DirEKt TRANSFER : A NEW CONCEPT

DirEKt transfer is a new concept which allows moving the product from its conditioning container to its deposit zone directly with no intermediate preparation operation.

That process calls for a totally enclosed transfer head to inject the product directly through the stencil apertures.

It replaces the printing process and removes the squeegee notion which pushes a roll of product to be transferred.

Our knowledge of the product characteristics and the consistency of the machine parameters lead to consistent and controlled results.

The contact time is known and constant, the rheology of the product to be transferred in the enclosed head is known and constant, the transfer force given by the piston is known and constant.

The print speed is 3 times higher than with a traditional squeegee for a 0.4 millimetre pitch and the cleaning frequency divided by 10 for a 0.3 millimetre pitch shows at which point the quality remains optimum even with a significant throughput increase.

A test on a real production run to compare the cycle times between the two systems shows that 266 printed circuit boards per hour were produced with PROFLOW against 125 with the traditional method.

That process widens the process window dramatically. It can be noticed that parameter combinations between pressure and speed varying in an order of magnitude from 1 to 3 does not affect the quality of the result.

Trials to compare the volume transferred depending on the pad orientation have been conducted on 375 prints. They show consistent results from the beginning to the end of the test run.

In conclusion, the direct transfer process brings real significant improvements:

• A key process in the printed circuit board production is controlled.
• The solder paste consumption is reduced by 30%.
• The process opens new horizons towards miniaturization.

Varidot®