Getting to the point

Selective soldering of sensors in the protective housing

The production of sensors for the automotive industry requires increasingly sophisticated solutions. A new machine concept developed by IPTE Factory Automation enables the fast and reliable soldering of printed circuit boards in the plastic housing. The ready-to-install industrial robot from Festo used in the concept makes cycle times of less than three seconds possible, despite a moving mass of more than 60 kg.

These days, a car is much more than just a means of getting from A to B. It can also provide intelligent feedback thanks to all kinds of comfort and safety functions. The typical car today has on average up to 100 sensors on board, with the number set to increase further in the future. With the number of sensors on the rise but the available space staying the same, more compact and in some cases also more robust sensors are increasingly required. Innovative production solutions are needed in order for the production process to keep up with this level of sophistication. Belgian company IPTE Factory Automation n.v. has met the new challenge head on with its latest systems. The experts in industrial automation worked with Festo to develop an innovative machine concept for the selective soldering of sensors directly in the housing.

Reliable soldering in the housing
Sensors located outside the car's interior have to withstand harsh environments, with temperatures ranging from below -40°C to over +100°C, and they also need to be corrosion and shock resistant. These sensors are enclosed in a tough housing to protect them. However, the inner parts of the sensor cannot be inserted into the housing fully pre-assembled. Certain soldering work has to be done directly in the housing. Conventional soldering techniques such as wave or reflow soldering are not possible here, since the plastic housing would not be able to withstand the temperatures involved. The only option is the more demanding technique of selective soldering. An essential requirement for this technique is applying the right force at the right angle. The high process quality, repetition accuracy and production speed required for this, call for fully automated processes.

Development of a new machine concept

IPTE developed a new, programmable selective soldering system for connecting the battery and printed circuit board directly in the sensors' protective housing. A complete machine concept was created for this in cooperation with Festo. The ready-to-install industrial robot by Festo makes a cycle time of less than three seconds possible through quick and precise movements along the X-, Y-, Z- and W-axes, despite a moving mass of more than 60 kg. The solder is fed in with an accuracy of 0.1 mm and the speed at which the solder is unwound from the reel is controlled. Other advantages of the compact IPTE system include automatic tip calibration, integrated tip cleaning, operation with solder reels, color detection and an option to switch to lead-free soldering. A reliable suspension system ensures that the soldering tip is applied to the printed circuit board with the right force for optimum thermal contact during soldering. An integrated crash sensor protects the boards against excessive pressure.

Custom-made and delivered as a complete package

IPTE designed the XYZW gantry system with four degrees of freedom, with support from Festo during the design and production process. The X-, Y- and Z-axes use standard spindle and type EGC toothed belt actuators with integrated displacement encoder and EGSL mini slide. Festo developed a custom-made module for the rotary unit (W-axis). The gantry for the flexible and controlled speed and acceleration of movement (XYZ-axis), and an ERMB rotary module were specially adapted to the system and are used for lifting and rotating the soldering needle. This means that the system can reach even difficult to access warehouses in the sensor housing, and solder at precisely the right angle with the right force. It is capable of high-speed positioning, despite the high moving mass.

More safety guaranteed

IPTE's new machine concept can be used anywhere. Apart from soldering applications, it can also be used for many other applications such as dispensing. The gantry, which includes servo motors and type CMMP controllers with EtherCAT interface, is adapted by Festo to the specific requirements of the different applications and supplied as a ready-to-install complete system. Festo provides an additional layer of safety by guaranteeing the function of the system on delivery. The customer not only receives a ready-to-install industrial robot, he can also be sure that it will function properly, right from the start.

IPTE Factory Automation n.v.

Geleenlaan 5
3600 Genk

Key activity: Development of ready-to-install automation systems for the production, testing and further processing of printed circuit board assemblies and end products