21 Basic Common Sense Of CNC Engraving Machining (1)

CNC engraving machine is good at fine machining of small tools, with the ability of milling, grinding, drilling and high-speed tapping. It is widely used in 3C industry, mold industry, medical industry and other fields.

This article focuses on 21 basic knowledge about CNC engraving.

1. What is the main difference between CNC engraving and CNC milling?

Both CNC engraving and CNC milling use the milling principle.

The main difference lies in the diameter of the tool used. Among them, the commonly used tool diameter for CNC milling is 6-40 mm, while the tool diameter for CNC engraving is 0.2-3 mm.

2. Does CNC milling can only do rough machining, and CNC engraving can only do fine machining?

Let us first learn the concept of the process. The rough machining process requires a large amount of machining, but the finishing machining amount is small, so some people habitually regard rough machining as “heavy cutting” and finishing as “light cutting”. In fact, rough machining, semi-finish machining, and finishing are process concepts, which represent different processing stages. Therefore, the accurate answer to this question is that CNC milling can do heavy cutting or light cutting, while CNC engraving can only do light cutting.

3. Can CNC engraving be used for rough machining of steel materials?

To judge whether CNC engraving can process a certain material, it mainly depends on how big a tool can be used. The tool used in CNC engraving determines its maximum cutting capacity. If the mold shape allows the use of tools with a diameter of more than 6 mm, it is strongly recommended to use CNC milling first, and then use the engraving method to remove the remaining material.

4. Can the CNC machining center add a speed-increasing head to complete the engraving process?

Can not finish it. This kind of product has appeared at the exhibition, but the engraving process cannot be completed. The main reason is that the design of CNC machining center considers its own range of tools, and the overall structure is not suitable for engraving processing. The main reason for this wrong idea is that they mistakenly regarded the high-speed electric spindle as the only feature of the engraving machine.

5. CNC engraving can use tools with a small diameter. Can it replace EDM?

Not a substitute. Although engraving has narrowed the range of tool diameters for milling, small molds that could only be processed by EDM can now be implemented by engraving. However, the length/diameter ratio of the engraving tool is generally around 5:1. When using small-diameter tools, only shallow cavities can be machined, and there is almost no cutting force in the EDM process. As long as the electrode can be produced, the cavity can be machined.

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6. What are the main factors affecting engraving machining?

Machining is a relatively complex process, and there are many factors that affect it, mainly including the following points: machine tool characteristics, cutting tools, control systems, material characteristics, processing technology, auxiliary fixtures and surrounding environment.

7. What are the requirements for the control system of CNC engraving machining?

CNC engraving processing is milling processing first, so the control system must have the ability to control milling processing. For the processing of small tools, the feedforward function must be provided at the same time to reduce the speed of the path in advance to reduce the breaking frequency of the small tools. At the same time, it is necessary to increase the cutting speed in a relatively smooth path section to improve the efficiency of engraving processing.

8. Which characteristics of the material affect processing?

The main factors affecting the engraving performance of the material are the material category, hardness and toughness. The material category includes metallic materials and non-metallic materials. In general, the greater the hardness, the worse the processability, the greater the viscosity, the worse the processability. The more impurities, the worse the processability, the greater the hardness of the particles inside the material, and the worse the processability. A general standard is: the higher the carbon content, the worse the workability, the higher the alloy content, the worse the workability, the higher the content of non-metal elements, the better the workability (but the non-metal content in general materials is strictly controlled of).

9. Which materials are suitable for engraving machining?

Non-metallic materials suitable for carving include organic glass, resin, wood, etc., and non-metallic materials not suitable for carving include natural marble and glass. Metal materials suitable for engraving include copper, aluminum, and mild steel with a hardness less than HRC40. Metal materials not suitable for engraving include quenched steel.

10. What impact does the tool itself have on processing, and how?

The tool factors that affect engraving processing include tool material, geometric parameters, and grinding technology. The tool material used in engraving is cemented carbide material, which is a powder alloy. The main performance index that determines the material performance is the average diameter of the powder. The smaller the diameter, the more wear-resistant the tool, and the higher the durability of the tool. The sharpness of the tool mainly affects the cutting force. The sharper the tool, the smaller the cutting force, the smoother the processing, the higher the surface quality, but the lower the tool durability. Therefore, different sharpness should be selected when processing different materials. When processing relatively soft and sticky materials, the cutting tool needs to be sharper. When the processing material is harder, the sharpness should be reduced to improve the durability of the cutting tool. But it should not be too blunt, otherwise the cutting force will be too large and affect the processing. The key factor in the grinding of the tool is the mesh number of the fine grinding wheel.

A high-mesh grinding wheel can grind a more delicate cutting edge, which can effectively improve the durability of the tool. A high-mesh grinding wheel can grind a smoother flank surface and improve the cutting surface quality.

11. What is the tool life formula?

Tool life is mainly the tool life in the processing of steel materials. The empirical formula is: (T is the tool life, CT is the life parameter, VC is the cutting linear speed, f is the amount of tool attack per revolution, and P is the tool depth). Among them, the cutting linear speed is the biggest influence on tool life. In addition, tool radial runout, tool grinding quality, tool material and coating, and coolant will also affect tool durability.

12. During the processing, how to protect the engraving machine equipment?

1) Protect the tool setting instrument from excessive oil erosion.

2) Pay attention to the control of flying debris. Flying debris is very harmful to the machine tool. Flying into the electric control cabinet will cause a short circuit. Flying into the guide rail will reduce the life of the lead screw and the guide rail. Therefore, the machine tool must be The main part is sealed well.

3) When moving the lamp, do not pull the lamp cap, it is easy to damage the lamp cap.

4) During the machining process, do not observe near the cutting area to avoid flying chips to injure your eyes. When the spindle motor is rotating, no operation is allowed on the work surface.

5) When opening and closing the door of the machine tool, do not open and close it violently. During the finishing process, the shock and vibration during the door opening process will cause the machined surface to have knife marks.

6) The spindle speed must be set, and then start processing. Otherwise, because the spindle starts to rotate slowly, it will start processing without reaching the desired speed, causing the motor to suffocate.

7) It is prohibited to place any tools or workpieces on the beam of the machine tool.

8) It is strictly forbidden to place magnetic tools such as magnetic suction cups and dial indicator holders on the electric control cabinet, otherwise the display will be damaged.

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