2D inspection (2Di) ensures the quality of the print by monitoring the printing process. 2Di determines when a stencil clean or paste dispense is required and if licensed, to warn for bridging, misalignment, stencil smear, stencil blockage and reduced paste volume.

2Di optimizes the cycle time by eliminating unnecessary stencil cleaning and paste dispensing operations. To achieve this the system inspects various areas of the board and/or stencil (sites) to detect the following:

Stencil Blockage - Solder paste remaining inside stencil apertures.
Stencil Smear - solder paste on the underside of the stencil.
Board: Paste Present - amount of the pad covered by solder paste, as a % of the aperture size.
Board: Alignment - accuracy of paste positioning compared to the learnt site image.
Board: Bridging - distance between adjacent deposits of paste or between pad and next pad.

Green v Gold

The DEK Gold camera system gives a field of view three times larger than that available with the Green camera system. This speeds up the inspection process by the reduction in the number of sites the system is required to visit to accomplish the inspection task.

Paste Volume Prediction

Using stencil aperture, blockage and paste present information the system can calculate the volume of paste on the pad.

Stencil Inspection

The vision system carries out various stencil inspections and are shown below:

Paste Volume Prediction

2Di combines the results of board and stencil inspections, and using a propriety formula calculates the predicted paste volume. This is only available while the inspection is set to advanced for both board and stencil.

In the example shown the aperture is 100% clear. The paste on pad value was 100%. This can be represented by the following model of the printed paste:

From this information the system predicts the volume of paste, in this case 100%.

In the following example the aperture has a blockage of 40%. Therefore the aperture is 60% clear. The 60% is equal to a rectangle of the same size as shown below. The paste on pad inspection results is 90%.

This represented by the following model of the printed paste:

From the information the system predicts the volume of paste, in this case 74.48%.



Summary Specification

Inspection	Specification
Maximum Number of Sites	1000 sites
Maximum Site Size	4 mm by 6.5mm (Green/graphite Camera) / 10mm x 7.5mm (Gold Camera)
Automatic Learn	Single Site
	Rows
	Columns
	QFP
	BGA
	BGA Frame
Stencil Inspection	Accuracy (Within)	Repeatability
Aperture Blockage	±6%	±5%
Stencil Smear	±0.1mm²	±0.05mm²
Board Inspection
Paste on Pad	±5%	±5%
Bridging	±0.05mm	±0.02mm
Paste Alignment	±0.02mm	±0.02mm
Predictions
Paste Volume	±6%	±5%
Programmable Inspection Rate	All sites inspected every cycle
	Selected sites inspected every cycle
	Inspection of sites every n cycles
General Inspection Parameters	Individual site limits
	Individual site naming option
	Each inspection site can be given a unique name to make it traceable
	Programmable warning and alarm levels for individual sites
Programmable Action on Alarm	Reprint after low paste detection
	Under screen clean after blockage or smear detection