Deep Cavity and Thin Wall CNC machining Process

Stainless steel CNC Machining

Deep-cavity thin-wall CNC machining refers to the use of CNC machine tools to process the workpiece with large depth and thin wall thickness. This machining process requires CNC machine tools with high precision, high stiffness and high stability to ensure the machining quality and accuracy.

Deep cavity and thin wall CNC machining is widely used in the manufacturing industry, especially in aerospace, automotive manufacturing, mold manufacturing and precision machining.

What is Deep Cavity Machining?

In general, the processing of parts with cavity depth greater than 100mm belongs to deep cavity processing.

This depth boundary is not a strict regulation, sometimes according to the actual situation and processing needs, can also be the cavity depth less than 100mm parts called deep cavity processing. But generally speaking, parts cavity depth is greater than 100mm processing need to consider more factors, such as the stability of the workpiece, cutting force, cutting temperature, etc.,

the processing equipment and tool requirements are also higher. Therefore, this type of processing usually requires the use of professional deep cavity processing equipment and technology, and detailed processing planning and quality control to ensure processing quality and efficiency.

What is Thin Wall Machining?

Thin Wall Machining

In general, the parts whose wall thickness is less than 2mm are called thin-wall CNC machining.

Machining parts with wall thickness less than 2mm requires special processing technology and equipment to ensure machining accuracy and surface quality. Because in such a processing process, the deformation and vibration of materials will be more prominent, the need to consider factors including cutting parameters, tool selection, processing technology, etc., the need for higher technical level and experience.

Machining Process Of Deep Cavity And Thin Wall Parts

The machining process of deep-cavity thin-wall parts generally includes:

  1. Part Design,
  2. Formulation of machining process plan,
  3. Preparation materials,
  4. CNC programming,
  5. CNC machining,
  6. Quality Inspection,
  7. Surface treatment.

1. Part Design

Part design is the first step of deep cavity thin-wall parts machining, and also the key of the whole machining process. Design quality directly affects the function and use effect of parts, but also affects the subsequent processing technology and processing difficulty. Here are some key design elements:

  • Shape And Structure:

The shape and structure of the parts should meet the requirements of use and processing technology restrictions, avoid the appearance of too many corners, internal and external wall complex structure design.

  • Size And Tolerance:

The design of parts size and tolerance should be based on the requirements of use and processing technology, formulate a reasonable tolerance strategy, and the size and tolerance should conform to the requirements of the design drawings.

  • Wall Thickness:

The wall thickness of thin-walled parts is a key parameter, which needs to be reasonably designed according to the physical properties of materials and processing difficulty to ensure the stability and strength of parts.

  • Internal Structure Design:

The internal structure design of deep cavity parts needs to take into account the feasibility of the processing technology, and try to avoid too complicated structure design.

2. Formulate Processing Technology Plan

The following aspects need to be considered in the formulation of the processing scheme of deep-cavity thin-wall parts:

  • Develop CNC Machining Scheme:

According to the shape, size, material and processing requirements of the parts, develop the corresponding CNC machining scheme, including tool selection, processing route, processing parameters, etc.

  • Choose The Right Processing Equipment:

According to the size and shape of the parts, choose the right processing equipment, such as CNC milling machine, CNC lathe, electric discharge machining, etc.

  • Developing Cutting Fluid Scheme:

Cutting fluid is very important for the machining of deep cavity thin-wall parts, which can effectively reduce the machining temperature, extend the tool life and improve the machining accuracy. Develop suitable cutting fluid plan, including cutting fluid type, concentration, flow and other parameters.

  • Determine The Processing Sequence:

For complex deep-cavity thin-wall parts, it is necessary to determine a reasonable processing sequence, as far as possible to reduce the number of processing and processing difficulty, improve processing efficiency and accuracy.

  • Design Fixture:

The processing of deep-cavity thin-wall parts needs to use fixture fixation, so it is necessary to design a suitable fixture to ensure that the clamping force is uniform and stable, to avoid the deformation or displacement of parts in the process of processing.

  • Determine The Detection Method:

The machining accuracy and surface quality of deep-cavity thin-wall parts have an important impact on the function and use effect of parts, so it is necessary to develop the corresponding detection method, including three coordinate measurement, projector detection, handheld measurement, etc.

3. Select Materials

316 Stainless Steel

Deep cavity thin-wall parts usually need to have high strength, hardness and corrosion resistance, so it is necessary to select appropriate metal materials, such as aluminum alloy, stainless steel, titanium alloy, according to the actual demand for selection.

Before processing, check the material, including its appearance, size, hardness, and chemical composition, to ensure that the material meets the requirements and avoid processing failures due to material quality problems.

According to the part size and requirements, the material is cut into the corresponding size and shape, ready for the subsequent processing. The cuts can be made using traditional hand cutting methods or CNC cutting equipment.

The surface of the material must be clean to ensure that the cutting fluid can effectively cool the tool and material during machining and avoid contamination by impurities.

4. CNC Programming

CNC programming is one of the important processes in machining deep cavity thin-wall parts. Numerical control programming is to convert the geometric figures, technological requirements and machining parameters in the parts design drawings into numerical control programs to guide the automatic machining of CNC machine tools.

Numerical control programming needs to be based on the geometric shape of the parts and processing requirements, combined with the CNC machine tool processing ability and tool selection, write numerical control machining program. Generally speaking, CNC programming consists of the following steps:

  • Set Coordinate System:

According to the geometric shape of the parts and processing requirements, determine the coordinate system of CNC machine tools. After the coordinate system is determined, the processing position of the parts can be determined according to the coordinate system.

  • Drawing Geometry:

Drawing the geometric shapes of parts into CNC programming software, including contour lines, internal contours, holes and other geometric shapes.

  • Select The Machining Tool:

According to the machining requirements and geometric shape of the parts, select the appropriate machining tool, including end milling cutter, ball cutter, drilling cutter, boring cutter, etc.

  • Programming:

The geometric figures and machining parameters into numerical control procedures, including tool path, feed speed, speed, etc.

  • Write Machining Instructions:

Write machining instructions of CNC machine tools to guide machine tools to carry out machining, including machining starting point, tool switching, cutting depth, etc.

  • Optimize The Machining Process:

Conduct machining simulation, check the correctness and feasibility of the program, and optimize to improve the machining efficiency and quality.

5. CNC Machining

what is cnc milling?

Numerical control machining is an automatic machining method, which uses numerical control machine tools to precision machining parts. The principle of numerical control machining is to convert the geometric shape and machining parameters in the parts design drawings into numerical control program through numerical control programming software, and then control the numerical control machine tool through the numerical control system for machining. Numerical control machining has the advantages of high efficiency, high precision, stable processing quality and suitable for complex parts. It has become an important production mode of modern manufacturing industry.

6. Quality Inspection:

Quality inspection is an indispensable step in the process of CNC machining, its purpose is to ensure that the quality of machining parts meet the design requirements and customer needs. In the machining process of deep-cavity thin-wall parts, quality inspection is very important, because these parts have higher processing difficulty and precision requirements. Quality inspection mainly includes the following aspects:

  • First part inspection:

Before batch processing, the first part inspection is needed, that is, the first part of the processing is comprehensively tested to ensure that its quality meets the requirements. The first part inspection includes appearance inspection, size inspection, process performance inspection, etc.

  • Online inspection:

In the process of CNC machining, the machining parts can be monitored and tested in real time through the online inspection equipment to ensure that the error control in the machining process is within the allowed range.

  • Final inspection:

After batch processing, it is necessary to conduct a comprehensive inspection of the final parts to ensure the quality of the parts processed in batch is stable.

  • Sampling inspection:

Sampling inspection of batch processed parts to ensure the quality of batch parts meet the requirements.

  • Special inspection:

Special inspection of some key parts or parts processed by special process to ensure that their quality meets the requirements.

7. Surface Finish

CNC Machining Surface Finish Polishing

After the machining of deep cavity thin-wall parts, surface treatment may be needed to meet the different requirements of customers on the surface of parts. Common surface treatments include the following:

  • Grinding:

Abrasive belt, grinding wheel and other grinding tools are used to grind the surface of parts to eliminate surface roughness and roughness and improve surface finish and smoothness.

The surface of parts is polished using a multi-pass polishing process to further improve the surface finish and gloss, so that it has a better appearance and touch.

  • Sand Blasting:

The use of high-speed sand blasting on the surface of parts, in order to eliminate surface oxidation skin, burr and other defects, improve the surface roughness and adhesion, but also increase the appearance of the surface.

The deposition of metal materials on the surface of parts to increase the surface hardness, wear resistance and corrosion resistance, but also to improve the surface finish and appearance.

  • Spraying:

Spraying process is used to spray the surface of parts to increase the corrosion resistance, corrosion resistance and wear resistance of the surface, but also to improve the color and finish of the surface.

Precautions For Processing Deep Cavity Thin Wall Parts

The processing of deep-cavity thin-wall parts needs to pay attention to the following points:

Material Selection

Because the deep cavity thin-wall parts usually need to bear greater load and stress, so the need to choose high strength, high hardness of metal materials, such as stainless steel, titanium alloy, aluminum alloy, etc.

Tool Selection

Tool Selection

For the special shape and size of deep-cavity thin-wall parts, it is necessary to select suitable tools for machining, such as long rod milling cutter, straight shank drill, etc., to ensure the stability and accuracy in the machining process.

Cutting Parameter

For different materials and parts shape, need to reasonably select cutting speed, feed speed and cutting depth cutting parameters, in order to ensure the stability and efficiency of the machining process, and avoid tool wear, workpiece deformation and other problems.

Coolant

Because the machining process of deep-cavity thin-wall parts is prone to high temperature, it is necessary to use sufficient coolant for cooling and lubrication to ensure the stability of the machining process and tool life.

Clamping Mode

Because the machining process of deep-cavity thin-wall parts is prone to high temperature, it is necessary to use sufficient coolant for cooling and lubrication to ensure the stability of the machining process and tool life.

Processing Sequence

The processing sequence of deep-cavity thin-wall parts needs to be determined according to the specific shape and processing requirements of the parts, so as to avoid the problem of workpiece deformation or crack caused by improper processing sequence.

Author

Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.

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