Cap In Head vs Pick-Off: Which Capping System to Choose?

Executive summary

Two systems dominate plastic cap application worldwide: Cap In Head (C.I.H.) and Pick-Off (P.O.). The fundamental difference is how the cap reaches the capping head — directly, in C.I.H., or through an external launcher with pre-torque, in P.O. This mechanical difference has implications for maintenance, spare parts, operating speed and format change flexibility.

In one sentence: C.I.H. for mechanical simplicity and dedicated lines; Pick-Off for precise orientation control and environments with frequent format changes. This article goes deep into operation, advantages, maintenance and when to choose each one.

What is Cap In Head (C.I.H.)

In the Cap In Head system, the cap is transferred from the sorter directly into the capping head. The cap is retained inside the head by a ball ring with O-ring: the balls lightly compress the outer wall of the cap, holding it in place until threading. Cap transfer to the head happens through a transfer plate, a disc synchronized with the capper turret.

Image: sistema-cih-cabecote.jpeg

Mechanical operation

1. The cap goes down the chute fed by the sorter.
2. The synchronized transfer plate brings the cap to the capping head position.
3. The head descends; the ball ring captures the cap.
4. Vertical load is applied; the chuck rotates the cap, threading it onto the bottle.
5. When static torque is reached, the head slips (mechanical clutch) or the magnets decouple (Magna Torq).
6. The head rises; the cap ejector pin (on some models) helps release the cap.

C.I.H. advantages

• Fewer moving parts outside the head. Maintenance concentrated on a few components.
• Mechanically simpler design — good for environments with limited maintenance resources.
• Smaller footprint — the capper takes up less line space.
• Quiet operation — no compressed air at the launcher (P.O. depends on air).

C.I.H. limitations

• Less flexible for format change — each finish requires its own set of parts (chuck, ring, plate).
• Balls and O-ring are consumables — they wear out and must be replaced periodically.
• When the cap enters the head misaligned, the defect cannot be corrected externally (in P.O., the pre-torque adjusts it).

What is Pick-Off (P.O.)

In the Pick-Off system, the cap does not enter the head directly — it passes through an external launcher equipped with serrated arms and compressed air. The launcher does three things: it positions the cap precisely on the bottle, applies a pre-torque (initial rotation), and only then delivers the pre-oriented cap to the head, which completes the threading.

Image: sistema-pick-off-lancador.jpeg

Mechanical operation

1. The cap goes down the chute fed by the sorter.
2. The launcher, with air pressure (~4-6 kg/cm²), captures the cap in its articulated arms.
3. The bottle passes under the launcher; the serrated pre-torque arm engages at mid-height of the cap.
4. Pre-torque rotates the cap ~180°, seating it on the finish.
5. The head descends onto the already pre-oriented cap and completes the threading.
6. Vertical load and final torque are applied as in C.I.H.

P.O. advantages

• Greater control over initial orientation — the cap arrives pre-oriented at the head.
• More flexible for format change — air pressure and arm opening (~25.4 mm standard) are adjustable.
• Pre-torque softens the impact on the liner — generates fewer tamper-evidence band defects on fragile caps.
• Enables high speeds — in premium beverage lines, P.O. is the standard.

P.O. limitations

• More external moving parts — maintenance distributed across multiple components (launcher, pre-torque, head).
• Depends on compressed air — compressor maintenance is critical.
• A misaligned launcher is a frequent root cause of defects — requires routine inspection.
• Larger footprint.

Side-by-side comparison table

When to choose C.I.H.

• Lines dedicated to a single cap format. If the plant only produces 28 mm PCO 1881 soft drink, C.I.H. is simple and efficient.
• Environments with limited maintenance. Fewer parts = fewer failure points.
• Space constraints. Smaller footprint fits compact lines.
• When initial cost is a priority. C.I.H. is typically cheaper.
• Operation with controlled noise (plants near residential areas, noise regulations).

When to choose Pick-Off

• Multi-format lines. Multiple SKUs or frequent finish changes.
• Fragile caps or tight pull test. Pre-torque reduces impact on the band.
• Very high speeds (above 25,000 bottles/hour). P.O. is the standard for premium beverages.
• Trained technical teams. Pneumatic adjustments require skilled operators.
• Lines with a history of systematic cocked cap. Pre-orientation tackles the problem at its root.

Maintenance: what changes between the two systems

Maintenance difference is where C.I.H. and P.O. diverge the most in practice. Gromar's technical guide separates root causes by system precisely because the exclusive causes are very different:

Exclusive C.I.H. causes

• Chuck balls/O-ring — wear causes cocked cap, broken band and bottle without cap.
• Cap ejector pin spring — when broken, generates cocked cap and bottle without cap.
• Transfer plate clearance — incorrect (should be 1-1.5 mm on CSI equipment with PCO cam) generates multiple defects.
• Lock mini-cylinder — misadjustment affects transfer.

Exclusive P.O. causes

• Launcher air pressure — outside the 4-6 kg/cm² range generates caps coming out of the launcher or misplaced caps.
• Pre-torque serrated arm spring — wrong tension generates cocked cap or broken band.
• Launcher adjustment — opening ~25.4 mm. Misalignment generates caps coming out of the launcher.
• Poorly adjusted pre-torque — serrated arm must engage at mid-height of the cap.

Causes common to both

Items 1.3.1 through 1.3.10 of the technical guide apply to both systems: star wheel, rear guide, vertical load, turret, radial clearance, static torque, chuck. Here there is no difference — diagnosis is the same regardless of the system.

Spare parts: what to keep in stock

For each system, the "line-stopping parts" list is different. Practical minimum stock recommendation:

For C.I.H.

• Chucks (1 per head + 20% reserve)
• Ball ring + O-ring (1 set per head + 30% reserve — high turnover)
• Ejector pin springs
• Transfer plate (1 + 1 reserve)
• Lock mini-cylinder

For Pick-Off

• Chucks (same criterion as C.I.H.)
• Pre-torque serrated arm + springs
• Launcher tension springs
• Complete launcher (1 reserve — critical part)
• Pneumatic components: valve, regulator, filter

Next step

Knowing which system you operate is the first step of diagnosis. Each of the 13 capping defects has common causes and exclusive causes — ignoring the C.I.H. vs P.O. distinction is the most frequent source of wasted diagnostic time. The Complete Guide to Cap Application Problems tags each cause with (C.I.H.) or (P.O.) for exactly this reason.