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Considerations when choosing a dispensing robot

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Dispensing robots enable automation to apply adhesives, potting compounds, encapsulants, sealants, form-in-place gaskets, temporary masking, lubricants and other liquids, fluids and pastes repeatably with absolute precision. Careful consideration of the requirements of an application is vital, says Peter Swanson, Managing Director of adhesives specialist Intertronics. Here he explains key considerations when choosing a dispensing robot.

According to the World Economic Forum, more than half of the world’s workplace tasks will be carried out by a machine by 2025. However, while 75 million jobs are likely to be lost to automation by 2022, a further 133 million will be created. The application of adhesives and other materials is a prime candidate for automation, with the redeployment of skills and the resultant productivity gains.

Why automate the dispensing process?

Manufacturers automate their dispensing processes for many reasons, including consistency, speed and accuracy. A dispensing robot can apply materials with positional accuracy and precise quantities, and repeat that all day long. Often, the output is faster than a manual process, and sometimes can achieve results that are not possible for a human. For example, the application of an even bead of gasketing around a complex profile is not feasible manually.

Return on investment for a dispensing robot can take just a few months, due to increased output, the decreased number of rejects, and the reduction in material waste. Skilled operators can be reallocated to other demanding tasks.

The function of a dispensing robot

In a dispensing application, it is important to note that the robot’s function is to position and actuate the dispenser. Best practice would be to select the dispensing methodology first – something which can be quite complex – and then choose the robot. The dispensing equipment selected will be dependent on several factors, such as the material to be dispensed, the level of accuracy, and the tolerance and repeatability required.

Considerations

Once the manufacturer has decided on an appropriate dispensing methodology, then a positioning system (robot) can be chosen.

Factors to understand when specifying a dispensing robot include the work area – robots are available from 200×200mm up. Decisions will be made on the size of the parts, and if multiple parts will be loaded onto the bed for each cycle. If the parts are tall, then robot height is consideration; for taller parts, a gantry-type robot may be required instead of a benchtop robot.

Most dispensing robots supplied are fully programmable in 3 axes, but 4-axis and 5-axis robots are available for more complex 3D dispensing paths. The robot will need to support (and maybe move) the weight of the parts and the holding jig, and support (and move) the dispenser, so weight is a potential issue. Finally, will the parts be loaded/unloaded manually, on a pre-loaded fixture, or fed by a conveyor? In the latter case a gantry robot is needed.

It is important to understand early in the specification process the expected tolerances and repeatability for the material application. Meeting these will depend on the dimensional consistency of the parts and the accuracy of the positional tooling, as well as the performance of the robot and dispensing methodology. It may be that the desired results are too demanding for this combination, so that add-ons like automatic dispensing tip alignment, height sensing or vision-based fiducial adjustment are required.

By working with an experienced supplier, manufacturers can carefully consider their options and select appropriate equipment. Your supplier can supply and integrate the dispenser with the robot and configure it with the tools, fixtures, benches and safety enclosures. Importantly, they will also provide the training needed to get the process running optimally. For more information see www.intertronics.co.uk.

 
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