01.1 SMD Process & Solder Technology

Question 1

How does a typical SMD Process look like and what are the key processes?

Answer 1

Question 2

Name the different types of voids:

Answer 2

Question 3

Name the potential defect during the soldering porcess (only some of them)

Answer 3

Question 4

what are the pre-conditions/ machine parameters to consider?

Answer 4

Question 5

Def Solder Paste

Answer 5

Solder Paste is a form of solder than can be easily applied on a Printed Circuit Board.
It has a viscous state and is grey in color.
The paste consists of a combination of tiny balls of solder and flux mixed together to form a paste.
It is applied to the pads on a PCB where electronic components need to be placed.
When heated this paste melts to form a connection between the pads and the leads of electronic components placed on the PCB.

Question 6

Soldering picture of process

Answer 6

Question 7

What is to consider when it comes to solder paste & before the use ?

Answer 7

Question 8

Solder Past Printing - different Steps to think aboubt

Answer 8

Question 9

Solder Past Printing: Typical defects 1

Answer 9

Question 10

Solder Past Printing: Typical defects 2

Answer 10

Question 11

Solder Past Printing: Typical defects 3

Answer 11

Question 12

Solder Past Printing: Typical defects 4

Answer 12

Question 13

Solder Paste Printing: –> SPI

What is to consider?

Answer 13

Question 14

How does a typical temperature profil look like?

Answer 14

Question 15

What are the differences when it comes to the heater systems (ovens)?

Answer 15

Question 16

Def AOI

Answer 16

The AOI system illuminates the inspected board from various angles and uses high-resolution CCD cameras that automatically scan the board and
take images of it. By comparing the images captured with the “golden board” or design specifications, it can evaluate the quality of the bare
boards and assembled boards. Technically, there are two methods used in AOI Technology, Design Rule Checking (DRC) and Image Recognition
Technique. As the name suggests, DRC checks the circuits based on the given design requirements. For example, the width of all leads should not
be less than 0.127 mm. If the tested board is not within the range, the defects will be highlighted. The Image Recognition Technique is to compare
the digital image stored in the AOI system with captured images of the tested boards. The detection accuracy of this method depends on the
standard image, the resolution, and the detection program used. As the PCB design rules and standards are constantly being updated, the DRC
method based on design rules is not very applicable. Instead, following the rapid development of computer technology and high-speed image
processing, the Image Recognition Technique has become the mainstream

Question 17

2S & 3D AOI

Answer 17

2D AOI (Automated Optical Inspection) is a type of inspection system that captures high-resolution images of PCBs (Printed Circuit Boards) from above, and uses algorithms to compare these images with the original design file to detect defects such as missing components, wrong component orientation, and solder joint issues. It operates under planar conditions and can only detect surface defects.

3D AOI is an advanced inspection system that captures images of the PCB from multiple angles and heights, in order to create a 3D model of the board. It allows for inspection of the top and bottom surfaces of the board, as well as the sides of components, and can detect more complex defects such as lifted leads, tombstoning, and skewed components.

Question 18

Trouble Shooting temperature profi

Answer 18