Introduction
In the SMT production process, insufficient solder paste, printing misalignment, or localized deposition anomalies can all increase quality risks in subsequent processes. As a result, an increasing number of electronics manufacturers are adopting SMT SPI equipment to automatically inspect solder paste printing results.
Faced with different types of SPI equipment, how should procurement personnel and engineers make their selection? Should they prioritize 3D inspection technology, or factors such as inspection accuracy, speed, PCB compatibility, and software functionality? How should equipment pricing be evaluated?
Based on practical procurement needs, this article provides a systematic overview of the key selection criteria for SMT SPI equipment. By referencing the product specifications of the NeoDen S1, it will help you determine which SPI equipment is best suited for your SMT production line.
What Is an SMT SPI System?
SPI stands for Solder Paste Inspection. SMT SPI systems are primarily used to inspect the quality of PCBs after solder paste printing. They measure relevant parameters of solder paste deposition before component placement, helping engineers identify printing anomalies.
In a typical SMT production line, the SPI system is usually installed after the solder paste printer and before the SMT machine.
1. What issues can SPI equipment detect?
Depending on the equipment's inspection technology and software capabilities, SPI can measure the following parameters:
- Solder Paste Volume: Measures the volume of solder paste deposited on the pad.
- Solder Paste Area: Checks the coverage area of the solder paste on the pad.
- Solder Paste Height: Measures the height of the deposited solder paste.
- Solder Paste Offset: Determines the deviation of the solder paste deposit from the target position.
This data helps engineers identify issues such as insufficient or excessive solder paste, misalignment, or height anomalies, and enables them to analyze and adjust the process according to actual requirements.
SPI cannot eliminate all soldering defects, but it can move the inspection process upstream, providing data support for solder paste printing quality control.
Should You Choose 2D SPI or 3D SPI?
When purchasing SMT SPI equipment, you must first clarify the inspection tasks and then determine whether 2D or 3D inspection technology meets your needs.
1. What Does 2D SPI Primarily Inspect?
2D SPI primarily analyzes the planar visual characteristics of solder paste through two-dimensional images. Depending on the equipment's capabilities, it can be used to inspect information such as the shape, coverage area, and position of the solder paste.
If inspection requirements focus primarily on planar visual characteristics, 2D inspection can serve as a viable evaluation method. However, two-dimensional images alone cannot provide the same direct height information as three-dimensional measurements.
2. What are the advantages of 3D SPI?
3D SPI can capture three-dimensional information about solder paste deposition, thereby supporting the measurement of parameters such as height and volume.
For example, two areas of solder paste deposition may have similar coverage areas in a 2D image, but their actual heights and volumes may still differ. Through 3D measurement, engineers can obtain more data for evaluating print quality.
Therefore, if production processes require quantifying solder paste height and volume, or if a more in-depth analysis of printing process consistency is needed, 3D SPI equipment should be prioritized for evaluation.
3. Is 3D SPI necessarily more suitable than 2D SPI for all production scenarios?
Not necessarily.
Equipment selection should be based on a comprehensive evaluation of PCB type, pad characteristics, process requirements, inspection accuracy, repeatability, processing speed, and budget. The suitability of a device for actual production cannot be determined solely by the "2D" or "3D" technical label.
The NeoDen S1 is equipped with a 3D raster camera and supports both 2D and 3D true-color image display. Companies needing to evaluate 3D solder paste inspection capabilities should include this model in their equipment selection.
Which inspection parameters are most important when selecting an SPI device?
Once the inspection technology has been determined, the next step is to compare the specific specifications of the devices. When purchasing, do not focus solely on a single accuracy figure; instead, understand the inspection capabilities corresponding to each parameter.
1. Height Detection Accuracy and Repeatability
Detection accuracy reflects the precision of the equipment's measurement results, while repeatability focuses on the consistency of repeated measurements under specified conditions. These are not the same concepts. If production involves fine-pitch pads or components with specific requirements for solder paste deposition height, it is essential to carefully verify the equipment's height detection accuracy and related test conditions.
When purchasing, you should also confirm with the supplier the definitions, testing methods, and applicable conditions for these metrics to avoid judging the equipment's actual inspection performance on PCBs based solely on parameter values.
2. FOV and Measurement Resolution
FOV stands for Field of View. It refers to the area covered by a single image captured by the equipment, while measurement resolution pertains to the system's ability to identify and measure fine details.
It is important to note that FOV, image resolution, and final measurement accuracy are not the same metric. Purchasing personnel should make judgments based on a combination of the equipment's technical specifications, actual inspection targets, and sample test results.
3. Maximum Inspection Height and Solder Paste Size Range
The maximum inspection height and the range of detectable solder paste sizes also affect the equipment's ability to meet specific process requirements.
If a PCB contains pads of different sizes, it is recommended to prepare representative samples to verify whether the equipment can meet actual inspection requirements.
4. Inspection Speed and Production Cycle Time
The processing speed of SPI equipment affects the overall line cycle time; however, the inspection time for an entire board or the line's throughput cannot be directly estimated based solely on the processing time per frame.
Therefore, when evaluating SPI equipment, it is recommended to simultaneously verify the actual inspection time for the target PCB and compare the results with the cycle times of the solder paste printer, SMT machine, and upstream and downstream equipment.
How to Verify Whether SPI Equipment Is Compatible with Existing PCBs?
No matter how advanced the equipment's inspection capabilities are, it will be difficult to put it into operation smoothly if it cannot accommodate the actual PCB dimensions, thickness, or conveyor systems used in production.
1. PCB Length, Width, and Thickness
Before purchasing, compile a list of current products' standard dimensions, maximum dimensions, and special board types, and verify each item against the equipment specifications.
The NeoDen S1 supports the following PCB parameters:
- Minimum PCB dimensions: 50 × 50 mm
- Maximum PCB dimensions: 500 × 460 mm
- PCB thickness: 0.6–6 mm
If production involves PCBs that exceed these ranges, further verification is required to confirm the equipment's suitability; it cannot be assumed that it can handle them.
2. Transfer Height and Track Compatibility
For companies needing to integrate the equipment into an existing SMT production line, it is also necessary to confirm the equipment's transfer height, the adjustable range of track width, and the connection requirements with upstream and downstream equipment.
Prior to actual installation, these factors must be verified in conjunction with the on-site layout, equipment interfaces, and maintenance space.
3. Adaptability to Different PCB Programs
Different PCBs may have varying pad layouts, mark point locations, and inspection criteria. Purchasing personnel should verify whether the equipment supports the required program import methods and whether inspection ranges can be configured based on different pad settings.
It is recommended to prepare typical PCBs, complex PCBs, and related design files during the equipment evaluation phase to confirm program settings and inspection results through actual testing.
How should one select the software and programming features for SPI equipment?
For factories that need to produce a variety of PCBs, software functionality not only affects program preparation but also impacts product changeovers and inspection data management.
1. Does it support the import of Gerber and CAD files?
Gerber and CAD files provide relevant design data for inspection program preparation; however, the specific file formats, versions, and import processes supported must be confirmed based on the equipment's actual capabilities.
For factories with a large number of product models, it is essential to verify before purchasing whether existing design files can meet the equipment's program preparation requirements.
2. Does it support offline programming?
Offline programming allows some program preparation work to be completed before the equipment performs inspection, but the actual time saved depends on the factory's operational processes and the complexity of the programs.
When purchasing, evaluate whether different programming modes meet actual needs by considering how engineers typically work.
3. Can different inspection ranges be set for different pads?
Different pads may have varying dimensions and process requirements, so inspection limits may not be suitable for a one-size-fits-all approach.
According to the NeoDen S1 operating manual, users can set upper and lower inspection limits for the stencil and adjust relevant parameters individually for specific pads.
This feature is suitable for use when process standards are clearly defined. Actual parameters should still be determined based on PCB design and production requirements, rather than directly applying a single set of limits.
4. Does it support SPC reports and data export?
SPC, or Statistical Process Control, can be used to observe trends in production data and provide a reference for process analysis.
When purchasing, you should also confirm the report content, data fields, export process, and whether the system meets your company's internal quality record-keeping and traceability requirements.
What are the key features of the NeoDen S1 SMT SPI machine?
After completing the requirements analysis, the NeoDen S1 can be considered as a candidate device, and its inspection capabilities and specifications can be verified item by item based on actual process requirements.
1. 3D Solder Paste Inspection and Multi-Parameter Measurement
The NeoDen S1 is equipped with a 3D raster camera that supports 2D and 3D true-color image display. According to the product documentation, its inspection data includes solder paste volume, area, height, and offset.
2. Key Specifications
| Parameter | NeoDen S1 |
| Inspection Technology | 3D raster camera |
| FOV | 48 × 40 mm (20 μm) |
| Single-Frame Processing Time | Less than 0.7 seconds |
| Maximum Inspection Height | 400 μm |
| Height Inspection Accuracy | 1 μm |
| PCB Dimensions | 50 × 50 mm to 500 × 460 mm |
| PCB Thickness | 0.6–6 mm |
When placing a formal order, please refer to the latest confirmed technical documentation and verify the test conditions for the relevant specifications.
3. Programming and SPC Data Support
The NeoDen S1 supports Gerber/CAD input, offline programming, and manual programming, and provides SPC reporting and data export capabilities.
For companies that need to manage multiple PCB programs, record inspection data, or conduct print process analysis, these features are worth further evaluation during the selection process.
4. Is the NeoDen S1 Suitable for Your Production Needs?
When contacting the supplier, it is recommended to provide the PCB dimensions and thickness, typical pad characteristics, target inspection parameters, production cycle time, and existing production line conditions. With this information, you can more effectively determine whether the NeoDen S1 meets your project requirements.
FAQ About SMT SPI Equipment Procurement
1. What are the most important parameters when selecting SPI equipment?
No single parameter applies to all production scenarios. You should first clarify the inspection objectives, then evaluate inspection accuracy, repeatability, processing speed, PCB compatibility, and software capabilities.
2. Is 3D SPI always better than 2D SPI?
Not necessarily. While 3D SPI can provide three-dimensional information such as solder paste height and volume, the suitability of the equipment also depends on actual inspection requirements, budget, and test results.
3. What level of inspection accuracy should an SPI machine achieve?
This must be determined based on pad size, process tolerances, and quality requirements. It is also important to distinguish between inspection accuracy and repeatability, and to verify the test conditions under which the equipment's specifications were measured.
4. What are the maximum PCB dimensions that an SPI system can inspect?
Support ranges vary by model. Before purchasing, verify the PCB's length, width, thickness, and conveyor system specifications. For example, the NeoDen S1's documentation specifies a PCB size range of 50 × 50 mm to 500 × 460 mm, with a thickness range of 0.6–6 mm.
5. Do SPI machines support Gerber files and SPC reports?
This depends on the machine's hardware and software configuration. The current documentation for the NeoDen S1 indicates support for Gerber/CAD input, SPC reports, and the export of related data. However, you should still confirm the required file formats and report content at the time of purchase.
6. Is PCB prototype testing necessary before purchasing an SPI machine?
For projects with specific process requirements, it is recommended to conduct testing using a representative PCB to verify that inspection parameters, program settings, actual processing time, and measurement results meet expectations.
Conclusion
When selecting an SMT SPI machine, one should start from actual production needs and comprehensively evaluate inspection technology, measurement capabilities, PCB compatibility, software functionality, and line integration requirements.
For companies planning a new SMT production line or upgrading their solder paste inspection process, we recommend first compiling PCB specifications and inspection requirements, then conducting prototype testing to confirm whether the equipment meets actual process needs.
Looking for SPI inspection equipment suitable for your SMT production line?