Precise Solder Paste Dispensing for PCBs, SMT, and Fine Structures
When assembling printed circuit boards, the application of solder paste determines the subsequent process quality. Too much paste can cause bridging, while too little paste leads to unstable solder joints. The process window becomes significantly narrower, especially with miniaturised assemblies, small pads, and tight spacing.
Solder paste dispensing offers a flexible alternative or complementary solution to traditional stencil printing. The solder paste is not transferred using a fixed stencil geometry, but is instead applied as defined dispensing points. If necessary, line-like structures can also be created by arranging multiple dispensing points in a row. This allows the paste volume, dot sizes, and positions to be adapted to the specific PCB structure.
To this end, marco develops precise system solutions comprising a dispensing head, dispensing cell, software, camera, and process expertise. The goal is not only to achieve a fine solder paste dot, but also to ensure a reproducible dispensing process under real production conditions.
Solder paste dispensing
When is solder paste dispensing advisable?
Solder paste dispensing is particularly useful when printed circuit boards become smaller, more densely populated, or more varied. The process works best where fine structures, varying layouts, or customised solder paste volumes are required.
Typical use cases include:
- Miniaturized printed circuit boards and SMT assemblies with fine structures
- Assemblies with very small, densely packed, or differently sized pads
- Prototypes and Pre-Production Run
- Small to medium batch sizes with frequent layout changes
- Printed circuit boards with varying solder paste volumes within a single layout, for example, to compensate for warpage, i.e. distortion of components or substrates
- Partially assembled printed circuit boards, for example in repair stations
- 3D-MID, LED Assembly, and Power Electronics
- Applications with high requirements for repeatability and process reliability
The advantage lies not only in the finer application. The key factor is that the solder paste can be applied with pinpoint accuracy and in a defined quantity. Instead of reproducing a complete paste pattern using a fixed stencil, the paste is placed exactly where it is needed: tailored to the solder pad, the component, and the process.
Solder Paste Dispensing - Challenges and Solutions
In the complex world of printed circuit board (PCB) assembly, solder paste dispensing is a critical process that requires precision and consistency. Whether you are an experienced engineer or a technician new to this field, understanding the challenges and solutions related to solder paste dispensing can significantly impact the quality and reliability of your electronic products. Let’s take a look at these aspects, focusing particularly on the advanced solutions offered by marco’s StepDot dispensing head and the marc1 Gantry System, our inline robotic system.
Solder paste dispensing for fine structures
As miniaturisation in electronics manufacturing increases, the demands on solder paste application are rising. Smaller pads, tighter spacing, and tighter tolerances increase the risk of bridging, satellites, missing solder joints, or uneven wetting. Clean dot formation, a reproducible paste volume, and precise positioning are critical. The StepDot dispensing head from marco, used in conjunction with the marc3 gantry system, compatible software, and camera systems, enables stable and traceable dispensing of even the smallest solder paste dots.
marco enables microdispensing of a very wide range of low and high viscosity media. This allows you to apply small amounts of liquid even on hard-to-reach and uneven surfaces. Of course, we take existing systems and production environments into account, and we adapt dispensing properties for different fluids. Our range includes dispensing accessories through to custom-made specialised tools. There are many reasons why marco solutions can be found in a wide variety of industries - whether smartphone manufacturing or medical technology, precision engineering or LED production, electronics or semiconductor technology.