How Manufacturers Use Robots in the Injection Molding Process

Plastic injection molding machines are often the most critical equipment for plastics manufacturers creating plastic parts and components. As a result, finding efficiencies around these machines can significantly impact overall productivity and profit margin. In addition, due to the complexity of the injection molding process, there are several tasks manufacturers can automate. 

Machine Tending

Machine tending is a common task that manufacturers automate through robotics.

Plastics manufacturers apply robots to automate the unloading process of the injection molding machine. Because of its repetitive nature, unloading molded parts has all the hallmarks of a traditionally automated process Also, assigning an operator to solely oversee the unloading task can be inefficient. Robots pose a solution to reassign operators to more complex jobs where they can have a more significant impact. 

Additionally, freshly molded parts are hot. This situation poses a safety hazard to operators handling these components. Applying a robot to this task reduces the risk of burns to operators.

Molded parts are sensitive to handling. Parts can become warped or otherwise misshaped from improper handling. Operators are prone to mixed results when handling plastic parts. Robots are much more precise. Consequently, automated part handling enables better quality assurance for molded components.

Insert Molding

It’s common to perform insert molding as part of the injection molding process. Insert molding involves inserting a component into a molded part. For example, the final part might require a thread, pins, or a flange to fulfill its function. 

However, insert molding poses problems for manufacturers when performed manually. For example, insert molding often requires handling small parts, which can be difficult for operators and lead to mistakes. As a result, it’s challenging to maintain high quality at scale when done manually. 

Furthermore, secondary machines often perform the insert molding task, but these machines typically include equipment like high-powered presses. As a result, these systems are dangerous to operators. Robots can handle this task to reduce the risk of injury associated with insert molding.

Overmolding

Overmolding involves combining to separate molded components to create a single part. Robots handle this job faster—higher speed results in greater throughput for your factory. In addition, robots perform at a higher level of quality than when done manually. Where people can make mistakes loading and unloading, robots handle tasks programmatically. 

Post-Processing

There are several post-processing tasks associated with plastic injection molding. Each offers an opportunity to automate for better productivity, efficiency, and quality assurance.

Assembly

Plastic components often require assembly to make a final product. Speed is crucial for the assembly process, so there is no substitute for automation here. Robots consistently outpace people over time for assembly tasks. 

Automating your assembly tasks can have an immediate impact on your production throughput. While robots can struggle to assemble highly-complex or difficult-to-handle parts, they’ll perform better than people in most assembly tasks.

In-Mold Labeling

In-mold labeling is commonplace for modern injection molded parts. This task is critical for the final appearance of the product. For this reason, it’s crucial to maintain the highest level of consistency during the labeling process. Robots, by their nature, perform their assigned task the same way every time. This characteristic enables the highest level of quality assurance unmatched by human operators.

Recycling

Manufacturers find better results and production efficiency by recycling leftover plastic. The molding process leaves scraps in some channels–notably in the sprue. By recycling these leftovers, manufacturers can reuse material and keep their machines running efficiently.

3 Factors to Consider Before Automating Your Injection Molding Process

With all the opportunities for injection molding automation, it’s exciting to think of potential projects. However, before jumping into your first injection molding robotics project, there are a few key considerations to keep in mind.

Robot Type

The optimal robot type will differ depending on the application. The most common robot types for injection molding include:

• Six-Axis 
• SCARA
• Cartesian

Each has its unique strengths and limitations. For example, six-axis robots have exceptional dexterity and range of motion. Six-axis robots support motion paths impossible for other robot types. This characteristic is crucial for some machine tending and assembly applications requiring complex motion. However, these robots are the most expensive option on the list. So be sure it’s the optimal choice before making a purchase. 

SCARA robots are great for simpler assembly tasks. Those that don’t require complex motion might be a good fit for a SCARA. Additionally, SCARAs feature a smaller reach than other robots due to their construction. As a result, they’re not a great choice for larger applications. However, SCARAs tend to be much more cost-effective than six-axis robots. Therefore, for the correct application, they can be an excellent investment.

Cartesian robots are great for simple machine tending, recycling, and assembly tasks. Like SCARAs, cartesians fall short on tasks requiring complex motion. However, cartesians scale up better than SCARAs due to their simple mechanics. This simplicity also lends itself to a lower cost, making cartesian robots an excellent value for the proper application.

End-of-Arm Tooling (EOAT)

How you manipulate the part is essential for all applications. However, it’s even more critical for plastic injection molding applications. Choosing the wrong EOAT can limit your robot’s productivity or damage your parts. Therefore, plastic injection molding applications often take advantage of more unique EOAT offerings. Standard options include mechanical grippers, suction cups, and soft grippers.

Plan for Testing

Due to the nature of plastic injection molding, be prepared to dedicate time to test your setup. Integrators spend a lot of time managing timing, temperature control, and pressure settings. Minor adjustments can significantly impact the final result of the process. Ultimately, rushing too quickly to production can limit the potential of your robotic system. For this reason, it’s essential to respect the importance of testing.

What’s Next?

You may be ready to take the next step toward automating your injection molding process, but where do you start?

The HowToRobot platform connects buyers of automation with a variety of suppliers in a streamlined, easy-to-use environment. 

Post your project on HowToRobot today for free, and begin receiving offers from vetted, relevant, and eager automation vendors from our certified supplier network. 

Have a question or want to know how to get started? Get in touch today, and we will be happy to help.