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Robots are used in various fields such as healthcare, food and beverage, steelmaking, and warehousing, completing tasks faster, more reliably, and/or more cost-effectively. Robots are even used to assemble new robots. Robots come with one to seven axes, each axis providing a certain degree of freedom. Two-axis Cartesian gantries typically draw on the XY or YZ axis. Three-axis robots have three degrees of freedom and perform their functions through XYZ axes. These small robots are rigid in form and cannot tilt or rotate, although they can be fitted with tools that can rotate or adapt to small payload shapes. Four-axis and five-axis robots have additional rotational and tilting flexibility. Six-axis articulated robots have six degrees of freedom and can flexibly move objects in any direction or rotate objects in any direction. When applications require complex manipulation of large or heavy objects, these six-axis robots are typically chosen. Seven-axis robots can provide additional orientation for manipulating tools in confined spaces. Compared to other articulated robots, they can operate closer to workpieces to save space.
Articulated Robots
The popularity of six-axis and seven-axis articulated robots reflects the great flexibility of six degrees of freedom. They are easy to program, come with their own controllers, and can have motion sequences and I/O activation programmed through user-friendly teaching pendants. They can have large coverage ranges, with certain models exceeding three meters. This size range makes articulated robots suitable for numerous industries and applications involving manufacturing or moving materials or finished products.
By design, articulated robots occupy space and footprint that cannot be used for other purposes. They also have singularities, positions and orientations in surrounding space that they cannot access. These spatial limitations require more complex safety precautions, as robots are typically used in areas where workers are present.
Cartesian Robots Coordinate Robots
These robots are adaptable and easy to install and maintain. Each axis's stroke and size can be customized according to the application. Its working range and payload are independent rather than intertwined. Linear axes come in multiple designs to further adapt to their performing functions.
The main limitation of Cartesian robots is comparative inflexibility. They can easily accommodate linear motion along three axes and rotation around the fourth axis. However, a motion controller must be added to perform rotation around multiple axes. Cartesian robots are rarely used in washdown situations because they cannot provide sufficient waterproof protection. Additionally, installation requires precision and thoroughness—each axis must be carefully aligned, and surface flatness must be adequate, especially in larger systems.
Multi-joint Robot SCARA Robot
SCARA robots are designed specifically for lightweight applications. They are streamlined versions of articulated robots, with their simplicity and small size making them easy to integrate into assembly lines. SCARA robots can achieve considerable cycle times and are highly accurate. They excel at inserting components in spaces with strict tolerances while maintaining their rigidity during such movements, making them an economical choice for many pick-and-place applications and small part handling.
Delta Robot Parallel Robot
Delta robots are known for their speed, with pick rates reaching up to 300 per minute. Their mounting type places them above the workspace, thus limiting footprint loss. They are typically used with vision systems to pick randomly placed parts in complex sorting and packaging applications. Like articulated and SCARA robots, they typically come with a teaching pendant for easy programming. Delta robots are commonly used in food production applications, but like Cartesian robots, they may require additional shielding or isolation from the surrounding environment.
Collaborative Robots
Collaborative robots or cobots represent a relatively new development with promising potential for enabling safe human-robot interaction. By allowing direct collaboration between workers and robots, they add a dimension to our understanding of how automation can be integrated into industry. Collaborative robots can be articulated, Cartesian, or SCARA robots. They have payload capacities of 4-35 kg, correspondingly expanding in size and range (and price). Models with up to seven axes are available; the latter can perform particularly ergonomic tasks. Collaborative robots are even used as standalone production line robots.
How to Choose Selecting Robots
Sipide Packaging Equipment recommends that when investing in robotics technology, all aspects of the application should be considered before making a final selection. Here are some of the more important factors to consider:
Range and payload should be the primary criteria considered in your robot selection process, as these factors may immediately narrow down the list of suitable options. For example, large and heavy loads will exclude consideration of any lightweight handling technology. On the other hand, if the distance is long but the payload weight is low, a lower-cost Cartesian robot may suffice.
Robot flexibility: In applications requiring five or six degrees of freedom, articulated robots may be the only viable solution. If so, for price-sensitive companies requiring one or two robots, one option might be to repurpose (reuse) equipment. However, for simpler applications such as small part positioning and loading, electronic part insertion, and box and machine tool loading—where two or three axes are sufficient—why pay for more axes than the application requires?
Robot speed: Does the application require high pick rates like delta robots, or would the lower pick rates of Cartesian gantry or SCARA robots be sufficient?
Robot space and footprint: Machine and production line footprint is becoming an increasingly critical planning issue. Footprint is expensive, and companies want to optimize their workshop layouts. Cartesian robots have a clear advantage compared to other technologies, as only vertical space is lost, which is typically less important.
Robot engineering and project development: Design, assembly, installation, and commissioning time and costs should be factored into comparison costs, especially when integrating robots into larger machines or systems. Delays in receiving and assembling robots can delay entire projects.
Robot maintainability, repairability, and availability. Unplanned downtime is every production manager's nightmare. Robots should be relatively easy to maintain and repair.
The popularity of robotics technology enables businesses of all sizes to benefit from automation. The most suitable robot for you is typically the one that best fits your application—not only gaining productivity benefits from the investment and meeting technical requirements of the application, but also considering related issues such as plant safety, space utilization, and of course, acquisition costs and after-sales support.
