Dispensing with added value

Experience is (almost) everything! And that also goes for dispensing.

The component is ready, the production processes are fully coordinated, production gets under way – but the results are disappointing. The problem is the dispensing process.

Perhaps there are gaps in the dispensing bead, or the wrong amount has been applied, or there are discrepancies in the contour, or bubbles in the material. So what’s the reason? Well, in order to develop a dispensing process that is perfectly suited to a particular project, it’s not enough simply to provide a dispensing system with the right parameters. Experience and know-how are indispensable here.

Efficient, tailored bonding and potting processes are crucial for the long-term reliability of electronic components. Even the smallest deviations or inhomogeneities during dispensing and potting can significantly impair the quality and service life of the components.

And who wants to take such a risk with a car battery? Or with an air taxi? Or with sensors for autonomous driving? Or, heaven forbid, with a pacemaker? Component failures here not only mean high costs, they damage reputations and, worst of all, they can endanger lives.

PCB with precisely applied dispensing material
Adhesive Bonding | Quality assurance
Rainer Haslauer, Scheugenpflug Academy
Rainer Haslauer
Academy

With almost 20 years of experience in the dispensing industry, Rainer Haslauer brings a lot of experience to the Academy as a trainer. With a passion for lifelong learning and knowledge transfer, he is dedicated to sharing valuable expertise with both our customers and Atlas Copco employees.

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So what do you have to consider?

There are the classic considerations, of course, such as the application method, heat dissipation, filling, sealing contour and encapsulation of printed circuit boards. You also have to consider the component and the material – so far so good. It sounds like a simple building block system where you put it all together step by step. But there is much more to it than that. First and foremost, it’s a question of mastering the entire process from preparation and pretreatment to inspection. Because by the time the dispensing process comes around, a large number of production steps will have already taken place, and any faults in those steps will jeopardize the entire outcome.

The true art of a dispensing process is to give full attention also to the period before bonding and potting.

Multi-Nozzle Dispenser combined with a vaccuum chamber for bubble-free potting
Dispensing system with integrated vision system for bead inspection
COMPONENTS & THE LOGISTICS FACTOR

Components are often exposed to widely varying ambient conditions as they get transported from place to place – from 35 degrees in a factory in a Mexican summer to minus 10 degrees outside a warehouse in a Norwegian winter, not to mention moisture, dust and dirt from packaging that has been left open. It is incredibly important to consider logistics because fluctuations in temperature and changes to surfaces can lead to different tolerances and create immense challenges for the dispensing process.

THE DISPENSING MATERIAL

Finding the right dispensing material for a bonding and potting task is just one challenge; clean handling is another. How does the bonding or potting compound behave in fluctuating temperatures, how does it behave as it ages? Does the viscosity change? What is the degree of sedimentation, what is the risk of deposits? How limited is the processing time?

Combining all these factors is a highly complex process. For example, what happens when cold material is applied to a warm component? Does it form condensation? Does it have to be predried? If this is not noticed before dispensing begins then it’s too late. So plan ahead and, for example, use laboratories that create realistic test scenarios. But you yourself need to know your conditions. An experienced consultant can then put together the best solution for you.

Rheological measurement in our Analytics Lab
Employees performing quality control with inline inspection using RTVision
THE PERSONNEL AND USABILITY FACTORS

Did you know that in the fields of medical technology and rail transport only trained specialists are allowed to carry out bonding procedures? The result is that the reject rate is very low indeed. This also applies to fully automated systems because despite all the automation there is still the human factor. It’s also important to make the individual processes as simple and reliable as possible. Errors and material waste can be reduced by following step-by-step guides and having each step confirmed, by using scanners or color sensors or by adopting the “poka-yoke” approach, for example.

According to a study by the Fraunhofer IFM on the circular economy and bonding technology, today’s adhesives are high-tech products that generally ensure zero-defect production.

However, bonding defects still occur, over 90% of which are due to errors in applying the adhesive. This contradiction is precisely what the quality assurance standards aim to address. If the main reason for defects does not lie with the adhesive but with its application, then the application process must be improved.

Source

MAINTENANCE

That’s not the end of it. You have found the optimum dispensing solution for your project. Production is up and running, your components are perfect. Air taxis and pacemakers are working smoothly. So here’s our tip: stop and take a break! What? Now? YES, and carry out maintenance work on your dispensing systems. Regular maintenance is essential. Especially after non-standard phases, for example after full-load cycles or changes in operating times.

Component after dispensing process in visual inspection
Experience and know-how are the keys to the dispensing process

When all is said and done, it’s experience that really counts. Experience is the supreme discipline of dispensing.

What should work in theory doesn’t always in practice. Never forget that dispensing is a highly complex process. Always keep your processes under review. Get your partners on the team and get the best out of them. There is always something that can be done better. ALWAYS.

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11/2023
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