Microdosing
Among micro-dosing means the dose of flowable media in volume areas of less than one micro- liter .
The advancing miniaturization in almost all technical areas presents industry, development laboratories and research institutions with ever new challenges. Microdosing is one of those challenges. Ever smaller amounts of adhesives , oils , greases and a multitude of other media have to be dosed accurately and precisely with the shortest cycle times.
Dosing method
There are basically two different dosing methods: classic touch dosing and non-contact dosing.
Touching dosage
Contact dosing is as old as the desire to divide a medium stored in a large container into smaller quantities and to apply it to specific areas. A good example of this is dosing with a tube of glue. To dispense the adhesive, the drop of adhesive emerging from the tip of the tube must be transferred to the component by touching it.
Characteristic:
- slow dosage
- Component must be touched
- Component could be damaged
- Glue pulls threads
- Glue is not exactly where it was intended
- Adhesive quantities are difficult to reproduce
Despite these disadvantages, contact dosing is still used today in the majority of automated processes. The reasons for this are:
- lack of awareness of contactless dispensing systems
- few system providers for contactless dosing systems
- no direct access to the dosing point (e.g. undercuts)
- Media cannot be metered without contact
Contactless dosing (jetting)
Due to increasing demands on cycle times and accuracy in almost all production areas, contactless dosing (also known as jetting or pulsing ) is gaining in importance. One example is the bonding of electronic SMD components to circuit boards and substrates. The component carrier only needs to be positioned in the plane. The adhesive can then be applied without contact.
The example clearly shows the advantages of the contactless dispensing method:
- The elimination of the feed movement and the firing of the adhesive onto the component mean time savings
- no contact with the component (no damage)
- uniform formation of the adhesive drop,
- regardless of component topography and surface properties media
With the appropriate dispensing know-how, a large number of media can be dispensed without contact.
Due to the variety of dosing media and their different material properties, there are also media that are not suitable for contactless dosing.
Web links
- Walther Systemtechnik GmbH: Contactless dispensing - In tune with the times (PDF; 1.31 MB), information on pulse valves
Individual evidence
- ↑ all-electronics.de: Contactless dispensing of SMD adhesive - Jetting of SMD adhesive (PDF; 77 kB). Retrieved March 4, 2014 .