CNC machining experience sharing (Part 3)

CNC machining experience sharing (Part 3)

  1. Sharpening knife:

The shapes of computer gongs are different, and it is often necessary to grind all kinds of knives. When all kinds of forming knives are worn, they also need to be grinded. To achieve the following several percentages, a usable knife 1 can be grinded. The four corners of the tool should be the same height 2. Point a is higher than point D. the front (face) of tool 3 is higher than the back, that is, there is a certain back angle.

  1. Over cutting check:

Overcutting is a common problem in MasterCAM. Be careful. Overcutting may occur in the process of multi curved surface opening, smooth knife, cutting path trimming, shape and groove digging, even if the parameter setting and stereogram of chest are correct, some are software errors. The main inspection method is to simulate the cutter path once again, and check repeatedly in the top view and side view. The tool path without inspection is not allowed to be used. In the process of contour milling, if the position of the lower tool is not selected properly, it will be over cut, which can be avoided by changing the lower tool position.

  1. Milling direction:

Computer gongs are generally downmilling, unlike milling machine reverse milling, because the rigidity of computer gongs is better, it is not easy to let the cutter, the back clearance is small, milling shape or inner groove are left compensation. When processing symmetrical shapes, the tool path can not be mirrored, otherwise the processing effect will be bad on the side where the mirror passes. In order to communicate with the operator of the machine tool, the program paper should include 1) program name 2. Tool size and length 3. Tool path method 4. Machining allowance 5. Rough or smooth knife 6. Drawing file name 18. Graphic management Computer drawings should be properly classified and managed. It is better to create a catalog for a product and give a specific name for each part. For example, the name of the Copper drawing is A10, the name of the back die drawing can be a10c, the name of the front die drawing is a10cav, and the name of the loose Copper drawing is a10s1. 19. Format conversion between different softwares: communication with AutoCAD, the version above mastcam7 can read the DWG file directly, and the version lower than 7 can be converted to DXF format in AutoCAD. Other cam software such as cimtron, Pro / E, UG can be converted to IGS format.

  1. DNC usage:

After the completion of the program, after checking, no problem can be copied to the DNC computer for actual processing. There are two ways to copy the program: one is to copy from disk; the other is to transmit it through LAN. Then start DNC software, find the program to run, and press enter.

  1. Coordinate system:

There are three kinds, mechanical coordinate system, machining coordinate system and temporary coordinate system. In the mechanical coordinate system, the mechanical zero point is a reference point on the machine. After each power on, the zero point is determined after the zero point is returned to zero. The position of the mechanical zero point is determined by the machinery factory and should not be changed. The machining coordinate system is used for workpiece processing, which is the sub coordinate system of the mechanical coordinate system. Take a point in the mechanical coordinate system (generally the center point of the workpiece) as the coordinate origin, record the mechanical coordinate value of this point as the origin of the machining coordinate series, and then set the machining coordinate system. Temporary coordinate system: reset each point as the coordinate origin at any time. There are also three coordinate values corresponding to coordinate values: mechanical coordinate value, machining coordinate value and temporary coordinate value (also called relative coordinate value)

  1. Common filter values:

The commonly used filtration values are 0.001 ~ 0.02, and the filtration radius r = 0.1 ~ 0.5. The larger the rough cutting path, the smaller the smooth surface path, the larger the surface radius and the smaller the larger the surface radius. Filtering can effectively reduce the program capacity and make the tool feed smoother, but if it is too large, the machining accuracy will be affected.

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