Assembly precision and changeover flexibility in the automotive sector
Case Study created in collaboration with SC Solutions
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The Balluff Case Study series are articles written by Balluff experts, our company's partners, integrators, and specialists implementing dedicated solutions for manufacturing companies using Balluff tools and solutions.
Production optimisation is often considered in terms of speed, such as assembly stations in the automotive industry. Less often, this process is combined with the precision of machine operation, as well as the elimination of the risk of downtime.
SC Solutions approached this issue in a comprehensive and innovative way, creating an intelligent machine for an international manufacturer of half-shafts for passenger cars.
Stated situation
CS Solutions specialists, specialised in designing equipment for the needs of the automotive industry, in cooperation with the customer, were tasked with improve the way joints are assembled in a Polish manufacturing plant.
Previously performed manually, the process was extremely time-consuming, but involved a great deal of responsibility for quality. This is because the assembled components have little assembly play. Add to this the need to separate the various products to be assembled and their weight, and you can see that the process was demanding from a handling perspective.
The problem
The customer was therefore looking for a solution that would allow him to simplify assembly while matching the specific production conditions, including the considerable weight of the individual joints (the components weigh between 7 and 8 kg) and the need to achieve precisely joined components, with an accuracy of up to 0.04 mm.
The fundamental changes that were therefore to take place after the implementation of SC Solutions' technology were to relieve the workload, speed up production, and eliminate assembly errors while maintaining the versatility of the workstation.
Solution
In order to achieve high production quality while increasing productivity, SC Solutions constructed a semi-automatic rotary assembly table with a diameter of 2 meters, equipped with RFID tracking, sensors and digital connectivity IO-Link by Balluff. Designed, built and implemented by the company, the machine enables the assembly of joints on pallets locked pneumatically on wheels, where the parts are then cut with wire and hollow, among other things. For this purpose, engineers have prepared tailored sockets that clamp the components with a precision of up to 0.1 mm and position them with an accuracy of 0.02 mm, thus ensuring an alignment that eliminates the risk of production errors while ensuring accurate processing of the components.
In the case of the proposed solution, its innovation is evidenced by the capability of fully controlled and flexible changeover, thanks to the use of an extensive system of components RFID. This gave the customer full freedom to identify different types of pallets for the production of different components, as well as interchangeable sub-assemblies.
In contrast to a completely manual station, where only one tool would be permanently present - the semi-automatic assembly table offers the possibility of easily changing the pallet, which is found using an RFID identification system. This kind of intelligent adaptation to production needs has resulted in a 20-second assembly cycle.
The challenge faced by engineers was the vision-based monitoring of the position of components that take the shape of a sphere. The peculiarity of these objects is that they have a greater tendency to reflect light. Even in the case of the inside of joints that are machined, there is an imitation of a sphere - flashes appear on the cage and inner raceway. Calibration of sensors for high-precision product checking has happily avoided difficulties and achieved satisfactory performance.
Also importantly, it was a conscious choice by SC Solutions to not to use a robot, which could theoretically operate and fully automate the station. Counterintuitively, this choice could have entailed losses in the form of regular stops of the robot every certain number of cycles due to shifts. This would be due to the extreme precision required to assemble high-end joints. With exceptional parts, the backlash can be as small as 0.02 mm, requiring constant monitoring of the work.
How it works.
The machine made by SC Solutions allows a single worker to handle the assembly of various types of parts with full accuracy and in a time that was previously unattainable for this position. The operator actually feeds the products into the machine and pulls out the already assembled ones after the cycle is complete.
Thanks to Balluff sensors the machine constantly monitors what is happening on the assembly table: it reads the positions of all parts, the positions in the pallets, the position of the manipulators and the position in putting the parts away.
Each pallet, or nest, in which assembly takes place, is smaller in size and is measured by a separate device that is part of the complete machine. It is equipped with two hubs IO-Link for data transfer and one coupler to power these pallets. The collection of signals and control of pneumatic valves is carried out directly on the machine (just thanks to the IO-Link masters). The size of the electrical cabinet is thus significantly reduced, and the collected signals on the rotary part of the machine are collectively connected via the rotary coupling. In addition, since each pallet is equipped with a receiver, and the transmitter connector is permanently in the machine structure, it is possible to read the status of the pallet and thus access information about the current work being performed on it. The inspection processes, on the other hand, are based on three vision systems.
At the very end, it is worth mentioning the customer-required 3D marking which, according to its specifications, takes place automatically on the joints.
Benefits for the customer
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High work speed- With the implementation of SC Solutions, the production cycle time has been reduced to 20 seconds.
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Precision of assembly- The design of the machine and the use of the latest industrial sensor solutions made it possible to achieve accuracy measured in parts of millimeters, thus matching the customer's exacting requirements.
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Relief of the worker -in the case of the implemented machine, the person working on the line is able to simultaneously work as a logistician and assembler, selecting, bringing in and out products from the assembly table.
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Efficiency- Working without downtime, in three shifts and at full capacity, the machine maintains aa rate of three products per minute. Its durability in continuous operation is the result of both intelligent design and the use of high-end mechanical components.
About the company
The company SC Solutions carries out projects in the field of machine design and construction, as well as implementation at target plants. The company began operations in 2015, at first creating primarily with industrial transportation in mind. Over time, the company's profile transformed, and its engineers began building customized unit machines.
Currently, the team constructs large and advanced equipment to order. In doing so, it is building an extensive portfolio of innovative solutions, particularly for the automotive industry.
The published case study took part in the Balluff Case Study Challenge 2023, aimed at recognizing and rewarding the most innovative case studies submitted by industrial machinery manufacturers.
Keywords
- Case Study
- IO-Link
- Efficient production
- Smart sensors
- RFID
Author
Balluff Sp. z o.o.
We have been active on the Polish market for more than 25 years. We serve our customers from Pomerania to the Tatra Mountains, providing first-class service and technical support. We are also present online, where we share our knowledge about the latest implementations, industry trends, events or technical aspects of our solutions.
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