Design & Automation Solutions’ machines are based on a successful design used for the assembly of a convex medical part and can be tooled for a variety of functions, providing bespoke solutions from standard parts.
At the heart of the machine, a 3-axis CNC controlled application head accurately applies a wide range of adhesives and sealants via appropriate dispensing equipment. For more complex shapes, the 3-axis head can be replaced with a 6-axis robot, and up to seven additional stations can be added for assembly, curing and inspection functions.
Problem: assembly machine for 2-piece convex medical part. Solution: a four-station rotary machine was developed incorporating a three-axis CNC-controlled adhesive application head to dispense two beads of hot-melt adhesive. This process demanded accurate positioning of the adhesive bead and, due to the unpredictability of the adhesive (high rubber content), there was a need to ‘fine tune’ the adhesive path.
The machine consists of a cam indexer driving a dial plate fitted with interchangeable location tooling to accommodate the range of different parts to be assembled. The 2 pieces of the assembly are loaded into the location tooling by hand (can be automated) and a 2 hand start used to index the tooling to the next position.
At the adhesive dispense station, the head moves into position and sensors check that both parts are present before dispensing can start. The sensors are fitted to the head, because of the range of parts being processed, which enables the control to provide different check positions for each component. Should parts not be present, the control inhibits further processing. With both parts present, the adhesive is applied on a pre-programmed path, which can be single or multiple beads in an almost limitless range of patterns. After dispensing, the head retracts to a purge position with collection container below. Purging can be manual or automatically activated, as required.
During the adhesive application process, the operator loads the next set of parts and, once this has finished, a light indicates to index again. Should the dial plate not be indexed within a preset time, (determined by the adhesive), the control again inhibits further processing.
At the assembly station, a specially shaped vacuum head picks the upper part and accurately places it on the lower part with the adhesive applied. This is held for a preset time to allow the initial bond.
The final station removes the finished parts and stacks them on an outfeed conveyor for transfer to a packing area or could lead directly to a packing machine or further process.
The machine has a PLC-based control system fitted with multi-axis interpolating servo drives for the adhesive application head and an HMI to allow general data entry & messaging and recipe handling for different product settings.
