The machining center integrates oil, gas, electricity, and numerical control, and can realize one-time clamping of various complex parts such as discs, plates, shells, cams, molds, etc., and can complete drilling, milling, boring, expanding, reaming, Rigid tapping and other processes are processed, so it is an ideal equipment for high-precision machining. This article will share the use of machining centers from the following aspects:
How does the machining center set the tool?
1. Return to zero (return to machine origin)
Before tool setting, be sure to perform the operation of returning to zero (returning to the origin of the machine tool) in order to clear the coordinate data of the last operation. Note that the X, Y, and Z axes all need to return to zero.
2. Spindle rotates forward
In "MDI" mode, the spindle is rotated forward by inputting the command code, and maintains a moderate rotation speed. Then change to "handwheel" mode, and move the machine tool by changing the adjustment rate.
3. X-direction tool setting
Gently touch the tool on the right side of the workpiece to clear the relative coordinates of the machine tool; lift the tool along the Z direction, then move the tool to the left side of the workpiece, down to the same height as before, move the tool and the workpiece Touch lightly, lift the tool, write down the X value of the relative coordinate of the machine tool, move the tool to half of the relative coordinate X, write down the X value of the absolute coordinate of the machine tool, and press (INPUT) to enter the coordinate system.
4.Y-direction tool setting
Gently touch the tool in front of the workpiece to clear the relative coordinates of the machine tool; lift the tool along the Z direction, then move the tool to the back of the workpiece, down to the same height as before, move the tool and the workpiece Touch lightly, lift the tool, write down the Y value of the relative coordinate of the machine tool, move the tool to half of the relative coordinate Y, write down the Y value of the absolute coordinate of the machine tool, and press (INPUT) to enter the coordinate system.
5. Z-direction tool setting
Move the tool to the surface of the workpiece that needs to face the zero point of the Z direction, slowly move the tool to lightly contact the upper surface of the workpiece, record the Z value in the coordinate system of the machine tool at this time, and press (INPUT) to input in the coordinate system.
6. Spindle stop
First stop the spindle, move the spindle to a suitable position, call up the processing program, and prepare for formal processing.
How does the machining center produce and process easily deformed parts?
For parts with light weight, poor rigidity and weak strength, they are easily deformed by force and heat during processing, and the high scrap rate of processing leads to a significant increase in cost. For such parts, we must first understand the causes of deformation:
Force deformation:
Such parts have thin walls, and under the action of the clamping force, it is easy to have different thicknesses in the machining and cutting process, and the elasticity is poor, and the shape of the parts is difficult to recover by itself.
Thermal deformation:
The workpiece is light and thin, and the radial force during the cutting process will cause the workpiece to be deformed by heat, thus making the size of the workpiece inaccurate.
Vibration deformation:
Under the action of radial cutting force, parts are prone to vibration and deformation, which affect the dimensional accuracy, shape, position accuracy and surface roughness of the workpiece.
Processing method of easily deformed parts:
The easily deformable parts represented by thin-walled parts can adopt the form of high-speed machining with small feed rate and large cutting speed to reduce the cutting force on the workpiece during processing, and at the same time make most of the cutting heat fly away from the chips of the workpiece at high speed. Take away, thereby reducing the temperature of the workpiece and reducing the thermal deformation of the workpiece.
Why should machining center tools be passivated?
CNC tools are not as fast as possible, so why passivate it? In fact, tool passivation is not what everyone understands literally, but a way to improve the service life of the tool. Improve tool quality through processes such as leveling, polishing, and deburring. This is actually a normal process after the tool is finely ground and before coating.
▲Tool passivation comparison
The tool will be sharpened by a grinding wheel before the finished product, but the sharpening process will cause different degrees of microscopic gaps. When the machining center performs high-speed cutting, the micro-notch will be easily expanded, which will accelerate the wear and damage of the tool. Modern cutting technology has strict requirements on the stability and precision of the tool, so the CNC tool must be passivated before coating to ensure the firmness and service life of the coating. The benefits of tool passivation are:
1. Resist physical tool wear
During the cutting process, the surface of the tool will be gradually worn away by the workpiece, and the cutting edge is also prone to plastic deformation under high temperature and high pressure during the cutting process. Passivation of the tool can help improve the rigidity of the tool and prevent the tool from losing cutting performance prematurely.
2. Maintain the finish of the workpiece
Burrs on the cutting edge of the tool will cause the tool to wear and the surface of the machined workpiece will become rough. After passivation treatment, the cutting edge of the tool will become very smooth, the chipping phenomenon will be reduced accordingly, and the surface finish of the workpiece will also be improved.
3. Convenient groove chip removal
Polishing the groove of the tool can improve the surface quality and chip evacuation performance. The smoother the groove surface, the better the chip evacuation, and the more consistent cutting can be achieved. After the CNC tool of the machining center is passivated and polished, many small holes will be left on the surface. These small holes can absorb more cutting fluid during processing, which greatly reduces the heat generated during cutting and greatly improves the cutting efficiency. speed.
How does the machining center reduce the surface roughness of the workpiece?
The rough surface of parts is one of the common problems of CNC machining centers, which directly reflects the processing quality. How to control the surface roughness of parts processing, we must first analyze the causes of surface roughness, mainly including: tool marks caused by milling; thermal deformation or plastic deformation caused by cutting separation; tool and machined surface friction between.
When selecting the surface roughness of the workpiece, it should not only meet the functional requirements of the surface of the part, but also consider the economic rationality. On the premise of satisfying the cutting performance, a larger reference value of surface roughness should be selected as much as possible to reduce the production cost. As the executor of the cutting center, the tool should pay attention to daily maintenance and timely grinding to avoid the unqualified surface roughness caused by the dull tool.
What should I do after the machining center is finished?
Generally speaking, the machining process rules of traditional machine tools in machining centers are roughly the same. The main difference is that machining centers perform continuous automatic machining to complete all cutting processes through one clamping. Therefore, machining centers need to carry out some " Aftermath work".
1. Carry out cleaning treatment. After the machining center completes the cutting task, it is necessary to remove chips and wipe the machine in time, and use the machine tool and the environment to keep it clean.
2. For the inspection and replacement of accessories, first of all, pay attention to check the oil wiping plate on the guide rail, and replace it in time if it is worn. Check the status of the lubricating oil and coolant. If turbidity occurs, it should be replaced in time, and the water level below the scale should be added.
3. To standardize the shutdown procedure, the power supply and the main power supply on the operation panel of the machine tool should be turned off in turn. In the absence of special circumstances and special requirements, the principle of returning to zero first, manual, jog, and automatic should be followed. The machining center should also run at low speed, medium speed, and then high speed. The low-speed and medium-speed running time shall not be less than 2-3 minutes before there is no abnormal situation before starting to work.
4. Standard operation, can not beat, correct or correct the workpiece on the chuck or the top, and the next operation must be confirmed after the workpiece and the tool are clamped. The safety and safety protection devices on the machine must not be dismantled and moved arbitrarily. The most efficient processing is actually safe processing. As an efficient processing equipment, the operation of the machining center when it is shut down must be reasonably standardized, which is not only the maintenance of the current completed process, but also the preparation for the next start.
Post time: Sep-19-2022