Robot dispensing of adhesive materials, such as epoxies and resins, pose pressure control problems that cannot be solved using conventional pressure transducers. The high viscosity of the dispensed material clogs up the conventional transducer pressure port and plumbing. The requirement was for the pressure control of the blending or extruding of two component compounds that are mixed at the tip of the dispensing robotic arm to form a quick setting adhesive. The adhesive is applied in dotted, thin straight lines. The control system has set pressure limits to assure proper placement of the adhesive.
The Model A105 was selected because of the flush diaphragm that responds to the rapidly changing pressures without clogging up. This model was also lightweight (less than 2 oz) so it would not effect the motion of the robotic arm. The Model A105 is rugged enough for the factory floor environment and easily cleaned with the flush pressure sensing diaphragm. A high level signal was needed for compatibility with the customer's control system, so the amplified version; the Model A105a was ultimately selected with a 4-20 mA output (two wire). The 4-20 mA output ensured a noise free signal for the customer's controller. The all-welded, hermetically-sealed Model A105a with the military-style, quick disconnect, bayonet connector provided the mechanical protection from solvents and the adhesive environment affording a quick sensor change if one were damaged.