How to deal with some problems encountered by lathes in injection mold processing

Author: MULAN -Plastic Molding Manufacturer

The vibration of the lathe during processing is accompanied by the phenomenon of vibrating and beating the knife, resulting in chatter lines on the surface of the workpiece, high rework rate and scrap rate. Where do we need to start investigating? Don't worry, the following injection mold processing manufacturers will introduce to you! 1. Workpieces and cutting tools 1. Workpieces (1) Cylindrical turning of slender shafts. Usually the distance between the cutting point and the clamping point, if the length-to-diameter ratio exceeds 3, it is easy to vibrate the knife, and you can consider changing the process; (2) Cylindrical turning of thin-walled parts; (3) Box-shaped parts (such as sheet metal welding Structural parts) turning; (4) superhard raw material cutting.

2. Tool factors (1) Turning with forming inserts; (2) The angle of view of the tool, especially the main declination angle, back angle, rake angle, etc.; (3) The sharpness of the blade; (4) The radius of the arc of the tool tip is It is not too large; (5) Whether the cutting parameters are suitable. First of all, remove the doubts about the tool, first check the stiffness of the turning tool itself, is it not clamped? Is it sticking out too long? Is the gasket uneven? Check whether the turning tool (boring tool) is worn? Is the tip rounded or the wiper edge too wide? Is the back angle of the turning tool too small? See if you are using a 90-degree knife or a 45-degree knife, and try it out. In addition, if the cutting (feed rate) is too small, it may also be an inducement to produce chatter marks, which can be slightly adjusted and increased.

You can adjust the speed, single-tool cutting depth, and feed rate to try to eliminate the resonance point. 2. Check the factors of the machine tool and the clamping position (1) Check whether the tip of your live top protrudes too long and whether the bearing is in good condition. There is a flat rolling bearing combination inside.

If you really doubt it, you can replace it with a dead top tip, and pay attention to the smoothness of the base hole; (2) Check the clamping condition of your tailstock top, whether the left and right sides, top and bottom sides are not concentric with the machine tool spindle under the clamping condition; ( 3) Tighten the large, medium and small carriages, especially the middle carriage; (4) If there are parts of the tailstock of the machine tool that you cannot check for the time being (points 1 and 2, you need some fitter foundation), you can try Grab the end and move the knife towards the tail. Reversing the car can eliminate the lack of power at the tail; (5) If there is still a problem in step 4, you need to check the main shaft. Of course, if you grab it three times, you should also check to see if the spiral groove is damaged. The four catches are manually adjusted automatically, so there is no need to check them.

3. Use other countermeasures to suppress the vibrating tool. If your main bearing bush is really tight in place, and the workpiece is not a thin-walled hollow part or the overhang is too long, there is no problem with chuck clamping. Use other countermeasures to suppress the vibration of the knife. Now there are some detailed and practical methods applied in the processing site: (1) reduce the work weight of the part that forms the vibration, the smaller the inertia, the better; (2) fix or clamp the vibration site, such as the base frame, Work retainer, etc.; (3) Improve the rigidity of the processing system, such as using a tool handle with a higher elastic coefficient or using a special shock resistance that is added to a dynamic shock absorber to absorb impact energy; (4) From the blade and the direction of rotation of the work Kung Fu; (5) Change the shape and timing of the tool, the smaller the radius of the tool nose, the better to reduce the cutting resistance.

The roll angle must be positive to make the cutting direction more straight. The back rake angle should be a positive value, and only chip removal can be relatively poor. Therefore, a grooved cutter can usually be used to make the inclination angle into a negative value, but still maintain a positive cutting effect.