July 2021 – CNC Machining & Turning, Milling, Metal parts

ey points for safe operation of CNC machine tools

Operators shall wear tight work clothes with tight cuffs; Female comrades should wear protective helmets; Wear protective glasses during high-speed milling; Wear masks when milling iron castings; During operation, it is strictly prohibited to wear gloves to prevent hands from being rolled between the rotating tool and the workpiece.
Before operation, check whether all parts and safety devices of the milling machine are safe and reliable; Check whether the electrical part of the equipment is safe and reliable.
When loading and unloading workpieces, the workbench shall be retracted to a safe position. When tightening workpieces with a wrench, the force direction shall avoid the milling cutter to prevent the wrench from hitting the cutter or fixture when it slips.
When assembling and disassembling the milling cutter, it shall be padded with a special pad, and do not hold the milling cutter directly by hand.
When the work piece is not evenly divided and the work piece is not evenly held by the vise, the special clamping fixture shall be placed in the middle of the work piece, and the special clamping fixture shall be avoided as much as possible.
During rapid or automatic feed milling, it is not allowed to move the worktable to two extremes to avoid crushing the screw rod.
When the machine tool is running, it is not allowed to adjust and measure the workpiece and change the lubrication mode, so as to prevent the hand from touching the tool and hurting the fingers.
Do not brake by hand until the milling cutter rotation has stopped completely.
During milling, do not remove chips by hand or blow with your mouth to prevent chips from damaging skin and eyes.
In case of motorized rapid feed, the hand wheel clutch shall be opened to prevent injury caused by rapid rotation of the hand wheel.
When reversing the workbench, stop the reversing handle at the middle position first, and then reverse. Direct reversing is not allowed.
When milling keyway shafts or cutting thin workpieces, strictly prevent milling the dividing head or worktable.
When milling the plane, the cutter head with more than four cutter heads must be used, and the appropriate cutting parameters must be selected to prevent the vibration of the machine tool in milling.
After work, stop the worktable at the middle position and the lifting table falls to the lowest position.
For CNC vertical milling machine, pre selection of relevant work procedures, spindle speed, tool feed, tool trajectory and continuous offside shall be carried out according to the process requirements before work. Put the electrical knob in the “adjustment” position for commissioning. After confirming that there is no problem, put the electrical knob in the automatic or semi-automatic position for operation.

About CNC Turniing

ken. tang@chengcg.com

Function of CNC processing equipment

Due to the increasing diversification of product demand, the acceleration of renewal and the shortening of product life cycle, multi-type mass production has become the mainstream of production shape in mechanical manufacturing industry. Therefore, the flexibility requirements for automatic processing equipment are higher and higher. For the automatic processing system used for small and medium-sized batch production, we should consider making it have the following functions.

The function of actively changing the processing sequence is related to automatic processing equipment. One or a group of electronic accounting machines can be set, which can make the system have the demand for production according to different products. Under the condition of continuous machine, it is convenient to quickly and actively change the task sequence of various equipment and reduce the re adjustment time of the system.
The function of actively completing the processing of multiple products or parts. The transportation system and processing system of workpiece and accompanying fixture set in the processing system have considerable universality and high initiative sequence, so that the whole system can actively complete the processing of multiple products or parts on the basis of group skills.
A highly flexible processing system for the function of processing sequence and production rhythm according to local conditions shall have the function of random transformation of process sequence and production rhythm of various product parts.
High efficiency active machining and active tool change technology. The CNC machine tool with tool magazine and active tool change installation can make the system have high efficiency active machining and active tool change function.
The active monitoring and fault diagnosis function sets up the active inspection, monitoring and fault diagnosis installation of the production process, and then improves the task reliability of the equipment and reduces downtime and waste damage.

About CNC Turniing

ken. tang@chengcg.com

Difference between NC machining and machining

Difference between machining and NC machining

Numerical control machining is a kind of machining. Numerical control is a full-automatic machining method. If you input the instruction manually, the machine can run according to the instruction and process the required parts. It has the advantages of convenient programming, flexible use, high efficiency and labor saving.

There are many kinds of machining, including manual, semi-automatic and full-automatic. The first two have low work efficiency.

CNC machine tools are generally composed of the following parts:

Host, which is the theme of CNC machine tools, including machine tool body, column, spindle, feed mechanism and other mechanical parts. It is a mechanical part used to complete various cutting processes.
NC device is the core of NC machine tool, including hardware (printed circuit board, CRT display, key box, paper tape reader, etc.) and corresponding software. It is used to input digital part program, complete input information storage, data transformation, interpolation operation and realize various control functions. CNC machinery
Driving device, which is the driving part of the actuator of NC machine tool, including spindle driving unit, feed unit, spindle motor and feed motor. He realizes spindle and feed drive through electrical or electro-hydraulic servo system under the control of NC device. When several feeds are linked, the machining of positioning, straight line, plane curve and space curve can be completed.
Auxiliary device, some necessary supporting parts of index control machine tool, to ensure the operation of NC machine tool, such as cooling, chip removal, lubrication, lighting, monitoring, etc. It includes hydraulic and pneumatic devices, chip removal devices, exchange worktables, CNC turntables and CNC indexing heads, as well as cutting tools and monitoring and detection devices.
Programming and other auxiliary equipment can be used to program and store parts outside the machine.

About CNC Turniing

ken. tang@chengcg.com

Factors affecting CNC machining efficiency

To see what is the efficiency factor of CNC machining, we must first know that CNC machining center belongs to numerical control equipment, which is mainly operated by the computer programming command of technical engineers. In the process of production, how to improve the efficiency of CNC processing

Selection of machine tools

Before arranging CNC parts processing, we must ensure the weight that the worktable can bear and consider the smooth processing of mechanical parts. Nowadays, the efficiency of production and processing has a direct impact on whether small and medium-sized processing enterprises can make profits. If the machine tool table can not meet the requirements of use, the processing efficiency will be reduced, and the accuracy of the machine tool itself will also be affected.

Reasonable processing steps

For the machining industry, it can be said that reasonable production and processing technology is one of the important steps. CNC parts processing is very difficult, so we must choose a reasonable processing route, which can save time and improve the production and processing efficiency. On the contrary, if the selection of processing technology is unreasonable, the production efficiency will be reduced.

Small batch processing

Many customers ask whether small batch processing is possible. When small batch and large batch parts are processed, the advantage of precision CNC processing is very obvious, which saves the time of programming and machine adjustment. Only need to clamp parts repeatedly, the production and processing efficiency can be improved many times!

The above is the factor of CNC processing rate.

About CNC Turniing

ken. tang@chengcg.com

Introduction to machining tolerance of CNC parts

A precision parts processing drawings will have dimensions, special position machining accuracy requirements, that is, positive and negative tolerance. The marked tolerance is to ensure that the actual geometric parameters are consistent with the dimensions specified on the drawing in the process of precision parts processing, and the degree of inconsistency between them is called processing error. In order to ensure the accuracy tolerance and avoid the machining error, the following three points should be paid attention to

Benchmark:

According to the shape of different parts, the same datum plane can be selected for processing to ensure that the clamping of parts in the processing process can reduce a certain error range, which is the importance of datum plane.

Shape:

For different drawings provided by our customers, the workpiece with special shape can’t be clamped normally. At this time, we can consider designing clamping fixture for positioning processing and selecting datum plane. Its main function is to assist the processing to meet the accuracy requirements and improve the production and processing efficiency.

Technology

In the precision machining industry, some people say that the drawing processing technology is an art, reasonable technology will save a lot of time, but also can improve the efficiency of production and processing. So a reasonable process is very important.

Machine tool:

Previous articles have also mentioned that the accuracy of the machine tool itself will affect the error, because there are several kinds of errors of the machine tool itself, mainly including the head spindle rotation error, guide rail error and transmission chain error.

About CNC Turniing

ken. tang@chengcg.com

Structure of CNC machining

The system structure principle of CNC machining, in the CNC machining process, can logically process the program with control code or other symbol instructions, and decode it, so as to make the machine move and process mechanical parts, collectively referred to as CNC machining.

The structure of CNC machine tool is as follows

Main machine, which is the theme of CNC machine tools, including machine body, column, spindle, feed mechanism and other mechanical parts. He is used to complete a variety of cutting precision parts processing.
Numerical control device is the core of CNC machine tool, including hardware and corresponding software, which is used to input digital part program, complete input information storage, data transformation, interpolation operation and realize various control functions.
Driving device, which is the driving part of CNC machine tool actuator, including spindle driving unit, feed unit, spindle motor and feed motor. Under the control of the numerical control device, he realizes the spindle and feed drive through the electric or electro-hydraulic servo system. When several feed linkage, can complete the positioning, straight line, plane curve and space curve processing.
Auxiliary device refers to some necessary supporting parts of CNC machine tool to ensure the operation of CNC machine tool, such as cooling, chip removal, lubrication, lighting, monitoring, etc. It includes hydraulic and pneumatic device, chip removal device, exchange table, numerical control turntable, numerical control dividing head, cutting tool, monitoring and detection device, etc.
Programming and other auxiliary equipment, which can be used to program and store CNC parts outside the machine.

The above is the structure of CNC processing. In the machining industry, precision CNC processing greatly improves production efficiency. It has the following advantages: (1) it can guarantee the accuracy and surface roughness of the workpiece to be machined; ② It can shorten the processing route, reduce the empty travel time and improve the processing efficiency; ③ The workload of numerical calculation should be simplified as much as possible, and the machining program should be simplified; ④ For some repeated programs, subroutines should be used.

About CNC Turniing

ken. tang@chengcg.com

Spindle is an important factor of CNC lathe

The important factors determining the spindle of CNC machine tool

Machine tool spindle refers to the machine tool to drive the workpiece or tool rotation axis. It is usually composed of spindle, bearing and transmission parts (gear or pulley). In addition to planer, broaching machine and other machine tools whose main motion is linear motion, most machine tools have spindle components. The motion accuracy and structural stiffness of spindle components are important factors to determine the machining quality and cutting efficiency. The main indexes to measure the performance of spindle components are rotation accuracy, stiffness and speed adaptability.

For the modular design of CNC machine tools, simplify the structure of machine tools, improve the performance of machine tools

a. Simplify the structure and promote the modularization of machine tool structure

Motorized spindle can form standardized and serial products according to the use, structure, performance parameters and other characteristics, which can be selected by the host machine, so as to promote the modular structure of the machine tool.

b. Reduce the cost of machine tools and shorten the development cycle of machine tools

On the one hand, standardized and serialized motorized spindle products are easy to form specialized and large-scale production, which can also shorten the development cycle of machine tools and adapt to the current rapid and changeable market trend.

c. Improve machine performance and reliability

The reliability of CNC machine tools with motorized spindle structure is improved because of its simplified structure and reduced transmission and connection links; With mature technology, perfect function, excellent performance and reliable quality, the performance and reliability of the machine tool are further improved.

d. Realize the special requirements of some high-grade CNC machine tools

Some high-end CNC machine tools, such as parallel motion machine tools, pentahedral machining centers, small hole and super small hole machining machines, must use motorized spindle to meet the perfect functional requirements.