1. Edge wear and burr measurement
It is customary to determine the burr size of the punched part by hand and to determine the sharpening time, which is too large an error. Of course, the degree of edge wear and edge dullness can only be determined by detecting the height and thickness of the burr of the punched piece, the uniformity of burr distribution, the size and shape accuracy of the punched piece and the quality of the punched surface, etc., so as to grasp the wear of the edge, the degree of dullness of the edge and to determine the timing of sharpening. The burr height of general punched parts can be measured by micrometer. In order to improve the measurement accuracy, each time to measure the last continuous punching more than three punches, and each piece of at least 3-5 points, take the average value. For complex shape and small size precision punches of thin materials, tool microscope and optical projector can be used for precision measurement.
2.Measurement of dimension and form accuracy of punched parts After many times of sharpening, the dimensions of concave molds will change. In particular, most of the punching dies used for punching medium-thick plates and thicker plates with a material thickness of more than 3-6mm are designed to push and unload the workpieces or waste materials smoothly from the convex die by the hole of the concave die, and adopt a conical concave die hole with a small top and a large bottom, so as to prevent the workpieces or waste materials from being gathered and clogged in the concave die. Since the edge wall of the die is tilted outward, an increment in the horizontal dimension is inevitable after sharpening the upper surface. In order not to make the size increment too large and exceed the permissible value due to repeated sharpening, and make the punched piece unqualified, therefore, before sharpening, the calculation should be made with reference to the given value, and the size of the punched piece should be measured after sharpening until the size of the punched piece is qualified. The feed distance deviation increases due to misalignment of the positioning device or wear and rotation of the stopper pin. For continuous punching and cutting parts, it often results in large error of internal and external coaxiality of punches, uneven indexing cuts and other problems, so special attention should be paid to the repair of the test mold. Measurement of test die punches should be carried out after the press has been in normal operation for a period of time and a certain number of punches have been punched. Measurement of punches, should first observe the quality of the punching surface to determine the uniformity of the gap; and then test the height of the burr and the degree of uniformity; and finally scribe the line to detect the dimensions and shape accuracy.
3. Gap measurement accurately determine the gap between the new system and overhaul or repair after various types of die is to test the mold, mold quality is one of the main means of repair, but also mold clampers and stamping adjustment of the basic skills of workers. With rubber cement indentation and fill the mold cavity, is in the absence of practical and accurate gap measuring instrument, more economical, accurate and very reliable gap determination method. With a uniform thickness and greater than twice the thickness of the punched material, but not more than 5mm of rubber cement, by hand, gently close the mold and achieve the design of the closed mold state, and then gently open the mold to remove the rubber cement, observe and measure the indentation left on the rubber cement on the upper and lower molds, you can get the accurate clearance value. For blanking die, indentation on the upper mold can be controlled in just pressed into the rubber clay 0.8-1.5mm position; for the majority of forming die should be in the closed state of the imprint; but stretching, flanging and other molds, but also to detect the concave die mouth radius and uniformity, so the imprinting of the convex die into the concave die 2-3 times the thickness of the material is suitable for the stamped part.
4. Installation and debugging of punching die Installation and adjustment of punching die must be particularly careful. Because the die, especially the large and medium-sized die, is not only expensive, but also heavy and difficult to move, the safety of the person should always be put in the first place. Infinite device of the die, especially no guide mechanism of the die, in the upper and lower die should be added between a cushion board. After the press table is cleaned up, place the die to be tested in the clamping state in a suitable position on the press table. Has been selected according to the process documents and die design requirements of the press slider stroke, in the mold before moving on the table has been adjusted to the lower dead center position and adjusted to a position greater than the mold closing height of 10-15mm, by adjusting the slider linkage, move the mold to ensure that the die shank aligned with the die shank holes, and to achieve the appropriate height of the die loading. General blanking die, first fix the lower die (not tighten) and then fix the upper die (tighten), the pressure plate T-bolt should be tightened using the appropriate torque wrench (lower die), to ensure that the same bolts have the same and ideal preload clamping force, can effectively prevent the manual tightening of the threads due to the physical strength, gender, feel the error caused by the preload is too large or too small, the same threads of the preload force is not the same, which causes the upper and lower die misalignment, clearance changes, the press process, the upper and lower molds, and the gap change, the die height. It can effectively prevent the occurrence of faults such as wrong shift of mold, change of gap and nibbling of edge during the stamping process due to the error of physical strength, gender and hand feeling.
Before the die test, fully lubricate the die, and with normal production material, start the die in the empty stroke 3-5 times to confirm that the die operates normally before the test punch. Adjust and control the depth of the convex die into the concave die, check and verify the performance and operational flexibility of the die guiding, feeding, pushing and unloading, side pressure and elasticity of the institutions and devices, and then make appropriate adjustments to make it reach the best technical state. For large, medium and small-sized punching molds, respectively, test punch 3, 5, 10 pieces of initial inspection for production stoppage, after passing the test punch 10, 15, 30 pieces for re-inspection. After scribing test, punching surface and burr inspection, all dimensions and shape accuracy are in line with the blueprint requirements before delivery to production.
5. Prefabrication and reserve of standard parts and components for the standard parts and components of the die should be focused on prefabrication, and leave a certain amount of reserves, so that they can be used at any time in the process of manufacturing and repairing the die. Especially the main working parts, including: various specifications of the round convex die, side edge, waste cutter, and various specifications of the template, mold handle, mold frame, side pressure device, the beginning of the blocking device, should be in accordance with the full range of specifications to reserve 3-5 sets or more; commonly used sizes and specifications, and should be stocked more.
Stamping die visual monitoring can effectively detect whether the material belt of continuous stamping die is transported in place, whether blocking and stacking occur, etc., effectively reducing the pressure die, protecting the stamping die, reducing costs and increasing efficiency, and improving the automation level of the factory; and at the same time, it can monitor the appearance defects of the stamped parts in a timely manner.