Injection Mold Design
We specialize in the production of high quality, low cost rapid prototypes and rapid molds. With a wide range of technologies at our disposal, we are the perfect one stop shop for all your prototyping needs. We offer low volume production from just 3 to 15 days!
Here you can see a technical drawing of the product on the left. On the right a CAD example of the product's mold and a 3D illustration of the finished design:
So What Is Injection Mold Design?
Injection mold design or plastic injection mold design, is the process of creating, developing and refining a mold which will be used for building a product, tool or part. During these initial creation stages it falls on developers or design engineers, tooling engineers, manufacturing and materials engineers and technicians to work together to determine a products’ specifications, the functionality of the mold, any operational constraints as well as any improvements or potential enhancements that they may make to the product, all key factors in plastic injection mold design basics.
During the injection mold design engineering, the team must be wary of any possible problems to do with the geometry or tolerance that may result in poor conditions. Mold flow evaluation must also be undertaken to determine the best type of gate and their locations, along with proper vent locations.
Once these factors have been determined the teams move on to the design stage. This is where preliminary 2D and 3D design models are built with injection mold design software in order to determine both the mold and steel sizes. Once this has been completed, reviewed and approved the design stage moves into tool design specifications for mold construction. Injection mold tool design takes the final adjustments and modifications that are done in-house, giving particular attention to the manufacturability and the critical dimension requirements. After this process we move onto the construction of the tools and begin the plastic molding process.
This image below shows a product we have made here at Shineyuu from developing the mold right up to a 3D design of the final part.
How Much To Design A Mold For Injection
So how much to design a mold for injection? Well, that depends. It’s not a simple matter of asking how much does it cost to have people design an injection mold casing and giving a specific answer. Let’s break down why that is exactly in order to get a better understanding of the cost for custom mold and design. First, we need to consider the one-off costs for injection mold tooling and the second is that of the cost of producing your production parts.
In terms of injection mold design costs, first thing you need to consider is the complexity of the part. This is the most critical factor when it comes to tooling costs. Those molded parts that have a lot of sharp corners prevent use of a round cutter for machining the mold features, so they require another process. Another are rib features that require machining deeper than 1/2 inch or thinner than 1/6 inch the mold may also require secondary machining. Undercut features are another aspect which may have to be taken into consideration. This is when the mold’s overall size is to be large in order to accommodate space needed for actions like moving parts.
Below on the left you will see our mold project team during a technical discussion.
On the right Shineyuu employees stack some plastic parts that have been created.
In the center is an example of an overmolding plastic part.
The mold’s construction itself is something to consider. Part cavities, for example, play into these costs. These cavities will directly affect the price of the mold. Multi-cavity molds certainly have a higher cost when compared to that of single cavity molds and is a key factor in price and understanding injection mold design. Also, the size of the part is perhaps the simplest tooling cost factor to understand when it comes to the relationship of mold costs since it directly ties into the size of the mold that would be required. Although bare in mind that a small mold with extremely complex parts may sometimes cost more than larger injection molds with simple design patterns.
That’s just the mold design aspect, the parts can also attribute their own set of costs. These would include material choice, part weight, cycle time, mold cavities, packaging and extras. We understand the process can be a bit overwhelming, that is why we recommend you get in touch with us on our contact page and we can assist you in your mold and tooling needs.
What Does A Good Plastic Injection Mold Design Have?
So exactly what does a good plastic injection mold design have? There are some critical components that must be considered. While some of these may be regarded as injection mold design basics, they are essential in order to have a solid, injection mold. These include:
- Gates: Gates are the openings that direct flow of the molten plastic into the mold cavities. They come in a wide variety of shapes and sizes, depending upon the design of the parts and the resin materials used. Design engineers must take many factors into account when determining gate types and locations in order to achieve optimum flow, fill pressures, tolerances, dimensions and cooling times. A key factor is determining where to place gates so that they won’t have a significant impact on the parts performance or appearance, resulting in flow marks, shrinkage and warping.
- Draft: One incredibly overlooked yet obvious issue is the ease of removal. The final product must come from the mold seamlessly, with no damage caused to the surface of the part upon removal. To accomplish this, a draft angle or taper is applied to the walls of the mold. The degree of this angle depends on several factors, including the parts design, depth of the mold cavity, surface finished, amount of shrinkage and textures used. Usually an angle of only a few degrees is applied to the mold, so that enough space is available and the part can be easily removed when the mold is opened. General rule of thumb is that the deeper the cavity, the more draft is needed.
- Finish: It’s important to consider surface finish as it directly ties into mold and part cooling. Finishing options should be discussed early within the design process, since the material that is chosen will directly have a significant impact on the type of finished implemented. For example, some glass-filled resin requires stringent temperature control, which in turn requires a hotter mold, which needs to take about ten percent longer with regards to cooling times.
- Texture: Textures and patterns can also be applied to the surface of a mold, which can even eliminate steps in assembly such as embedding a company logo in the plastic. Texture may also provide better functionality within the product, like reduced friction wear or enhanced grip. There are a wide selection of textures that can be applied, for example: matte, gloss, logos, geometric patterns to name a few. During the injection mold design process, draft may need to be adjusted to facilitate the parts ejection, depending on the type, depth and location of the texture.
Below left, you can see a model of mold inserts on our example project. On the right we preform a mold flow analysis on the product.
Below you can see a couple of production molds that we have used previously.
Injection Molded Parts
Here you will see some samples of our injection moulded parts created in production.
Take a look at some of our facilities.
How Shineyuu Does Injection Mold Design
Here at Shineyuu, we happily provide superior rapid tooling services at extremely competitive prices. We utilize steel molding tooling techniques, which is utilized as part of the molding process to create multiple copies of your parts. Our services include rapid tooling and mass production tooling. For more information or to get a quote from us, please contact us today!
If you have any questions, check out our FAQ section here.
Please provide 3D files and give us as much information as you can.
- Application Data (mold material, finish, etc.)
- Volume of parts required from the tool.
- Tolerances of the component.
- Life of the project.
We can then complete our specification sheet and evaluate the costs more exactly.
Below is how Shineyuu goes through the process of injection mold design.