The best use of the hottest plastic flow simulatio

2022-10-18
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The best use of plastic flow simulation software

plastic flow analysis software is one of the most powerful tools developed to improve the quality of injection molded parts, and successful examples abound

since the commercialization of plastic flow simulation software in 1975, molders have been considering its best use, and many people have been doubting its practicality or accuracy. Those who have doubts about plastic flow simulation find that there is no good correspondence between the computer model and the actual molding results. This may be due to the wrong application of the software or unrealistic high expectations for the accuracy of the software

some molders believe in the accuracy of the software but doubt its practicality. The common reasons that restrict molders are that they do not have enough human and financial resources to use simulation software, or they are unable to conduct rigorous mold analysis in mold manufacturing procedures. Their attitude is: "we have skilled engineers and molding workers. We know what we are doing, and why do we spend money on software?"

correct analysis

as a mold analysis consultant, our answer is that successful examples of simulation software application are everywhere - the mold maker completely eliminates the hot drop pattern on the automobile dashboard mold, saving users $7500; Injection molding business it can provide accurate molding cycle time; Original equipment manufacturers can quickly bring products to market without repeated tests. However, in order to make efficient use of mold analysis, users should avoid several easy mistakes

the following three points are the basis of successful analysis:

● a set of clear goals. Clear goals can help determine which analysis software to use

● an experienced analyst who fully understands the meaning of the model and the limitations of the software

● good communication among all members of the project, including product designers, mold designers, molders, material suppliers and plastic flow analysts

get good information

users often complain that mold analysis does not provide all the information required for the analysis engineer. The correct analysis should be based on a set of proposed processing conditions, not just the design of a mold or module. Understanding the processing habits of molders helps analysts analyze within a specific range of parameters. For example, if the analyst uses one set of processing temperatures and the molder uses another set of processing temperatures that he is more familiar with, the molding results may not match the analysis results

the user should inform the analyst of all the details about the module, mold and processing process. Information that is often missed includes the flow of refrigerant in the mold, the location of the gate, and the typical processing temperature for molding a particular resin. Cooling information is usually a weakness, because mold designers usually consider mold cooling in the final stage of mold development. In addition, if it is not clearly stated that the runner shaft torsion durability tester is an instrument used in the product to detect the mechanical properties such as the service life, torsion, compression resistance, bending resistance of the shaft, and other details, it may lead to the wrong estimation of analysts. If the user decides to "modify" the gate in the future, he/she may not realize that the moldability prediction of the analyst may be mostly invalid

not only that, the user should confirm that the mold maker actually manufactures the mold according to the suggestions of the plastic flow analyst. Usually, mold makers will also carry out plastic flow analysis at the request of users, but they ignore the analysis results of analysts. Similarly, after the processed mold is installed in the molding machine, the pouring speed, processing temperature and cooling conditions for predictive moldability analysis must also be used, otherwise no one should be surprised that the processed mold is different from the expected one

important raw material data

wrong raw material data is the main source of wrong analysis results. A detailed list of resins that have been properly characterized has been developed for plastic flow analysis. Even though most of the analysis items are completed with these standard resin data, if the analyst replaces the data of the resin to be molded with the data of a "similar" resin, the user may also be deceived. New resins or customized materials should be tested in detail before analysis

sometimes users do not realize that the raw material data required for plastic flow calculation cannot be found in the standard data table, and these data can only be obtained from special tests. For example, melt flow index (MFI) cannot explain plastic flow behavior under the high shear rate of actual molding

realistic expectations

users need to know what plastic flow analysis can and cannot provide. It seems that it is generally believed that Professor edwardkosior, general manager of nextek, a plastic recycling consulting company and the project leading group, said that because the analysis was carried out on a computer, all the results were correct. Another view is that if the analysis result is not what users expect, then the analysis is completely wrong

users must realize that this is only simulation. Estimates and simple assumptions made by software make it impossible to be 100% correct. However, if all the actual processing conditions, mold design details and material properties are quite consistent with the input values of computer analysis, we can expect to get very accurate results. Even if the analysis result is not 100% perfect, one of the most powerful applications of simulation software is to observe the trend when the result changes from one state to another

the hot runner balance is completed on the mold of two junction box modules. For such a complex simulation model, the use of "fast estimation" software will lead to the imbalance of plastic flow in the two cavities

using the right tools

another reason for the confusion or wrong use of plastic flow analysis is the emergence of a large number of different tool software, each of which is developed for different purposes. The wrong choice of simulation software type may lead to disappointing analysis results, production delays, mold remanufacture and overall cost increase

the most common question answered by simulation software is: can you pour modules? Where is the weld? Where is the gate? What is the size of the gate? How much capacity of the molding machine is suitable? Is the cooling design adequate? How long is the molding cycle? How much shrinkage and warpage will occur when the pressure is higher

however, not every software can answer all these questions, or all of them can answer with the same accuracy. Some plastic flow simulation software aims to make the fastest estimation with the least data, while others require longer time and more detailed input values, but produce more accurate information

the early simulation software is only suitable for "thin shell" modules such as chassis and dial, and cannot complete the practical simulation of thick modules. There are optimization software for various types of modules

economic rationality evaluation

when you confirm that the simulation software is technically feasible and is of great help to the development of molds, then the next step should be to understand whether the whole process is saved compared with the cost of purchasing the software or inviting others to analyze. The exact cost saved may vary greatly depending on the mold, but the following factors should be considered

how much is the cost of removing a mold from the production line and reprocessing it? What is the cost of not reaching the expected cycle time, producing excessive waste, or delaying delivery due to any of the above reasons? All these can help us give a fair judgment to the simulation analysis

plastic flow analysis can save a lot of trials in the development of complex modules such as automotive instrument panels, including the inspection of medical implant devices, but good communication must be carried out between module designers, mold designers, molders, material suppliers, mold makers and plastic flow analysts

the hot runner balance is completed on the mold of two junction box modules. For such a complex simulation model, the use of "fast estimation" software will lead to the imbalance of plastic flow in the two cavities. (end)

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