Page 54


www.us-tech.com


April/May 2023


Potting Optimized Component Design By Markus Jacobi and Dr. Karin Steinmetzer, Scheugenpflug Global I


f engineers and designers take production and potting into account during design, there


are a variety of benefits that can be obtained. These include: longer product life, fewer complaints, shorter cycle times, optimized system costs, and greater func- tional reliability. To achieve the best possible


results there must be a compre- hensive interchange between the system planning, production and after-sales departments so that experience with previous prod- ucts can be leveraged. The involvement of system and mate- rial suppliers is also useful in order not to miss any new, eco- nomical design options. If all these aspects are incorporated in the component design, the over- all result will also be impressive in terms of total cost of owner- ship.


Potting optimized compo-


nent design involves displacing air during the potting process and facilitating such displace- ment. This will prevent the pres- ence of bubbles in the potting material which sometimes have serious consequences for the cor- rect operation of the product. Air pockets in the potting


material have adverse effects. Depending on the product, they may reduce service life or even cause complete failure. In some circumstances they may con- tribute to thermal loads and therefore stresses inside the component and even cracks in the outer skin. Air bubbles have poor thermal conductivity, reduce insulation and therefore reduce the dielectric strength of components, for example. They also encourage corrosion.


Design Security “Errors” made in component


design can be corrected later only at great expense in terms of time


and money, if at all. Design secu- rity results from adherence to the potting rules and early dialog with all the various departments in the company and with materi- al and system suppliers. If exist- ing experience is not sufficient for potting-optimized component design or if new materials are


ic components, sustainable use of materials — all these things define the requirements for absolutely bubble-free potting. Following these tips represents an important step forward. It does not matter whether the “potting” is for filling, sealing or impregnating electronic compo-


gradually escapes during potting under atmospheric pressure or not at all, it is advisable to pot the components under vacuum. There are two design meas-


ures that will facilitate the escape of air: If components with large horizontal surfaces are arranged vertically the air can escape more easily. If the overall design does not allow this, open- ings should be provided in the horizontal surface for the air to flow out. Also, provide spacing for flat


components. Flat components should be installed with suffi- cient clearance from the housing. This will allow the potting com- pound to flow better and fill the gaps.


Generously proportioned or


tall component designs make for a faster potting process. If neces- sary, small supports may be used to create sufficient clearance from the housing and provide a smaller barrier for ascending air bubbles. Select the component size


Testing under production conditions can help to optimize component design.


being used, testing under pro- duction conditions in a technolo- gy center will help. This will ensure that all the questions are clarified at an early stage and within a reasonable timeframe. This creates security for an eco- nomical and sustainable potting process and the required product quality. Potting-optimized compo-


nent design has high sustainabil- ity potential. Minimal waste, reduced material use and shorter cycle times are not only econom- ic but also ecological aspects that are becoming increasingly important.


Component miniaturization,


more complex shapes, increasing security-relevant use of electron-


nents. The direction of flow of the potting material and therefore the free displacement of the air is always the crucial element.


Tips for Success First, avoid horizontal sur-


faces. Components embedded horizontally are obstacles to ris- ing air bubbles. They may pre- vent the underlying contacts from being completely enclosed by the potting compound because of the formation of air bubbles. Next, provide space for air to


escape. The larger the number of components the smaller the pot- ting spaces. A large amount of air is stubbornly trapped in the fine gaps of windings, such as those of ignition coils. If this only


carefully. The size of the compo- nent affects later potting in vari- ous ways. The different require- ments may result in conflicts. Let’s assume the potting


material we are using has a slow reaction time. A larger potting space, if possible, would allow for faster potting. In this case, the entire amount will flow at once. As the resulting air pockets escape upwards the potting com- pound will continue to flow down and fill all the gaps. If the housing dimensions


are tight it may be necessary to pot in several stages. After each dispensing process, there will be a waiting time until the material has completely disappeared and the air pockets have escaped. This results in longer cycle times.


Continued on page 56


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100