1、 General rules of knife path:

Roughing: under the maximum load of the machine tool, in most cases, the cutter as large as possible should be selected, the feed amount as large as possible and the feed as fast as possible. In the case of the same tool, the feed is inversely proportional to the feed. Generally, the load of the machine tool is not a problem. The principle of tool selection mainly depends on whether the two-dimensional angle and three-dimensional arc of the product are too small. After the cutter is selected, the cutter length is determined. The principle is that the cutter length is greater than the machining depth, and whether the collet interferes with large workpieces should be considered.  
 
Light knife: the purpose of light knife is to meet the machining requirements of workpiece surface finish and appropriate allowance. Similarly, the light knife shall be as large as possible and as fast as possible, because the fine knife needs a long time, and the most appropriate feeding and feeding shall be used. Under the same feed, the larger the transverse feed is, the faster it is. The feed amount of the curved surface is related to the finish after machining, and the feed size is related to the surface shape of the curved surface. Under the condition of not damaging the surface, leave the minimum allowance, use the maximum knife, the fastest speed and appropriate feed.  
 
 

2、 Clamping method:

1. All clamps are long horizontally and short vertically.  
 
2. Vice clamping: the clamping height shall not be less than 10mm. The clamping height and machining height must be indicated when machining the workpiece. The machining height shall be about 5mm higher than the plane of the vise, so as to ensure the firmness and do not hurt the vise. This kind of clamping is a general clamping, and the clamping height is also related to the size of the workpiece. The larger the workpiece is, the higher the clamping height will be.  
 
3. Clamping of splint: the splint is coded on the workbench with code, and the workpiece is locked on the splint with screws. This kind of clamping is suitable for workpieces with insufficient clamping height and large processing force. Generally, medium and large workpieces have better effect. > If you like the wechat platform of cutting-edge NC technology, please remember to pay attention!  
 
4. Code iron clamping: when the workpiece is large, the clamping height is not enough, and it is not allowed to lock the wire at the bottom, the code iron shall be used for clamping. This kind of clamping requires secondary clamping. First code the four corners and process other parts, and then code the four sides and process the four corners. During secondary clamping, do not let the workpiece loose, code first and then loosen. You can also code both sides first and process the other two sides.  
 
5. Clamping of cutting tools: the diameter is more than 10mm, and the clamping length is not less than 30mm; The diameter is less than 10mm, and the clamping length is not less than 20mm. The tool shall be firmly clamped to prevent the tool from colliding with the workpiece directly.  
 
 

3、 Classification and application scope of cutting tools:

1. By material:  
White steel knife: easy to wear, used for roughing copper and small steel materials.  
Tungsten steel knife: used for angle clearing (especially steel) and light knife.  
Alloy knife: similar to tungsten steel knife.  
Purple knife; Used for high-speed cutting, not easy to wear.  
 
2. By cutter head:  
Flat bottom knife: used for plane and straight side to clear plane angle.  
Ball knife: used for medium light and light knife on various surfaces.  
Bull nose knife (single side, double side and five sides): used for roughening steel materials (r0.8, r0.3, r0.5 and r0.4).  
Rough leather knife: used for rough cutting. Pay attention to the allowance (0.3).  
 
3. By tool bar:  
Straight rod knife: straight rod knife is suitable for various occasions.  
Inclined rod cutter: but not applicable to straight body surface and surface with slope less than rod slope.  
 
4. By blade:  
With two, three and four edges, the more the number of edges, the better the effect, but the more the work is done, the speed and feed are adjusted accordingly, the more the number of edges and the longer the service life.  
 
5. Difference between ball knife and flying knife and light knife:  
Ball knife: when the concave ruler is smaller than the ball ruler and the plane ruler is smaller than the ball R, the light cannot be seen (the bottom angle cannot be cleared).  
Throwing Knife: the advantage is that it can clear the bottom angle. Comparison of the same parameters: v = R* ω The rotating speed is much faster (flying knife), the power is large, and the light is bright. Flying knife is mostly used for contour shape. Sometimes flying knife does not need medium light. The disadvantage is that the concave size and plane ruler are less than the diameter of flying knife.  
 
 

4、 CNC cooperates with EDM, and the practice of copper is as follows:

1. Under what circumstances do you need to be a copper company:  
If the knife can't go down at all, it needs to be a copper male. There are still some that can't go down in a copper male. The shape is convex and needs to be divided again.  
The knife can go down, but those easy to break the knife also need to be made of copper, which needs to be determined according to the actual situation.  
The products with spark pattern shall be made of copper.  
If the copper male cannot be made, the bone position is too thin and too high, the male is vulnerable and easy to deform, and it is deformed during machining and sparking. At this time, inserts are required.  
The East-West surface processed by copper can overcome many problems in precision Gong and drawing.  
When precise shape or large allowance is required, rough copper must be made.  
 
2. Practice of Copper Company:  
Select the surface to be made of copper, complete the surface to be repaired, or extend the surface to ensure that all edges of copper are larger than the edges to be punched, and do not damage the surface of other products, Remove unnecessary plane corners (there is a deeper glue position at the intersection with the plane angle) and make it into a regular shape; find out the maximum shape of the copper bar, use one side boundary, and then project it to the supporting surface; determine the size of the reference frame, cut off the supporting surface, and basically complete the copper bar drawing; material preparation: length * width * height, length and width ≥ ymax and xmax are the reference frames, and the length and width of the actual copper material must be greater than the reference frame on the drawing. Height ≥ the theoretical size of the copper bar Frame height clamping height.  
 
 

5、 Drawing sizing:

1. When there is no ready-made machining surface, the plane is divided into four sides, the center is to the origin, the top is to zero, and the top surface is not flat (for copper), leave an allowance of 0.1, that is, when the number of touches is, it is actually 0 (z), which is 0.1 lower in the figure.  
 
2. When there is a ready-made processing surface, make the ready-made surface on the drawing 0 (z), and if the plane can be divided, it will be divided. Otherwise, if the ready-made edge collision number (single side) is used to process the surface, check the difference between the actual height, width and length and the drawing, and program according to the actual material. Generally, first process the size on the drawing, and then process the shape on the drawing.  
 
3. When multiple bits are to be processed, for the first bit (standard bit), the reference gongs of other bits shall be made, and the length, width and height shall be made. All the next processing benchmarks shall be subject to the surface processed in the previous time.  
 
4. Positioning of inserts: put them in the whole, pad the lower part to a certain height, and then raise the height in the drawing. The plane is divided into two parts according to the whole, and the height is locked with screws according to the drawing; If it is square, it can be divided directly; A little rough can be divided by the maximum shape; Cut a fixture, center it according to the fixture, determine the relative position between the insert drawing and the fixture, and then place the origin of the drawing at the center point of the fixture.  
 
 

6、 Tool path selection for roughing:

1. Curved surface grooving  
The key is the selection of range and face.  
The area of tool path processing is: the selected surface within the selected range is the end surface, and it is the principle that the tool can go down from the highest point to the lowest point. The selected face should preferably be full face, and the boundary can only be the area to be machined. The distance extending from no face is less than half the tool diameter, because there is enough allowance for other faces, so it is automatically protected; It is best to extend the lowest line, because there is an R gong at the lowest point.  
Selection of cutter: if the cutter cannot feed with spiral or oblique line, or the area that cannot be processed, the area that cannot be fed with cutter shall be sealed and reserved for secondary roughing.  
Before the light knife, be sure to open all the rough areas, especially the small corners, including two-dimensional angles, three-dimensional angles and sealed areas, otherwise the knife will be broken. Secondary roughing: generally, three-dimensional grooving is used to select the range, flat bottom knife, and plane grooving and contour knife path are used. Under the condition of not damaging other surfaces, the tool center is to the selected boundary, and the boundary is generally not refined. The fast two-way angle is determined according to the situation. The spiral feed has an angle of 1.5 degrees and a height of 1. When the groove shape is strip and the spiral cutting cannot be performed, the oblique feed is used. Generally, the filtering is turned on, especially the surface is rough, the feed plane cannot be low to avoid tool collision, and the safe height cannot be low.  
Knife retraction: generally, relative knife retraction is not used, but absolute knife retraction is used. When there is no island, relative knife retraction is used.  
 
2. Plane grooving: milling various planes and concave grooves. When milling some open planes, it is necessary to determine the boundary. In principle, it can feed (greater than one tool diameter), the outside of the opening is greater than half of the tool diameter, and the periphery is closed.  
 
3. Profile: when the selected plane is suitable for profile layering, use profile layering to lift the knife (plane profile). When the lifting point is one point with the lower knife point, it is not necessary to lift the knife. Generally, the z plane does not lift the knife, and the relative height is not used as far as possible; the correction direction is generally right (along the knife).  
 
4. Tool path setting for mechanical correction: the correction number is 21. Change the computer to correct the mechanical correction. The feed is vertical. If the tool cannot pass through, change the R to large without allowance.  
 
5. Contour contour: it is suitable for the closed surface. If the open surface is four circles, the item surface shall be sealed. If it is within four circles or not, the range and height shall be selected (certain arc feed roughening). It is used for roughening: the machining distance in any plane is less than one tool diameter. If it is greater than one tool diameter, a larger tool or two contour contours shall be used.  
 
6. Curved streamline: with the best uniformity and dry brittleness, it is suitable for light knife and can replace contour shape in many cases.  
 
7. Radial knife path: it is suitable for the case with large hole in the middle (less use). Precautions: when bouncing the knife, the knife is not sharp, the knife is too long, and the workpiece is too deep, it should walk around, not up and down; the surfaces on both sides of the sharp angle in the workpiece should be divided into two knife paths, which can not be crossed. The edge of the light knife should be extended (with arc forward and backward knife).  
 
 

7、 Angle clearing:

1. The angle clearing here is a two-dimensional dead angle, which is the part that has not been reached in the previous process. If the light knife needs to go to the place, the angle should be cleared first and then the light knife. The angle that is too small, large and deep can be cleared by several knives. Do not use the small knife to clear too many places.  
2. Clear three-dimensional corners: open some small grooves and some three-dimensional corners.  
3. If the knife is easy to break, it must be considered that the thin knife is too long and the processing capacity is too large (mainly in Z direction and depth direction).  
4. Knife path: when using two-dimensional shape, only small angle (r0.8) and two-dimensional plane angle can be cleared; parallel knife path is used; contour shape is used; there is a curved surface where the knife cannot go and the dead angle where the shape cannot go, the knife shall be sealed first, and then the angle shall be cleared finally. Generally, the small gap in the large surface shall be sealed first.  
 
 

8、 Medium light:

1. Medium light: steel and fine fair light as a surface.  
2. Principle: there is more allowance between layers when the big knife is rough, which is a process to get better effect when using the light knife,  
3. Features: fast clearing, large knife throwing, large feeding and large spacing; Do not worry about surface quality; Flat workpieces do not need medium light; The workpiece with equal height profile does not need medium light. When the equal height profile is rough, the two processes can be put together. The finer point refers to the distance between the surface allowance and the layer; Whether medium light is needed or not, another important factor is the working material. The harder the material, the medium light shall be considered; The processing direction of medium light is better relative to the rough opening of light knife. In this way, the processing effect will be good and uniform.  
 
 

9、 Light knife:

Light knife is to meet the assembly requirements of various products and molds, so we should be very careful and give different knife path settings and parameter settings according to different requirements.  
 
1. The cutting height and final height of the light knife are changed to 0. The tolerance is designed to be within 1 wire, and there is no need to filter (the smaller the workpiece is, the smaller the tolerance is, and the tolerance affects the appearance).  
 
2. The front mold and parting surface shall have the best finish, the rear mold can be second, and other non matching and void avoidance positions can be rough.  
 
3. The tool path design is determined by the following factors:  
Specific shapes (such as planes and other surfaces), steep surfaces and flat surfaces.  
Whether there is a sharp angle between the two sides (sharp angles are separated).  
Whether the requirements of the two parts are different (whether to leave allowance, how much allowance, and different requirements for finish).  
The problem of protective surface in light knife is a big problem. The machined surface must be protected according to the error in machining and the requirements of protective surface. Range protection, 0 protection regardless of error, height range and plane range; Protective surface protection.  
The extension of the tool path. In the light knife, when the tool path is processed to the edge, it is best to make a circular arc forward and backward tool, otherwise the surface will be slightly extended in advance.  
Knife lifting problem in light knife. Lifting the knife is a waste of time, so try to avoid lifting the knife.  
Method 1: set knife lifting clearance (small notch)  
Method 2: cover and seal the knife lifting part (small gap)  
Method 3: avoid gap (large gap)  
Method 4: extend the contour to the same height  
For the feeding problem in the light knife, the first knife must feed from the outside of the workpiece to avoid vibration and bumping the workpiece. All light knives must be equipped with feeding.  
Tool wear: when the workpiece is large, it is necessary to finish the same workpiece with more knives.