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CNC tool grinding machine diamond grinding wheel dressing method
Add_time:2018-09-18 The number of click:148

【Abstract】: The grinding method of the grinding wheel is an important factor affecting the grinding performance of the grinding wheel. The reasonable selection of the dressing method will directly affect the surface quality and grinding precision of the workpiece.
 The use of CNC tool grinding wheel diamond wheel directly affects the normal use of CNC tools. A small part can sometimes cause the whole project to fail. Therefore, we will introduce the automatic dressing and compensation method of CNC tool grinding machine diamond wheel today.

The development of automatic CNC grinding technology has put forward high requirements for its supporting equipment. As one of the supporting technologies, the online automatic grinding wheel dressing technology must meet the needs of modern CNC grinding technology, and it is developing in the direction of high precision, super stability and full automatic control. As an efficient grinding tool, diamond grinding wheels are widely used in the processing of hard materials such as cemented carbide, ceramics and CBN. The dressing and automatic compensation method of the diamond grinding wheel determines the performance of the fully automatic CNC grinding machine, which largely determines the performance and service life of the grinding wheel.

Diamond wheel dressing principle

The diamond grinding wheel dressing method is an important factor affecting the grinding performance of the grinding wheel. The reasonable selection of the dressing method will directly affect the surface quality and grinding precision of the workpiece. At present, the commonly used diamond wheel dressing methods are: online electrolytic dressing, EDM wheel dressing, cup wheel dressing, electro-mechanical compound dressing and laser trimming. Because the cup-shaped grinding wheel dressing method is simpler and easier to implement than other dressing methods, this paper uses the GC cup-shaped grinding wheel dressing technology to automatically trim the diamond grinding wheel.

The dressing of a superabrasive grinding wheel such as a diamond wheel is usually divided into two stages: shaping and sharpening. Shaping is a micro-cutting of the grinding wheel. The purpose is to remove the shape error and surface defects of the grinding wheel after initial installation to ensure the geometric accuracy of the grinding wheel. The sharpening is due to the passivation of the grinding wheel after working for a period of time. In order to make the cutting micro-blade protrude the bonding agent and have an appropriate height, a sufficient space for the chip is formed between the abrasive grains, and the number of effective abrasive grains per unit area is as large as possible.

Method for dressing bowl type diamond grinding wheel by GC cup grinding wheel

The actual geometrical relationship between the GC cup wheel and the bowl diamond wheel is shown in Figure 1. The bowl-shaped diamond grinding wheel and the GC cup-shaped grinding wheel are completely interlaced and rotated at a certain speed, and the rotational speed of the dressing wheel and the grinding wheel is 8:1. The dressing wheel is fixed, and the diamond grinding wheel is trimmed and fed in the axial direction, so that the GC cup grinding wheel and the bowl type diamond grinding wheel form mutual abrasive grinding. Through the grinding of the end faces of the two grinding wheels, the passivation abrasive grains of the diamond grinding wheel are removed to form a chip space, and the surface of the diamond grinding wheel is re-sharpened to achieve the purpose of dressing.

Grinding wheel dressing automatic control method

In the grinding process, the wear state of the grinding wheel is an important factor affecting the quality of the grinding. The CNC tool grinder can monitor the state of the grinding wheel in real time during the entire process of blade grinding. Depending on the size and material of the machine insert, the volume required for grinding and the grinding time will vary. Consider the various factors and set the interval for automatic trimming. By counting the number of grinding wheels for the grinding wheel, and comparing it to the trimming interval set by the system in real time. When the number of grinding times reaches the set number of dressing intervals, the trimming module is automatically called in the NC program to realize automatic dressing of the grinding wheel. In order to ensure the safe operation of the machine tool, the control method also adds real-time monitoring of the life of the grinding wheel and the life of the dressing wheel. As long as it is detected that this dressing may cause the grinding wheel or dressing wheel to reach the warning thickness, the machine will automatically send out an alarm signal and stop waiting for manual processing. If the grinding wheel and the dressing wheel do not reach the alarm thickness, the trimming proceeds smoothly. After the trimming is finished, the compensation value after the dressing of the grinding wheel is output through data processing.

Grinding wheel dressing compensation method

The consistency of the dimensions of the workpiece being machined depends to a large extent on the consistency of the state of the process system. After the grinding wheel is trimmed once, the thickness of the abrasive is reduced, and the end face of the grinding wheel changes to the specified calibration position, which causes the state of the entire process system to change, and the size of the workpiece to be processed also changes, and dimensional consistency cannot be guaranteed. Therefore, compensation for the dressing after the grinding wheel is particularly important.

The process of analyzing the dressing of the grinding wheel is the mutual grinding of the two grinding tools. Not only the thickness of the grinding wheel will be reduced, but also the thickness of the grinding wheel of the dressing wheel will be reduced, which is a comprehensive result. Therefore, the method of compensation for grinding wheel dressing was determined by using multiple tests.

Because the hardness and wear resistance of the diamond wheel is much larger than the GC cup dressing wheel. It is foreseeable that during a dressing process, the thickness of the abrasive reduced by the diamond wheel is much less than the thickness of the abrasive reduced by the dressing wheel. As shown in Fig. 4, the dressing wheel is fixed in position, and the dressing wheel advances in the feeding direction by a dressing amount. Due to mutual grinding, the thickness of the grinding wheel and the dressing wheel are simultaneously reduced. The relationship between them is: dressing amount = grinding wheel reduction amount of dressing wheel reduction. In order to ensure the dimensional consistency of the workpiece to be machined, the reduction of the grinding wheel after trimming should be compensated. The actual trimming test data shows that when the dressing amount is 0.03 mm, the grinding wheel thinning amount is 0.0015 mm, and the dressing wheel thinning amount is 0.0275 mm.

TAIZHOU MEIRI NEW ENERGY CO., LTD. is a manufacturer that specialized in developing and producing small specialpurpose tool grinders, precision machinery tools. Main products include: drill bit sharpener, end mill sharpener, screw tap sharpener, lathe tool grinder, saw blade sharpener, universal cutter grinder, universal tool grinder, chamfer, tapping machine, gear chamfering machine, universal head, rotary table, etc.

 

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