Cognex vision tools are the key to solving a variety of Vision Guided Robot applications
All companies manufacturing robotic inspection cells must possess the ability to design and produce automated inspection cells with technologically innovative solutions that are reliable, simple, and safe to use to order to compete. The use of vision guided robot solutions optimizes production and assembly processes and is essential in order to be competitive in the global market today.
Tiesse Robot, based in Italy, is a leader in industrial automation processes and invests substantial resources in R&D, particularly in vision systems for robotics destined for various industrial sectors. They use flexible and configurable Cognex vision software to perform a wide range of tasks including part location for vision guided robotic applications, part measurement, part inspection and the capacity to carry out dimensional and qualitative checks.
Maurizio Ravelli, Commercial Director of Tiesse Robot, explains: “The vision systems market is moving away from traditional part recognition toward 3D vision for handling the part directly from the container or pallet. This process will also enable refining, deburring, and finishing of parts. Additionally, companies are developing vision systems with linear cameras and laser light sources for quality control of mechanical items and components for safety systems (automotive brakes, etc.). In parallel, the market requires the facility to make dimensional measurements on parts leaving the machining units in order to carry out any corrections on operating units in real time.”
Tiesse Robot + Cognex vision solutions
In order to offer their customers high performance, maximum reliability, and simplicity in use, Tiesse Robot has developed an artificial vision platform based on Cognex VisionPro® software. These libraries are highly adaptable to customers’ requirements.
The platform offers a wide range of features and offers hardware-independence in terms of camera choice, making it easy to customize the system per application. And to address the frequent problem of locating complex objects with varying part positions as they arrive on a belt, Tiesse has designed a system that can recognize a part no matter the position.
Easy to use
In order to make the system as simple as possible to use and manage for production operators, Tiesse has equipped the vision system with a user-friendly, interactive, multilingual interface (Italian, English, French, German, and Japanese). Environmental variations such as the lighting is a standard issue. For this challenge the key factor is the wide portfolio of Cognex vision tools that include: PatMax®, PatFlex®, PatInspect®, non linear calibration and measuring tools and the robot guide tool with XYZ capability. Also, in addition to these features, assistance and reprogramming of the system can be achieved by remote access.
White goods—washing machine part assembly
The Tiesse Robot group has produced an inspection cell for the automated mounting of the caps and sliding rollers of washing machine valves with the assistance of two robots programmed with Cognex VisionPro software. The cell consists of a pallet store for the parts to be fitted, a measuring station with remote camera for the hole centers, a station for fitting the caps, a turntable for fitting and riveting the roller bolts, and two Kawasaki robots that handle the parts between the various stations and prepare the preassembly of the roller on the turntable.
The special features of the cell include production in random mode, the correction of errors in hole spacing to ensure correct fitting of the caps and the insertion of the roller mounting bolts. All actions are controlled by PC which manages the details of the product, the system data and parameters, the settings, the display of the status of the plant, the daily production report and alarms.
The robot performs a measurement cycle for the height of the pallet carrying the parts by means of a distance sensor mounted at the edge, then frames and recognizes the outline of the profile with the remote camera. At the end of the procedure, it carries the part to the cap fitting station. The system then obtains a code that dictates the insertion sequence and roller type for the turntable station to complete assembly. It is lastly deposited on the pallet for finished products.
Automated refining island for iron castings
Another interesting automated inspection cell example is the use for vision-equipped anthropomorphic robots (up to 500kg capacity) to refine and finish medium and large iron castings.
The operator places the castings on a transporting device with rolling shutters and Cognex VisionPro software transmits the code to the robot that indicates the orientation of the arriving part. The special feature of this cell is the presence of a second vision system that, together with the use of sensors, defines the exact position of the castings in the X, Y, Z planes. These methods show that it is possible to determine the positions of machining areas with vision systems, irrespective of tolerances of shape and without other precise positioning requirements for the part in the tool. In practice, the vision software supplies the conditions for recreating the machining lines with their orientation vectors, thus enabling the robot tool to be positioned with accuracy.
Inspection cell for finishing seats— handles up to 32 different product codes
An additional application of robots and vision systems concerns an installation for finishing plastic backrests of office chairs and fitting them with metal inserts to attach the seat to the chair frame.
The inspection cell is located downstream of a press that stamps eight different product codes at random. To handle random production, Cognex VisionPro software was incorporated in the island that makes it possible to handle up to 32 different product codes without changing speed or flexibility.
The system also handles the challenge of the various product removals due to either changes in shape or varying machining times in the pressing phase.
The cycle of each robot includes: picking up the part arriving on the belt in the position and orientation as calculated by the vision system, visual inspection to ascertain the dimensions, sequential placement of all the inserts according to the position measured by the vision system and depositing the finished product on the removal transporter.
To complete this short overview of applications performed by vision guided robots a robotized plant for machine tooling deserves special mention.
Robots designed for tooling are fitted with a vision system that can recognize the part. The solution consists of various part feeder systems depending on the production rate and the dimensions of the parts as well as their movement logistics.
The machining cell can then be equipped with fully automated feeding and loading. In particular, on fully automated work centers, the parts are positioned by conveyor belts and/or pallets in a 3D macro-area. The robot then identifies the part using Cognex PatMax technology to measure the spatial XYZ and angular coordinates. Additionally, Cognex non linear calibration tools make it possible to completely cancel out any calibration errors making it possible to achieve high performance, reliability and efficiency at a competitive cost.
The use of vision systems in automation processes is a continuously developing technology with a lot of future potential with applications and projects that both Cognex and Tiesse are ready to confront given their experience and constant research in the field.