Increase production capacity and flexibility by tightening with cobots

Find out all the details in this successful case study

The customer's needs

Our customer Despol TM, a Polish system integrator, is a supplier of robotised production solutions, specifically collaborative ROBOTS, and uses Fiam technology when its machines must perform assembly using threaded components.

The integrator relied on Fiam to create the solutions for its end customer: one of the most important European television set manufacturers with a plant near Poznan in Poland, which employs more than 500 operators.

These three partners collaborated to create a winning synergy, which led to a contract totalling 20 units over a period of two years.

Summary of the end customer's needs:

• Stations for automatic tightening by means of cobots (controlled remotely) integrated into production lines composed of conveyor belts

• Introduction of collaborative robots to carry out repetitive operations and work alongside operators to support them, exploiting sensors and 4.0 technologies in a very wide range of service operations, for example interconnection with the warehouse for automatic component picking or to perform tightening support tasks. Moreover, their use is increasingly needed to comply with the operating distances imposed by the current health emergency

• Respond quickly to a wide variety of ever-changing production flows.

The product/component variants to be processed when manufacturing television sets are becoming more numerous. Consequently, also the complexity in managing the production lots results in the need to schedule different production cycles according to the different materials and screw types to be used on different production shifts

• In-process checks to monitor production quality in real time so that errors do not build up until the end of the process

• Post-process checks to collect data, monitor processes and perform quality control.

What solution does Fiam propose?

The MCA automatic tightening module that can be built into the integrator’s cobot. Here are five reasons for this choice:

1. Because cobots can be quickly reprogrammed and used for different applications: the perfect choice even for low-volume runs or for variable workflows with quick operating setup changes

2. Because a “smart machine” is increasingly necessary in existing production systems. A solution that is not destined to replace humans, but to collaborate with them and free them from the heavier and more dangerous tasks so that they can carry out work with real added value

3. Because operators can carry out complex operations, and their skills are extended through a process of “job enlargement”, in which they are asked to perform the more critical tasks so that their daily work is more motivating and their jobs are more highly qualified

4. Because it offers great process automation flexibility as it can be programmed to work in reduced mode when a person comes within range of the robot, and resume full speed as soon as the person leaves, and specifically when working at a conveyor belt, it can adapt to the overall cycle times

5. Because, when installed in a cobot, the tightening system uses electronic tightening technology, which is the most suitable to fulfil the needs of: operating versatility, interconnection, production process scheduling and monitoring, both in-process and post-process.

Find out what the Fiam cobot tightening module consists of. What benefits does it offer?

1. AUTOMATIC SCREW FEEDER

The screw feeder has a built-in PLC, which not only controls and synchronises the entire tightening cycle, but also dialogues with the cobot and company network: it uses the Modbus TCP/IP communication protocol via Ethernet connection to remotely control all the parameters of the feeder and therefore the tightening cycle.

Fiam customises the screw feeder to the screw type used by the customer. In this case a Pozidrive screw with rubber washer under the head. Feeder customisation is a decisive factor when creating a reliable, high-performance automatic solution for a specific operating situation.

Advantage: continuous and consistent automatic screw feed directly at the tightening point, accelerating the production rate and synchronising with the speed of the cobot

2. TIGHTENING DEVICE WITH FORWARD BIT STROKE

The tightening device clamped to the cobot's wrist allows the bit to advance to the screw automatically, thus not allowing the bit to pull back. This exclusive system patented by Fiam offers three main benefits:

- IT IS SAFE FOR USE ON COBOTS: controlling three work steps (synchronised screw transfer stroke, intermediate screw-bit coupling stroke, final tightening stroke) entirely within the device means there are no exposed moving parts, making it perfectly compatible with the applicable safety regulations

- IT DOES NOT DAMAGE COMPONENTS: the device head does not rest on the surfaces during tightening, so there is no contact that could damage delicate components such as those found on the electronic boards in television sets

- MECHANICAL SCREW RETENTION AND EMBEDDED TIGHTENING: the head holds the screw mechanically rather than by suction, which is prone to dropping screws into the components, especially during fast handling by cobots. In this solution, the head has been customised to the screw and component with embedded tightening, and has an “anti-overturning” device to prevent the screws from overturning in the head, which prevents them from jamming during assembly since they are very small, with a screw length/head diameter ratio from 1.1 to 1.5.

The device is correctly positioned on the tightening point as follows:

- The cobot is equipped with a camera that captures the electronic board in transit

- The cobot uses the coordinates of the capture point to calculate the position of the electronic TV board on the conveyor belt

- It calculates the transit speed

- It determines the precise positions of the tightening points on the board

- It follows the positions defined in preset tightening programs, which provide the number of screws and tightening torque parameters set for that production run.

3. ELECTRONIC MOTOR DRIVE AND CONTROL

This technology is the highest performance exposed tightening method, especially where there is interaction with the factory system. The motor is brushless and the control system monitors the tightening parameters with a built-in torque transducer and resolver, which ensure high torque/angle measurement resolution. Together with the control units, the system ensures the following performance:

- Remote cobot control

- Interface with the line PLC and other device via freely programmable I/O signals. They communicate with the working conveyor belt to activate or deactivate the workpiece clamping jigs according to the components to be assembled and the set tightening programs

- Management of the number of tightening operations by component type and by torque/angle/time parameters, as required for correct assembly

- Has 32 pre-settable “tasks” that can be recalled for perfect control of tightening sequences

- There are 8 programs available for each task, within which you can set the 3 different tightening strategies available (torque control, torque control-angle monitoring, angle control-torque monitoring) and the other tightening cycle parameters (clockwise/anticlockwise rotation, minimum/maximum torque, speed reduction during tightening, time limit).

What are the benefits of using this technology?

- precise control over tightening and sequences

- screw/work cycle counts ensure production continuity

- process faults are detected, e.g. stripped threads (through the tightening time parameter)

- DATA STORAGE FOR STATISTICAL PROCESSING, thereby transforming the tightening results, and consequently productivity/process quality results, into analysis and monitoring KPIs. A fundamental response to the needs of data digitization and use that results from using machines as tools for creating value through optimisation and enhancement of production processes

- INTERCONNECTIVITY: through the Ethernet port, the system can interface with Ethernet IP, ACOP and ToolsNet protocols, as well as with barcodes, PLCs, and printers.