As an injection molding service provider, GO4mould constantly explores ways to improve our products and services. Our workforce continuously looks for ways to optimize the injection molding process, whether through new technologies or simply by paying close attention to it and making minor adjustments.
One area we’ve been focusing on lately is injection molding wall thickness consistency. We’ve been experimenting with different ways to measure molding thickness and working on new techniques to ensure that the wall thickness is consistent throughout the entire part.
In this blog post, we want to share some tips on controlling wall thickness injection molding.
Importance of wall thickness – Injection molding
One of the essential factors in successful plastic injection molding is maintaining consistent wall thickness throughout the entire part. It can be a challenge, as the nature of molten plastic is to flow towards areas of lower pressure. When designing a part for injection molding, keeping the wall thickness as consistent as possible throughout the entire piece is essential. Too thin of a wall thickness can cause the plastic to cool and solidify too quickly, resulting in a weak and brittle part. On the other hand, if the wall thickness is too thick, the plastic will take too long to cool and solidify, which can cause warping and other issues. The ideal wall thickness for an injection molded part is between 2.5mm and 4mm.
Uneven wall thickness can cause the plastic to cool and solidify at different rates, resulting in a weak and distorted part. The best way to ensure consistent wall thickness is to use a molding machine or CAD program that can accurately calculate the dimensions of the mold part.
Injection molding wall thickness – Uniform wall thickness guide
One of the most important design considerations regarding injection molded plastic parts is wall thickness. A part’s injection molding wall thickness will determine its strength, rigidity, and overall durability. It also affects the manufacturing process, as different wall thicknesses require different design parameters and materials.
In general, it is best to maintain a uniform injection molding wall thickness throughout a part. A non-uniform wall thickness can cause warping, uneven cooling, and other issues.
Figure 1: Uniform wall thickness
There are several ways to achieve uniform injection molding wall thickness in an injection-molded part. Let’s examine each method in more detail.
- Maintains surface appearance
The first method involves using a thin layer of material called “skin” that covers the outside of the part. The skin helps distribute stress and prevent warping evenly. It also gives the part a smooth, finished appearance.
- Balanced shear stress
Another way to achieve uniform injection molding wall thickness is to balance the shear stress within the part. This can be done using a thicker material in the areas that experience the highest pressure.
- Improved gating
Improved gating means ensuring the material flow is evenly distributed throughout the mold. You can do this by using a larger gate or adding more gates.
- Rapid cooling
Another way to achieve uniform injection molding wall thickness is to cool the plastic rapidly. You can do this using a water-cooled mold or adding a cooling agent to the plastic. Rapid cooling will help to prevent warping and uneven cooling.
- Reduces molding cost
Uniform injection molding wall thickness can also help reduce the cost of injection molding. This is because it helps prevent warping and other issues that can lead to scrap parts. In addition, it can also help improve the efficiency of the molding process.
No matter which method you choose, it is essential to maintain a uniform injection molding wall thickness throughout your part. Our trained workers at Go4mould can assist you. This helps make mold parts solid and stable and prevents potential problems during the manufacturing process.
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Considerations for designing part walls
When creating injection mold part walls, there are several factors you should take into account to create a successful product. Some of them are:
- Ribs
Ribs support the part’s loads and must be appropriately designed to avoid premature failure. They should be positioned perpendicular to the direction of the load and evenly spaced to distribute the load evenly. The rib thickness should be greater than the surrounding material to provide adequate support.
- Corners
Corners are usually the weakest points in an injection-molded part and should be avoided if possible. If corners are necessary, they should be rounded to reduce stress concentrations. The corner’s radius should be at least three times the part’s injection molding wall thickness.
- Holes
Holes provide passages for air and water and must be designed to avoid leaks. The injection molding wall thickness around the hole should be at least 50% greater than the thickness of the part. The diameter of the hole should be at least twice the wall thickness of the mold part.
- Weld Lines
Weld lines are created when two adjacent molten plastic resins meet and solidify together. They are usually located at the junction of two or more cavities. Weld lines should be avoided if possible because they are potential points of weakness. If weld lines are necessary, they should be positioned so they will not be subject to high-stress levels.
- Angles
Draft angles are used to change the direction of the flow of the melted plastic and help to avoid premature failure. The injection molding wall thickness of the angles should be greater than that of the surrounding material to provide adequate support. The angle of the corners should be at least 45 degrees.
Consider all of these factors to create a successful injection molded part. By designing your part correctly, you can avoid costly mistakes and ensure that your mold is of the highest quality.
Disadvantages of ununiformed wall thickness
A part with a nonuniform injection molding wall thickness will not be as substantial as one with a uniform thickness. The thicker areas will be stronger, but the thinner spots will be weaker. It can cause the part to break quickly, especially if the more delicate areas are subject to stress or strain.
Its disadvantages include:
- Marks or Scratches
If the part’s injection molding wall thickness is not uniform, it can leave marks or scratches on its surface. This can be unsightly and may reduce the overall quality of the finished product.
- Uneven Plastic Distribution in the Mold
It can lead to voids or pockets of air in the finished product, weakening the part’s structure and making it more susceptible to breakage.
- Wrappage
Wrappage can lead to defects in the finished product and increased production costs.
- Increased Cycle Time
If the part’s injection molding wall thickness is not uniform, it can take longer to fill the mold and cool the plastic, increasing the overall cycle time for the production of the parts.
With Go4Mould, Choose the right material and wall thickness
When choosing the suitable material and wall thickness for your project, there are many factors to consider. The most crucial factor is the intended use of the product. Many different materials can be used for mold making, but some of the most popular include plastic, metal, and silicone. Plastic is the most common type of material used for mold making.
Go4Mould can help you choose the suitable material and wall thickness for your project. We offer a wide range of products, and our experts can help you find the perfect solution for your needs. Contact us today to learn more!
Conclusion
Injection molding is the best method for creating mold parts with uniform wall thickness. By carefully controlling the injection process and using the proper tooling, you can produce parts with consistent wall thickness throughout. Go4mould also provides customizable solutions to meet your dimensional tolerances and have the desired cosmetic appearance.
Frequently Asked Questions
How thick should the walls of injection mold be?
As a rule of thumb, the walls of an injection mold should be a minimum of 3 mm (0.118 inches) or between 2mm to 4mm thick. However, some applications may require thicker walls, such as molding large or complex parts.
Is injection Molding Cheap?
Injection molding is a popular manufacturing method for producing plastic parts. It is typically used for mass production but also for small-scale manufacturing. Injection molding is relatively fast and inexpensive, making it a popular choice for manufacturers.
How do we determine the wall thickness of any product?
There are a few different ways to determine the wall thickness of any product.
- One way is to use a micrometer. It is a tool used to measure the mold’s thickness.
- Another way is to use calipers. Calipers are also used to measure the thickness of an injection mold.
- Lastly, you can use a ruler to measure the thickness of an object.
All you need to do is measure the length and width of the mold and then divide it by two. It will give you the wall thickness of the mold
