figure 3-2, the material is 45 steel, and the blank is 60×122.

1. Tools: T1 - 93° right-hand carbide cutting knife;

T2 - 3mm wide carbide cutting knife, D1 - left tip. Processing process material tool

Circular carbide T1 for turning

Grooving carbide T2

This part has a relatively simple structure and is a typical shaft part. The axial size is 120mm and can be clamped using a three-jaw chuck. Select the intersection of the workpiece rotation axis and the right side as the origin of the processing coordinate system.

2. Select the tool number and determine the tool change point

Select 2 packages of tools according to the processing requirements: No. 1 is a rough turning tool on the left side of the outer circle, and No. 2 is a cutting tool for the outer circle. tool and grooving tool, the tool changing point coincides with the tool setting point 3. Programming

Program instruction description

N10 G56 S300 M3 M7 T1; Select the tool and set the process data

N20 G96 S50 LIMS=3000 F0.3; Set the constant linear speed for rough turning

N30 G0 X65 Z0; Quickly lead the tool close to the workpiece and prepare the end face

N40 G1 X-2; Turning end face

N50 G0 R106=0.2 R108=4 R109=0

R110=2 R111=0.3 R112=0.15; Blank cycle parameter setting

N80 LCYC95; Call LCYC95 cycle contour roughing

N90 G96 S80 LIMS=3000 F0.15; Set the constant line speed of finishing machine

N100 R105=5; Adjust the cycle parameters

N110 LCYC95; Call the LCYC95 cycle profile Finishing

N120 G0 Change the T2 cutting knife D1 to be valid, adjust the process data

N140 G0 8 slots

N160 G0 X0 Z0;

N20 G3 X20 Z-10 CR=10;

N30 G1 Z-20;

N40 G2 X30 Z-25 CR=5;

N50 G1 X39.98 CHF=2.818;

N60 Z-100;

N70 ;

LCEXP2

N10 G91 G1 X-14;

N20 G4 S2;

N30 G1 X14;

N40 G0 Z-8;

N50 G90 M17; Part 4: Drawing CAD Parts Drawing