Mold Burst Analysis
Mold bursts during the injection molding process are not uncommon. There are various reasons that can lead to such failures. Some of these reasons can be associated with the design of the mold, while others can be due to improper operation of the injection molding machine. In order to determine the cause of the burst, an analysis of the mold must be conducted.
The first thing to look for when analyzing a mold for burst is the presence of stress concentrations. This can be determined by reviewing the areas of the mold that are potentially higher stressed. These are usually found around the areas of high thermal gradients, pressurization, and injection pressures. It is important to note that these points can be either positive or negative. If they are negative, they can cause the material in the mold to become brittle during the injection process.
Another common cause of mold failure is worn out tooling. When the tooling is worn out it can cause the mold to become distorted and thus cause stress concentrations. This can be easily spotted when examining the mold design. The tooling that is used to create the mold must be of high quality in order to ensure proper injection and cooling of the material.
Mold bursts can also be caused by improper injection pressure. If the pressure is too high, it can cause the material in the mold to break or deform. This is usually seen when the material is not able to flow freely through the mold due to resistance. Additionally, improper dwell times in the mold can also lead to burst due to over pressurization. This means that too much pressure is applied to the material in the mold resulting in a burst.
Finally, improper maintenance of the injection molding machine can also lead to burst. Regular maintenance must be conducted to ensure that the equipment is functioning properly. This includes checking for leaks around the mold, checking for excessive flash formation, and making sure that the pressure relief valves are working properly. If any of these are not in tip-top condition, it can lead to the mold bursting.
When analyzing a mold for burst, it is important to look at all of the possible causes. From there, the solution involves making sure that everything is in good condition and that the mold itself is properly designed. By taking the time to do a thorough analysis, it can help to eliminate future mold burst issues.
