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Direct Dispensing

Direct dispensing is used to apply fluid and jellylike substances directly at the component which have to be processed. Using this, the coating is directly applied to the bottom of the component. A similar method is the stamping process, which is also called pin transfer. In contrast to the pin transfer, the direct dispensing method uses the component itself is the reference for applying the substance, i.e. the component is used as a stamping tool. For the application of the substance single surfaces like contact pads or the whole component bottom surface can be used as a reference surface for the wetting process. The substance is provided on a membrane, which can be structured using a concave vauum matrix underneath. The ambient air pressure pushes the membrane onto that structure, which causes that only the topmost features of the struture are used for the direct dispensing process.

General process sequence of direct dispensing:

  1. The component is pushed into the substance. The bottom surface and possibly the surfaces on the side of the component are wetted.
  2. The substance is structured using a concave vacuum matrix underneath the membrane. This process is conducted before or after the plunging of the component.
  3. The component is extracted from the substance.
  4. If the component is extracted high enough the substance shows a fluid breakup. Parts of the substance remain at the component.
  5. After a correct wetting of the component, it can be moved to the place of further processing, e.g. placing on a substrate.

The direct dispensing is useful for the following production processes:

  • Full or partial wetting of component bottom surfaces
  • assembly processes with a need of direct dispensing of substances on the component
  • chip bonding at COB
  • time-critical production processes
  • special kind of substances or the structure on the surface of the component

References

[1]           Patent Application DE000010145396A1
[2]          Patent Specification DE000010145396B4
[3]          International Patent Specification WO002002022278A2
[4]          International Patent Specification WO002002022278A3

continuative Articles

Requirements for Direct Dispensing
Things to Know for a good Direct Dispensing
Available Devices for Direct Dispensing

Abb. 1 Darstellung einer Direkt-Dosier-Einheit mit vorbereiteten Dosiermaterial (blau)

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