SPI (Solder Paste Inspection)

Solder paste is applied during the printing process and is necessary to attach the components to a circuit board to assure the proper electrical connection. The printing process has become extremely complex due to today's circuit board configurations that pack very small components into extremely tight spaces. Over 50% of circuit board defects are rooted in problems related to solder paste printing. To accurately determine the accuracy of the printing process, 3D solder paste inspection has become a requirement.

When to use SPI

SPI is used after the printing process to check for solder paste volume, insufficient, missing, or excessive solder, stains, bridges, defects in solder shape, mask misalignment, and foreign material. SPI is also used in the printing test set-up to review the stability of the process prior to a substrate change, to detect any mask cleaning failures, and to catch any printing condition changes. When the SPI system detects a failure, it can immediately feed that information back to the printer to automatically adjust the machine's settings.

Saki's 3D SPI Advantages

Saki's BF-3Si 3D SPI system uses a combination of 2D and 3D images and, using Saki's proprietary software, can rapidly scan the board in one pass, making it one of the fastest 2-projector solder paste inspection systems available. The system creates 3D images of the whole board, providing pad-based warpage compensation, and, with Saki's closed-loop process functionality, feeds that information back in real-time to make course corrections in the assembly process.

Saki's BF-3Si 3D Solder Paste Inspection System uses its proprietary Phase Measurement Profilometry with Liquid Crystal on Silicon (LCoS) technology to optimize measurements for printed solder paste and ensure high repeatability of inspection results with

  • Height inspection repeatability of 2μm at 3σ
  • Volume inspection repeatability of +/- 3%
  • High gauge repeatability and reproducibility (GR&R)
  • Height range of 0-500 microns

Both Saki's 3D SPI and 3D AOI share the same machine platform for interchangeability of hardware, and Saki's entire 3D lineup of SPI, AOI, and AXI share the same software for easier programming, operation, and training.