Designing a reliable vacuum system starts long before selecting a vacuum generator. Proper sizing and circuit design are critical to achieving consistent part handling, minimizing energy consumption, and avoiding downtime.
The foundation of any vacuum system is the product being handled. Before selecting suction cups or vacuum generators, it’s important to understand several key characteristics of the part.
Material and Surface Condition
Different materials directly affect vacuum performance. A flat, non-porous part such as sheet metal allows the use of a deeper vacuum-level venturi, generating high holding force. Porous materials like corrugated cardboard require higher vacuum flow (SCFM) to overcome leakage through the surface. Remember:
• Higher flow generators improve evacuation and compensate for leakage
• Higher vacuum level generators increase holding force on non-porous parts
Weight
Holding force is determined by vacuum level and cup size. Heavier parts require either larger cups, higher vacuum levels, or a combination of both to ensure a safe handling margin.
Holding force is calculated by Force = Pressure × Area
Part Dimensions
Product size and shape dictate how many cups are required. Using multiple cups helps distribute the load and create a stable grip, especially for large or flexible parts.
Cycle Speed
Fast cycle times demand rapid evacuation to reach the required vacuum level quickly. This directly influences vacuum generator selection, plumbing layout, and overall circuit efficiency.
Orientation
Vacuum suction cups generate the greatest holding force when lifting a part vertically (parallel to the ground). Applications involving horizontal movement or shear forces require additional safety factors and careful cup selection.
Vacuum Systems: Centralized vs. Decentralized
Once cup size and quantity are determined, attention shifts to vacuum circuit design. The two most common approaches are centralized and decentralized systems.
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Centralized Vacuum Systems
A centralized circuit uses one larger central vacuum generator to supply multiple cups. This approach can reduce upfront cost and simplify controls by using a single vacuum switch. However, if one cup loses seal or misses the part, the resulting vacuum loss can affect the entire system.
Decentralized Vacuum Systems
In a decentralized design, each vacuum cup has its own dedicated generator. This is often the preferred approach in modern automation systems. Benefits include:• Improved reliability—one missed cup does not affect others
• Faster response times
• Cleaner, more compact plumbing
The Piab Vacuum Gripper System (VGS) is an excellent example of decentralized design, as it allows for flexible configuration and easy integration at the end of arm.
Plumbing Best Practices: Often Overlooked, Always Critical
Even the best vacuum generator can underperform if the plumbing is poorly designed. Common mistakes include long tubing runs, undersized hoses, and excessive fittings. Proper plumbing improves evacuation speed, increases holding force, and reduces energy consumption.
Some best practices to consider include:
• Positioning the vacuum generator as close to the cup as possible
• Matching tubing diameter to the generator outlet size
• Use straight tubing runs whenever possible
• Minimize elbows and sharp bends
Piab is one of the pioneers of venturi-based vacuum technology, and has built a strong reputation for performance, energy efficiency, and application expertise. Piab offers a comprehensive range of solutions including vacuum generators, suction cups, area grippers, and complete end-of-arm tooling.
Our local technical expertise combined with Piab’s proven product quality and broad portfolio provides a complete solution - from concept and design to product selection, installation, and ongoing support. Whether you’re handling metal, packaging, plastics, or complex assemblies, we can help engineer a vacuum system that performs reliably in real-world production environments.
If you need assistance with vacuum circuit design or Piab product selection, contact us today to work with a local automation specialist.
