Non-standard parts to customize how to avoid parts deformation?

Non-standard parts to customize how to avoid parts deformation?

Non-standard parts to customize aluminum alloy is an important industrial raw material.

Because of its relatively small hardness and large thermal expansion coefficient, it is easy to deform in the mechanical processing of thin wall and thin plate parts.

In addition to improving the performance of the tool and the advance use of aging treatment to eliminate the internal stress of the material, from the perspective of the processing process, we can also take some means to reduce the processing deformation of the material as far as possible.

For aluminum alloy parts with large processing allowance, in order to create better heat dissipation conditions and reduce thermal deformation, we must try to avoid too concentrated heat, and the method that can be taken is symmetrical processing.

For example, there is a 90 mm thick aluminum alloy plate, which needs to be milled to 60 mm thick. If one side is turned over and the other side is milling immediately, because each side is processed once. After the size, the continuous processing allowance is large, will cause the problem of heat concentration, so that the milling good aluminum alloy plate plane can only reach 5 mm.

If the symmetrical processing method of both sides into the knife is used, each surface is processed at least two times until it reaches the size, which is conducive to heat dissipation, and the planarity can be controlled at 0.3 mm.

Layered multiple-processing method

When the non-standard parts to the customized aluminum alloy plate parts have multiple cavity to be processed, if the type of a cavity a cavity processing method is adopted, it is easy to make the cavity wall due to uneven force and deformation.

. The good solution is to adopt the layered multiple processing method, that is, processing all cavities at the same time, but not at one time, but at several layers, layer by layer to the required size.

In this way, the parts will be more uniform in force, and the chance of deformation is less.

Select the cutting amount appropriately

Choosing the appropriate cutting amount can effectively reduce the cutting force and cutting heat during the cutting process.

In the process of machining, the amount of cutting leads to the cutting force of a knife is too large, easy to cause the deformation of parts, and the rigidity of the machine tool spindle and the durability of the tool.

In the cutting amount of each element, the cutting force. The big one is the knife on the back.

According to reduce the back eating knife amount is conducive to the parts without deformation, but at the same time will reduce the processing efficiency.

CNC machining high-speed milling can solve this problem, only need to reduce the back at the same time, correspondingly increase the feed, and improve the speed of the machine, can reduce the cutting force, and processing efficiency.

Improve the cutting capability of the cutting tool

The material and geometric parameters of the tool have an important influence on the cutting force and the cutting heat. The correct choice of the tool is crucial to reduce the deformation of the parts processing.

Reasonable selection of the tool geometry parameters.

Front Angle: under the condition of maintaining the strength of the blade, the front Angle is appropriately selected larger, on the one hand, it can grind the sharp edge, and reduce the cutting deformation, make the chip discharge smooth, and then reduce the cutting force and cutting temperature.

Do not use a negative front corner cutting tool.

Rear corner: the size of the rear corner has a direct impact on the rear blade wear and processing surface quality.

Cutting thickness is an important condition for selecting the rear angle.

Rough milling, due to the large feed amount, heavy cutting load, large heat value, the required tool cooling condition is good, therefore, the rear Angle should be selected smaller.

When milling, the blade mouth is required to be sharp, reduce the friction between the rear blade surface and the processing surface, and reduce the elastic deformation. Therefore, therefore, the rear Angle should be selected larger.

Spiral Angle: in order to make the milling smooth and reduce the milling force, the spiral Angle should be selected as large as possible.

Main deflection Angle: appropriately reducing the main deflection Angle can improve the heat dissipation conditions, so that the average temperature of the processing area decreased.

Improve the tool structure.

Reduce the number of milling cutter teeth, increase the dust space.

Due to the large plasticity of aluminum alloy material, the cutting deformation in processing is larger, need a larger debris space, so the radius of the debris groove should be larger, the number of milling cutter teeth is less.

For example, mills below φ 20mm use two teeth; φ 30~ φ 60mm use three teeth to avoid the deformation of thin-wall aluminum alloy parts caused by chip blockage.

Fine grinding teeth: the roughness value of the cutting blade should be less than Ra=0.4um.

Before using the new knife, fine talite should be gently ground in front of and behind the knife teeth to eliminate the residual burrs and slight sawtooth lines during the blade grinding teeth.

In this way, not only can reduce the cut heat and the cutting deformation is relatively small.

Strictly control the wear standard of the tool: after the tool wear, the surface roughness value of the workpiece increases, the cutting temperature increases, and the workpiece deformation increases accordingly.

Therefore, in addition to the selection of good wear resistance tool materials, the tool wear standard should not be greater than 0.2mm, otherwise it is easy to produce debris tumor.

When cutting, the temperature of the workpiece should generally not exceed 100℃ to prevent deformation.

The knife order is exquisite

Non-standard parts to customize rough machining and non-standard parts to customize finishing should be used in different knife order.

Crude processing requirements to. Fast cutting speed, in the. The excess material on the surface of the blank is removed in a short time to form the geometric contour required for finishing.

Therefore emphasize the processing efficiency, the pursuit of material resection rate per unit time, reverse milling should be used.

And finishing to processing accuracy and surface quality requirements are higher, emphasize processing quality, should be used shun milling.

Due to the cutting thickness of the milling from. Gradually decrease to zero, will greatly reduce the processing hardening phenomenon, and the deformation of the parts also has a certain degree of inhibition.

Thin-wall parts secondary compression

When processing non-standard parts to customize aluminum alloy thin-wall parts, the pressure force when clamping is also an important reason for deformation, which is difficult to avoid even if the processing accuracy is improved.

In order to reduce the deformation of the workpiece due to clamping, it can be achieved in finishing processing. Before the rear size, loosen the pressed parts, release the pressing force, so that the parts are freely restored to the original state, and then slightly pressed again.

The action point of the secondary compaction. Fortunately, on the support surface, the clamping force should be used in the rigid direction of the workpiece, and the pressing force to the clamp of the workpiece does not loose, which has high requirements for the experience and feel of the operators.

The compression deformation of the parts processed in this way is smaller.

Drilling before milling method

In the non-standard parts to customize the parts with the cavity, if the milling cutter directly downward into the parts, it will cause the discharge of the milling cutter, resulting in the accumulation of a large amount of parts, and expansion deformation, and may even cause the knife collapse, broken knife and other accidents.

. A good method is to drill after milling, that is, first drill the hole with the size not less than the milling cutter, and then use the milling cutter into the hole to start milling, which can effectively solve the problems mentioned above.

high pressure casting