A good SMT paste process

Cimar Electronics cooperates with leading suppliers in order to ensure a good quality. It definitely goes for our supplier of solder pastes and screens. After all, various researches have shown that 50% of the possible soldering defects are a result of this first step in the SMT production process.

Results print assembly predictable

Goal is to minimize the number of defects at this stage. Our supplier Rotec offers a combined solution. Thanks to extensive research to the interaction between screen and paste, these two products have been perfectly fine-tuned, allowing print assembly results to become predictable.

One of the results of these researches is that screen thickness can be determined based on a mathematic model. Small components won’t get too much soldering paste, yet larger components will get enough. It is even possible to process several thicknesses in the same screen, for example if a sensitive connector needs more soldering paste compared to the rest of the components on the PCB.

High accuracy screen

For most outsiders, a screen simply looks like a metal place with holes, but actually it is a unique tool designed by a trained team of CAD-engineers, according to design rules that have an impact on:

- Optimizing BGA design rules, especially for fine pitch BGA’s

- Avoiding fasteners at fine pitch connectors and QFP’s

- Avoiding soldering balls at passive components

- Anti-tombstone design

- Optimized QFN-design

To get an impression of the high accuracy of such a screen:

By means of 6 sigma optimization of the climatized laser accuracies of 3-5 (!) micron can be achieved on a cut screen hole.