2020 – Page 69 – CNC Machining & Turning, Milling, Metal parts

CNC machining method

It is the primary cause of deformation that the bearing is damaged most by using brute force and striking bearing directly with hammer.

If the equipment is not in place, the equipment is wrong or not installed in the bearing position, the bearing clearance is too small. The inner and outer rings are not in the same center of rotation, forming different concentricity.

Suggestion: select appropriate or professional bearing equipment, and use special instrument to test the equipment.

According to investigation, poor lubrication is one of the primary causes of bearing premature failure. The main reasons include: not filling lubricant or lubricating oil in time; not filling lubricant or lubricating oil in place; improper selection of lubricant or lubricating oil; incorrect lubrication method, etc. Or to consult and then use CNC computer gong processing equipment correctly

Suggestion: choose the right lubricant or lubricating oil, and use the correct lubricating filling method.

Pollution can also lead to premature failure of bearings. Pollution refers to dust and metal chips entering the bearing. The main reasons include: open the bearing package too early before use, causing pollution; the working environment of the equipment is not clean, causing pollution; the working environment of the bearing is not clean, and the working medium is polluted.

Stainless steel part 2

Suggestions: it is better not to unpack the bearing before use; keep the equipment environment clean and clean the bearing to be used; strengthen the sealing equipment of the bearing.

Fatigue damage is a common way of bearing damage. The common causes of fatigue damage may be: Bearing long-term overload operation; not timely repair; improper repair; equipment aging, etc.

Suggestion: select the appropriate bearing type and replace the tired bearing in time.

The processing center and CNC computer gong processing center are rarely introduced since the establishment of the station, because C computer gongs processing center in the market is relatively small, the user purchase center is also very few, generally choose the vertical machining center more users. The reason is that the vertical machining center occupies a small area and has high cost performance; while the computer gong processing center occupies a large area and its price is more expensive than that of the vertical machining center

What parts are suitable for processing?

It is not possible to carry out fine processing for all materials. Some materials are too hard, and if they cross the hardness of the machined parts, the parts may be broken. Therefore, these materials are not suitable for fine machining, unless they are parts made of special data or laser cutting. So what are the requirements for the information of fine parts processing? Let’s understand it together.

The data about CNC lathe processing in Dongguan can be divided into two categories, metal data and non-metallic data.

For metal data, the hardness of stainless steel is the largest, followed by cast iron, followed by copper, and finally aluminum.

The processing of ceramics and plastics is attributed to the processing of non-metallic materials.

1. The first is the requirement for the hardness of the data. For some occasions, the higher the hardness of the data, the better. It is only limited to the hardness requirements of the machined parts. The processed data should not be too hard, and it is impossible to process if it is harder than the machine parts.

2. Secondly, the software and hardware of the data should be moderate, at least one level lower than the hardness of the machine parts. Together, we should also see what the function of the processed devices is, and select reasonable materials for the parts.

In a word, there are still some requirements for data in fine machining. Not all data are suitable for processing. For example, if the data are too soft or too hard, the former is not necessary to be processed, while the latter cannot be processed.

Stainless steel parts

Therefore, we must pay attention to the density of the data before processing. If the density is too high, it is equivalent to the hardness. If the hardness crosses the hardness of the machine part (lathe tool), it will not be processed. It will not only damage the parts, but also pose risks, such as turning tool flying out to hurt people. Therefore, generally speaking, regarding the mechanical processing, the data material should be lower than the hardness of the machine tool, so that the ability can be processed.

The automatic numerical control lathe is a kind of machine tool which uses the numerical control technology, the numerical control lathe processing completes the action according to the program which has been programmed in advance. It consists of program carrier, input equipment, CNC unit, servo system, position feedback system and mechanical parts of machine tool. CNC lathe parts processing basic knowledge, parts processing steps

In NC lathe parts processing parts generally go through the following steps:

1. According to the drawing and process plan of the processed parts, compile the program sheet with the specified code and program pattern, and record it on the carrier; do not want to work at the bottom,

2. Input the program on the program carrier into CNC unit through the input device;

3. After the input program is processed by CNC unit, the signal is announced to the servo system of each coordinate of the machine tool;

4. According to the signal announced by CNC unit, the servo system drives the moving parts of the machine tool and controls the auxiliary operation;

5. Through the mechanical parts of the machine tool to drive the relative movement of the cutter and the workpiece, the required workpiece is processed;

6. Detect the movement of CNC lathe and feed back to CNC unit through feedback equipment to reduce machining error. Of course, there is no detection and feedback system for the open-loop CNC lathe.

What’s the reason why the hardware factory didn’t order

1. Weak technical foundation

Most of the hardware processing plants without order information have no technical ability to talk about. They only produce and process some simple metal stamping parts, such as sheet metal bending, blanking, hole opening, etc.

2. The working capacity of supporting facilities is limited

Now there is no way to see the simple metal stamping parts in the sales market. The common products are made by the combination of stamping die, welding, riveting, machining and other processing technologies, and the metal surface treatment must be carried out. If there is no relevant mutual cooperation, only do stamping die, the sales market has been greatly limited!

3. Single marketing channel

There are a lot of small and medium-sized hardware processing factories, and there are only a few or even no professional salesmen in the market. They are all complacent, just a lot of old customers. This makes their own processing plant in a very big risk

4. Lack of brand effect

Nowadays, no matter what kind of goods, the added value is all famous brands of commodities. If a company produces and processes small spare parts for others and does not have its own famous brand, it will not be able to stand on the sales market in the future.

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How to deal with the hardware factory without a single?

1. First you can ensure the quality of the goods, and then the price should be valid.

2. There must be a certain way. That is to say, with your long-term purchase of customers, such as decoration companies, hardware stores, kitchen cabinet stores, such as the boss or logistics management, in a word, it works. Invite them to dinner, give gifts and red envelopes on time, and have a good relationship with them, so as to ensure the basic operation of the factory.

3. Always observe the changes in the sales market, accurately identify the sales market, and ensure that their products can not fall behind the sales market or be too excellent.

Some key points to improve the quality of CNC machining workpiece

1. Reasonable CNC machining tools

The smooth knife for processing steel and copper should be strictly distinguished and used, and the allowance of the smooth knife should be reasonable, so that the smoothness of the workpiece and the service life of the cutter will be better.

2. Before CNC machining, check whether the tool swings within the allowable tolerance range with the calibration table. Before machining, the tool head and locking nozzle can be installed only after being blown clean with the air gun or wiped clean with a cloth. Too dirty will have a certain impact on the accuracy and quality of the workpiece.

3. When clamping, pay attention to see whether the name and model of CNC machining workpiece and program sheet are the same, whether the material size matches, whether the clamping height is high enough, and use calipers to count.

4. The CNC processing program sheet shall be consistent with the direction of the reference angle indicated by the die, and then check whether the upper 3D drawing is correct, especially for the workpieces that have been drilled for water transportation. It is necessary to see whether the 3ddrawing is consistent with the water transportation of the upper workpieces. If it is unclear, it is necessary to timely feed back to the programmer or find a fitter to align the lower 2D drawing to see whether the 2D and 3D reference angles are consistent.

5. The program list of CNC processing documents shall be standardized, including die number, name, program name, processing content, tool size, feed amount, especially the safe length of tool clamping, reserved allowance of each program, and smooth tool. The place where the R-plane and plane should be connected shall be indicated on the program list. The operator shall increase the processing speed by 0.02-0.05mm, and first process several tools Stop to see if it’s connected, touch it with your hand to see if it’s up, and if it’s not, lower the gong.

6. Before processing, understand the contents of CNC processing program list. The program list must have 2D or 3D drawing, and mark “x length, y width, Z height” six side data,

If there is a plane, the “Z” value shall be marked. It is convenient for the operator to check whether the data is correct after machining. If there is a tolerance, the tolerance data shall be marked.

7. The machining speed of the machine tool shall be strictly controlled by the operator. The rotation speed of F-speed and s-axis shall be reasonably adjusted to each other. When F-speed is fast, it shall be faster than s-axis, and the feed speed in different areas shall be adjusted. After processing, the machine can be removed only after the quality is checked and no problem is found, and one-time processing is required to be perfect.

What is CNC boring

What is CNC boring? CNC boring refers to expanding or refining the original holes on the workpiece. The boring feature of CNC machining is to correct the eccentricity of the lower hole, to obtain the precise position of the hole, and to obtain high-precision roundness, cylindricity and surface finish. Therefore, boring is often used in the final process.

Compared with other machining, CNC boring is a kind of difficult machining. By adjusting only one blade (or blade holder), it processes micron sized holes like H7 and H6.

What are the characteristics of CNC boring?

1. Tool rotation

CNC machining is different from lathe machining. Because of the tool rotation, it is impossible to control the condition of the tool tip in time to adjust the feed amount. It is also impossible to change the machining diameter just by adjusting the CNC button like the CNC lathe. This has become a big obstacle to fully automated processing. Because the machining center does not have the function of automatic machining diameter adjustment (except for the one with U-axis function), it is required that the boring cutter must have a fine adjustment mechanism or automatic compensation function, especially in the case of fine boring, sometimes it must be adjusted at the micron level according to the tolerance requirements.

In addition, the direction of chip flow out is constantly changing when boring in machining center, so the cooling of tool tip, workpiece and chip discharge are much more difficult than when machining in lathe. Especially when the vertical machining center is used for steel blind hole rough boring, this problem has not been completely solved up to now.

2. Spring knife

The most common and troublesome problem in boring is the spring knife. The main reasons for the spring knife in the machining center are as follows

① Rigidity of tool system: including the rigidity of tool handle, boring bar, boring head and intermediate connecting part. Because it is cantilever machining, especially the machining of small holes, deep holes and hard workpieces, the rigidity of the tool is particularly important.

② Dynamic balance of tool system: relative to the rotating axis of tool system, if the tool itself has an unbalanced mass, it will cause chatter due to the effect of unbalanced centrifugal force during rotation. Especially in high-speed machining, the dynamic balance of tools has a great influence.

③ Fixed rigidity of workpiece itself or workpiece: for example, some smaller and thinner parts cannot be fully fixed with reasonable jigs due to insufficient rigidity or workpiece shape.

④ Blade tip shape: the cutting resistance is also different due to the different front angle, escape angle, tip radius and chip breaking groove shape of the blade.

Speed control of CNC machining

CNC machining in China is developing towards high speed and high efficiency. This includes the speed control of CNC machining in China. If we want to make full use of the effective working stroke, we must make the moving parts accelerate to the high-speed stroke in a very short time, and stop at the instant in the high-speed stroke. This is why it is necessary to control the speed of CNC machining in Dongguan.

According to the open control idea, we propose a method of automatic acceleration and deceleration control for the movement of CNC machine tools according to any curve. This method will push the automatic acceleration and deceleration control from the traditional fixed mode to the new flexible mode, and explore a new way to effectively improve the dynamic performance of CNC machine tools.

1. Flexible acceleration and deceleration control

In Dongguan CNC machining, the system program directly realizes the specific automatic speed control function. In this way, it is necessary to change the acceleration and deceleration characteristics of the system or modify the numerical control program by adding and subtracting control, so ordinary users can not make the numerical control machine tool have the best acceleration and deceleration performance according to their own wishes. Therefore, our flexible acceleration and deceleration control method adopts the principle of database, divides acceleration and deceleration control into two parts: acceleration and deceleration description and implementation, and separates acceleration and deceleration description from system program. In the software of CNC system, a general control channel is designed, which has nothing to do with the content of acceleration and deceleration database.

2. Flexible automatic acceleration control

Set the acceleration curve, analytical curve and non analytical curve, and store them in the acceleration and deceleration curve library as a template in the form of a number table.

3. Flexible automatic deceleration control

As a sample, acceleration control is stored in acceleration and deceleration curve Library in the form of data table. Reasonable automatic acceleration and deceleration control is an important link to ensure the dynamic performance of CNC machine tools. Because of the lack of flexibility, the traditional automatic acceleration and deceleration control based on fixed curve is not easy to ensure that the acceleration and deceleration process is compatible with the performance of the machine tool, and it is difficult to achieve the best dynamic characteristics of the machine tool movement.

The importance of machining factory management

For the machining plant, no matter the scale, as long as it is an organization, it must be managed. Only in this way can we ensure the long-term development of enterprises. However, for small and medium-sized mechanical processing plants in China, most managers do not pay enough attention to scientific management. Therefore, there will be a variety of problems in machining, which will affect the future development. So, what problems should be paid attention to in strengthening the management of machining plants?

1. Standardization of factory management

Whether the factory implements standardized system management is one of the conditions to measure whether the factory management is competitive, efficient and sustainable. As the staff are changing, a set of mature management system should be established. No matter what the characteristics of the factory are, its basic management is unchanged, which needs to be determined by the system to form a consensus so that everyone can understand and abide by it.

Factory management is not standardized. In the long run, factory management is unstable, basically hovering at a low level, and it is difficult to reach a new level. Its common performance is that the factory system is not perfect, the task is often difficult to complete on time, the problem is difficult to find the reason, excuses and disputes occur from time to time. However, it is also necessary to pay attention to humanization, not just paper documents.

2. Factory performance, employee performance evaluation

If we can’t evaluate the performance of the factory effectively, it’s difficult to find out the key problems accurately, and it’s difficult to grasp the next step. Only use some incomplete data and experience or feeling to deal with the daily production tasks, the daily work of employees will become inefficient, low efficiency will only make a factory lack of core competitiveness!

A perfect employee performance evaluation system is mainly to affirm the achievements, promote the employees to have a positive attitude towards work, help to find and correct the existing deficiencies, and make a plan to correct within a time limit. Therefore, we can not only find talents, train reserve forces of machining plants, but also solve the general unreasonable phenomenon of “governing by inaction”.

Machining plant – knurled nuts

3. Professional people do professional things

The concept of “responsibility is greater than power” should be set up in the machining factory, and the working attitude should be put into practice. Employees should perform their duties and care about the development of the factory. Work hard and work together. To cultivate the development concept of employees, everyone should be enterprising. Instead of being a monk and banging a clock.

4. Production flexibility

Some factories shuffle and kick each other, but they don’t work at last. Simple things are extremely complicated. What else can we talk about in the case of work delay? In fact, many factories have not achieved satisfactory results in this regard. There are many reasons for this. The key is to release the centralized management system and give the responsible person enough management responsibility and rights.

Machining plant – stainless steel nuts

5. Professional talent management and factory development culture

Factory culture is accumulated by the joint efforts of all the people in a company, and it is the promotion of factory management accumulated by the factory for a long time. Good corporate culture is the core competitiveness of the factory, which is the soul of the factory. In particular, a manufacturing factory should have the spirit of research in technology, rather than a word that can’t be done when encountering difficulties. A good technician often helps the factory to expand the scope of business processing. With such a healthy development of internal environment, it is the basic element for the factory to be invincible to cultivate young employees for rapid growth and the factory to constantly cultivate high-quality reserve forces.

Precautions before starting NC machining

1. Precautions before starting NC machining:

(1) Before the start of NC machining, be familiar with the performance, structure, transmission principle, operation sequence and emergency stop method of NC machine tools.

(2) Check the lubricating oil and the oil quantity in the gearbox.

(3) Check the fastening screws and do not loosen them.

(4) Clean the surrounding environment of the machine tool, keep the machine tool and the control part clean, and do not remove the cover to start the machine tool.

(5) Correct the tool and meet the use requirements.

CNC machining

2. Precautions for NC machining programming:

(1) Use the correct tool, strictly check whether the machine origin and tool parameters are normal.

(2) Confirm whether the operation procedure and processing sequence are consistent.

(3) It is not allowed to undertake operations beyond the machining capacity of CNC lathe.

(4) Adjust the tool when the machine stops, and make sure that the tool does not collide with other parts during tool change.

(5) Confirm whether the fixture of workpiece has enough strength.

(6) After the program is adjusted, it shall be checked again, and the processing can be started only after it is confirmed to be correct.

CNC machining

3. Precautions after the CNC machining is started:

(1) After the machine tool is started, the running state of the machine tool must be monitored before its automatic and continuous operation.

(2) Make sure the coolant output is smooth and the flow is sufficient.

(3) When the machine tool is running, the protective cover shall be closed, the size of the tool and the measuring workpiece shall not be adjusted, and the hand shall not be close to the rotating tool and workpiece

(4) When the machine is stopped, remove the chips from the workpiece or tool.

CNC machining

4. Precautions when finishing machining of CNC lathe:

(1) Clean the machine tool.

(2) Anti rust oil lubricates machine tools.

(3) Turn off the system, turn off the power.

CNC machining knowledge

Create CNC process function and CNC process plan:

(1) CNC process considers the process of machining parts, clamping and positioning of machining parts, tool selection, simplified process route, cutting method and process parameters in conventional process.

(2) CNC machining process design is mainly used to guide CNC programming. Our company combines the responsibilities of CNC technicians and programmers, and the programmers are responsible for the whole CNC machining process of the mold, which improves the working efficiency.

(3) CNC machining has a high degree of automation and many influencing factors. Quality and safety are very important in CNC machining and must be guaranteed.

(4) The preparation of CNC machining process should be strict with the rationality of strip steel. The CNC process is complex and has many influencing factors. It is necessary to think deeply about the whole process of CNC processing and have good strip rationality in order to program the CNC process well. Due to the high degree of automation and poor adaptability of CNC processing, when there are problems, it is difficult for the staff to correct them on site, and the manufacturing and processing defects of the light-duty people occur safety accidents on the way, so it is necessary to systematically design CNC process in advance.

(5) good inheritance of CNC technology. It has been proved to be a good CNC technology in production. It can make templates and save them as documents. It can be used to process similar parts in the future, saving time and ensuring quality.

For CNC machining process planning, it will be considered as the state space of a series of programs from the initial state (male and female die core blank) to the final state (part). CNC sequence sorting must conform to the following general rules:

1. The primary parameter is followed by the secondary parameter.

2. Face before hole, milling before drilling.

3. First coarse, then fine.

4. The inner cavity is processed first, and then the shape is processed.

5. According to the sequence of working procedure, the diameter of cutter varies from large to small.

6. The processing of the previous process will not affect the clamping and positioning of the next process.

7. Put the same tooling and fixture together to reduce repeated clips and positions.

8. CNC process must be centralized.

9. Do not use the program instruction to weaken the part stiffness first.

Good CNC process planning needs to consider the following aspects:

Whether it can meet the technical requirements of parts, whether it can improve the efficiency of CNC processing, low processing cost and good quality control.

Therefore, the overall CNC processing plan is generally as follows:

1. Selection of CNC machine tools.

2. Select the treatment method.

3. Determine how to clamp the part and select clamp.

4. Positioning method.

5. Inspection requirements and methods.

6. Select the tool.

7. Error control and tolerance control in machining.

8. Define CNC process.

9. CNC sequence.

10. Select cutting parameters.

11. Prepare NC machining program table.

Process of metal parts processing

We have hardware everywhere in our daily life, which can be said to be endless. So what is hardware? Most people don’t understand, I don’t know, I haven’t touched. Therefore, hardware, as the meaning of five kinds of metals shows, is made of gold, silver, iron, copper and aluminum as raw materials, through cutting, pressing, brazing and other physical processing, to produce all kinds of metal device parts we need.

Our common screws, nuts, etc. Do not look at the small screws so common, hardware processing into finished products seems easy. In fact, the process is quite tedious. One is to have drawings of screw samples, and then select processing equipment according to the tolerance and accuracy requirements of the drawings. After the semi-finished products are made by the equipment, the burr on the burr shall be removed by fine vibration grinding to make the surface smooth and glossy, so as to prevent the contact from hurting the user.

Finally, the surface plating process to prevent rusting is carried out according to the material requirements. Such a small screw was born, and every program should be taken seriously. In the fastener market, ordinary parts can not meet the requirements of high-end consumers, but as long as there are models and drawings, we can process them by CNC or ordinary lathe to make the parts we want. Parts are an indispensable part in our life, and play an important role in all places.

It can be said that with the transformation and upgrading of industrial modernization and the growth and development of social economy, the fastener industry of hardware processing will play an important role