One of the greatest industrial advancements in human history is mass production. The ability to produce and deploy goods on a large scale changed the course of human history. And since then, we’ve been steadily perfecting the methods of production.
Injection molding is one of the methods widely employed in the industry for rapidly creating parts and components to exacting specifications. Its many advantages have made it popular in the industry.
However, with its advantages comes its main disadvantage, the tooling. The high costs and requirements for tooling have made Injection Molding a method suitable for only high-volume mass production. But now, that narrative is changing.
Rapid tooling is currently emerging as a way to bring the speed and flexibility of rapid prototyping manufacturing to Injection molding. As a result, lead times and production costs are decreasing across the board. This is leading to new applications for injection molding.
In this article, we’ll be showing you how rapid tooling is changing manufacturing, specifically Injection Molding. We’ll also introduce you to the different capabilities that you can unlock by combining both of those methods.
So, to begin our journey, let’s first understand what Rapid Tooling is.
What Is Rapid Tooling?
Rapid tooling, as the name denotes, is simply manufacturing tools on a tight or slim deadline. It refers to a series of processes or methods that we can use to create tools quickly and cheaply.
It combines Rapid prototyping techniques with conventional tooling methods to create the tools in a short time. Rapid tooling is usually done in the pre-production run to test out the design before production starts.
√ What is this “tooling”?
Tooling is the process of sourcing or designing and creating the tools needed for a manufacturing process. Tools comprise a wide range of manufacturing aids. They can be anything from jigs and fixtures to dies and molds.
With rapid tooling, the traditionally lengthy process of making them is sped up considerably. When the tooling process time is reduced, then the lead times are also reduced. The product can get in the hands of the consumer far quicker and at a lesser cost.
√ How Does Rapid Tooling Affect Injection Molding?
Like we mentioned earlier, injection molding is a popular method for manufacturing objects. It involves using a ram or a screw to force the molten material into a mold’s cavity. The material solidifies in the mold cavity to form the product.
The tooling required for injection molding is the mold. Under conventional tooling procedures, it is often very complex and takes a long time to manufacture. With rapid tooling, we can manufacture molds quickly and cheaply for relatively short production runs.
When Can I Use Rapid Tooling?
Rapid tooling is a useful aid in production. We can use it for many reasons. Let’s highlight some of these reasons below:
To manufacture tools for low to medium volume production runs.
To create high-quality accurate prototypes with production-grade materials for testing.
To test the production process design and catch any flaws before production begins.
Benefits of Rapid Tooling
In the manufacturing industry, we view rapid tooling as a gamechanger due to the advantages it offers. Let’s take a look at some of these advantages.
Reduced Lead Times: With rapid tooling, the time usually spent on tooling in the manufacturing process decreases rapidly. As a result, the manufacturing timeline speeds up, and products get to market quicker.
Reduced Production Costs: Rapid tooling cuts out many of the production costs usually associated with conventional tooling. Since the bulk of the work done is digitally through CAD, it is accomplished in a relatively short time. This saves both time and money.
Increase in Research and Innovation: Since the time and costs for creating tools using rapid tooling are short, engineers can innovate more designs. They can run more tests, learn from those tests and iterate through successive designs with ease.
Wide Range of Materials Available: Rapid tooling offers access to a wide range of production-grade materials. The prototypes we create with rapid tooling can accurately model the finished product. As a result, engineers can run their tests with more confidence.
How Are Injection Molds Created Using Rapid Tooling Processes?
Rapid tooling is a broad term that encompasses many processes we can employ in tool creation. To understand how we make molds using rapid tooling processes, let’s look at the two main Tool fabrication methods:
√ Direct Tool Fabrication
Direct tool fabrication is the method we use the most in fabricating tools for injection molding. It involves building the mold’s tooling using additive or subtractive manufacturing methods without the need for any master patterns.
Here, we make the tools directly from the CAD file. Using this method, we can create the mold’s cavities without an initial prototype or pattern.
√ Indirect Tool Fabrication
Indirect tool manufacturing uses a high-quality master prototype to create the tool and subsequent copies. The prototype can be created with methods like SLA or CNC machining. After that, we use a casting method to lift the pattern into a mold and make more copies.
In indirect tool fabrication, the quality of the Tool depends on the quality of the prototype. So, the prototype is always made to the highest standards possible.
So now, we’ve seen the different ways of rapid tooling for manufacturing. However, we are going to be focusing on direct tool fabrication methods in this article.
Direct fabrication tooling processes are the ones we use in making molds for injection molding.
Common Injection Molding Rapid Tooling Processes
Like we said earlier, we are going to focus mainly on Direct tool fabrication processes. In making these tools, there are three methods commonly used. These are:
3D Printing (SLS, DMLS)
Electrical Discharge machining.
Let’s take a quick look at these three methods:
√ CNC Machining
CNC (Computer Numerically Controlled) machining is one of the most popular rapid tooling processes. It involves using a computer-controlled cutting tool to remove material gradually from a large block until it attains the required shape.
CNC machining is a term that covers many activities, including CNC milling, CNC turning, and CNC grinding. Most of the time, CNC milling is the process we use in creating tools for manufacturing. It involves using a spinning cutting tool to remove excess material until the final shape is attained.
CNC machining is a very accurate method of creating tooling. With it, we can maintain tight tolerances, reproduce intricate details and produce great surface finishes. It is also compatible with a wide range of materials.
√ 3D Printing
3D printing is a relatively new production method that is finding applications in the field of rapid tooling. It involves building an object from a CAD or a 3D model.
The 3D printing processes we use in creating metal molds are SLM (Selective Laser Melting) and DMLS (Direct Metal Laser Sintering). Both of them use lasers to build up the metal parts.
They do this by slicing the 3D model into thin layers and using the laser to fuse metal powder into the shape of layers. Successive layers are then fused to create the final part.
3D printing is a relatively accurate method for creating tooling. It is useful in creating parts with complex internal geometries. However, it produces poor surface finishes, and it only works with a narrow range of materials.
Electrical Discharge Machining
Electrical Discharge Machining (EDM) uses electrical current to remove excess materials from metals to create the final component. It involves directing high-frequency electrical sparks from an electrode to vaporize the excess metal.
EDM is a very accurate method for rapid tooling. It can work with hard materials like titanium, and it produces good surface finishes. Also, it does not put any mechanical stresses into the tool.
Materials for Rapid Tooling Injection Molds
Rapid prototyping and tooling processes use a wide variety of materials to create tools. They vary from “soft mold” materials like silicon, rubber, and wax to “hard mold” materials like steel and aluminum.
In creating tooling for injection molds, we use hard mold materials. Aluminum and various grades of soft steel remain the best. Let’s look at some of the advantages they offer:
√ Aluminum (7075 or 2024 alloy)
Aluminum molds make up about 80% of the molds we make and this is for a good reason. Aluminum has many material properties that make it uniquely suited to rapid tooling. Let’s look at them:
It is easy to machine.
It dissipates heat very efficiently leading to superior dimensional stability.
It is cheap compared to other materials.
It is much more suitable for low production runs.
It takes less time to prepare an aluminum tool.
√ Steel (Stainless, P-20, D-13)
We can also make molds out of steel. Although steel is not as popular as Aluminum, there are still specific applications that require steel molds. Let’s look at the advantages of steel molds:
They are harder and stronger than aluminum.
Steel Molds are very durable and can last for long production runs.
It can handle a wide range of materials like advanced resin without getting damaged.
It is more suitable for high-volume production.
It can reproduce intricate details better.
How to Select the Right Rapid Tooling Process?
When it’s time to choose the rapid tooling process or mold material, what should you consider?
Let’s take a look at some factors that should influence the sort of rapid tooling process you should use:
√ Material Suitability
The materials we specify for making the product play a big role in influencing the rapid tooling process for the mold. Molding some materials requires extra strong molds. This influences the sort of process and mold material chosen.
√ Lead Times
Although rapid tooling speeds up the production process, some tooling processes are still faster than others. So, in choosing the tooling process, we also factor in the tool’s delivery timeline.
Cost also plays a role in selecting the rapid tooling process. The materials used in mold making are not cheap. To maximize the cost-efficiency of rapid tooling, we have to take special care in selecting materials and tooling processes.
As always, the idea is to balance cost with quality.
√ Mold Lifespan
The Mold’s lifespan or production run refers to the number of products that we can get with a mold before it we replace it. It weighs into the final conversation because production requirements vary, so balancing costs with mold lifespan is necessary.
√ Mold Complexity
The tool’s complexity also has a part to play in choosing the rapid tooling process. Some processes are better than others at reproducing minor details. Some mold materials are also better at holding these intricate patterns.
So, it necessary to make the right choice during the mold design stage.
Q1: Which Rapid tooling method is the best for creating injection molds?
A: Different Rapid tooling processes bring different advantages to the table, but the overall best method is CNC machining.
Q2: Which Is best, Aluminum Molds or Steel Molds?
A: For the best overall strength, quality and durability, the consensus will be steel molds. But, during prototyping or low volume production runs, these properties aren’t always needed. So, to balance cost with quality, we use Aluminum molds.
As we’ve seen, Rapid Tooling can unlock new capabilities in injection Molding. Combining these two methods gives rise to a new form of cost-effective manufacturing. And here at RapidDone, from China, we are ready to help apply this to our business.
At RapidDone we believe in using new technology to maximize and amplify the productivity of conventional methods. If you trust us with your project, we will do just that.
With over ten years of experience in Injection Molding in China, multiple high-quality certifications, and highly motivated staff, you can be sure that your project is in safe hands.
So, get in touch with one of our Engineers today and see how best we can optimize and manufacture your product.