Monthly Archive October 29, 2021

Method for processing nylon material by CNC

In the field of machining, different processing processes are selected for different material processing. Now the processing method of lower plastic nylon material is discussed. Nylon material belongs to plastic. When machining a hole less than 30mm in diameter, due to the narrow space in the hole and difficult heat dissipation, it is necessary to reduce the lathe speed to less than 300 rpm and cool it with cutting fluid; Slow and uniform drilling and timely chip removal; When the drill bit is about to penetrate through the hole, it needs to be more careful to reduce the drilling speed. The cutting fluid or cooling water must be sprayed evenly to the orifice position.

Secondly, when machining holes larger than 30mm in diameter with nylon materials, first sharpen the drill bit to facilitate processing and avoid damage to the workpiece; Reduce the lathe speed to less than 180 rpm. For holes larger than 55mm, the lathe speed can be reduced to about 60 rpm; Drill in slowly and at a uniform speed, remove chips in time and spray sufficient cutting fluid; When the bit is out of the hole, be careful of the withdrawal speed. When the lathe processes small diameter holes, the speed shall be less than 60 rpm; When drilling at a constant speed and low speed, the operator must stabilize the tailstock handle to prevent the drill bit from being quickly brought into the hole by the lathe, resulting in product cracking; The cutting fluid is sprayed evenly.

For nylon material excircle processing, it is best to use white steel tools instead of alloy tools. The tools should be kept sharp; The lathe speed shall not be less than 200 rpm; Proper feed speed can improve machining accuracy and surface finish.

The above is a brief discussion on the methods of CNC processing plastic nylon materials. Thank you for your attention.


Causes of rust in chrome plating of 45# steel

Why does chrome plating on 45# steel rust? In fact, 45# steel chrome plating will not rust. If there is rust, there must be a reason. Let’s have a look

There are several reasons for the rust of chrome plating of spare parts during the processing of mechanical parts,

  1. The part is not thrown to the position during chrome plating, and the chrome plating chemical solution cannot hold the part surface, so it will rust after use for a period of time;
  2. The mechanical parts are not placed in the liquid medicine for enough time, so that the chromium plating layer on the surface is thin, and the surface will rust if it is scratched during the assembly of mechanical parts;
  3. When the surface is chrome plated, the temperature of the liquid medicine is not enough, so that the machined parts can not meet the treatment requirements, and it will be easy to rust later! The inquirer listened to us and understood why 45# steel rusted after chrome plating. This is also caused by incorrect chromium plating surface treatment and addition process.

The above is 45# why the chrome plating of steel rusts. Thanks for sharing!


CNC machining of small holes in stainless steel materials

Compared with ordinary materials, the processing technology of stainless steel materials is more complex. How to process the small holes of stainless steel parts? Here are some skills on how to process the small holes of stainless steel parts?

In the field of machining, first of all, the design of process route and the selection of machining tools: according to the actual situation of small holes of stainless steel parts to be machined, the following process route can be formulated: rough inner shape – semi fine inner shape – fine inner shape – fine inner hole annular groove – end groove. The selection of cutting tools should be based on the characteristics of stainless steel and comprehensive consideration from all aspects. It includes the following points:

  1. In order to avoid the phenomenon of workpiece falling off, it is necessary to select the right-hand tool opposite to the thread of the thread mould.
  2. Try to choose the shape of the tool and the shape of the cutting groove (not smooth) with the smallest cutting force, so as to reduce the impact on the rigidity of the part.
  3. The arc of the tip should be moderate. If the arc is too large, it will produce chattering lines; If the arc is too small, the tool tip is easy to be damaged, which affects the service life of the tool.
  4. In the selection of cutter bar, the form of internal cooling should be selected, so that the parts will be fully cooled in the processing process, and the chip removal direction should be controlled accordingly.

Small hole machining control of stainless steel parts: due to the structure of mechanical parts, the positioning mode of thread mould can only be used for clamping during inner cavity turning. For the special requirements of workpiece machining, if the center of gravity is irregular, it will be easy to be unbalanced in the clamping system. At the same time, there are high requirements for dimensional accuracy, coaxiality and verticality. If there is a little error in the processing process, it may have a serious impact on the practical performance of the parts.

Therefore, for the machining of small holes in stainless steel parts, there should be strict requirements for the selection of tools, cutting parameters and the setting of process route. These factors will affect whether the part is qualified after machining. The machining accuracy of machining equipment itself is also very important!

The above is how to process stainless steel holes of precision machined parts. Thank you for your attention!


How to prevent aluminum alloy processing deformation

In the field of mechanical parts processing industry, aluminum alloy parts processing is the most common metal material. In the processing of aluminum alloy parts, such parts are generally processed by aluminum alloy plate as a whole. Such parts have large metal removal and low rigidity. In the processing process, the material deformation will be caused by residual stress, clamping force and cutting movement.

Residual stress: during the formation of metal processing materials, the arrangement of metal crystals is not neat in the ideal state. The size and shape of crystals are different. There is original residual stress, which is slowly released over time and produces certain deformation. In addition, in the process of machining precision mechanical parts, the plastic deformation of metal cutting and the friction heat between the tool and the workpiece make the temperature difference between the machined surface and inner layer larger, produce greater thermal stress and form thermal stress plastic deformation.

The deformation produced in the cutting process of aluminum alloy materials is not caused by a single reason, but often the structure of the combined action of several reasons, and this combined action is not invariable in the machining process. With the continuous change of machining, it is difficult to judge which reason has the greatest impact on the deformation. We can only start from the cause of deformation, Adopt corresponding process methods to minimize machining deformation.

Clamping force: as the wall of aluminum alloy thin-walled cavity mechanical parts is relatively thin, whether clamping with Bench Vise or chuck will produce transverse or radial clamping force, which will inevitably produce clamping deformation. The degree of clamping deformation is related to the clamping force. If the clamping force is large, it will form unrecoverable plastic deformation.

If it is small, elastic deformation will be formed. The elastic deformation will recover after the part is unloaded, but the cutting is carried out when the elastic deformation does not recover. The recovery of single elastic deformation will bring new deformation to the processed part.

Cutting motion: the cutting process is the process of interaction between the tool and the workpiece, which enables the tool to remove part of the material from the workpiece. Cutting motion causes the phenomena of extrusion, tension and fracture between the crystal particles of the material. These phenomena will cause the displacement between the atoms of the crystal and form unrecoverable plastic deformation.

The above is how to control the deformation of aluminum alloy processing in mechanical parts processing. Thank you for sharing!