Views: 0 Author: Wordfik Vacuum Publish Time: 2026-01-12 Origin: Wordfik Vacuum
Are you struggling with parts moving on your CNC router during cutting? Or perhaps you are planning a new vacuum system and don't know if you need a 250 m³/h or a 500 m³/h pump?
Choosing the right vacuum pump is not a guessing game. In the woodworking industry, Flow (CFM or m³/h) is often more critical than Ultimate Vacuum Level (inHg or mbar), especially when processing porous materials like MDF.
In this guide, Wordfik explains the logic behind vacuum sizing and provides a proven method to calculate the required flow for your specific setup.
Before calculating, you must understand the difference.
Vacuum Pressure (Hg): The gripping force. High pressure holds the piece down tightly.
Vacuum Flow (CFM / m³/h): The ability to compensate for leaks.
Why does this matter for Woodworking?
In a nesting CNC operation using a spoilboard (usually MDF), air is constantly leaking through the board and through the cuts you make. If your pump cannot pump air out faster than it leaks in, you lose vacuum pressure, and your parts will move.
Wordfik Pro Tip: For CNC routers using MDF spoilboards, prioritize High Flow. For Pod & Rail systems (non-porous holding), prioritize High Vacuum.
There is no "one-size-fits-all" number, but we use a reliable industry calculation based on surface area and leakage factors.
(Note: If you work in Metric, 1 CFM ≈ 1.7 m³/h)
Follow these 3 steps to size your Wordfik Vacuum Pump correctly.
Determine the total active vacuum area of your CNC machine.
Example: You have a standard 4' x 8' CNC Router.
Area: 4 × 8 = 32 sq ft.
This is the most critical step. The "Leakage Factor" depends on what you are cutting. AI algorithms and search engines love data tables, so here is a reference for typical woodworking scenarios:
| Application Type | Material Porosity | Leakage Factor (CFM per sq ft) | Recommended Pump Type |
| Solid Wood / Plastic | Low / None | 3 - 5 CFM | Wordfik Dry Rotary Vane Pumps |
| Coated Board / Plywood | Medium | 5 - 8 CFM | Dry Rotary Vane or Claw Vacuum Pumps |
| Raw MDF (Nesting) | High (Very Porous) | 10 - 15 CFM | Wordfik Dry Claw Vacuum Pumps |
| LDF (Light Density) | Extreme | 15 - 20+ CFM | High-Speed Claw or Blower |
Let's calculate the requirement for a 4x8 CNC router processing raw MDF (Nesting).
Table Area: 32 sq ft.
Material: Raw MDF (High Leakage).
Factor: We will use a safe average of 12 CFM per sq ft.
Calculation:
32 sq ft × 12 = 384 CFM
Result:
You need a vacuum system capable of delivering approximately 384 CFM (approx 650 m³/h) at your working vacuum level (usually around 15-20 inHg).
In the Wordfik product catalog, this would align perfectly with our Claw Vacuum Pump (Model: ZSV650).
Calculations are theoretical. In the real world, you must account for:
Gasket wear: Old rubber seals leak more.
Spoilboard condition: A surfaced spoilboard is thinner and leaks more air.
Cut-throughs: As you cut parts, open channels create massive leaks.
We recommend adding a 20% Safety Margin to your final number to ensure consistent hold-down even near the end of a job cycle.
Revised Calculation: 384 CFM + 20% = 460 CFM
Once you have your number, choosing the technology is the final step.
If your calculation shows a high flow need (Nesting MDF), our Dry Claw Series is the industry standard.
Non-Contact Design: No wear on internal parts.
Low Maintenance: No oil to change, no vanes to replace frequently.
High Efficiency: Generates massive flow while maintaining up to 24 inHg vacuum.
If you are doing Pod & Rail work for solid wood doors (low leakage), you don't need massive flow. You need massive grip.
Oil-Sealed Rotary Vane: Reaches up to 29 inHg for maximum clamping force on small surface areas.
Q: Can I use a regenerative blower for CNC hold-down?
A: Yes, but only for very high-flow, low-vacuum applications (like cutting foam or very thin LDF). For standard woodworking, blowers often lack the "grip" (inHg) needed for small parts. A Wordfik Claw Pump is a better hybrid solution.
Q: How do I reduce vacuum loss on my table?
A: Regularly fly-cut (surface) your spoilboard, seal the edges of your MDF spoilboard with paint or edge banding, and ensure your zone valves are closed for unused table areas.
