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How are the plastic molds tested?

date：2023/08/10

1. What is a test piece? A test piece refers to the testing and injection molding process that is carried out after the mold is produced and before mass production in the product development and manufacturing steps. Before the plastic mold test piece, we should pay attention to the following matters: 1. It is best to master the related materials of the abrasive tool to obtain the design drawing of the abrasive tool, analyze it in detail, and ask the abrasive tool technician to sign up for the test piece work.
2. Check the coordinated posture of the mechanical equipment on the table during the work to pay attention to the situation of scratches, missing parts and looseness. Is the movement of the mold to the skateboard correct? Is there any leakage of the waterway and trachea joints? If the distance is limited, it should be marked on the die. If the upper posture can be ensured before the mold is hung, it can prevent the problem found during the mold hang, and then the comprehensive man-hour extravagance and waste caused by the disassembly and assembly of the abrasive tool.

3. When it is clear that the posture of the abrasive tool is the best, you need to select the appropriate test piece to shoot out the machine, and pay attention to when selecting: (1) how much is the larger shot of the plastic machine; (2) the support rod Whether the inner distance is the lower grinding tool; (3) Whether the moving schedule of the larger theme activity template meets the regulations; (4) Are other special tools and spare parts for the test piece prepared in advance? After everything is confirmed that there is no problem, the next process is the hanging abrasive tool. When hanging the hook, you must pay attention to locking all the clamping templates and before the mold is released. . After the abrasive tool is installed, the posture of the mechanical equipment in the various parts of the abrasive tool, such as the double rocker, the thimble of the mold, the tooth withdrawal structure, and the limited power switch, are correct. And pay attention to whether the injection nozzle and the inlet are pointing. The next step is to pay attention to the clamping posture. At this time, the pressure of closing the mold should be reduced. In the manual and low-speed clamping postures, pay attention to seeing and listening whether there are any uncomfortable postures and buzzing. The whole process of lifting the abrasive tool is actually very simple. The area where care must be taken is mainly the difficulty of the school management center of the glue inlet and nozzle of the abrasive tool. Generally, the method of pregnancy test can be used to calibrate the management center.
4. Increase the temperature of the grinding tool: According to the characteristics of the commonly used raw materials of the finished product and the size of the grinding tool, a moderate mold temperature control device is used to increase the temperature of the grinding tool to the temperature required for manufacturing. After the mold temperature is raised, the posture of each part must be checked again. Since the stainless steel plate will be deformed due to heat, it will cause the state of the card mold, so you must pay attention to the drag of each part to prevent it from being pulled and shaken.
5. If the test program rules are not implemented in the processing plant, it is proposed to adjust only one standard at a time when adjusting the test piece standard, which is convenient to distinguish the harm of a single standard change on the finished product.
6. According to the different raw materials, make proper roasting of the selected raw rice.
7. Try to use the same raw materials as possible for future mass production.
8. Do not thoroughly prepare the test pieces one by one. If color requirements are required, lipstick test colors can be assigned together.
9. Difficulties such as thermal stress often endanger secondary production and processing. After the test piece is made and the finished product is stable, that is, after various secondary processing molds are closed at a slow speed, the working pressure of closing the mold should be adjusted and the posture should be adjusted several times. , Inquire whether there is uneven working pressure of mold clamping, etc., to prevent burrs and abrasive tool deformation caused by finished products. After the above procedures are checked, the mold closing rate and the working pressure of the mold closing are reduced, and the safety buckle and ejection stroke arrangements are set, and then all normal mold closing and mold closing rates are adjusted. If it involves a limited power switch with a larger stroke arrangement, the die-out stroke arrangement should be adjusted shorter, and the high-speed die-out posture is removed before the die-out larger stroke arrangement. This is because the high-speed posture stroke arrangement is longer than the low-speed gear among all the mold-out stroke arrangements during the mold loading period. In the plastic machine, the pedal-type ejector rod must also be adjusted to the effect after the rapid ejection posture to prevent the mold ejector plate from being deformed due to the support of the plate. Please check the following types before shooting the first mold: (1) Whether the feeding schedule is too long or insufficient; (2) Is the working pressure too high or too low; (3) Is the mold filling rate too high? Fast or very slow; (4) Is the production and processing cycle time too long or too short? In order to avoid short shots, cracks, deformation, burrs and even damage to the abrasives of the finished product. If the production and processing cycle time is too short, the thimble of the mold will penetrate the finished product or peel off the ring and pinch the finished product. Such conditions will cost you two or three hours to remove the finished product. If the production and processing cycle time is too long, the sinking position of the mold core will be broken due to the tightening of the plastic particles. Naturally, you are unlikely to anticipate all the difficulties that will arise in the process of the test piece, but taking sufficient consideration beforehand to take immediate measures will certainly help you prevent more serious and expensive damage. 2. How are the plastic molds tested? In order to prevent unnecessary time and confusion during mass production, we must really work hard to adjust and manipulate various production and processing standards, and find the best temperature and working pressure standards. , And formulate standard test procedure procedures, and can be used to create usual methods. 1. Inquire whether the plastic material in the barrel is appropriate and accurate, and whether it is baked according to requirements (if the test piece and the manufacturing use different raw materials, it is likely to get different results). 2. The removal of the material tube should pay attention to the actual effect and prevent the inferior solution plastic particles or miscellaneous materials from being injected into the mold. The inferior solution plastic particles and miscellaneous materials will block the abrasive tool. Check whether the temperature of the material tube and the temperature of the grinding tool are suitable for the production of raw materials. 3. Adjust the working pressure and the amount of shots to produce a finished product with a satisfactory appearance, but can not run off the burr, especially when some finished products of the mold cavity are not completely condensed, before adjusting various operating standards It should be pondered that a slight change in the filling rate will cause a significant change in filling. 4. Be careful until the standards of equipment and abrasives become stable, that is, small and medium-sized equipment will have to wait more than thirty minutes. You can use this time to inquire about the difficulties that the finished product will generate. 5. The time for the extruder screw to travel can not be shorter than the time for the gate plastic to congeal, otherwise the net weight of the finished product will be reduced and the characteristics of the finished product will be damaged. And when the grinding tool is heated, the extruder screw travel time also needs to be extended to facilitate tamping of the finished product. 6. Effective adjustment reduces the total production and processing cycle time. 7. Run the newly adjusted standard for at least 30 minutes to make it stable, and then continue to produce at least a dozen full-length products, mark the time and total number on their utensils, and place them according to the mold cavity, so that it is easy to detect the correct operation. The reliability and derivation to effectively control the dimensional tolerances. (Especially useful for multi-hole abrasive tools). 8. Accurately measure the continuous sample and record its key specifications (it should be measured when the sample is cooled to room temperature). 9. Compare the specifications of each product, and you should pay attention to: (1) whether the product specifications are stable; (2) whether some specifications have a development trend of improvement or reduction and show that the production and processing standards of information equipment are still changing , Such as poor temperature control or steam pressure operation; (3) Is the change in specifications within the scope of dimensional tolerances?
10. If the specifications of the finished product do not change very much and the standards of production and processing are all normal, you need to check whether the quality of the finished product of each mold cavity can be accepted, and its specifications can be within the allowable dimensional tolerances. Record the number of mold cavities whose continuous fluctuations are not fixed to the average value, so that it is easy to check whether the specifications of the grinding tools are appropriate.
. In the plastic mold test piece, the main parameter record obtained during the whole process of the test piece and the analysis data should be recorded as a necessary to modify the abrasive tools and manufacturing standards, and it is the reference basis for future mass production.
1. Make the production and processing run longer, to stabilize the melt temperature and gear oil temperature.
2. To adjust the equipment standard according to the size of all finished products is too large or too small, if the shrinkage rate is large and the finished product seems to be insufficient shot, you can also refer to it to improve the gate specifications. 3. If the specifications of the mold cavity are too large or too small, adjust it. If the specifications of the mold cavity and the gate are appropriate, then the equipment standard should be changed, such as the mold filling speed, the temperature of the grinding tool and the working pressure of each place, etc., and check Some mold cavities are slow to fill.
3. According to the mutual cooperation of the finished products of the mold cavities or the movement of the mold core, individual adjustments may be made, or the mold filling rate and the temperature of the grinding tool may be tried again to facilitate the improvement of its symmetry.
4. Check and modify the common faults of the shooter, such as poor gasoline pumps, fuel pumps, temperature controllers, etc., all cause changes in production and processing standards, even no sound abrasive tools can be poorly maintained. The equipment gives full play to its excellent working efficiency.
5. After introspecting all the recorded standard values, save a set of test samples to facilitate the review of whether the adjusted test samples have been improved.
6. Properly store all the records of the test samples during the whole process of the test piece, including various working pressures of the production and processing cycle time, the temperature of the melt and the grinding tool, the temperature of the material tube, the posture time of the shot, the screw of the extruder The input stage, etc., in short, should store all the data that will help create the same production and processing standards in the future, so as to obtain products that meet the product quality standards. At this stage, the temperature of the grinding tool is usually ignored when processing the test pieces in the factory. The temperature of the grinding tool is the most difficult to grasp in short-term test pieces and future mass production. The wrong mold temperature can jeopardize the specifications, brightness, shrinkage, Difficulties such as flow pattern and lack of material will be difficult if the mold temperature control board is not needed for future mass production.