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Automated Optical Inspection Guide

The document discusses various techniques for automated hardware testing, including automated optical inspection (AOI), boundary scan testing, Joint Test Action Group (JTAG), and burn-in testing. AOI uses cameras and image processing to detect defects on printed circuit boards and other parts during production. Boundary scan testing examines connections between integrated circuit pins using test cells. JTAG is a standard developed for printed circuit board testing that is also used for integrated circuit debugging and testing sub-blocks. Burn-in involves operating components under stress prior to deployment to identify early-life failures.

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Yosikan Catalin
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123 views5 pages

Automated Optical Inspection Guide

The document discusses various techniques for automated hardware testing, including automated optical inspection (AOI), boundary scan testing, Joint Test Action Group (JTAG), and burn-in testing. AOI uses cameras and image processing to detect defects on printed circuit boards and other parts during production. Boundary scan testing examines connections between integrated circuit pins using test cells. JTAG is a standard developed for printed circuit board testing that is also used for integrated circuit debugging and testing sub-blocks. Burn-in involves operating components under stress prior to deployment to identify early-life failures.

Uploaded by

Yosikan Catalin
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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27-03-2012

Hardware testing

Dr.ing. Antonius STANCIU

Automated optical inspection

AOI is a type of white box testing.

Used for testing: PCB, LCDs,


transistors, automotive parts.

Detects problems early in the


production process.

Automated optical inspection

Capturing an image: scanner or camera

Type of cameras: Streaming video 2D frame


grabbers, Line Scan Still Image Camera and CCD
camera.

Learning methods for AIO systems:


image matching;
algorithm based.

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27-03-2012

Automated optical inspection

To obtain the necessary data one can use 3D software imaging or LED
light measurements (for accurate measurements, typical systems use
both).

System speed is influenced by the size and complexity of the board


being inspected and the level of inspection.

Type of machines
Stand-alone and inline AOI systems
Closed-and open-top AOI systems
AOI and combined AOI/AXI systems

Automated optical inspection

AOIs can inspect this features:


Area defects;
Component polarity;
Component presence/absence;
Excessive solder joints;
Height defects;
Insufficient paste around Leads;
Insufficient solder joints;
Severely damaged components;
Solder bridges;
Volume defects;
Wrong part.

Boundary scan

Method for testing interconnects.

Test cells are connected to each pin of the device.

Devices that support boundary scan contain a shift-register


(BSR) cell for each signal pin of the device.

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27-03-2012

Boundary scan

Joint Test Action Group (JTAG)

The year 1990: IEEE 1149.1 Standard Test Access Port and Boundary-Scan
Architecture.

Intel released, in 1990, the first processor with JTAG: the 80486.

Devised for testing printed circuit boards using boundary scan.

Used for accessing sub-blocks of integrated circuits.

Joint Test Action Group (JTAG)

TDI (Test Data In)


TDO (Test Data Out)
TCK (Test Clock)
TMS (Test Mode Select)
TRST (Test Reset) optional.

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27-03-2012

Joint Test Action Group (JTAG)

Joint Test Action Group (JTAG)

Debugging architectures built up using JTAG: ARM CoreSight and Nexus.

JTAG is used by FPGA developers.

By using JTAG and Boundary Scan chain you can test the combinational
logic.

Devices expose one or more test access ports (TAPs).

Bead probe technology

Used to provide electrical access.

Bead probes do not affect the signal


quality.

The bead probe leaves a coating


of flux.

Require the trace being tested to be


located on the surface.

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27-03-2012

Burn-in

Components of a system are exercised prior to


being placed in service.

If the burn-in period is made sufficiently


long, the system can then be trusted.

A precondition for a successful burn-in is a


bathtub-like failure rate.

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