Multi-Axis Robots Provide Flexible Automation Solutions For Mobile Phone Manufacturers
by Bob Turner, Quadcom Ltd., and Mr. Simon Whitton
Stäubli Robotics Posted 07/26/2001
It is estimated that there are now more than 40 million users of mobile phones in the UK and approaching 500 million worldwide. Growth rates of around 60% are forecast for the next couple of years at least. This breathtaking demand has presented a considerable challenge to the major manufacturers of mobile phones requiring the commissioning of new factories and production lines while at the same time expanding their product range and improving design asthetics and functionality.
Without the legacy of existing manufacturing facililities the opportunity has been taken, indeed has been a necessity to meet the demand, to invest in state-of-the-art manufacturing processes and practices. Not surprisingly a high degree of automation is being incorporated into the new production lines. These are not the dedicated but inflexible automation systems of old, but adaptable and flexible automated lines built around the multi-axis precision industrial robot. This results in manufacturing facilities that are capable of switching easily between product designs and models as the fast moving trends in demand require.
Among the most common requirements quoted by manufacturers when selecting automation systems for the production and assembly of mobile phones are:
- High throughput
- Precise and repeatable production processes
- Complete flexibility to accommodate new products
- Highly adaptable production systems to allow frequent model changes
- Reliable and established production equipment
- Excellent product support and service
The 6-axis robot ideally meets these requirements, with hundreds upon hundreds of robots in use today producing mobile phones, working in applications from moulding machine unloading through to applying the decorative paint finish to the fascia and onto final packaging.
Unloading injection moulding machines
The moulded parts, mainly front and back covers, need to be unloaded as fast as possible minimising machine opening time. The speed and accuracy of the multi-axis robot coupled with the attachment of a slim gripper tool, gives significant operating advantages over linear 3-axis pick & place automation solutions, cycle times being reduced by over 40%.
Painting & Coating
Mobile phones require a conductive EMC coating to be applied to parts of the inner surface and other lacquers to shield the sensitive equipment from interference. These are often expensive copper, nickel or silver based pigments bound in resin, which require very precise application to the designated areas. Complete coverage and constant coating thickness are crucial to the phone's performance.
The final decorative paint and lacquer finish also has to be of extremely high quality. Mobile phones are increasingly treated as a fashion item and are now available in a kaleidoscope of colours and designs that test the control of the painting operation.
For these applications, compact 6-axis robots are available to help manufacturers avoid the need for huge painting cells, while the very precise trajectory control of today's technology can provide the coating thickness and consistency needed even at the high production rates encountered. User friendly, visual interface based software allows new spraying programmes to be set up easily by the painter, avoiding the need to call in IT specialists.
The 6-axis robot has the flexibility and adaptability required in assembly. New models can be easily accommodated, different parts can be added by adjusting the sequence at any workstation and the robot will operate within the cycle times and at a level of repeatability equal to any dedicated linear system.
Most of the mobile phone data displays are fixed by tape onto the plastic cover. As the gaps between the plastic cover and the display window reduce the placing of the window requires increasing precision. The latest applications even need vision systems to control and adjust the positioning of the display onto the tape and as a second step place the display with the tape onto the plastic cover. This is where the advantage of precision robots comes to the fore, with some systems capable of positioning the screen with a repeatability of +/-0.02mm, as well as providing the high speed and accuracy demanded by the tight cycle times.
Handling, testing and packaging
Removing parts from a pallet and placing onto a conveyor system, testing components and putting the final product into its packaging are all operations that can easily be performed reliably with linear pick & place automation systems.
The main advantage in these applications of multi-axis robots is their flexibility to accommodate new products. This is particularly important in this sector where models rarely last for more than one year. When a new model is introduced most of the dedicated pick & place automation systems will be unsuitable for the new line and discarded while the multi-axis robot can readily be re-programmed and integrated into the new line, even if completely different motion sequences are required.
Today's robots include models of a suitable size for many specific applications, with payload and reach easily up to the task, and designs that occupy a minimal footprint with mounting options for floor, wall or ceiling placement. Users can choose robots capable of following complex trajectories, with excellent repeatability, even at very high speeds. Depending on the robot supplier, model variants are available that are specifically adapted for paint spraying, clean room and metrology applications.
In the fast changing world of mobile phone manufacturing, 6-axis robots are rapidly becoming the standard against which other automation solutions are compared. Their ability to adapt to new models, their precision and capability to provide reliable and repeatable operations within the short cycle times demanded has been recognised by all major manufacturers as well as the growing number of 1st tier and 2nd tier specialist suppliers.