2020 – Page 44 – CNC Machining & Turning, Milling, Metal parts

Efficiency factors of CNC machining

In the process of processing, there must be some factors that affect our work efficiency, of course, it will also affect our work effect. When these problems occur, we must deal with them in time to avoid more failures in the future. We must deal with them in time. There are many factors affecting the processing effect. Let’s learn about the influence of CNC plus What are the labor factors?

Before processing, it is necessary to determine the processing technology, make clear the content of the process card, especially to determine the shape of the parts to be processed, and know the content of the next processing program.
The blank size should be measured before clamping, and the blank placement must be carefully checked to see if it is consistent with the programming.
After the rough machining of the blank is completed, maintenance should be carried out to determine whether the workpiece is correctly divided? Is the workpiece dislocated and loose? Is the dimension from the processing part to the reference point meet the drawing requirements? After checking, the shape and scale of rough machining should be measured timely and accurately.
Semi finish machining or finish machining can only be carried out after the rough machining and maintenance is completed. After finishing the processing, the technician shall check the shape and size of the processing parts, mainly check the vertical and inclined plane processing parts and the base point size marked on the measurement drawing for approval.
After the completion of manual maintenance, it can be removed only after confirming that the drawing process meets the relevant requirements, and the workpiece is sent to the quality inspector for special inspection

Precision machined parts

For example, for example, the diameter of a cylinder has strict requirements, and the positive and negative deviation is within the boundary required by the articles of association. Otherwise, they are all different parts; For example, if the diameter of an embedded cylinder is too large to exceed the allowable limit of deviation, it will form a situation that cannot be inserted. If the intrinsic diameter is too small and exceeds the lower limit of the allowable negative value of deviation, it will form the problem of too loose insertion and instability.

These are the products of divergent lattice. Perhaps the length of the cylinder is very long or too short, which exceeds the allowable deviation line. They are all the products of divergent lattice, and they will be scrapped or processed from scratch, which will inevitably increase the cost.

The second is the advanced non-standard parts processing equipment and testing equipment, advanced processing equipment makes the processing time of careful parts more simple, higher precision and better efficiency.

These are the requirements of precision parts processing, I hope to help you.

The cutting quantity is important in CNC machining

In the work, we have a lot of things are very important, because in the production process, we have a lot of matters to pay attention to, in the process, there are factors that will lead to the effect of the work. There are many times because of a small choice and affect the final effect, then in the process of CNC machining, the cutting amount is very important, so let’s understand how important the choice of cutting amount of CNC machining is?

Cutting speed, feed rate and cutting depth are the three factors of cutting conditions of CNC lathe, which directly cause tool damage. With the increase of cutting speed, the tool tip temperature will rise, which will produce mechanical, chemical and thermal wear. If the cutting speed is increased by 20%, the tool life will be reduced by 1 / 2.

The relationship between feed condition and tool back wear occurs 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 of the material to be cut will also affect the tool life.

The user should select the cutting speed according to the material to be processed, hardness, cutting state, material type, feed rate, cutting depth, etc. The most suitable processing conditions are selected on the basis of these factors. Regular and stable wear is the ideal condition for service life. However, in practice, the choice of tool life is related to tool wear, size change, surface quality, cutting noise and processing heat. When determining the processing conditions, it is necessary to study according to the actual situation. For stainless steel and heat-resistant alloy and other difficult to machine materials, can use coolant or choose a good rigid blade

Improve machining efficiency

In the process of work, we certainly want to improve our work efficiency through some methods, but this is not what we say we can improve if we want to improve. First of all, we must guarantee the quality of products on the premise that our efficiency is not high, or the quality of products will not be guaranteed, which is in vain. So we will learn how to improve the efficiency of Dongguan machining?

In the process of using speed control machine tool for processing, it is necessary to ensure that the worktable can bear the most sufficient weight and ensure that the machining process can be carried out smoothly. Modern processing is to be able to improve production, if the processing table can not meet the requirements of use, in the production process will be affected.

In the process of mechanical processing, due to the increasing speed of modern high-speed cutting, in order to adapt to the processing method, then only to reduce the radius of the tool, improve the moving speed of the main bearing of the machine tool. Meet the use requirements in the process of processing, improve the quality of use. For the mold in the production process, need to achieve high precision, high stability and high speed processing requirements. Only in this way can we improve the cutting ability of the machine tool in the process of cutting and ensure the effect of machining.

Considerations in purchasing mould

In the purchase of products, the premise is generally quality. Only the products with good quality can ensure the efficiency of our work and the quality of products. For example, when we CNC processing, the most important is the mold, only good mold can make good products, this matter is very important. The mould will wear after a long time of operation, which will definitely affect the product. So it is very important to choose a good mold, so let’s understand what problems should be considered when choosing a mold?

There are many kinds of molds, which can be roughly divided into ten categories. According to the different requirements of parts material, physical and chemical properties, mechanical strength, dimensional accuracy, surface finish, service life and economy, different types of die forming are selected.
The die with high precision needs to be processed by high-precision CNC machine tool, and the die material and forming process have strict requirements, and CAD / CAE / CAM die technology is also needed to design and analyze.
Due to the special requirements of some parts, the mold also needs to use advanced technology such as hot runner, gas assisted molding, nitrogen cylinder and so on.
The manufacturer shall be equipped with CNC, EDM, WEDM and NC profiling milling equipment, high-precision grinder, high-precision CMM, computer design and relevant software.
Generally, large stamping dies (such as automobile cover parts mould) should consider whether the machine tool has blank holder mechanism, or even edge lubricant, multi position progressive, etc. In addition to stamping tonnage, punching times, feeding device, machine tool and die protection device should be considered.
The above mold manufacturing means and technology are not owned and mastered by every enterprise. When selecting the mold processing factory, we must understand its processing ability, not only depends on the hardware equipment, but also combined with the management level, processing experience and technical strength.
For the same set of mould, there is sometimes a big gap between quotations from different manufacturers. You should not pay more than the value of the mold, at the same time, should not be less than the cost of the mold. Mold manufacturers like you, to make a reasonable profit in the business. Ordering a set of molds with a much lower price would be the beginning of trouble. Users should start from their own requirements and measure comprehensively

Causes of die punch fracture

In the process of our processing, it is a normal phenomenon to encounter problems, because during the operation of the equipment, there will be wear between the parts. If there is wear, the fault will occur naturally. If the fault occurs more, it will certainly affect the service life of the equipment. So if we want to extend the service life, we must do well in the maintenance The problem must be solved in time, so let’s understand what causes the die punch fracture?

In the blanking process, the punch is subjected to unbalanced lateral pushing force, which makes the punch bend or even break. This kind of force mainly includes the following aspects:

① When rubber is used as elastic unloading part, rubber compresses to produce lateral expansion and extrudes punch to one side due to improper assembly.

② The imbalance of spring force in the unloading device makes the unloading plate incline, which makes the punch bend and break when it is pushed by transverse force.

③ The position of the big punch and the small punch are close. In the blanking process, the material around the big hole deforms, and the small punch may break.

If the ratio between the diameter of punch section and the length of its working part is improper, the punch may be broken.
When a small punch is used to punch thick and hard materials, the punch is easy to break, and the diameter of common punch should be larger than the material thickness of metal stamping parts. Otherwise, punch sheath structure should be adopted.
Die fracture is also often caused by incorrect design and manufacturing, small fillet radius at corner of step punch, rough machining, no edge mark and grinding crack, decarburization layer caused by forging is not completely removed by machining, carbide segregation is not improved during forging of high alloy tool steel, improper heat treatment process and so on. Especially for cold extrusion punch.

Prevent CNC parts from machining deformation

In the production process, we always encounter some new problems, of course, problems will directly affect our work efficiency, in this process, there will be many uncontrollable factors, resulting in the quality of products can not be guaranteed, not only external factors are very important, but also the original mold equipment has a great impact. Parts will also deform during processing. If this happens, we need to stop working immediately and carry out correct treatment. What should we do to prevent this situation in the later stage?

1、 In order to reduce the influence of cutting force and cutting heat, the deformation caused by rough machining can be corrected in finish machining.

2、 To reduce the influence of clamping force, the following measures should be taken to reduce the influence of clamping force:

When using radial clamping, the clamping force should not be concentrated on a certain radial section of the workpiece, and the operator should make it distributed over a large area to reduce the clamping force on the unit area of the workpiece.
The position of clamping force should be selected at the part with strong rigidity to improve the deformation of thin-walled parts under the action of clamping force.
The direction of clamping force is changed from radial clamping to axial clamping.
It is suggested that before purchasing computer gong equipment, the manufacturer must have a detailed understanding and investigation. In order to reduce the clamping deformation, special claws are used to clamp the workpiece, and the convex edge is cut off at the end of processing.

Route determination of CNC specular

As we all know, CNC high gloss machine is a kind of automatic machine tool controlled by program. The control system can process the program with control code or other symbol instruction rules logically, and decode it from beginning to end by computer, so that CNC lathe can act and process parts, and the blank material can be processed into semi-shaped articles and molded parts by cutting tools all the time. So how to determine the route of CNC highlight machine? Let’s take a simple look:

The feed machining route of CNC high gloss machine refers to the path from the start of tool setting point (or CNC lathe’s unchanged origin) to returning to the point and ending the machining program, including the path of cutting and the non cutting path of tool cutting in and cutting out. The feed path of finish machining is basically carried out in sequence along the appearance of the parts. Therefore, the focus of confirming the feed path is to confirm the feed path of rough machining and empty stroke.

The above is the principle to determine the machining route of CNC high gloss machine. Due to its good rigidity, high manufacturing accuracy, accurate tool setting, and convenient dimensional compensation, it can process parts with high dimensional accuracy and complex contour shape.

CNC processing and installation environment requirements

We all know that many mechanical equipment in the installation of the environment are certain requirements, because the installation directly affects our later use, one step of the installation is not correct, or in other words, there are some environmental impact during the installation process, so the later work is also likely to be affected, so let’s learn about CNC plus What are the environmental requirements for installation?

Location requirements

It should be far away from the vibration source and direct sunlight. If there is a seismic source nearby, an earthquake proof trench should be set up.

Temperature and humidity

The optimal processing temperature of CNC machining center is below 30 ℃. If the ambient temperature and humidity are too high, the service life of the control system components may be reduced. If the ambient humidity is too high, it may lead to the short circuit and fault of the integrated circuit board.

Voltage and current control

There are many processing equipment in the workshop, which will cause excessive fluctuation of the power grid. We need to control the voltage and current within the allowable range of the machining center and keep it stable, otherwise, the work of the system may be affected

Control CNC machining center cutting spring cutter

In the process of processing, we will certainly encounter some unexpected accidents. If there are some accidents in the process of processing, there must be a certain degree of danger, so we must do some preventive measures to avoid the real failure and injury to people. Then we will learn how to control the spring knife in the cutting process of CNC machining center.

In the process of machining, the length of the tool should be shortened as far as possible to reduce the risk of tool bounce. The relationship between tool deformation and tool diameter is the fourth power. For the same length of tool, when the tool diameter is reduced by one time, the deformation will increase by 4 times. In the process of processing, if possible, select large-diameter cutting tools or use reinforced cutting tools to reduce the risk of knife snapping. (as shown in the figure on the right below: a uses the heat cable and taper neck knife, and B uses the tool with strong handle for processing)

The deformation of the tool is in direct proportion to the force exerted on the tool in the process of machining. Reducing the force on the tool can reduce the chance of snapping the tool. The following methods can be used to reduce the force on the tool in machining.

Reduced force analysis:

Cutting is a process of shear deformation. Each material has its own strength (σ). In order to separate the materials, the strength from outside must be greater than that of the material itself.