Injection Molding – Machine Tending

Robots used in injection molding are often of the Cartesian type—this type of robot pairs well with the geometry of molding machines for the removal of finished parts.

Alternatively, manufacturers often use six-axis articulated arms with injection molding machines. The articulated arm is more flexible and can perform multiple functions.

A combination of robots can also be used. The Cartesian robot can remove a finished part from the molding machine, and then pass the piece over to a six-axis articulated robot arm that does additional operations.

Trimming and Removing Excess Material

Trimming off excess material is necessary with injection molding processes. If the material is still pliable, a blade cutter can be used. If the material has hardened, a spindle with a grinding tool can be employed for deflashing and trimming. In either case, a robot with the appropriate End-of-Arm-Tooling can accomplish the job.

Utilizing a robot to remove unwanted material after a molding process results in higher quality and greater consistency than manual methods.

In addition, workers are shielded from potential hazards. The highly repetitive nature of the injection molding and part removal process means that repetitive motion injuries are common. If hands or limbs are placed between the halves of a mold, crushing injuries and amputations can occur. According to the US Bureau of Labor Statistics, workplace injuries cost $1 billion per week. Using robotics keeps people safer.

Because robots don't get tired or need breaks, manufacturers can increase output from injection molding operations with robotics. And associates are freed from dangerous and dull work to perform other, more high-value tasks.

Assembly

Sometimes, assembly operations are elementary, like inserting a cardboard disc into a bottle cap. The assembly process may be more complex, involving perhaps screws to be inserted and tightened. 

Manual assembly carries many familiar problems: quality control problems, low productivity, risk of worker injury, and risk of damage to the product.

Robots can perform most assembly operations exceptionally well. Delta-style robots are very fast for lightweight applications. Heavier-duty robots are available for those applications that require such capabilities. Cobots can work safely alongside associates.

Computer vision with advanced AI enables the robot to insert and position parts repeatably and accurately. End-of-Arm-Tooling with appropriate sensors can apply just the right amount of torque whenever tightening screws.

Adhesive can be applied in reliable amounts with minimal variance at just the right speed.

The benefits of using robotics in assembly include higher speed, greater consistency, and lower cost. Workers are no longer required to be tied to a tiresome, repetitive task. Instead, they can perform tasks requiring human intelligence, improving employee morale and overall company productivity.

Quality Control/Inspection

Machine vision systems are commonly used to check the quality of plastic and rubber parts. Robots equipped with computer vision can inspect the results of all processing methods such as injection molding, rotational molding, extrusion, compression, and more.

Sometimes highly reflective surfaces can interfere with the effectiveness of computer vision inspections. The reflection can be mistaken as an imperfection. Autonomous machine vision can optimize the angle and lighting to remove errors. In other cases, physical measurements can be made using calipers, depth gauges, or other appropriate End-of-Arm-Tooling.

Automating quality inspection increases traceability and helps to improve the quality of the finished product

Labeling and Engraving

Traceability has become more and more important in manufacturing. If problems arise with a part, customers and manufacturers alike want to track the issue back to the date and batch number. Labeling parts has thus become a crucial part of the manufacturing process, yet placing labels on every part can be labor-intensive and add cost. Modern robotics can assist in labeling and engraving.

Robots can apply stamps and adhesive labels. Computer vision and AI ensure that the label is positioned correctly every time.

Companies are always trying to make their product look good and be more cost-effective. With in-mold labeling, the labels can be pulled down into the injection molding machine by a robot. This makes the label a permanent part of the product. As a result, it is much less likely the label will become damaged. And the durability of the label is greatly increased.

Another alternative is laser engraving. Lasers can etch and engrave both plastic and rubber. A robot arm is well-suited for such labeling when equipped with the appropriate End-of-Arm-Tooling.

One Robot, Many Tasks

Many manufacturers will use one robot arm to perform several steps in sequence. First, a part is removed from the molding machine. Then excess material is trimmed off. Next, the piece is inspected using computer vision. Finally, the part is placed in a tote or on a conveyor belt. In many cases, one robot arm can perform all these tasks.

Sometimes two robots working in tandem are employed to do what needs to be done. One robot removes the part from the molding machine and passes it to the second robot for post-production processing.

Whether with one robot or multiple robots, a higher degree of automation has corresponding benefits in productivity and lower cost.

Having robots perform multiple tasks means the end-user can accomplish more with a single investment.

Obstacles to Automation and How to Overcome

Small or medium-sized companies may lack skilled personnel with advanced computer and robotics programming skills. Until recently, this was a real obstacle that hampered the adoption of robotic automation.

Programming

Modern programming methods have dramatically changed the picture. In many cases, a collaborative robot or cobot can be "shown" what to do with no code-writing. The operator merely grabs the robot arm, manually moves it into a position, and pushes a button. Then, the worker physically manipulates the robot into the next pose and again taps the human interface (often a computer tablet) to indicate this is the desired next step. In this way, operators with no robotics knowledge can "train" robots in performing a new task. Fine adjustments can be made by tapping on buttons moving the robot arm left and right, up and down.

In addition, computer vision and enhanced AI make robots easier to program. Specially purposed robots already know what they are supposed to do. Setting up the robot becomes a process of "filling in the blanks" with the particulars of an application.

In general, between training supplied by vendors and the advancement of technology, even firms with no prior robotics experience can successfully implement robots in their manufacturing processes.

Where to Start?

It is not always obvious to see where to start. You can consult with robotics vendors, but often a more impartial advisor would be helpful. HowToRobot has knowledgeable and independent experts with whom you can consult. Your unbiased consultant can help identify those areas of operation that will benefit the most from automation and give you the quickest ROI, tailored to your specific needs.

Calculating ROI

HowToRobot offers an online investment calculator. The calculator will help you discover the actual cost of a process in your company and estimate how much you can save by automating it.

Save Time with HowToRobot

Even if you know exactly what you want and need, it is still time-consuming to find and identify qualified vendors. You can save time by taking advantage of the world's largest directory of robot vendors and find the right company with the right expertise. And HowToRobot can also help with the process of obtaining multiple quotes with a planned and guided approach. HowToRobot provides four simple steps from defining your need to receiving your offers.