Metal Parts Products Manufacturers at China

Metal Parts Products —Stamping & CNC Machining Manufacturers

45 Steel Parts CNC Machining Design

In this paper, through the analysis of a simple base part structure designed by ourselves, and programming, drilling, milling and other numerical control machining, it can better meet the actual precision requirements and improve the processing quality and design efficiency.
Analyze parts from the structure and formulate the process specifications required for processing, from the determination of the blank to the design process route.
Select the appropriate machine tool, tool, corresponding fixture, preparation of the machining program and inspection of the part according to the requirements. The programming of the program is generated by the combination of MasterCAM automatic programming and manual programming.
Keywords: CNC machining, CNC programming, Pro/E, AutoCAD


With the rapid development of science and technology, social demands on the mechanical product structure, performance, accuracy, efficiency and variety of increasingly high proportion of single-piece and small batch production is growing (now accounts for more than 70%) , Traditional general-purpose, special-purpose machine tools and process equipment are not well suited to high-quality, high-efficiency, and diverse processing requirements. Therefore, the numerical control technology based on microelectronics technology and computer technology organically combines mechanical technology, modern control technology, sensing detection technology, information processing technology, network communication technology and group technology. The production methods and machine manufacturing technologies of the machine manufacturing industry have undergone profound and revolutionary changes.

processing analysis of the base parts
2.1 Check the table to select different parts, the table is as follows:
Table 2-1 Grades, compositions, properties and uses of steel

Brand Chemical composition ωMe/% Hardness Use example
C Mn Si Annealed state Sample quenching
HBS is not greater than Quenching temperature / ° C and coolant HRC is not less than
T7、T7A 0.65~0.74 ≤0.40 ≤0.35 187 800~820水 62 After quenching and tempering, it is often used to manufacture tools that can withstand vibration and impact, and have good toughness under moderate hardness conditions, such as chisels, punches, woodworking tools, sledgehammers, etc.
T8、T8A 0.75~0.84 ≤0.40 ≤0.35 187 780~800水 62 After quenching and tempering, it is often used to manufacture tools that require high hardness and wear resistance, such as punches, woodworking tools, shearing metal scissors, and the like.
T8Mn、T8MnA 0.80~0.90 0.40~0.60 ≤0.35 187 780~800水 62 The performance and use are similar to those of the T8, but the addition of manganese improves the hardenability, so it is possible to make a tool with a larger cross section.
T9、T9A 0.85~0.94 ≤0.40 ≤0.35 192 760~780水 62 Tools for making certain toughness, such as die, punch, chisel for chiseling, etc.
T10、T10A 0.95~1.04 ≤0.40 ≤0.35 197 760~780水 62 It is used to manufacture various tools that require high wear resistance, are not subject to severe vibration, have certain toughness and have sharp edges, such as planing knives, turning tools, drill bits, taps, hand saw blades, wire drawing dies, and cold dies.
T11、T11A 1.05~1.14 ≤0.40 ≤0.35 207 760~780水 62 The application is basically the same as that of T10 steel. It is customary to use T10 steel.
T12、T12A 1.15~1.24 ≤0.40 ≤0.35 207 760~780水 62 Used to manufacture tools that are free from impact and require high hardness, such as taps, trowels, scrapers, reamers, dies, gauges, etc.
T13、T13A 1.25~1.35 ≤0.40 ≤0.35 217 760~800水 62 Suitable for manufacturing various tools that are not subject to vibration and require extremely high hardness, such as razors, scrapers, engraving tools, etc.

Table 2-3 grades, mechanical properties and uses (from GB9439-88)
Brand Casting category Casting wall thickness / mm Casting minimum tensile strength sb /Pa Scope and examples
HT100 Ferrite
grey cast iron
2.5~10 130 Low load and unimportant parts such as covers, covers, handwheels, brackets, heavy hammers, etc.
10~20 100
20~30 90
30~50 80
HT150 Pearlite + ferritic gray cast iron 2.5~10 175 Parts subject to moderate stress (with bending stress less than 100 MPa), such as struts, bases, gear boxes, work benches, tool holders, end caps, valve bodies, pipe fittings, and parts that generally have no working conditions
10~20 145
20~30 130
30~50 120
HT200 Pearlite
grey cast iron
2.5~10 220 Subject to large stresses (bending stress less than 300 MPa) and important parts such as cylinder block, gear, frame, flywheel, bed, cylinder liner, piston, brake wheel, coupling, gearbox, bearing housing, hydraulic cylinder Wait
10~20 195
20~30 170
30~50 160
HT250 4.0~10 270
10~20 240
20~30 220
30~50 200
HT300 Breeding cast iron 10~20 290 Important parts that withstand bending stress (less than 500 MPa) and tensile stress, such as gears, cams, lathe chucks, shears and press bodies, bed, high pressure hydraulic cylinders, spool housings, etc.

2.2 Fixture, tool selection and cutting amount setting
2.2.1 Selection of fixtures and setting of workpiece clamping method
1. Fixture selection
There are two major requirements for CNC machining on fixtures: first, the fixture should have sufficient accuracy and rigidity; second, the fixture should have a reliable positioning reference.
2. Type of fixture
There are two main types of fixtures on CNC lathes: one for discs or short shafts.
The workpiece blank is clamped in a chuck with adjustable claws (three claws, four claws), and is rotated by the chuck drive; The other type is used for shaft parts, and the blank is placed between the top of the spindle and the tip of the tailstock. Toggle the workpiece chuck is rotated by the spindle drive. CNC milling jig, typically mounted on a table, which may be varied according to the form of the workpiece features.
Such as: general bench vise, CNC indexing turntable, etc.

2.2.2 Tool selection and setting of tool point and tool change point
1. Tool selection

Compared with the ordinary machine tool processing method, CNC machining puts higher requirements on the tool, not only requires good rigidity, high precision, but also requires dimensional stability, high durability, good chip breaking and chip discharging performance; At the same time, it is easy to install and adjust, so as to meet the high efficiency requirements of CNC machine tools. The tools selected for CNC machine tools often use tool materials that are suitable for high-speed cutting (such as high-speed steel, ultra-fine-grained carbide) and use indexable inserts.
(1) Cutting tools and their choices The commonly used turning tools for CNC turning are generally divided into three types: sharp turning tool , circular-shaped turning tools and forming turning tools.
1) Pointed turning tool The pointed turning tool is a turning tool characterized by a linear cutting edge.
The tip of this type of turning tool consists of a straight primary and secondary cutting edge.
For example, 90° inner and outer round turning tools, left and right end turning tools, grooving (cutting) turning tools and various outer and inner hole turning tools with small chamfering edges. The selection method of the geometric parameters of the pointed tool (mainly geometric angle) is basically the same as that of ordinary turning. However, it should be considered in combination with the characteristics of CNC machining (such as machining route, machining interference, etc.), and should take into account the strength of the tool tip itself.
2) The circular turning tool is a turning tool characterized by a circular arc-shaped cutting edge with a small roundness or line contour error. Each point of the turning edge of the turning tool is the tip of the circular arc turning tool. Therefore, the tool point is not on the arc but on the center of the arc.
The circular turning tool can be used for turning the inner and outer surfaces, and is particularly suitable for turning various smooth joints (concave) forming surfaces. Two points should be considered when selecting the arc radius of the turning tool: First, the arc radius of the cutting edge of the turning tool should be less than or equal to the minimum radius of curvature on the concave contour of the part to avoid machining interference; Second, the radius should not be chosen too small, otherwise it will not only be difficult to manufacture, but also cause the tool to be damaged due to the weakness of the tip or the poor heat dissipation of the blade.
3) Forming turning tools are also called model turning tools. The contour shape of the machined parts is completely determined by the shape and size of the tool blade.
In CNC turning, common forming turning tools include small radius arc turning tools, non-rectangular grooving knives and thread knives. NC machining, molding tools should be used sparingly or not.
4) When milling the bottom of the inner groove with a flat-bottom end mill, the lap radius of the bottom edge of the groove is required to be overlapped, and the radius of the bottom edge of the tool is Re=R-r. That is, the diameter is d=2 Re=2(R-r), and the tool radius is set to Re=0.95 (R-r) during programming. For the machining of some three-dimensional and variable-angle contours, spherical milling cutters, ring milling cutters, drum milling cutters, conical milling cutters and disc milling cutters are commonly used.
(3) Standardized tools: At present, most of the CNC machine tools use serialized and standardized tools. There are national standard and serialized models for the shank and cutter head of the indexing machine with external turning tools and end turning tools; For machining centers and machine tools with automatic tool changers, the tool holders have been serialized and standardized. For example, the standard code of the taper tool system is TSG-JT, and the standard code of the straight tool system is DSG-JZ.
2. Setting of the cutter point and tool change point
After the machine tool is determined, the workpiece coordinate system is determined by determining the workpiece origin. The motion axis codes in the machining program control the relative displacement of the tool. For example, the first block of a program starts with N0010 G90 G00 X100 Z20, which means that the tool moves quickly to the workpiece coordinate X=100mm Z=20mm.
Where does the tool move from the position to the above position?
Therefore, at the beginning of the program execution, it is necessary to determine the position at which the tool starts moving in the workpiece coordinate system. This position is the starting point of the tool movement relative to the workpiece during program execution, so it is called the program starting point or the starting point. This starting point is generally determined by the tool setting, so this point is also called the cutter point.
When programming, it is necessary to correctly select the position of the tool point. The principle of setting the knife point is:
1) Facilitate numerical processing and simplify programming.
2) Easy to align and easy to check during processing.
3) The processing error caused is small.
The tool point can be set on the machined part or on the fixture or on the machine. In order to improve the machining accuracy of the part, the tool point should be set as much as possible on the design basis or process reference of the part. Example: To position a part by a circle or a hole, the intersection of the center and the end of the outer circle or hole can be taken as the tool point.
When the machine is actually operated, the tool position of the tool can be placed on the tool point by manual tool setting operation, that is, the “cutter-location point” and the “ cutter point” coincide. The so-called "tool position point" refers to the positioning reference point of the tool, and the tool position of the turning tool is the tool tip or the center of the tool edge arc; The flat end mill is the intersection of the tool axis and the bottom surface of the tool; The ball end milling cutter is the center of the ball head, and the drill bit is the drill tip. With manual tool setting, the tool setting accuracy is low and the efficiency is low. In some factories, optical pairing mirrors, tool setting instruments, and automatic tool setting devices are used to reduce tooling time and improve tool setting accuracy.
When a tool change is required during machining, the tool change point should be specified. The so-called "tool change point" refers to the position when the tool holder is rotated and the tool change point is set. The tool change point should be set outside the workpiece or the clamp, and the workpiece and other components are not affected when the tool is changed.

2.2.3 Determination of cutting amount
During NC programming, the programmer must determine the amount of cut for each process and write it in the program as an instruction. Cutting quantities include spindle speed, depth of cut, and feed rate. For different processing methods, different cutting amounts are required. The selection principle for cutting amount is: Ensure the machining accuracy and surface roughness of the parts, give full play to the cutting performance of the tool, and ensure reasonable tool durability; And give full play to the performance of the machine to maximize productivity and reduce costs.
1. Spindle speed determination
The spindle speed should be selected based on the allowable cutting speed and the workpiece (or tool) diameter. Its calculation formula is:
n=1000v/πD
In the middle
v----cutting speed in m/min, determined by the durability of the tool;
N-- - spindle speed in r/min;
D----Workpiece diameter or tool diameter in mm.
The calculated spindle speed n is finally selected according to the machine tool specification.
2. Determination of feed rate
The feed rate is an important parameter in the cutting amount of CNC machine tools. It is mainly selected according to the machining accuracy and surface roughness requirements of the parts and the material properties of the tools and workpieces. The maximum feed rate is limited by the machine stiffness and the performance of the feed system.

The principle of determining the feed rate:
1) When the quality requirements of the workpiece can be guaranteed, in order to improve production efficiency, a higher feed rate can be selected. Generally, it is selected in the range of 100 to 200 mm/min.
2) When cutting or machining deep holes or machining with high speed steel tools, it is advisable to select a lower feed rate, generally in the range of 20 to 50 mm/min.
3) When the machining accuracy and surface roughness are high, the feed rate should be selected to be smaller, generally in the range of 20 to 50 mm/min.
4) When the tool is in the free travel, especially when the distance is “return to zero”, the maximum feed speed set by the CNC system of the machine can be set.

3. Depth of cut
The depth of cut is determined by the stiffness of the machine tool, workpiece and tool. Under the condition of stiffness, the depth of cut should be equal to the machining allowance of the workpiece. This can reduce the number of passes and increase the production efficiency. In order to ensure the quality of the machined surface, a small amount of finishing allowance can be left, generally 0.2 to 0.5 mm. In summary, the specific value of the cutting amount should be determined by analogy based on machine performance, relevant manuals and practical experience. At the same time, the spindle speed, depth of cut and feed rate can be adapted to each other to form the optimum cutting amount.

2.3 Base CNC machining process specification:
     2.3.1 Analysis of parts drawing:
The parts to be processed are shown in the figure, the material is HT200, the blank is 300×250×50 square material, and the single piece is produced by vertical milling machine. The outer contour of the blank was machined into a base of 285 x 240 x 45 and a rounded corner R = 8 mm. A through hole of diameter Ф=26 mm is milled in the center of the top surface of the base, and a cross-shaped groove is cut beside it, the depth is 5 mm, and the detailed dimensions are as shown. A groove having a depth of 1.5 mm is milled on the bottom surface of the blank to leave four protrusions on the bottom surface.
A through hole with a radius R=8 mm is drilled on the base.
    2.3.2 Review of the parts drawing: the examination is qualified.
    2.3.3 production program: single piece, small batch.
    2.3.4 Determining the blank:
The blank material is LY12, which is cold-rolled and has a blank size of 95×95×10.
2.3.5 Process Route:
The bottom surface of the blank is used as a machining reference, and the holes, grooves, and contours are machined by milling, and the small holes are processed by drilling. In order to ensure the quality of the part processing, the processing stage is divided into the roughing stage, the finishing stage, and the process is organized according to the principle of process dispersion.
employee ID Name Processing part Election machine Fixture Tool type
Cutting amount
test
 
 
 
1
Milling the upper and lower surfaces of the blank and milling it into a 95×95×10 square Milling rough surface CNC vertical milling machine Universal fixture Tool: Carbide end mill Ф = 16
S=1000
F=100
δ=2.5
Vernier caliper
        
 
 
 
 
2
Milling a through hole with a radius = 13mm in the center of the blank and milling the plum-like groove beside it Milling groove radius CNC vertical milling machine Pressure iron Tool: Carbide end mill Ф = 16
S=1000
F=100
δ1=10
δ2=5
Vernier caliper
Inner diameter micrometer
 
 
 
 
3
The outer contour of the blank is machined to 90×90×10 and the round radius R=8mm Rough outer contour CNC vertical milling machine Universal fixture Tool: Carbide end mill Ф = 16
S=1000
F=100
 
 
 
Vernier caliper

 
 
 
4
A groove having a depth of 1.5 mm is milled on the bottom surface of the blank to leave four protrusions on the bottom surface. Milling bottom groove  CNC vertical milling machine Pressure iron Tool: End mill Ф = 10
S=1000
F=100
δ=1.5
Vernier caliper
 
 
 
5
A through hole having a radius of R=8 mm is drilled in the four legs of the base to be formed.
 
Drill through hole  CNC vertical milling machine  
 
 
Pressure iron
Tool: Center drill ø8
S=1000
F=100
δ=10
Vernier caliper
Inner diameter micrometer

2.3.6 Determine the machining allowance for each process and calculate the process dimensions and tolerances:
1. The machining allowance for the hole and the upper and lower grooves is 0.2.
2. The design requirements of the large through hole are: 260+0.052, Ra=1.6, and the edge of the hole is perpendicular to the bottom surface with a tolerance of 0.02.
The groove design next to the through hole requires:
1) The depth is 5+0.048, and the bottom edge requires a parallelism tolerance of 0.02 based on the bottom surface.
2) The width of the four corners of the groove is designed to be: 20+0.033
The four sides of the square base are designed to be 90 ± 0.05.
Design requirements for the bottom groove: 1.5mm depth, no tolerance requirements.
Four small through hole design requirements for the base:
1) The distance between adjacent holes is designed to be 70+0.03.
2) Hole design requirements: A through hole with a diameter Ф=8 is required.

2.4 CNC programming coordinate system:
The coordinate system is established with the center of the workpiece as the origin. The coordinate axis parallel to the spindle is the Z coordinate axis, and the direction of the tool away from the workpiece is the positive direction. It is perpendicular to the Z axis and parallel to the workpiece clamping plane in the X direction. When viewed in the direction of the main axial column of the tool, the tool direction is again in the +X direction. The Y axis is perpendicular to the X and Z coordinates, and the +Y direction is determined by the right hand flute method.
CNC programming coordinate system

2.5 parts CNC machining program:
Process Processing program Description
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
N10G90G54G00Z60.000
N12S1000M03
N14X-4.480Y4.480Z60.000
N16Z50.000
N18Z22.500
N20G01Z12.500F10
N22X4.480F100
N24Y-4.480
N26X-4.480
N28Y4.480
N30X-9.480Y9.480
N32X9.480
N34Y-9.480
N36X-9.480
N38Y9.480
N40X-14.480Y14.480
N42X14.480
N44Y-14.480
N46X-14.480
N48Y14.480
N50X-19.480Y19.480
N52X19.480
N54Y-19.480
N56X-19.480
N58Y19.480
N60X-24.480Y24.480
N62X24.480
N64Y-24.480
N66X-24.480
N68Y24.480
N70X-29.480Y29.480
N72X29.480
N74Y-29.480
N76X-29.480
N78Y29.480
N80X-34.480Y34.480
N82X34.480
N84Y-34.480
N86X-34.480
N88Y34.480
N90X-39.480Y39.480
N92X39.480
N94Y-39.480
N96X-39.480
N98Y39.480
N100Z50.000F800
N102G00Z60.000
N104M05
N106M30
Plane area processing track
    
Tool: Ф16(10) Tool radius = 8.000 tool radius = 0.000
    
Spindle speed = 1000.000 approach speed = 10.000
    
Cutting speed = 100.000 retraction speed = 800.000
    
Lower knife speed = 100.000 line connection speed = 100.000
    
Starting and ending height = 60.000 safe height = 50.000
    
Slow lower knife relative height = 10.000
 
    
Feeding method: vertical
    
Retracting method: vertical
    
Way of cutting: circumcision processing (from inside to outside)
    
Draft reference: the bottom layer is the benchmark
    
Contour parameters: compensation mode (TO) margin = 0.200, draft angle = 0.000
    
Island parameter: compensation mode (ON) margin = 0.000, draft angle = 0.000
    
Top height = 15.000 bottom height = 12.500 height per floor = 2.500
    
Corner transition mode: arc
    
Processing line spacing = 5.000
    
Machining accuracy = 0.001
    
Whether to raise the knife in the area: no knife
    
Knife cutting method: vertical
    
The position of the lower knife point: the end point of the diagonal line or the tangent point of the spiral line
    
Clear roots: not clear roots
    
Island clearing roots: not clearing the roots
    
Clear root feeding method: vertical
    
Clear root retreat method: vertical
    
Processing time = 15.63 minutes
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2
N10G90G54G00Z60.000
N12S1000M03
N14X5.000Y-0.000Z60.000
N16Z50.000
N18Z15.000
N20G01Z5.000F10
N22G42D10G02X5.000Y0.000I-5.000J0.000F100
N24G01Z50.000F800
N26G00Z10.000
N28G01Z0.000F10
N30G42D10G02X5.000Y0.000I-5.000J0.000F100
N32G01Z50.000F800
N34G00Z60.000
N36M05
N38S1000M03
N40X-25.000Y2.000
N42Z50.000
N44Z15.000
N46G01Z5.000F10
N48G42D10X-20.000F100
N50G03X-2.000Y20.000I0.000J18.000
N52G01Y25.000
N54G02X2.000Y25.000I2.000J0.000
N56G01Y20.000
N58G03X20.000Y2.000I18.000J-0.000
N60G01X25.000
N62G02X25.000Y-2.000I-0.000J-2.000
N64G01X20.000
N66G03X2.000Y-20.000I-0.000J-18.000
N68G01Y-25.000
N70G02X-2.000Y-25.000I-2.000J0.000
N72G01Y-20.000
N74G03X-20.000Y-2.000I-18.000J0.000
N76G01X-25.000
N78G40G02X-25.000Y2.000I0.000J2.000
N80G01Z50.000F800
N82G00Z60.000
N84M05
N86M30
Tool: Ф20,12(10)
Spindle speed = 1000.000 approach speed = 10.000
Cutting speed = 100.000 retraction speed = 800.000
Lower knife speed = 100.000 line connection speed = 100.000
Starting and ending height = 60.000 safe height = 50.000
Slow lower knife relative height = 10.000
Feeding method: vertical
Retracting method: vertical
Way of walking: reciprocating
Contour compensation method: TO
Corner transition mode: arc
Machining accuracy = 0.001 Knife = 1
Through hole: top layer height = 10.000 bottom layer height = 0.000 height per layer = 5.000
Groove: top height = 10.000 bottom height = 5.000 height per layer = 5.000
Knife cutting method: vertical
The position of the lower knife point: the end point of the diagonal line or the tangent point of the spiral line
Draft reference: the bottom layer is the benchmark
Crossing between layers: reciprocating
Line spacing definition: line spacing
Machining allowance = 0.200
Processing line spacing = 5.000
Machine tool automatic compensation (G41/G42)

 
 
 
 
 
 
 
 
 
 
3
 
 
 
N10G90G54G00Z60.000
N12S1000M03
N14X-53.000Y-35.000Z60.000
N16Z50.000
N18Z15.000
N20G01Z5.000F10
N22G41D10Y35.000F100
N24G02X-35.000Y53.000I18.000J-0.000
N26G01X35.000
N28G02X53.000Y35.000I-0.000J-18.000
N30G01Y-35.000
N32G02X35.000Y-53.000I-18.000J-0.000
N34G01X-35.000
N36G40G02X-53.000Y-35.000I0.000J18.000
N38G01Z50.000F800
N40G00Z10.000
N42G01Z0.000F10
N44G41D10Y35.000F100
N46G02X-35.000Y53.000I18.000J-0.000
N48G01X35.000
N50G02X53.000Y35.000I-0.000J-18.000
N52G01Y-35.000
N54G02X35.000Y-53.000I-18.000J-0.000
N56G01X-35.000
N58G40G02X-53.000Y-35.000I0.000J18.000
N60G01Z50.000F800
N62G00Z60.000
N64M05
N66M30
Tool: Ф16(10) Tool radius = 10.000 corner radius = 0.000
     Spindle speed = 1000.000 approach speed = 10.000
     Cutting speed = 100.000 retraction speed = 800.000
     Lower knife speed = 100.000 line connection speed = 100.000
     Starting and ending height = 60.000 safe height = 50.000
     Slow lower knife relative height = 10.000
 
     Feeding method: vertical
     Retracting method: vertical
     Way of walking: reciprocating
     Corner transition mode: arc
     Machining accuracy = 0.001 Knife = 1
     Top height = 10.000 bottom height = 0.000 height per floor = 5.000
     Contour draft angle = 0.000
     Knife cutting method: vertical
     The position of the lower knife point: the end point of the diagonal line or the tangent point of the spiral line
     Draft reference: the bottom layer is the benchmark
     Crossing between layers: reciprocating
     Line spacing definition: line spacing
     Machining allowance = 0.200
     Processing line spacing = 5.000
     Machine tool automatic compensation (G41/G42)
     Processing time = 9.46 minutes

2.6 processing track:
Base Parts processing track   Machining program simulation
  
Machining program simulation check:
   It can be simulated in the numerical control laboratory and can simulate its processing trajectory.

Summary
Through this design, the entire process of CNC machining has a comprehensive understanding. Through reading the map and reviewing the map, I have a deeper understanding of the mechanical drawings, and enhanced my ability to map, and at the same time, avoid many mistakes when drawing my own drawings;
By selecting the tool, I have a deep understanding of the characteristics of the CNC machine tool system and the NC tool material and the scope of use, and basically master the selection method of the CNC tool; After formulating the technological plan, we will further understand the six-point positioning principle, the positioning method and the types and characteristics of the positioning components and the commonly used fixtures for CNC machine tools, and have a deeper understanding of the selection principle of the machine tool-related positioning reference and the selection method of the CNC machining fixture. The principles, steps and methods for designing special fixtures; After programming the parts, I am familiar with the main contents and steps of CNC programming, programming and types, and the structure and format of the program. I have re-learned the drawing software such as CAD, CAM, Pro/E, etc., so that I have mastered the application of these kinds of software better and skillfully. At the same time, I also learned to use the automatic programming software for NC-assisted programming.


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