Category Archive CNC Technology

With the advent of the industrial 2.0 era, China’s manufacturing industry is generally growing, and the requirements for the processing and manufacturing industry are higher. Taking the aluminum parts processing and manufacturing industry as an example, the CNC machining accuracy of aluminum alloy is more stringent. However, this is also the trend of the times. It is obvious that aluminum parts are widely used in high-precision instruments. Now we talk about the matters needing attention in CNC machining of aluminum alloy.

1. The speed of white steel knife should not be too fast.
2. When the workpiece is too high, please thicken it with a knife of different grade length.
3. After roughening with a rough knife, remove the excess with the knife, and grind the knife after ensuring the excess.
4. The plane is processed with flat bottom edge instead of ball edge to reduce processing time.
5. The four corners of the calibration plane must be flat.
6. The inclination is an integer, which is processed with an inclined cutter, such as tube position.
7. Before each work, want to clear the remaining amount of the previous work after processing, to avoid empty tool and redundant processing.
8. Try to take a simple path. For example, shape, trenching, avoiding single side, lapping, etc.
9. When taking wcut, if you can go to finish, please don’t take rough.
10. In the case of shape light knife, the light should be coarsened first and then exposed. When the workpiece is too high, it should be illuminated first and then.
11. The tolerance should be set reasonably to balance the machining accuracy and computer calculation time. The tolerance is set to 1 / 5 of the remaining value when it is turned on, and 0.01 for a light knife.
12. Add more projects to reduce the time of empty knife. Think more and reduce the chances of mistakes. Increase the auxiliary surface of the auxiliary line slightly to improve the processing condition.

In the process of production problems are also common things, because the friction between parts will certainly affect our work, so we must pay attention to methods in operation to avoid some unnecessary problems, so we will learn about the common problems of CNC machining?

CNC processing in Dongguan

1、 Workpiece over cutting:

reason:

1. The tool strength is not too long or too small, resulting in the tool bouncing.
2. Improper operator operation.
3. The cutting allowance is not uniform. (e.g. 0.5 for side of curved surface and 0.15 for bottom surface)
4. Improper cutting parameters (such as too large tolerance, too fast SF setting, etc.).

improve:

1. The principle of using knife: it can be big or small, short or not long.
2. Add corner clearance procedure, and the allowance should be uniform as far as possible (the allowance of side and bottom should be consistent).
3. Reasonable adjustment of cutting parameters, large margin corner rounding.
4. Using the SF function of the machine tool, the operator can adjust the speed to achieve the best cutting effect.

2、 The problem of the division is as follows:

reason:

1. Operator manual operation is not accurate.
2. There are burrs around the mold.
3. There is magnetism in the center rod.
4. The four sides of the mold are not vertical.

improve:

1. The manual operation should be checked carefully repeatedly, and the points should be at the same height as far as possible.
2. Deburring the periphery of the mould with an oilstone or file, wipe it with rags, and finally confirm it by hand.
3. Demagnetize the center bar before parting the mold (ceramic bar or others can be used).
4. Check whether the four sides of the mould are vertical by checking the table. (the scheme should be reviewed with the fitter if the perpendicularity error is large)

1. A large number of cutting tooling, processing parts with disordered shapes do not need messy tooling. If you want to change the shape and scale of parts, you only need to modify the part processing program, which is suitable for new product development and modification.
2. The machining quality is stable, the machining precision is high, and the repetition precision is high.
3. In the case of multi type and small batch production, the production power is higher, the time of production preparation, machine tool adjustment and process inspection can be reduced, and the cutting time can be reduced by using the optimal cutting amount.
4. It can machine the disordered surface which is difficult to machine by conventional method, and even can process some parts which cannot be observed.

The defect of NC machining is the high cost of machine tools, which requires high level of repair personnel.

CNC, also known as processing center, has a wide range of applications, not limited to furniture production. Therefore, the experience summary of CNC application in various industries is worth learning. The following points are summarized:

1. The speed of white steel knife should not be too fast.
2. Copper roughing less white steel knife, more use flying knife or alloy knife.

CNC machining

1. When the workpiece is too high, it should be sliced with different length of knife.
2. After roughening with a large knife, use a small knife to remove the remaining material, and smooth the knife only after ensuring the same allowance.
3. The plane is processed with flat bottom cutter and less ball cutter, so as to reduce the processing time.
4. When the copper worker cleans the angle, first check the R size on the angle, and then determine how large the ball knife is used.
5. The four corners of the calibration plane should be smooth.
6. If the slope is an integer, use the slope cutter to process, such as pipe position.
7. Before each process, think about the remaining allowance after the previous process to prevent the tool from being empty or excessive.
8. Try to take simple cutting path, such as shape, grooving, single side, less walking around the same height.
9. When taking wcut, if you can walk finish, don’t go rough.
10. When the shape of the light knife is smooth, first rough and then fine. When the workpiece is too high, polish the edge first and then the bottom.
11. Set tolerance reasonably to balance machining accuracy and computer calculation time. The tolerance is set to 1 / 5 of the allowance for roughening and 0.01 for smooth knife.
12. Do more procedures and cut down the idle time. Think more and cut down on mistakes. Make more auxiliary lines and auxiliary surfaces to improve the processing conditions.

1. A large number of cutting tooling, processing parts with disordered shapes do not need messy tooling. If you want to change the shape and scale of parts, you only need to modify the part processing program, which is suitable for new product development and modification.
2. The machining quality is stable, the machining precision is high, and the repetition precision is high.
3. In the case of multi type and small batch production, the production power is higher, the time of production preparation, machine tool adjustment and process inspection can be reduced, and the cutting time can be reduced by using the optimal cutting amount.
4. It can machine the disordered surface which is difficult to machine by conventional method, and even can process some parts which cannot be observed.

The defect of NC machining is the high cost of machine tools, which requires high level of repair personnel.

CNC, also known as processing center, has a wide range of applications, not limited to furniture production. Therefore, the experience summary of CNC application in various industries is worth learning. The following points are summarized:

1. The speed of white steel knife should not be too fast.
2. Copper roughing less white steel knife, more use flying knife or alloy knife.

CNC machining

1. When the workpiece is too high, it should be sliced with different length of knife.
2. After roughening with a large knife, use a small knife to remove the remaining material, and smooth the knife only after ensuring the same allowance.
3. The plane is processed with flat bottom cutter and less ball cutter, so as to reduce the processing time.
4. When the copper worker cleans the angle, first check the R size on the angle, and then determine how large the ball knife is used.
5. The four corners of the calibration plane should be smooth.
6. If the slope is an integer, use the slope cutter to process, such as pipe position.
7. Before each process, think about the remaining allowance after the previous process to prevent the tool from being empty or excessive.
8. Try to take simple cutting path, such as shape, grooving, single side, less walking around the same height.
9. When taking wcut, if you can walk finish, don’t go rough.
10. When the shape of the light knife is smooth, first rough and then fine. When the workpiece is too high, polish the edge first and then the bottom.
11. Set tolerance reasonably to balance machining accuracy and computer calculation time. The tolerance is set to 1 / 5 of the allowance for roughening and 0.01 for smooth knife.
12. Do more procedures and cut down the idle time. Think more and cut down on mistakes. Make more auxiliary lines and auxiliary surfaces to improve the processing conditions.

The metal cutting tool cuts off the surplus metal on the workpiece through the CNC machine tool, so that the workpiece is formed. CNC machine tools, east-west system and tool management are the basis of CNC machine tool power and quality assurance. So CNC machine tools in the processing of common problems and solutions and tools have a direct relationship.

The following are some problems frequently encountered in the process of NC machining, and there are many solutions. Therefore, if you do not have enough experience to directly find the breakthrough point of the problem, you can also use the “elimination method” for comparison.

These defects and detection methods are processed and tested for reference when we encounter problems in work.

1. The scale of workpiece is accurate and the surface finish is poor

Cause of the problem

The tool tip is damaged and not sharp; the machine tool resonates and is not placed smoothly; the machine tool crawls; the processing technology is not good.

Solution:

If the tool is not sharp after being worn or damaged, it is necessary to grind the tool from the beginning or select a better tool to set the tool from the beginning; if the machine tool resonates or is not placed stably, adjust the level, lay the foundation and fix it stably; the reason for the creeping of the machine is that the guide rail of the carriage is severely worn, and the ball screw ball is worn or loosened, so the machine tool should be maintained.

Clean the iron wire after work and add lubricating oil in time to reduce friction; select the coolant suitable for workpiece processing, and select a higher spindle speed as far as possible when it can meet the processing requirements of other processes.

CNC machining

1. Large and small taper of workpiece

Cause of the problem

The placement level of the machine tool is not adjusted well, one high and one low, resulting in unstable placement; when turning the long shaft, the contribution material is relatively hard, and the cutting tool is relatively deep, resulting in a tool yielding phenomenon; the tailstock thimble is not concentric with the spindle.

Solution:

Use level to adjust the levelness of the machine tool, lay a solid foundation, fix the machine tool and improve its toughness; select a reasonable process and appropriate cutting feed rate to avoid the force on the tool; adjust the tailstock.

1. The driver phase light is normal, but the size of the workpiece processed is large or small

Cause of the problem

The carriage of the machine tool runs at high speed for a long time, which leads to the wear of screw rod and bearing;

The carriage can return to the machining starting point accurately every time, but the scale of the workpiece still changes. This phenomenon is generally caused by the spindle. The high-speed rolling of the spindle makes the bearing wear seriously, resulting in the change of machining scale.

Solution:

Use the dial indicator to lean against the bottom of the tool rest, and at the same time, modify a fixed cycle program through the system, check the repeated positioning accuracy of the carriage, adjust the screw clearance, and replace the bearing; use the dial indicator to check the repeated positioning accuracy of the tool rest, adjust the machinery or replace the tool rest; use the dial indicator to check whether the workpiece is accurately returned to the starting point of the program. If it can, overhaul the spindle and replace the bearing.

No matter what kind of work, there are certain requirements for the technology. If the technology is not good, the effect produced in the later stage is certainly not good. Therefore, if you want to ensure the effect of the product, the technology must be excellent. In CNC machining, the technology is also divided into many parts. Today, we will learn about the technical requirements of bearings?

1. It is allowed to heat the rolling bearing with oil, and the oil temperature shall not exceed 100 ℃.
2. The semicircular hole of bearing outer ring, open bearing seat and bearing cover shall not be stuck.
3. The outer ring of the bearing shall be in good contact with the semicircular hole of the open bearing seat and the bearing cover. During the color coating inspection, the outer ring and the bearing cover shall be evenly contacted within the range of 120 ° symmetrical to the center line and 90 ° to the center line with the bearing cover. When the feeler gauge is used for inspection within the above range, the 0.03mm feeler gauge shall not be inserted into 1 / 3 of the outer ring width.
4. After assembly, the bearing outer ring should contact with the end face of the bearing cover at the locating end evenly.
5. After the rolling bearing is installed, it should rotate flexibly and stably by hand.
6. The joint surface of the upper and lower bearing shells should be close to each other and cannot be checked with a 0.05mm feeler gauge.
7. When fixing the bearing bush with locating pin, the reaming and pin distribution should be carried out under the condition that the bearing mouth surface and end face are in line with the opening and closing surface and end face package of the relevant bearing hole. The pin shall not be loose after being driven in.
8. The bearing body and bearing seat of spherical bearing shall be in uniform contact, and the contact shall not be less than 70% by color coating method.
9. When the surface of the alloy bearing liner is yellow, it is not allowed to use, and there is no nuclear separation within the specified contact angle. The area outside the contact angle shall not be greater than 10% of the total area of the non-contact area.

Shaft parts is a common type of parts, its structure is a rotating body, the length is generally greater than the diameter, it is widely used in various mechanical equipment, used to support transmission parts, transmit torque and bear load

The processing technology of CNC lathe is similar to that of general lathe. However, since CNC is one-time clamping and automatic processing, it can complete all turning processes. Therefore, attention should be paid to the following aspects.

1. Select cutting parameters reasonably

For high efficiency metal cutting, the processed data, cutting tools and cutting conditions are the three major elements. These determine the processing time, tool life and processing quality. The economical and effective machining method must be the reasonable choice of cutting conditions.

The three factors of cutting conditions: cutting speed, feed rate and cutting depth directly cause tool damage. With the progress of cutting speed, the tool tip temperature will rise, which will produce mechanical, chemical and thermal wear. With the increase of cutting speed, the tool life will be reduced by 1 / 2.

The feed condition is related to the tool back wear in a very small range. But the feed rate is large, the cutting temperature rises, and the back wear is large. It has less effect on the tool than the cutting speed. Although the influence of cutting depth on the tool is not as great as the cutting speed and feed rate, but when the cutting depth is small, the hardened layer generated by the cutting data will also affect the tool life.

The user should select the cutting speed according to the processed data, hardness, cutting state, data type, feed rate, cutting depth, etc. As shown in the table below:

The most suitable processing conditions are selected on the basis of these elements. Regular, stable wear and tear to reach the longevity is the condition of ambition.

However, in practice, the selection of tool life is related to tool wear, dimension change, surface quality, cutting noise and processing heat. When confirming the processing conditions, the requirements should be studied according to the actual situation. For stainless steel and heat-resistant alloy and other difficult to machine data, you can choose coolant or choose a good rigid blade.

1. Select cutting tools reasonably

1) In rough turning, the tool with high strength and good durability should be selected to meet the requirements of large back cutting amount and large feed rate.

2) When finishing turning, the tool with high precision and good durability should be selected to ensure the machining accuracy.

3) In order to reduce the tool changing time and facilitate tool setting, the machine clamping tool and machine clamping blade should be selected as far as possible.

CNC machining

1. Select fixture reasonably

1) Try to select general fixture to clamp workpiece, and avoid using special fixture;

2) Parts positioning datum coincide to reduce positioning error.

1. Confirm the processing road

Machining path refers to the path and direction of the tool relative to the parts in the process of NC machining.

1) The machining accuracy and surface roughness requirements shall be ensured;

2) The processing road should be shortened as far as possible and the tool idle travel time should be reduced.

1. Contact between machining road and machining allowance

At present, under the condition that the CNC lathe has not been widely used, the excessive allowance on the blank, especially the allowance containing forging and casting hard layer, should be processed on the general lathe. If it is necessary to use CNC lathe processing, it is necessary to pay attention to the flexible organization of the program.

1. Key to fixture installation

At present, the connection between the hydraulic chuck and the hydraulic clamping cylinder is completed by the pull rod. The key points of clamping the hydraulic chuck are as follows: firstly, remove the nut on the hydraulic cylinder with a handler, remove the pull pipe, and pull it out from the rear end of the spindle, and then remove the chuck fixing screw with the handler to remove the chuck.

The polishing edge on the cutting tool refers to a small section of the edge parallel to the tool tip grinded out in the direction of the offset angle behind the tool edge. It is mainly used for the secondary cutting after the cutting edge, which is equivalent to removing the burr and other scars in the finishing process. The purpose is to improve the surface roughness of the workpiece, and is mostly used in the tool for finishing.

The following problems should be paid attention to in the process of CNC hand board processing

(1) Determine the processing content of CNC machining center, determine the installation base surface, processing base surface and machining allowance of workpiece, and organize the machining process with the intention of giving full play to the power of CNC machining center.

(2) As for complex parts, due to thermal deformation during processing, internal stress after quenching and deformation after parts clamping, it is difficult to complete the whole process after one clamping. At this time, it can be considered to clamp twice or repeatedly.

(3) The principle of “from rough to fine” should be followed in the organization of machining process. First, organize heavy cutting, rough machining, remove the machining allowance on the blank, and then organize the content with low machining accuracy.

(4) In order to reduce the influence of a large amount of heat on the machining accuracy, and to improve the tool life, large flow cooling method should be used actively.

CNC machining method and tool selection.

1. Try to use a big knife to cut thick, and then use a small knife to clear the corner. For example, the diameter of? 32 tool is 4 times that of? 8 tool, while the processing area is 16 times. Moreover, the large diameter tool has good rigidity, and the cutting depth and feed speed are significantly greater than those of the small diameter tool.
2. Try to use the fillet knife for roughening and flat bottom knife for corner cleaning. Because of the better force on the round blade, and it can be used repeatedly, the square grain can only be used twice.
3. Generally, the plane should not be processed with ball cutter, but with flat bottom knife. It is better to leave 0.2mm for polishing.
4. For straight wall groove processing, first finish the bottom surface of the workpiece, and then finish the side surface. For the side surface with height less than 50 mm, large number of reciprocating machining with carbide grain cutter shall be avoided as far as possible, and all straight shank cutters shall be selected for contour processing. (the depth of each tool is about the tool radius. )

CNC machining

1. Proper selection of forming tools to process regular shaped workpieces to improve power. For example: taper cutter milling slope, finger knife milling rib, fillet cutter (r0.3-r1) small fillet, etc.
2. In order to ensure the constant cutting load of the cutting tool, the layer by layer winding processing method should be selected as far as possible to avoid the upper and lower tool feeding.
3. The rigidity of the tool should be enough. Generally, the length diameter ratio (measured by the ratio of tool length to diameter) should not exceed 5. For example, the extension length of a 16mm diameter cutter should not be greater than 80mm, and a clamping length of 25-45mm should be reserved. Please refer to the tool specification table (Appendix 2) to select the machining tool to avoid over cutting due to lack of rigidity in the process of machining.
4. According to the shape of the workpiece, the programmer can select the self-made taper shank cutter or small cable head clamp to enhance the rigidity; for narrow groove and deep cavity dead angle, please use EDM, and do not have to force milling out.
5. If there are upper boss and pits in multi curved surface machining, please use a tool with small diameter to partially clean the corner, or make a protective surface to avoid bouncing.
6. Please process from center to corner. If the flat bottomed cutter is used for downward machining, please first use the ball cutter to cut the lower edge, or the horizontal feed part should be processed layer by layer to avoid the excessive allowance of the first cutter, resulting in over cutting of the “top and bottom”.
7. For the molding of the surrounding inclined plane and the bottom fillet, it is usually wound layer by layer with a ball cutter, and the fillet will appear “undercut” and affect the quality. Please use a flat bottomed cutter for semi finishing, and then use a ball cutter with a radius less than 1-2mm for finishing, or use a flat bottomed cutter to go back and forth for machining.
8. For the vertical or steep surface, please use the unidirectional cutting method to process from top to bottom, or use the winding method to process layer by layer downward.
9. For deep cavity or high column machining, please use ball cutter or R6 fillet cutter for winding and finishing layer by layer. Avoid using

When machining flat bottomed cutter or fillet cutter without R1, the tool tip of flat bottomed cutter is easy to wear, resulting in inaccurate shape, while the position of cutting contact point of ball cutter and fillet cutter changes with the change of machining position, and the wear is more uniform, which can ensure the machining quality.

1. For deep cavity or high column position (greater than 200 mm), please use square cutter for roughening, do not use R6 fillet cutter for roughening, because the contact surface of fillet cutter is large, it is easy to vibrate and spring the cutter.

In the process of work, mold failure is also a common thing. In general, when we encounter failure problems, we first need not to solve the problem, but to find out what causes the failure. In this way, we can better solve the fundamental problem. If the cause is not found, then even if it is solved, it is basically a temporary cure rather than a root cause. So let’s To understand the CNC machining center spindle abnormal noise causes what is it?

CNC machining

1. Overload.

Fault causes: excessive cutting amount, frequent positive and negative rotation, spindle motor failure, spindle drive device failure.

1. The spindle does not rotate

Fault causes: spindle drive device failure, CNC device can not output speed signal, spindle motor fault, spindle drive device fault, drive belt fracture.

1. Spindle speed deviates from the command value

Fault causes: motor overload, problems with spindle speed command output from CNC system, fault of speed measuring device or disconnection of speed feedback signal.

1. Abnormal noise and vibration of spindle

Different types of CNC machining centers adopt different types of spindles. According to the different transmission systems, the spindle system can be divided into the main drive spindle with variable speed gear, the main transmission spindle through belt drive, the spindle driven by dual motors and the spindle integrated by motor and spindle

What are the problems of computer gong processing?

1. In the process of processing products, when the size of height direction changes greatly, do not adjust the depth of wear tool compensation, first check whether there is aluminum slag in the handle and spindle, and then add wear cutter compensation after admitting that there is no slag.
2. When using the jaw to clamp the products, the thickness is different, the outer dimension is thinner and the inner dimension is thicker. This is when the product is jacked up by clamping the external jaw. It is necessary to pay attention to whether the movable parts of the jaw are too loose, and the problem of different product thickness can be handled after locking it.
3. When CNC machining deep hole has accuracy requirements, it simply presents taper, especially when the hole depth is longer, it is difficult to ensure that the upper and lower are reached. It can be rough first and leave a small amount of allowance before boring.
4. When processing products with high surface finish requirements, the rough blade pattern is difficult to meet the requirements of customers. At this time, the flying cutter can be used to install PCD cutter grain for large surface, and PCD flat cutter can be customized for small surface to improve the surface finish.

CNC machining

1. 304 stainless steel material, it is very simple to wear the tool during processing, cold cutting fluid can be changed to oil cooling, oil cooling can improve the service life of the tool. The tapping diameter of aluminum material is small, the wire tapping is simple, and the oil cold cutting is also available.
2. Corner flick knife

When it is found that there is a product corner spring knife, the first analysis of the product corner size, the use of less than corner R angle of the tool. It can also be handled by reducing the spindle speed.

1. Burr on chamfering

When there are burrs after chamfering, the first thing to check is whether the tool is worn. If the tool is intact, then check the depth and range of chamfering. Generally, these two aspects can deal with the problem of chamfering burr.

1. Pinch injury

Pinch injury is a common problem in CNC machining. On the one hand, it may be that the operator is clamping the product or the tooling is not blown clean, which can be completed by strengthening training. On the other hand, it may be that the contact surface of clamping products is large, which can be treated by replacing the steel jaw. The tooling can also be placed in the direction of the oil pipe when adjusting the machine, so as to clean up the residual materials and reduce the formation of clamping injury.