Insights and Experiences in Injection Molding of Automotive Parts+ View more
Insights and Experiences in Injection Molding of Automotive Parts
+ View more
Date：2024-09-04 10:53
The crucial part that injection molding plays in producing automotive parts cannot be overstated. I present my thoughts and insights on this process—from my perspective as a professional who has encountered several pitfalls along the way—that include what not to do, what to watch for, and how to complete the process more successfully than I did in the past.
The materials used for automotive parts must meet very stringent standards. Because they serve different functions, various parts need materials with different properties. For instance, exterior parts require materials with very high gloss and scratch resistance; when you consider that auto parts make up a big percentage of all the plastic parts in the world, those requirements alone signal the need for some pretty extraordinary materials. Structural parts require materials with very high strength and impact resistance. Fluidity, shrinkage rate, heat resistance, and chemical resistance are critical; part P1-related factors must also be taken into consideration. My company got in the habit of working closely with suppliers to ensure that they deliver materials of stable quality.
Injection molding hinges on the mold. The mold is the key. It is the key to making the good parts that our customers demand. And it is essential that the build of the mold be precise to hold the close tolerances required to ensure that the parts are made with the needed shape, form, and dimensional accuracy.
Once the good design for the mold has been achieved, the next step is to make the mold. And it is the act of making the mold that we will consider next. In making the mold, we must also ensure that the build process for the mold is good and that the materials used in the making of the mold are the right materials at nearly the right prices.
The injection molding process has several key parameters that require meticulous adjustment to yield a quality part. These include temperature, pressure, and the speed and time of the injection. Temperature, pressure, and time are the trio of molding parameters that most directly affect the softening, flowing, and solidifying of the material. The mold temperature affects the quality of the part in terms of dimensional stability and surface appearance. The pressures involved in the process must not only be high enough to fill the mold but also must not be so high that they endanger the part's integrity during the filling and solidifying phases. The time required for these processes must also be carefully calibrated. If the flowing material cools before it completely fills the mold, the part will not be of good quality.
During the injection molding process, mixing materials with dissimilar properties can yield unstable parts and even result in significant poor quality problems. Since different materials mix easily during the production process, it is crucial to keep them separate in order to avoid mixing.
With regular use, the mold will slowly wear down. If it is not sustained properly, this could potentially lead to several issues, including a drop in the part's dimensional accuracy and a reduction in the surface quality. To keep a mold performing well over its life, it is necessary to maintain the mold regularly. The actual maintenance is fairly straightforward and consists of keeping the mold clean, making sure the moving parts are lubricated and functional, and checking the mold for wear.
The injection molding process parameters must be adjusted according to the specific part being produced. Improper adjustments can lead to defects in the part. For instance, if the pressure is set too high, the part may have flash. If the speed is too fast, the material may decompose. Therefore, when the process parameters are adjusted, it is important to be cautious and to make the adjustments in a stepwise fashion while closely monitoring the quality of the part.
From my past experiences in the injection molding of automotive parts, I've made some mistakes and learned valuable lessons from them. For example, when I was trying to cut costs, I selected a less expensive material instead of the higher quality one we had been using. When we switched to the new, more economical material, we found it had very poor flow properties and wouldn't fill the mold properly. We got almost no good parts. I had to switch back to the first material (which performs much better) and adjust the process to work with that instead. Wasted time, wasted money.
The scratches and deformations on the molded part indicate that I did not fully account for the demolding method during the design of the mold. Consequently, I had to rework the mold and implement a mechanism for safely extracting the part from the mold.
When changing the process parameters to quickly remedy defects in parts, I was adjusting them too quickly and, thus, improperly. This reaction to the situation created even more serious defects and didn't solve the original problem. Of course, I had to go back and redo the work and spend more time and energy in the end.
The materials used for automotive parts must meet very stringent standards. Because they serve different functions, various parts need materials with different properties. For instance, exterior parts require materials with very high gloss and scratch resistance; when you consider that auto parts make up a big percentage of all the plastic parts in the world, those requirements alone signal the need for some pretty extraordinary materials. Structural parts require materials with very high strength and impact resistance. Fluidity, shrinkage rate, heat resistance, and chemical resistance are critical; part P1-related factors must also be taken into consideration. My company got in the habit of working closely with suppliers to ensure that they deliver materials of stable quality.
Injection molding hinges on the mold. The mold is the key. It is the key to making the good parts that our customers demand. And it is essential that the build of the mold be precise to hold the close tolerances required to ensure that the parts are made with the needed shape, form, and dimensional accuracy.
Once the good design for the mold has been achieved, the next step is to make the mold. And it is the act of making the mold that we will consider next. In making the mold, we must also ensure that the build process for the mold is good and that the materials used in the making of the mold are the right materials at nearly the right prices.
The injection molding process has several key parameters that require meticulous adjustment to yield a quality part. These include temperature, pressure, and the speed and time of the injection. Temperature, pressure, and time are the trio of molding parameters that most directly affect the softening, flowing, and solidifying of the material. The mold temperature affects the quality of the part in terms of dimensional stability and surface appearance. The pressures involved in the process must not only be high enough to fill the mold but also must not be so high that they endanger the part's integrity during the filling and solidifying phases. The time required for these processes must also be carefully calibrated. If the flowing material cools before it completely fills the mold, the part will not be of good quality.
During the injection molding process, mixing materials with dissimilar properties can yield unstable parts and even result in significant poor quality problems. Since different materials mix easily during the production process, it is crucial to keep them separate in order to avoid mixing.
With regular use, the mold will slowly wear down. If it is not sustained properly, this could potentially lead to several issues, including a drop in the part's dimensional accuracy and a reduction in the surface quality. To keep a mold performing well over its life, it is necessary to maintain the mold regularly. The actual maintenance is fairly straightforward and consists of keeping the mold clean, making sure the moving parts are lubricated and functional, and checking the mold for wear.
The injection molding process parameters must be adjusted according to the specific part being produced. Improper adjustments can lead to defects in the part. For instance, if the pressure is set too high, the part may have flash. If the speed is too fast, the material may decompose. Therefore, when the process parameters are adjusted, it is important to be cautious and to make the adjustments in a stepwise fashion while closely monitoring the quality of the part.
From my past experiences in the injection molding of automotive parts, I've made some mistakes and learned valuable lessons from them. For example, when I was trying to cut costs, I selected a less expensive material instead of the higher quality one we had been using. When we switched to the new, more economical material, we found it had very poor flow properties and wouldn't fill the mold properly. We got almost no good parts. I had to switch back to the first material (which performs much better) and adjust the process to work with that instead. Wasted time, wasted money.
The scratches and deformations on the molded part indicate that I did not fully account for the demolding method during the design of the mold. Consequently, I had to rework the mold and implement a mechanism for safely extracting the part from the mold.
When changing the process parameters to quickly remedy defects in parts, I was adjusting them too quickly and, thus, improperly. This reaction to the situation created even more serious defects and didn't solve the original problem. Of course, I had to go back and redo the work and spend more time and energy in the end.
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