Robot dispensing system accurate to two decimal places

Citation

(2005), "Robot dispensing system accurate to two decimal places", Assembly Automation, Vol. 25 No. 1. https://doi.org/10.1108/aa.2005.03325aad.003

Robot dispensing system accurate to two decimal places

Robot dispensing system accurate to two decimal places

Keywords: Robots, Adhesives

TM Robotics, system integrator AMT and Failsafe Metering have worked together to develop a groundbreaking method of using robots to dispense 100 per cent accurately mixed two-part reactive chemicals. The work was conducted in Failsafe Metering's R&D lab in Kettering. It uses a Shibuara Cartesian linear actuator supplied by TM Robotics as the robot “guinea pig” (Plate 3). AMT provided its integration expertise to ensure that the robot operates to its full potential.

Plate 3 Failsafe Metering and TM Robotics are working together to integrate a Cartesian Linear Actuator into Failsafe's innovative adhesive bonding process TMR0129

There are countless two-part reactive chemical systems that are essential to a vast number of manufacturing processes. These range from performance critical gluing and sealing on vehicle production lines to civil engineering projects. Such processes rely on the ratio content of the two- part adhesive system, which typically ranges from 1:1 to 10:1 by weight, being completely accurate. Imagine an airplane where the tail assembly bonded composite structure delaminates and fails and one can begin to see why accurate two-part mixing is truly mission critical. Failsafe's process is already being used on vehicle spoilers and in several different kinds of vehicle door sealing systems.

The process is based on the fundamental properties of a liquid under pressure. In this case, the two reactive liquid parts of a reactive system are subjected to high pressure, thus, becoming hydraulic, and producing a maximum density per unit volume. Each liquid part can then be uniformly divided into two precise, volumetric units in the specified ratio relative to each other (usually from 1:1 to 10:1, by weight) prior to being electronically checked for accuracy. This is where the biggest distinction between this system and a conventional two-part reactive chemical mixing system lies. In most processes, the manual taking of random weight checks of the two outputs, prior to the mixer is the only way to check the theoretical ratio of each liquid in the mix.

After checking, the adhesive components are rapidly fired forward towards, and combined within, a dispensing head, from which the output forms a shot or flow. The qualification of this metering process is based on an electronic signal, which is generated when each dot is tested for the correct volume. These high-speed signals are sent to a meter, which will shut down the system if the mix is incorrect thus preventing it from reaching the point of application. At present, the entire system is correct to two decimal points. For example, if you require a mixture of one part to 50 and you actually have 1/49.99 the process is stopped.

“Automation, by itself, only increases the efficiency of a process,” said Nigel Smith, managing director of TM Robotics. “It doesn't mean that the product being manufactured is of any higher quality. Unless the raw materials or quality assurance process is improved, a line of glue will always be a line of glue, with all the faults inherent in that. However, Failsafe Metering's process actually allows the end product to be improved. When combined with the innovation delivered by automation this represents a formidable proposition.”

For further information contact: Nigel Smith, TM Robotics (Europe) Ltd, Unit 15, The Weltech Centre, Ridgeway, Welwyn Garden City, Herts, AL7 2AA. Tel: +44 (0) 1707 871535; Fax: +44(0) 1707393959; E-mail: sales@tmrobotics.co.uk; web site: www.tmrobotics.co.uk