Eight Epson SCARA robots, distributed by Sinta on the Italian market and belonging to three different families, are currently working in a highly modular and configurable line, developed by Camas and designed for assembling and testing a safety valve in the automotive industry. Without turning down operational speed, the robots ensure flexibility in pick & place tasks and play a key role within a line capable of producing 15 different valve types.
by Fabrizio Dalle Nogare
Since their introduction – it was the early Eighties – SCARA robots have been associated with high speed and repeatability. Two features that have indeed contributed to the success of this type of robot within assembly lines. The fast evolution of the sector has made OEMs express different needs, such as flexible and reconfigurable production. In this scenario, SCARA robots, while basically keeping their peculiarities unchanged, are proving to be particularly suited to meeting such new requirements. How is it possible? Thanks to features such as simplified programming, easier integration into assembly lines or ease of use. And, above all, greater versatility. We could experience quite a clear demonstration of all this by visiting in Rovato (BS) the production site of Camas, a company that has been designing and manufacturing for over 30 years special assembly and testing machines addressed to several industrial sectors. Camas has, in fact, designed and developed an automatic assembly and testing line for a safety valve for vehicle tanks. The line, made of 5 assembly islands (4 rotary tables plus one free pallet belt) for the subcomponents and by a final testing cell, is able to produce 15 different types of the same product: a requirement, the latter, implying higher care in the design stage, with the aim to make retooling much easier.
A guarantee as for pick & place
The line developed by Camas has 8 Epson SCARA robots – supplied by Sinta, distributor for the Italian market – belonging to three families and having different features in terms of size and performance. “A line of such complexity hides many pitfalls in terms of design”, Camas representatives explain. “Not having troubles as for the handling systems helps us a lot to be more competitive with our customers. We chose the SCARA robots for pick & place tasks for several reasons. First of all, unlike other manipulators, SCARA robots allow us to pick even two components at the time. Furthermore, both programming and set up are simplified and maintenance requirements are reduced, however without affecting performance in terms of speed”. In fact, it is quite important to remind that the line must be able to produce a finished piece every 3.6 seconds. Analyzing the line more into detail, the first machine takes care of assembling the subcomponent that manages the vale opening and closing.
In this machine, the SCARA robot was chosen to pick two very small components each cycle with extreme accuracy and using both vacuum technology and grippers. The second machine is equipped with two SCARA robots which, in addition to greatly facilitating retooling – Camas people explain – make it possible to load the pieces in the machine with the desired orientation.
When the piece arrives, it is read by a system developed by Camas that detects its features and communicates with the SCARA robot that is able to place the workpiece with the right orientation. Time is then reduced because there is no need for any mechanical system that may place the piece with the right orientation according to the valve type.
Software is programmed in-house
The two following stations are devoted to assembling the other subcomponents that make up the valve, with different features according to the selected product type. Along the whole line, extremely accurate controls are carried out, in compliance with the strict requirements of the automotive industry. In the last assembly area, which features two more SCARA robots, the last components are loaded to complete the valve final assembly, according to the specific type selected among the 15 possible options. “A PLC oversees the management of the entire line”, Camas people add.
“All the production data, including the production batch where each single component comes from, are automatically tracked, saved and sent to the end user’s management server. Our well-equipped IT department allows us to fully support our customers, helping them to identify and build the most suitable system according to the customer’s requirements”. The system that collects and manages production data, as well as the HMIs, have been entirely developed by Camas, in order to provide the customer with the highest flexibility.
In this specific line, between 200 and 250 values are exported for each piece, counting only those related to the assembly process. In addition to advanced pick & place systems like the SCARA robots, the line also features programmable pallets, so that the different types of placements, therefore suitable for the different product types, are already available in the machine. By setting the correct reference, therefore, the system chooses which placement can be used, thus relieving the operator from such a task and thereby reducing the risk of human errors.
The back-up and testing machines complete the line
The final stages of the line have some more peculiarities related to the use of SCARA robots, as Camas technicians explain. “In this specific case, the customer wanted to have a back-up station where, at the end of the working day, the rejected pieces are taken up, evaluated, eventually fixed and then sent back to the machine without having to throw the valve away. Thanks to the flexibility guaranteed by the SCARA robots, the workpieces, manually loaded into the working area, are picked up by the same robot that during the ordinary production is connected pick the pieces from the automatic assembly machine. This allowed us not to have to design a pick & place system processing only rejected pieces”.
The SCARA robot with the highest performance rate is at work in the final testing machine, a multi-test system made of 12 stations and managed by an Epson G10 Series robot that picks up the finished piece from the assembly stations and takes it to the first station available, places the piece and the station can starts the testing stage.
When the test is finished, the robot picks up the processed piece and places two new pieces.
“The system is not a sequential one: the PLC communicates the closer station available and leads the robot there. This makes it possible to optimize the entire testing cycle and ensures that the system may skip a station if the latter is temporarily unavailable.
The characteristics of the SCARA robot, able to reach each of the 12 stations and to orient the piece properly, facilitate the machine management”.
A broad range of options
A well-known brand on the market, certainty of competence and assistance by the distributor – Sinta, in this case – but also the possibility to choose the right solution within a broad range of options. “On this line, Camas has installed SCARA robots belonging to three different families of products”, Sinta representatives explain. “T Series robots were released a few years ago, are truly plug & play with integrated controller.
LS Series SCARA robots feature greater speed and rely on the QMEMS technology, and electro-mechanical micro-system that, thanks to high frequency stability and accuracy, significantly reduces kinematic vibrations, so to allow for extremely fast and precise movements, increase speed and ensure high assembly quality; on the other hand, the G Series is by far the best performing in terms of precision and speed, provides ample choice in terms of robot assembly configurations as well as in terms of availability of clean room, IP54, IP65 and so on. When supporting a customer, we try to provide him with the best technical solution for every single application, without neglecting the issue of costs. Finally, we provide a unique programming system for either SCARA or six-axis robots”.