Matters needing attention when high-speed bottom die machine is used in fiber bottom die processing

High-speed bottom die machining fiber bottom die is mainly aimed at die-cutting bottom die substrates such as fiberboard and fiber composite board. The material itself has the characteristics of fiber texture, easy pilling, delamination, moisture absorption and deformation, and the impact caused by high-speed cutting of equipment. The processing process needs to be controlled from raw materials, clamping, tools, parameters, operation and finished product protection to ensure the accuracy and service life of the bottom die.

The entry of raw materials is the primary control link before processing. The fiber bottom die material is greatly influenced by temperature and humidity, so it needs to be fully kept at constant temperature and humidity before processing to avoid uneven moisture content in the plate and warping and shrinkage deformation after high-speed cutting. It is necessary to check whether there are bubbles, delamination and holes on the surface of the plate, whether the flatness and thickness tolerance of the plate are up to standard, and the fiber direction of the material should be marked in advance. When typesetting, the cutting path should be planned according to the fiber direction. Cutting along the fiber direction can reduce edge collapse and pilling, and cutting across the fiber is more prone to fiber tearing. The process allowance should be reserved in advance for the sharp corner position of the contour. At the same time, there should be no oil stain and dust on the surface of the plate to prevent slippage during processing and affect the positioning accuracy.

Fixation of workpiece directly determines the stability of high-speed machining. High-speed bottom die machine has high spindle speed and fast feed, and the fiber sheet is thin. Excessive clamping force is easy to collapse the sheet and cause local depression, while insufficient clamping force will cause sheet jitter, dimensional deviation and vibration. The vacuum adsorption workbench is preferred, and the suction cup should be checked for tightness, and the impurities in the groove of the table top should be cleaned to ensure that the board surface fits without hanging area; Large-area plates can be matched with auxiliary briquetting, and the briquetting position avoids the cutting trajectory. After the clamping is completed, it is necessary to retest the coordinates of the reference edge and the origin to confirm that the plates are not displaced. During the processing of multi-layered plates, the plates should be flat and jointed to prevent interlayer slip, and the number of stacked plates should not be too much, so as to avoid the cutting of the bottom plate is not in place or burrs.

Tool selection and maintenance is the key to control the pilling and delamination of fiber bottom die. Fiber material belongs to non-metallic composite material containing fiber. Ordinary high-speed steel cutter wears quickly, so diamond milling cutter or cemented carbide cutter is preferred, and the cutting edge of the cutter should be kept sharp. High-speed cutting with a blunt knife will pull the fiber, resulting in a large number of fuzz on the incision and delamination of the plate. According to the machining requirements, the tool specifications are selected, the large cutting edge tool is selected for rough machining to quickly remove the allowance, and the small diameter tool is selected for fine machining to deal with small holes and special-shaped corners. Check the tool jumping before machining, and clean the clamping handle to avoid scratching the board surface due to excessive jumping. Pay attention to the tool wear during machining. Once the burr of the incision suddenly increases and the machining noise becomes louder, stop the machine and change the tool in time to prevent the contour of the bottom die from being damaged.

The setting of cutting parameters needs to match the characteristics of high-speed equipment and the properties of fiber sheet. The spindle speed of high-speed bottom die machine is high, so the feed speed cannot be blindly increased. In the rough machining stage, the allowance is mainly removed, the cutting depth is appropriately increased, and the cutting depth is reduced in the finish machining, which reduces the feed and reduces the tearing of the fiber. Deceleration should be set at the corner to avoid the impact of high-speed turning and tearing the plate; The forward milling method is preferred, which can reduce the problems of fiber drawing and fuzzing, while the reverse milling is easy to lift the surface fiber and cause rough section. At the same time, the cutting mode should be set reasonably, and the inclined downward cutting or spiral cutting should be adopted as far as possible, and vertical direct cutting is prohibited. Vertical cutting has great impact, which can easily lead to cracking and delamination of the surface layer of the plate. A small amount of air cooling dust removal can be used in the processing, and a large amount of water cooling is not recommended. Fiberboard will expand and deform when it absorbs moisture, which will affect the final accuracy of the bottom die.

On-site safety and equipment monitoring during processing can not be ignored. Fiber cutting will produce a lot of fine fiber dust, and the dust will spread faster under high-speed machining. Therefore, it is necessary to start the dust removal system, keep the dust removal pipeline unobstructed, prevent dust from accumulating on moving parts such as guide rails, screw rods and spindles, and aggravate equipment wear, and at the same time do a good job in personnel protection. Closely observe the cutting state during machining. Once the plate shakes, abnormal noise and dust increase abnormally, immediately stop machining and investigate the reasons, and cannot continue to run forcibly. Do a good job of program verification, the first piece must be cut, check the size and incision quality, and batch processing can be carried out only after the first piece is qualified; Program origin and tool compensation value are rechecked before each processing to prevent tool collision accidents.

The blanking of finished products is as important as the later protection. When the finished fiber bottom die is taken out, handle it gently to avoid scratching the contour edge benchmark. Clean up the fiber crumbs on the board surface, and do not scrape the section forcibly to prevent the fiber from falling off. After processing, put it on a flat platform and let it stand, and then test it after stress is released. The bottom die that has passed the test should be packaged with moisture-proof, and the storage environment should be kept dry and ventilated to avoid deformation caused by moisture and water absorption, which will affect the subsequent die-cutting production. At the same time, make a good record of the finished product size, track the use of the bottom die on the customer die-cutting machine, and continuously optimize the processing parameters.

To sum up, the core difficulty of machining fiber bottom die with high-speed bottom die is to control the deformation of plate and the delamination of fiber. It is necessary to control the whole process from plate pretreatment, vacuum clamping, tool selection, cutting path and parameters, dust protection and finished product storage, to balance the high-speed machining efficiency and bottom die accuracy, reduce defective products and prolong the service life of fiber bottom die.