Adjustment of injection molding machine is an essential skill for injection molding operators. Although many adjustment techniques are based on theory, they rely on experience as indispensable. Here are three ways to adjust the high-speed injection molding machine:
1. Mold transparency method
When we adjust the machine, we often sigh like this: If the mold is transparent, it will be fine! In this way, you can see the entire filling process of the melt, and see how and when the defects occurred. When we design a certain glue injection process, whether the glue injection process is actually completed according to the envisaged requirements, whether the starting point is set correctly, etc., we hope to be able to see a series of questions.
We only need to increase the injection time every second, one beer for each additional second, and then arrange the unmatched beer pieces in order, so that the filling of the melt can be clearly seen Process until the cavity is filled. If you want to take a closer look at a key position, only 0.1 second per beer will increase at this key position, so you can see clearly.
It’s even easier if you just want to see if the starting point is not accurate. You only need to adjust the pressure and speed of the next level to 0, and you can see where the starting point is, instead of using a second-by-second increase method to slowly observe.
It should be reminded here that since the melt will have a little inertial expansion after the injection is stopped, the actual shape of the beer part when the injection is stopped will be slightly different from the moment when the injection is stopped. The actual starting point should be earlier than the beer that you see.
2. Positioning injection method
The so-called "positioned shot glue" method is a tuning method that evolved from our commonly used fast shot glue to lower-level slow shot glue. This method is to adjust the slow speed and pressure of the next stage to zero, so that the rapid injection of the previous stage will stop immediately when it reaches a set starting position, and the pressure stored in the cavity is naturally released. For the final filling of the cavity and holding pressure. Usually the starting point is set at the point where it just fills the cavity, and then adjusts to move forward and backward according to the actual situation.
In the commonly used "fast-turn and slow-shot glue method" adjustment technique, the three levels of slow speed, fast speed, and starting point are all related to each other and affect each other, so those with inexperience are not easy to hold.
What are the advantages of the "positioned injection" method?
1. "Positioning the glue" method because the pressure and speed of the latter stage are cancelled, and two influencing factors are missing. Therefore, only the pressure and speed of the previous stage need to be adjusted and the starting point is moved forward and backward appropriately, and the adjustment becomes It is easier and can be set more accurately, and it is easier to hold and hold for beginners.
2. In production, when we encounter some raw materials and parts that cannot be produced at a slower speed, such as large parts, thin-walled parts, large PC parts, etc., once they start slow injection, injection molding parts The material will be uneven or there will be clip lines or vibration lines, so it must be shot to the end quickly. The "positioned shot glue" method is a good choice. Therefore, the injection molded parts will not cause problems such as cracking, topping, and sticking due to excessive injection of glue. On the contrary, in order to prevent problems such as criticizing and disapproving, we can use this tuning technique to help solve the problem.
3. In fact, this technique can solve many problems if used well. When there is a shrinkage problem in injection molded parts, as long as the front pressure is appropriately increased and the starting point is slightly moved forward, the general shrinkage problem can be solved. Unless the shrinkage problem is quite serious, there will be no problems such as criticism and whitening.
What are the limitations of the "positioned injection" method?
Of course, it is not a panacea, and it cannot completely replace the tuning technique of "fast-turn and slow-shot glue". For example, when air is trapped, it is difficult to solve the problem by using the "positioned injection" method, but it is much easier to use the "fast turn and slow injection method".
3. Slow first and then fast shot glue method
Slow first and then fast injection, that is, first-stage slow injection, when it reaches a set position, second-stage fast injection, the starting point is usually set at the beginning of injection into the cavity At the early stage of filling. According to different problems, sometimes it is necessary to transfer a small part of the glue (about 10-15MM) to the second stage, and some need to switch to the second stage when the glue is a little bit (about 3MM), and sometimes It must be transferred to the second stage before the glue is added.
With the first-level slow-spraying glue, the melted glue can be filled smoothly from the beginning, which is beneficial to prevent air trapping, gas lines and explosion-proof shooting, spiral or folding (snake-shaped) glue injection. The second-level rapid injection is beneficial to overcome the resistance to ensure filling, reduce the temperature drop of the melt, and prevent the dull color and material shortage of injection molded parts.