Irving Rodriguez | Essemtec: What are the trade-offs between the different valve technologies offered, particularly concerning material compatibility and dispensing precision?

Why does the viscosity of your jetting material drop by a factor of 1000 during ejection?

Fluid rheology is the cornerstone of successful high-speed jetting in microelectronics and display packaging. When a material containing suspended particles is subjected to high shear rates inside a jetting chamber, it undergoes dramatic shear thinning, reducing its viscosity by up to three orders of magnitude. This non-Newtonian transition is crucial to control, as temperature fluctuations of just ten degrees Celsius can also significantly alter the baseline viscosity.

As particle concentration increases—common in conductive adhesives and structural epoxies—the fluid behavior shifts from Newtonian to highly non-Newtonian. Under extreme shear rates, these concentrated suspensions can transition from shear thinning to shear thickening. This chaotic particle behavior increases viscosity abruptly, potentially clogging the nozzle or causing unstable jetting.

Understanding these complex rheological transformations is essential when selecting the appropriate jetting technology and material formulation. Optimizing parameters like chamber temperature and drive energy prevents processing failures and ensures consistent droplet deposition for fine-pitch electronics.

In this short video, you can learn:
* How shear rates reduce material viscosity by a factor of 1,000 during the jetting process.
* The transition of suspension fluids from Newtonian behavior to shear thinning and shear thickening.
* The critical impact of minor temperature variations on the rheological stability of structural glues.

📋 **Clip Abstract** This clip explains the complex rheological behavior of particulate fluids during high-speed jetting processes. It highlights the transition from shear-thinning to shear-thickening under high shear rates and the critical role of temperature and particle concentration on fluid viscosity.

What are the real-world tolerances and throughput limits for high-speed micro-dispensing systems?

Implementing micro-jetting and pick-and-place systems in high-volume manufacturing requires a clear understanding of practical tolerances and throughput constraints. In precision dispensing, droplet volume tolerance typically lands within a plus or minus twenty percent margin of the target value. This variance is highly dependent on substrate conditions, such as surface energy, which influences the final spread and contact angle of the dot.

Valve selection in modern dispensing equipment is not based on a single variable but on a complex matrix of viscosity, jetting speed, and desired dot sizes. Achieving high-yield assembly requires systems to dynamically manage these parameters while maintaining impressive throughputs. Typical production speeds reach twelve to sixteen thousand components per hour for pick-and-place, and up to fifty thousand dots per hour for specialized dispensing.

Fine-pitch components place strict limits on the mechanical capabilities of the assembly machine. For surface-mount devices (SMD) and micro-scale components, modern all-in-one systems can reliably achieve minimum pitch sizes down to 0.3 millimeters, ensuring high-density packaging capability.

In this short video, you can learn:
* The standard volume tolerances for high-speed micro-dispensing and the impact of substrate surface energy.
* How viscosity, velocity, and dot size are used to select and configure jetting valves.
* The throughput metrics and minimum pitch limits achievable in integrated pick-and-place and dispensing systems.

📋 **Clip Abstract** This Q&A segment outlines the performance benchmarks of Essemtec's dispensing systems, highlighting a plus or minus twenty percent droplet volume tolerance. It details the operational speeds for pick-and-place and dispensing, alongside the 0.3 mm minimum pitch capability for fine-pitch SMT assembly.

What causes the dreaded donut dot or tower dot effect in high-speed dispensing?

Dot morphology control is a critical factor in printed electronics assembly, directly affecting electrical and mechanical joint integrity. When dispensing structural adhesives, achieving the correct dot height and profile is paramount to ensuring robust physical contact with surface-mount components. Variations in jetting parameters can lead to undesirable profiles like "tower dots" or "donut dots" rather than the ideal hemispherical shape.

The formation of these distinct shapes is governed by the interplay of jetting speed, drive energy, and material viscosity. Low jetting velocities combined with low material temperatures (high viscosity) result in narrow, high-aspect-ratio tower dots. Conversely, applying high jetting energy to low-viscosity materials causes the droplet to spread outward violently upon impact, creating a hollow-centered donut dot.

Achieving the perfect balance between dot design and throughput requires precise calibration of nozzle parameters. System operators must coordinate the physical setup with material temperature controls to prevent weak structural joints or open circuits.

In this short video, you can learn:
* The physical mechanisms that cause the formation of undesirable tower dots and donut dots.
* How the combination of jetting energy, velocity, and fluid viscosity dictates droplet morphology.
* Strategies for optimizing the balance between dot volume, deposition speed, and component contact reliability.

📋 **Clip Abstract** This segment details how jetting speed, drive energy, and material temperature interact to shape the final morphology of dispensed adhesive dots. It explains how to avoid structural defects like tower and donut dots to secure reliable mechanical and electrical connections.