Plastic Injection Molding Factory – The Design Guide

Apr 28, 2021

How to Deal With the Designs of Plastic Injection Molding Factory

Injection molding is a manufacturing process that is used by the plastic injection molding factory. The manufacturers use this process for the mass-production of plastic parts that are completely identical. Not only this, but the plastic parts that are produced are of good tolerance as well. The process involves melting polymer granules and then injecting the liquid into a mold.

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The plastic injection molding factory manufactures a lot of products such as car parts, kitchen appliances, and electronic enclosures. But, several factors might affect the quality of the final design of the product. Want to know more about it? Keep reading then.

What is the Process of Plastic Injection Molding?

Plastic injection molding is the process of engineering plastic molds. That’s because plastic has resilient qualities. It allows the easy absorption of heat. Plastic injection molding is not only used in engineering applications but consumer products as well.

It is capable of producing identical plastic products that have high volumes. Moreover, the cost incurred by the plastic injection molding factory is extremely low as well. The molding machines are extremely easy to maintain and produce identical batches that quite impossible to differentiate.

How Do Injection Molding Machines Work?

Primarily, the injection molding machine is constructed with three main parts. These parts are known as the injection unit, the mold, and the clamping unit. The clamping unit is the most important part of the entire plastic injection molding process.

The main purpose of the injection unit in an injection molding machine is to melt the raw plastic and direct it into the mold. To carry out its assigned work, it consists of the reciprocating screw, hopper, and barrel.

The next step is to manufacture the mold. The mold is just like the negative part of the photograph. The texture of the mold is transferred to the injection molded part of the molding machine.

You will notice the clamping and the ejection system at the farthest side of the injection molding. The clamping system of the machine serves two main purposes. It not only keeps the parts of the mold shut tightly but also plays an important role in pushing the part out of the mold once the molding is complete.

What are the Applications of Plastic Injection Molding?

The resistance to heat and other chemicals makes plastic injection molding extremely popular. Due to its popularity, plastic injection molding is used in a lot of industries. Some common applications are mentioned below.

  • Electronic Appliances
  • Home Appliances
  • Automotive Parts
  • Construction Appliances
  • Engineering Equipment

What is the Reason behind the Popularity of Plastic Injection Molding?

Plastic injection molding is a common manufacturing process among plastic injection molding factories. That’s because of the benefits that this manufacturing process offers. Let’s take a look at some of its amazing advantages below.

  • Recyclable
  • Easier to glue
  • High tensile strength
  • Low cost
  • Strong impact resistance
  • Suitable for extreme temperature
  • Scratch resistance
  • Shock absorbance
  • Easier to color
  • Heat resistance

Some Common Designing Defects Incurred By a Plastic Injection Molding Injection Factory

Sometimes, a defect may occur in the design of the final product of the plastic molding. The plastic injection molding factory incurs these defects due to several reasons. Let’s check out some common designing defects below.

1.     Warping

When a certain part of the plastic product cools down faster than the other parts, it starts shrinking. The shrinking of that specific part can result in permanent bending of the object. That’s due to the internal stress that the product faces. This is what warping is called. The parts of the plastic product that have thick walls than other parts are more prone to warping.

2.     Sink Marks

When the inside of any part of the plastic product solidifies quicker than its surface, a small sink mark may appear in that specific part. This is why it is known as a sink mark. The parts of the plastic product that have a higher risk of sinking are the parts that have poorly designed ribs or have thick walls.

3.     Drag Marks

Another common defect in the design of a plastic product manufactured by a plastic injection molding factory is known as drag marks. It occurs due to the shrinking of the plastic. That’s because when the plastic sinks, it applies pressure on the mold.

As a result, the walls of those specific parts will slide during the ejection process. Not only this, but the walls will also scrape against the mold. This may result in drag marks. The parts that are more prone to drag marks are the parts that have vertical walls.

4.     Knit Lines

When two flows of a plastic product meet, you may notice it developing hair-like discolorations. These hair-like discolorations are extremely small. That’s called knit lines. The parts of the product that are more prone to knit lines are the ones that have holes in them. Knit lines not only ruin the aesthetics of the product, but it makes the plastic product weaker as well.

5.     Short Shots

Short shots may occur in plastic products that have extremely thin walls. Sometimes, the air that is trapped in the mold can block the flow of the plastic during the injection molding process. This might result in the product coming out as incomplete. For this reason, it is extremely important to design products that have a flawless design. When the design is good, it will improve the flow of the melted plastic.

Final Words

Plastic injection molding is extremely popular among the manufacturing industries these days. That’s due to the many benefits offered by this process. For this reason, many plastic injection molding factories are using it as well.

But, some common design defects may incur if you do not observe the process closely. This is why you must observe the entire process extremely carefully. For more information, contact us now!

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