Completely ergonomic tightening operation, unbeatable safety, high production rate, extreme reliability of tightenings and optimal adaptability to the existing production line: these important objectives are achieved with the new semiautomatic tightening system, Autovite, designed by Fiam for customers who need to fasten circuit boards on plastic base boards for aerials. We were asked to come up with a solution, to be inserted in the existing production line, that was to enable self-tapping screws to be used for the tightening job, making it extremely reliable and hence providing a high level of torque repeatability.
Excellence in terms of productivity, reliability and ergonomics has been achieved thanks to:
Screw feeding system
The system can be used in conjunction with electrical solutions thanks to the versatility of the PLC, which enables:
- screw jamming to be eliminated in the selection channel by virtue of the new fibre-optic sensor, which assures high levels of continuous productivity (when the optical fibre detects the presence of screws after a time preset by the PLC, it activates a solenoid valve, which produces a jet of air, eliminating excess screws)
- a considerable increase in speed and hence system productivity (feeds 130 screws/minute)
- screw speed to be optimized by virtue of screw shooting in a closed chamber. No compressed air is lost and all its energy is instead used to speed the screw along its path. This results in a considerable increase in speed for the whole system, which has a positive effect on process productivity.
Electric nutrunner motor
The latest-generation BL 40/05 MDW brushless motor provides extremely high consistency in tightening, while assuring unbeatable continuity. For a maximum torque range of 5 Nm, the motor features a telescopic fitting and a torque-angle transducer, which, together with the encoder, sends signals for the management of the programmed tightening cycles. The motor has auxiliary grips for handling, one of which features the tightening cycle start lever.
Cartesian arm BC 25/4
The arm supports the electric motor and keeps it perfectly perpendicular to the piece the tightening job is to be performed on. Extremely flexible, the system provides a wide working range both in height and parallel to the X-axis, allowing the operator to work on an area over the full 180° in a very ergonomically correct way
Single-channel computerized control unit TOCS-TAC
In the "panel" RACK version, it controls tightening cycles and assesses/monitors the tightening cycle in real time (torque/time curve). With its multiple features, this computerized control unit can handle a whole host of different tightening situations based on 20 storable programs and produce statistical reports on tightening operations stored in its memory (up to 1,000 results). The panel, which has a graphic display, allows the operator to call up results, which can even be "represented visually" by means of graphs
Power supply unit mod. BL – L-2
Supplies the motor and provides the right power supply parameters (voltage) in keeping with the control unit's preset data
What are the advantages of this new Autovite solution?
Completely ergonomic tightening operation
No effort required to hold the tool
No work involved in getting and positioning screws
No physical strain owing to awkward hand-arm system positions
Low noise of electric system
Unbeatable safety, thanks to low voltage
High production rate
The screw feeding system means there is no need for the operator to get screws and position them manually, so production rate is increased. The feeding rate is extremely high, as is the actual speed of the screw feeding system
Extreme reliability of tightenings
In the electric motor, the brushless static electronic transducer has an unlimited service life and the encoder (for measuring the angle) is a high-resolution model (n° of pulses/rev). These motors guarantee satisfactory results even if the characteristics of the joint vary from one piece to be assembled to the next: indeed, they are not affected by such variations, which are quite common in assembly operations, and ensure that the programmed parameters are met regardless.
Lastly, they do not produce any electromagnetic interference in the workplace and are not affected by such interference
Extreme adaptability to the existing production line
The system's small overall dimensions mean it can be integrated in any existing workstation.
|
