Which cam is commonly used to make holes at regular intervals on production lines?

The Geneva cam—also known as the Geneva mechanism or Maltese cross—is the cam most often used to index workpieces so holes can be drilled or punched at regular intervals. It converts continuous rotation into precise intermittent motion with built-in dwell periods, making it ideal for evenly spaced operations on automated lines.

What is a Geneva cam and how does it work?

The Geneva cam is a motion-conversion mechanism that uses a rotating drive wheel with a pin to intermittently engage a slotted wheel (the “Geneva” or “Maltese cross”). Each engagement advances the slotted wheel by a fixed angle, then disengages to provide a dwell—an interval where the output does not move. This behavior is crucial for tasks like drilling, punching, or assembly, where the part must be stationary during the operation and then precisely advanced to the next position.

Why the Geneva mechanism suits evenly spaced hole-making

By design, the Geneva cam indexes the workpiece by exact angular increments (for example, 6, 8, or 12 stations around a rotary table). The dwell allows the tool—such as a drill or punch—to act while the part is motionless, ensuring accuracy and repeatability. After the operation, the mechanism advances the part to the next position for the following hole or operation.

Key advantages of using a Geneva cam in production lines

Manufacturers select Geneva cams because they offer a reliable balance of precision, simplicity, and cost-effectiveness. The points below outline the core benefits that make the mechanism popular for hole-making stations and other indexed processes.

• Precise indexing: Fixed, repeatable angular steps ensure holes are equally spaced.
• Dwell periods: Built-in stops hold the work steady during drilling or punching.
• Mechanical simplicity: Few parts and straightforward geometry reduce maintenance needs.
• Robustness: Handles continuous duty cycles typical of transfer lines and rotary index tables.
• Synchronization: Easy to gear or chain to upstream/downstream stations for coordinated motion.
• Cost-effectiveness: Lower complexity than servo systems for fixed indexing patterns.

Taken together, these attributes make the Geneva mechanism a dependable choice for high-throughput operations requiring consistent spacing and timing, such as multi-station drilling, riveting, or inspection.

Common alternatives and when to consider them

While Geneva cams are widely used, other indexing solutions may be better depending on speed, load, noise, or flexibility requirements. The following options are typical substitutes or complements in modern automation.

• Globoidal/Barrel (indexing) cams: Offer smoother acceleration profiles and higher-speed indexing with reduced shock compared to classic Geneva designs.
• Ratchet-and-pawl mechanisms: Simple intermittent motion for lighter loads or coarse indexing but with less precision and more backlash.
• Programmable servo indexers: Software-defined index counts and dwell times for flexible manufacturing, at higher cost and complexity.
• Face/disc cams with custom dwell profiles: Used where specific motion laws or special dwell/acceleration curves are needed.

Selection typically depends on desired cycle time, allowable shock and vibration, required flexibility in hole patterns, and total cost of ownership.

Typical applications in hole-making and beyond

Geneva cams commonly drive rotary indexing tables on drilling or punching cells, where parts visit multiple stations for hole creation, deburring, or inspection. They are also used in packaging, assembly, and testing lines, and historically in film projectors—anywhere intermittent, precise movement with dwell is essential.

Design considerations for a Geneva cam system

Effective implementation requires careful attention to kinematics and durability. The considerations below help ensure smooth, accurate operation and long service life.

• Number of slots: Sets the indexing angle (e.g., 6-slot equals 60° per index) and station count.
• Motion profile: Acceleration and deceleration shaping to reduce impact loads and tool chatter.
• Drive pin and slot geometry: Proper clearances and hardening to minimize wear and backlash.
• Speed and load limits: Balancing throughput against shock, noise, and component fatigue.
• Lubrication and materials: Bearings, surface treatments, and lubrication regimes to extend life.
• Tooling synchronization: Aligning dwell times with drill/punch cycle times for clean, accurate holes.

Optimizing these parameters yields stable indexing, reduces maintenance, and safeguards hole quality across long production runs.

Summary

The Geneva cam (Maltese cross mechanism) is the go-to cam for producing holes at regular intervals on production lines. Its precise, intermittent motion with built-in dwell aligns perfectly with drilling and punching operations, delivering reliable spacing and high repeatability. While alternatives like globoidal cams or servo indexers can address higher speeds or flexible patterns, the Geneva mechanism remains a durable, cost-effective standard for fixed-index applications.

How does a cam help something move up and down?

The basic principle of the cam is to turn a circular motion into a linear one. This is referred to as reciprocating movement. In it’s simplest form you turn a handle to make something move up and down. The cam-follower is connected to, and part off, a shaft known as the Push-Rod.

What does a cam mechanism look like?

A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion. It is often a part of a rotating wheel (e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path.

What kind of cam is often used in production lines to make holes at regular intervals?

Snail or drop cams have the appearance of a snail shell. It causes the follower to remain stationary for half a turn before gently rising and suddenly falling. They can only work by rotating in one direction. Used on production lines to make regular holes or cuts in an item as it rotates and drops at regular intervals.

Where are cam mechanisms used?

Cams are pretty hard to spot in real life, as they are often hidden inside machines such as engines, printing machines, sewing machines, or toys. This walking toy, for example, has cam mechanisms attached to the legs, that help it walk. Remember, cam mechanisms help convert circular motion into reciprocating motion.