Duct Beading Machine Buying Guide 2026: CNC vs Manual vs 5-Groove

Why Duct Beading Matters

Duct beading (also called duct grooving or stiffening) adds structural rigidity to sheet metal ductwork. Without beading, large duct panels vibrate, bulge, and whistle — creating noise and reducing system efficiency. A good beading machine ensures your ducts meet SMACNA stiffness class requirements and install without deflection.

Preda offers three beading machine configurations, each suited to different production needs.

Rotary vs CNC vs 5-Groove

CNC Rotary Beading Machine: Precision and Speed

The CNC Rotary Beading Machine is our premium beading solution. With Mitsubishi PLC control and servo-driven feeding, it delivers programmable bead patterns, automatic positioning, and consistent quality — every time.

• Programmable patterns: Store unlimited bead configurations in the PLC — recall any pattern with one touch
• Automatic feeding: Servo-driven feed system positions the sheet precisely — no manual measurement
• 1.5mm capacity: Handles thicker gauge material for high-pressure duct systems
• Fast production: Up to 30 m/min — process a full sheet in seconds
• Consistent quality: Every bead identical — no human error in positioning or depth

View CNC Rotary Beading details →

Manual Rotary Beading Machine: Budget Option

The manual Rotary Beading Machine offers reliable beading at an affordable price. The operator feeds the sheet manually, adjusting position for each bead. Ideal for small shops or low-volume production.

View Manual Rotary Beading →

5-Groove Duct Beading Machine: Multi-Groove in One Pass

The 5-Groove Duct Beading Machine forms five parallel grooves in a single pass — perfect for shops that need consistent multi-groove stiffening on large duct panels. Reduces handling time and ensures even groove spacing.

View 5-Groove Beading →

How to Choose

1. Daily volume? >100 sheets/day → CNC Rotary. 50–100 → 5-Groove. <50 → Manual Rotary
2. Do you need multiple patterns? Different duct sizes require different bead spacing → CNC Rotary's programmable patterns save setup time
3. Material thickness? ≤1.2mm → all work. ≤1.5mm → CNC Rotary only
4. Operator skill? CNC is easier to operate consistently — manual requires more operator experience

Bead Spacing, Depth and SMACNA Stiffness Class

Beading is not decoration — it is a structural requirement. SMACNA's HVAC Duct Construction Standards allows lighter gauge material on wider ducts only when the panel is stiffened, typically by cross-breaking, beading or an external reinforcement. Get the pattern wrong and the panel will still oil-can, no matter how thick the steel.

Three variables control how much stiffness a bead adds:

Rule of thumb used on our shop floor: for rectangular duct in 0.7 mm (24 ga) galvanised, bead every 250 mm on any face wider than 600 mm. At 1.0 mm (20 ga) you can extend that to 400 mm on faces up to 1200 mm. Above 1200 mm face width, move up a gauge rather than adding more beads.

Throughput: Matching Beading Capacity to Your Order Book

Beading is rarely the bottleneck in a duct shop — until it is. Because beading happens after slitting and before folding, a slow beader gates the whole rectangular line. Here is how the three configurations compare on a real shift.

How to size it. Take your peak-month rectangular duct area, divide by working days, then by shift hours, and add 30 % for changeovers and rework. If the result is under 1,500 m² per shift, a manual rotary is sufficient and the $3,700 you save is better spent elsewhere. Between 1,500 and 3,500 m², the 5-groove machine is the value leader — it puts down five beads in the time a manual machine puts down one, which matters when your order book is dominated by long straight runs. Above 3,500 m², or if you are running an auto duct line upstream, the CNC rotary is the only option that will not back up the line.

Payback maths. CNC rotary versus manual rotary is a $3,700 premium. At the throughput above, the CNC machine saves roughly 1.5 operator-hours per shift. At a loaded labour cost of $25/hour, that is $37.50 a day, or about 100 working days to pay back — under five months. Every shift you run two machines per operator halves that again.

Roller Life, Set-Up Errors and Maintenance Schedule

Beading rollers are the consumable most shops forget to budget. Preda machines run hardened, ground tool-steel rollers at roughly HRC 58–62; in galvanised sheet you should get 300,000–500,000 linear metres before the profile needs regrinding. Stainless cuts that roughly in half because of work hardening at the bead root.

Four set-up errors account for most bead-quality complaints:

• Roller gap set by eye. A 0.3 mm error in gap shows up as a 1 mm error in bead depth — that is the difference between passing and failing a stiffness check. Use a feeler gauge, not a visual estimate.
• Beading coated or laminated sheet with the wrong roller profile. Narrow-radius rollers crack the zinc layer; use a larger radius and reduce depth by about 20 %.
• Beading too close to a punched hole or a corner notch. Keep at least 25 mm clearance or the bead will tear out at the hole edge.
• Ignoring the entry guide. If the sheet enters skewed, the bead walks off the panel edge by 5–10 mm over a 2 m length — a visible defect on an exposed spiral run.