How Delta Robots Do What Others Cannot

Leaps in manufacturing come in many forms. In some cases new software capabilities may need to be developed, in others a component may need to reach a better economy of scale in order to become affordable, and sometimes it calls for a complete rethink of how something is designed. Delta robots fall squarely in the third category.


Today they do their particular brand of automation better than any other type of robot out there. So it may be surprising to hear that delta robots both had a rough start and that they still can be be overlooked as a driver of growth and profitability.



Origins Of The Delta Robot


Unlike their 6-axis cousins whose form is akin to the human arm, the design for delta robots did not come from mimicking the human body but rather solely from advanced mechatronics to get the job done.


The first delta robot was designed by Reymond Clavel and his team at the Robotics Systems Laboratory at Ecole Polytechnique Federale de Lausanne in Switzerland. It's origin sprang from a visit to a chocolate factory where the team found the laborious task of packaging pralines. The high speed of the packaging line ruled out integrating any robots that were currently on the market. So the team set out to create something entirely new that would solve the problem and the delta robot was born.


The delta design focuses around three high-torque motors mounted to linkage bars that ultimately all meet at a center platform where an end-effector can be connected. A fourth motor either mounted on the platform or overhead allows the end-effector to rotate any product about the z-axis. The entire robot is designed to be mounted overhead of the work area to save on floor space constraints.



When the robot first became commercially available it was met with caution from the marketplace. “They would not take the first step and risk their reputation with a robot similar to an umbrella," Clavel said. However, the unique advantages of the technology would soon override any hesitancies and the robot has become extremely popular in high speed, low payload applications.



Why The Different Design


From the robot's perspective, the packaging process is a simple pick and place that needs to be completed within a relatively small work area. By designing the nearly all of the control system to be fixed within the robot base and mounted above, the motors only need to accommodate the weight of the very light arms, the end effector, and any product being carried. This is in sharp contrast to 6-axis robots that have to deal with the weight of the metal housing along with each subsequent motor in the chain. The delta design helps the robots post the highest speeds and pick rates on available on the market.


Since the robot is mounted overhead it essentially calls for zero additional floor space. The robot uses the footprint already allocated by any automation below and horizontal footprint is minimized via the compact robot construction that allows for mounting multiple robots close to one another.


The result is a robot that can move with high speed, high precision, and very low space requirements.




Applications


We now fast forward to today and look into the future. How are these robots being used? We explore some surprising, and not so surprising use cases.



Case Packing


Delta robots excel in packing operations at the end of the production line where there is pressure to keep up with upstream flow. This includes operations where products are loose on a conveyor and need to be packaged or already in their packaging and need to be packed into boxes.


The first video below shows four delta robots working to pack links of salami from the outside conveyors into product containers located at the center. The second is an example of case packing product that is in their final packaging into boxes for shipment.





Sorting & Kitting


Since delta robots have to image objects on the conveyor in order to determine pick locations, they are well suited for high speed sorting and kitting of light weight products. Unique features such as size, shape, or color can all be used by the camera system to help the robot make fast decisions in getting the right product into the right container or diverted to a alternative conveyor.


In the demo application below we see this in action as the robot separates pieces of brink from stones.




Product Enhancement


Although they thrive performing them, delta robot applications are not completely constrained to simply picking and placing. Rather than mounting suction cups or a gripper, an end effector can be used to add value to products without having to move them off of a central conveyance line.


The video below takes us to Italy where the task of uniformly spreading pizza sauce onto dough is handled by a series of deltas that successfully complete the process without stopping product or diverting it to another work area.




How To Tell If You Should Be Considering Delta Robots


Deltas have become standard in end-of-line packing and packaging processes, especially in the food and beverage industry. If you check both of those boxes, it is worth moving an analysis of a delta robot system up on your priority list.


Their ubiquitous use at end-of-line processes shouldn't steer you away from looking at the start-of-line and mid-line processes as well. Step through your production line and see where any sorting, kitting, packing, or product enhancement processes could performed robotically. What value would a performance improvement via robotics in these areas yield?



Engaging With An Integrator


The unique factors of delta systems extend past the robot design. System architecture, component construction, and programming are also unique skills that must be developed for successful system integration.


IAS is an experienced system integrator that is well versed in the demands of delta systems. Our engineers are available to help evaluate your production needs, provide system concepts, and calculate future system performance. Assuring your manufacturing team that the correct decision is being made and that ultimately an optimal system is integrated.

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