Work Holding
CNC Vacuum Hold Down Systems
Secure workpieces without clamps in the way. Vacuum hold down enables faster setups, full sheet access, and cleaner production.
How Vacuum Hold Down Works
Vacuum hold down uses air pressure difference to hold workpieces flat against the table. Remove air from under the workpiece, and atmospheric pressure (14.7 psi) pushes down on top. That’s nearly 15 pounds per square inch—plenty to hold material secure during cutting.
The system requires a vacuum pump, a table with channels or a porous surface, and sealing around the workpiece edges. When vacuum is applied, material is pulled flat and held firmly without mechanical clamps.
For flat sheet goods—plywood, MDF, melamine, plastics—vacuum is the production standard. Fast setup, full access to the entire sheet, and consistent holding across the surface.
Benefits of Vacuum Work Holding
No Clamps in the Way
Full access to the workpiece surface. No repositioning clamps mid-job. Nested parts cut completely through without obstruction.
Fast Setup
Place sheet, turn on vacuum, run program. No measuring clamp positions or worrying about tool paths clearing fixtures.
Flat Holding
Vacuum pulls material flat against the table. Warped sheets flatten under vacuum. Consistent Z height across the surface.
Holds Small Parts
Even small nested parts stay in place until removed. No flying parts when cutting through. Safer and more efficient.
Clean Cuts
Material can’t lift or chatter during cutting. Better edge quality, especially on through-cuts. Consistent results.
Higher Production
Less time clamping means more time cutting. The efficiency gains compound across every sheet you run.
Vacuum Table Types
Spoilboard Tables
MDF or phenolic spoilboard with drilled vacuum holes or routed channels. Most common setup. Spoilboard surfaces periodically to maintain flatness and seal. Versatile and cost-effective.
Zoned Vacuum Tables
Table divided into independently controlled zones. Turn on only the zones under your material. Smaller pieces get full vacuum without wasting pump capacity on open areas.
Phenolic Tables
Phenolic spoilboard surface is denser and more durable than MDF. Machines flatter, lasts longer, and seals better. Worth the upgrade for production machines.
Aluminum T-Slot with Vacuum
Combines mechanical clamping capability with vacuum zones. Versatility for both sheet goods and odd-shaped parts. Common on machines that do diverse work.
Grid/Plenum Tables
Aluminum grid with dedicated vacuum plenum underneath. No spoilboard to surface. Used for high-production applications where the extra cost is justified.
Vacuum Pump Specifications
Larger tables and porous materials need more CFM. Size the pump for your worst-case scenario.
Vacuum Pump Types
Regenerative Blowers
High flow, moderate vacuum. Most common for CNC routers. Handles leakage well, reliable, reasonable cost. Good all-around choice.
Rotary Vane Pumps
Higher vacuum levels, lower flow. Better for non-porous materials that seal well. Requires oil changes and more maintenance.
Rotary Claw Pumps
Oil-free, high vacuum. Premium option for demanding applications. Lower maintenance than rotary vane, higher initial cost.
Liquid Ring Pumps
Handles wet applications and high leakage. Less common in woodworking, more in industrial/wet environments.
Tips for Effective Vacuum Holding
Seal the Perimeter
Vacuum only works if you can maintain it. Seal around your workpiece with gasket material, tape, or dedicated vacuum fixtures. Open areas bleed vacuum and reduce holding force.
Use Zones Efficiently
If you have zoned vacuum, turn off unused zones. This concentrates vacuum power under the workpiece. Small parts benefit especially.
Surface Your Spoilboard
A flat spoilboard seals better and holds more consistently. Surface it regularly—at least monthly for production shops. Replace when it gets too thin to surface.
Check for Leaks
Hoses crack, fittings loosen, seals wear. If holding force decreases, check the system for vacuum leaks. A small leak can significantly reduce performance.
Consider Material Porosity
MDF and particleboard are somewhat porous. Plywood less so. Non-porous plastics and metals seal completely. Porous materials need more CFM to compensate for bleed-through.
Leave Onion Skin
For nested cutting, don’t cut completely through. Leave a thin “onion skin” that holds parts in place. Finish with a light sanding or break parts out manually.
Vacuum System Accessories
Vacuum Pods
Individual suction cups for holding smaller or odd-shaped parts. Position where needed, connect to vacuum system.
Gasket Material
Foam strips for sealing workpiece perimeters. Various widths and compressibility for different applications.
Vacuum Tape
Quick perimeter sealing for sheet goods. Apply around the sheet edge to seal against spoilboard.
Zone Valves
Control vacuum to individual table zones. Manual or automatic depending on system sophistication.
Vacuum Gauges
Monitor vacuum level to verify holding. Alerts if vacuum drops due to leaks or pump issues.
Pop-Up Pins
Registration pins that retract below spoilboard surface. Locate material precisely, then lower pins before cutting.
Need Vacuum System Help?
We configure vacuum systems for your specific application. Let’s discuss your needs.