Plugging Systems from MASS – Precision Under Vacuum
With MASS vacuum chamber plugging systems, through-holes and blind vias are reliably and bubble-free filled – double-sided in a single cycle. This ensures the highest quality and process reliability.
Your Benefits
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Maximum process reliability: entire PCB inside the vacuum chamber for bubble-free filling
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Flexibility: multiple plugging cycles or re-filling possible
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Efficiency: up to 6× faster cycle times, cleaning and head change in just 45 minutes, low paste consumption
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Clean results: external smoothing unit reduces paste layer to just 6 µm
Optional features: automatic cartridge refilling (LCS), data recording, and heated filling heads.
VCPM+ — Breakthrough PCB Plugging with Vacuum Cleaning I & II
The VCPM+ from MASS sets a new standard in PCB plugging with its innovative Vacuum Cleaning I & II process:
- Vacuum Cleaning I removes air, moisture, and outgassing before filling—ensuring complete, dense hole filling, avoids bulk bubbles.
- Vacuum Cleaning II eliminates residual surface bubbles after filling by lowering chamber pressure, allowing trapped gases to escape, avoids surface bubbles.
This process is powered by advanced vacuum control and the effects of capillary forces and the Kelvin effect, which prevent paste boiling or leakage—even under deep vacuum conditions. The result: unmatched defect-free filling, higher yields, and maximum reliability for modern PCB manufacturing.
The VCPM+ will be presented for the first time at Productronica 2025, November 11–14, 2025, Hall B3.528 in Munich.
Die VCPM+ wird erstmals auf der Productronica 2025 vom 11.–14. November 2025, Halle B3.528 in München vorgestellt.
VCPM+ Next Gen: The future of vacuum chamber PCB manufacturing
The new VCPM+ will be unveiled for the first time at Productronica 2025 in Munich.
This next-generation system combines decades of expertise with the latest technological innovations — delivering maximum precision, efficiency, and process reliability in the vacuum chamber.
The Highlights of the VCPM+ Next Generation
- Reduced paste consumption – optimized processes lower material costs and increase overall efficiency.
- State-of-the-art vacuum technology – ensures maximum process stability and reliable results, even for the most demanding applications.
- Intelligent software control – smart process monitoring, intuitive operation, and maximum production control.
The VCPM+ sets new standards in vacuum process technology for PCB manufacturing.
It combines precision, sustainability, and digital intelligence in one system – engineered to meet the demands of tomorrow’s electronics production.
👉 Visit us at Productronica 2025 or contact us for a personal presentation of the complete system.
Technical Data
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Dimensions: Length 2,500 mm, Width 740 mm, Height 2,100 mm
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Weight: 900 kg
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Panel size: 610 × 762 mm
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Panel thickness: 0.25 – 9 mm
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Power supply: 400 V, 50 Hz, 3P/N/PE, 5 kW or 480 V, 60 Hz, 3P/PE
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Control: PLC with HMI touch panel
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Compressed air: 6 bar (88 psi), 30 NL per panel
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Ambient temperature: 22 ± 2 °C
Optimal plugging results thanks to full vacuum chamber and external squeegee unit
Why MASS Delivers Better Results
Conventional systems only evacuate locally and for a short time, limiting their effectiveness in removing air and moisture from PCB holes. In contrast, the MASS VCP system uses a complete vacuum chamber, exposing the entire panel to a controlled vacuum for an adjustable duration. This enables efficient gas evacuation and significantly improves the quality and reliability of the subsequent filling process.
At low pressures – especially in the Knudsen and molecular flow regime – gas evacuation is dominated by the statistical motion of molecules. Adequate evacuation time is therefore essential to minimize residual air and moisture in the holes. The attached CFD simulation illustrates this behavior.
By drastically reducing residuals, the MASS VCP system enables high-quality, void-free filling. In addition, multiple filling cycles are possible without displacing previously applied paste – a problem that conventional systems with vacuum limited to the filling head cannot avoid.
Hagen-Poiseuille law
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With the famous and well known Hagen-Poiseuille law, the VCPM+ software automatically calculates the ideal plugging recipe. Instead of trial and error, production starts right away – faster, smarter, and with perfect results.
advantages MASS VCP
| Item | Conventional Systems | MASS Full Vacuum Chamber | Advantage |
|---|---|---|---|
| Via hole subject to vacuum | <1 s | Adjustable | Longer evacuation reliably reduces the number of molecules. |
| Cycle time | Slow | Fast | The vacuum chamber enables higher traverse speeds without overheating. |
| Setup and cleaning | 8 h | 1 h | The traverse has a simple design and can be easily removed. |
Automatic Leak Rate Measurement in the VCPM+
Determining the integral leak rate of a vacuum chamber is usually complex and time-consuming. At first, pressure increases are influenced not only by leaks but also by outgassing. Only after some time does the pressure rise primarily reflect the chamber’s leak rate.
Since the leak rate is a critical factor for reliable and reproducible PCB production, MASS has integrated an automatic measurement and calculation feature into the VCPM+.
Leak rates are measured continuously and logged automatically. This provides the operator with immediate feedback and allows for prompt action — without the need for complex manual measurements and evaluations.
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Basics of Plugging Under Vacuum
Under vacuum, the flow properties of gases change depending on the pressure range. At first, the gas behaves like a viscous liquid with laminar or turbulent flow. As pressure decreases, a transitional range (Knudsen regime) follows, before entering the molecular flow regime, where gas molecules move freely and statistically distributed through the vacuum chamber. |
In the viscous regime, gas flow is laminar, as shown in the image. However, at edges and corners, local turbulence can occur. In this flow regime, the Hagen–Poiseuille law applies, which describes the relationship between pressure, viscosity, and volumetric flow. |
In the molecular regime, gas molecules move statistically distributed through the vacuum chamber. There is no directed suction mechanism to the pump. Molecules reach the chamber outlet purely by chance, which means reaching deeper pressures is only possible with longer pumping times. |
The Different Vacuum Regimes
| Description | Rough Vacuum | Fine Vacuum - FV | High Vacuum - HV | Ultra-High Vacuum - UHV |
|---|---|---|---|---|
| Pressure [mbar] | 1000 - 1 | 1 - 10-3 | 10-3 - 10-7 | 10-7 |
| n [cm-3] | 1019 - 1016 | 1016 - 1013 | 1013 - 109 | <109 |
| MFP | 100 µm | 100 µm - 100 mm | 100 mm - 1 km | 1 km |
n: Number of molecules per cubic centimeter, MFP: Mean free path of gas molecules
The vapor pressure curves of water and typical pastes for plugging PCBs show at which pressure the respective materials start to boil. If chamber pressure drops below the paste’s vapor pressure, boiling begins. This causes the low-molecular components to evaporate, changing flow properties. Precise vacuum control is therefore essential to prevent boiling of the paste and resulting process deviations.
Optimal hole filling in PCBs through precise vacuum plugging
The Myth of Plugging in UHV
The lower the chamber pressure, the fewer gas molecules exist in the chamber and in the holes. However, the pressure cannot be reduced below the vapor pressure of the paste — otherwise the paste begins to boil, changing its composition and flow properties. Only after fully filling the hole can the pressure be reduced below the vapor pressure. Then both the Kelvin effect and capillary forces act to reduce the effective vapor pressure and allow controlled evacuation. See also: Vacuum Cleaning II
FAQs – Vacuum Plugging of Printed Circuit Boards (PCBs)
Why is vacuum needed for plugging vias in PCBs?
PCBs contain numerous vias (holes) with diameters well below one millimeter. Under atmospheric pressure, these holes contain millions of molecules (1019 cm-3) — mainly nitrogen, oxygen, and water vapor. These molecules hinder the complete and uniform filling of the holes with paste.
Vacuum plugging reduces the pressure inside and around the vias, allowing the paste to enter more easily. In addition, vacuum removes water molecules from the holes. This ensures a stable and reproducible process, resulting in bubble-free filling of all vias.
Why is a complete vacuum chamber needed for plugging?
It is not enough to evacuate holes briefly or locally. The entire PCB must be processed in a vacuum chamber. This ensures a uniform, defined state in which all molecules have enough time to leave the holes.
This effect becomes increasingly important at very low pressures: molecules then move only randomly, and there is no natural flow toward the vacuum pump. A full vacuum chamber ensures that the process is efficient and reproducible.
What is the main advantage of vacuum plugging?
The biggest advantage is a bubble-free and reproducible filling of all vias. This significantly improves PCB quality and reduces rework or scrap.
Why might it be useful to expose plugged PCBs to vacuum a second time?
In specialized applications, minimal surface bubbles may still occur even when bulk filling is optimal. A second vacuum treatment removes even these small bubbles completely. This capability is uniquely offered by a MASS vacuum chamber.
Why doesn’t the paste evaporate once it is inside the hole?
This is explained by the Kelvin effect: the paste’s surface tension and capillary forces prevent evaporation even if the surrounding pressure drops below the paste’s vapor pressure. This ensures a stable, long-lasting fill.