Aspects of the disadvantages of injection molded parts

I. Description of disadvantages

The disadvantages of injection molded parts refer to the failure of the injection molded parts to meet the original design, use and other quality requirements of the injection molded parts during the injection molding process. The quality requirements such as use. The description of a defect may include a possible cause.

For example, under the molding, i.e. incomplete injection may be described as insufficient filling pressure in the mold or insufficient plastic to fill the mold. It is useful to try to describe it in the simplest terms without involving any possible causes. With this approach, we will not hold any preconceptions when looking for the cause of the shortcoming in the next step.

II. Finding the cause of the shortcomings

This can be a long process because he needs to consider the plastic. Injection molding machine. The process of the mold. The following guidelines are recommended.

A. Plastics: Check the grade or type, check for impurities and verify that the manufacturer's specifications are met. If this drawback is evident in several batches of plastic from the same manufacturer or the same plastic from another supplier, this indicates that there is no problem with the plastic. Observe the effect of the reused material, paying special attention to its different processing characteristics from the same new material.

B. Injection molding machine: Check all the functions of the injection molding machine and consider any possible effects on pressure. Temperature. Ratio and time factors. If the shortcomings appear intermittently, this usually suggests an error in the operation of the injection molding machine, such as temperature fluctuations caused by a bad thermocouple. If the defect occurs in the same location in a single-cavity mold, this suggests that the cause of the problem lies in the injection cylinder mechanism (e.g., reflux valve) or in the control adjustment of the injection molding machine.

C. Mold: Make sure that the mold is properly installed and at the correct temperature and that all parts are running smoothly. If the defect is always in the same cavity or cavities of a multi-cavity mold, then the defect is usually in the feed system (i.e. the runners or gates of these cavities).

D. Process: Check the pressure. Temperature and time are set according to the plastic supplier's recommendation. If the shortcomings disappear when the mold is used on another injection molding machine, the shortcomings are most likely due to the consistency of the processing conditions used with those produced on the original machine. If the defect disappears when another person operates the machine, the defect may be due to human error. The speed should be checked. The management of the injection operation and the dwell time of the safety door opening and closing should be checked.

III. Solutions to the shortcomings of injection molded parts

The appearance of shortcomings in injection molded parts undoubtedly brings hidden quality problems to injection molding production.

A. Determine the impact of the shortcoming: If the shortcoming makes the injection molded part unusable or unsellable, this shortcoming must be eliminated. If it is only a weak effect, it may not be necessary to eliminate it completely.

B. Determine where the responsibility lies: This may only be of academic research interest, but if shortcomings reappear, the operator. Plastics. Injection molding machine. Molds and processes all need to be reviewed.

C. Take action to avoid shortcomings: Failure to take appropriate action can result in poorly molded parts and the resulting devastating impact on the profitability of the project.

D. Take steps to prevent the recurrence of defects: Document all the conditions that were used to confirm the elimination of defects. Identify repairs or changes to the mold or injection molding machine and the type of plastic. The change in the quality of the grade of work. If recycled material is used, indicate the quality of the proportion used.

These steps to cope with shortcomings may seem redundant, but no method of finding shortcomings is perfect unless all methods are taken into account. Although the defective products can be recycled and used, it is not economical to manufacture them.

IV. Shortcomings of injection molded parts and remedies

There is a desire for a logical, systematic approach to shortcomings, and many actual injection molders have their own operational strategies. The most important thing in compiling these strategies is to ensure that the semantics of all terms are clear and understood by all who care. To clearly describe the shortcomings of an injection molded part, all possible causes should be examined. Their effects should also be accounted for, and when the causes are identified, the necessary steps should be taken to reduce and prevent their reoccurrence. There are six strategies.

1. name the disadvantage. Because there are different names for disadvantages, so when you decide to use that name, do not change it.

2. describe the drawback. When describing a drawback, you may include a possible cause. For example, "under-injection", i.e., incomplete injection, might be described as "insufficient filling pressure in the mold" or "insufficient plastic to fill the mold" Try to use the simplest terms without It is useful to try to describe it in the simplest terms without involving any possible causes. With this method, we will not grab any preconceptions when looking for the cause of the shortcoming in the next step. 3.

Find the cause of the weakness. This can be a long process because it needs to consider the plastic, the injection molding machine. The process of the mold. Here are the recommended guidelines to use.

A: Plastics: Check the grade or type, check for impurities, and verify that it meets the manufacturer's specifications. If the drawback is similar on several batches of plastic from the same manufacturer or the same plastic from another supplier, it means there is no problem with the plastic.

B. Injection molding machine: Check the function of all parts of the injection molding machine and consider anything that may affect the pressure. Temperature. If the defect occurs intermittently, this usually indicates an error in the operation of the injection molding machine, such as a temperature fluctuation caused by a bad temperature sensing line, or if the defect occurs in the same position in a single-cavity mold, this implies that the cause of the problem lies in the injection cylinder device or the control adjustment of the injection.

C. Mold: Determine if the mold is properly installed and at the correct temperature and that all parts are running smoothly. If the flaws disappear the flaws always appear in the same cavity or cavities of a multi-cavity mold, then the flaws usually appear in the feed system, (i.e. the runners or gates serving those cavities).

D. Process: Check that the pressure, temperature, and time are set according to the plastic supplier's recommendations. If the shortcomings disappear when the mold is used on another injection molding machine, the shortcomings are most likely due to problems with the consistency of the processing conditions used with those produced on the original machine. If the defect disappears when another person operates the machine, the defect may be due to human error. Check the speed, the management of the injection action, and the dwell time of the safety door opening and closing. 4.

4. Determine the effect of the defect. If the shortcoming makes the injection molded part unusable or unsellable, the shortcoming must be eliminated.

5. Determine where the responsibility lies. This may only be of academic research interest, but if the shortcoming reappears, the operator still has the raw material. Injection molding machine. Mold and process should be reviewed. 6.

6. take action to avoid the shortcomings. Failure to take appropriate action can result in poorly molded parts and the resulting impact on the profitability of the project.

In each example of injection molding shortcomings, the shortcomings of the injection molded part is usually caused by several factors: the operation of the injection molding machine, the function of the mold or the processing performance of the plastic, etc. The problem or shortcoming usually has more than one cause. Each of the following shortcomings is provided under the headings of Injection Molding Machine. Suggested remedies are provided under the headings of mold and plastic.