How do gear teeth determine flexo repeat length?

For circular-pitch gears, repeat length equals tooth count multiplied by circular pitch. On a 1/8-inch CP system, each tooth adds 0.125 inch of repeat, so an 80-tooth gear gives a 10-inch repeat.

How is a flexo cylinder diameter calculated from repeat length?

The print-surface diameter equals repeat length divided by pi. Bare cylinder diameter is smaller because the plate and mounting tape add radial buildup; confirm the required undercut and buildup with the press specification.

Flexo cylinder sizes: choose by repeat, gear system, and actual press inventory

Q: What are standard flexo cylinder sizes?

There is no universal set of standard flexo cylinder sizes. A press supports a defined gear or sleeve system, face width, and repeat range, while the printer owns only part of that range. Quote and prepare the job against the actual press inventory rather than a generic chart.

Q: What cylinder information belongs on a flexo job ticket?

Record the press, cylinder or sleeve ID, tooth count, CP or DP system, approved print repeat, usable face width, plate and tape buildup, and distortion reference. This prevents a valid repeat from being assigned to a cylinder the pressroom does not actually have.

There is no universal flexo cylinder size chart that works across every press. A press has a specific gear or sleeve system, repeat range, face width, and plate buildup. The printer then owns only a subset of the cylinders or sleeves that the press could theoretically run.

That makes the practical rule simple: choose from the pressroom’s actual inventory first, then verify the math.

Size starts with the gear system

On a circular-pitch (CP) geared press:

Repeat = gear teeth × circular pitch

With a 1/8-inch CP gear, each tooth adds 0.125 inch of repeat. An 80-tooth gear therefore produces a 10-inch repeat; a 96-tooth gear produces a 12-inch repeat.

Diametral-pitch (DP) gears use a different designation. Convert DP to circular pitch before calculating repeat:

Circular pitch = π ÷ DP
Repeat = gear teeth × circular pitch

A tooth count without the CP or DP system is incomplete. The same number of teeth can describe a different repeat on another gear standard.

Repeat is not bare cylinder diameter

The repeat is the circumference at the printing surface. Its diameter is:

Print-surface diameter = repeat ÷ π

The bare cylinder is smaller because the mounting tape and photopolymer plate add radial buildup. Press undercut, plate gauge, tape thickness, and the OEM’s stated reference all matter. Do not order or assign a cylinder from a calculated diameter alone without checking the press specification.

For the actual conversion, use the Flexo Repeat Length & Cylinder Calculator. It handles CP, tooth count, print-surface diameter, plate-and-tape buildup, and images around.

The inventory check comes before quoting

A mathematically valid repeat is not automatically available on press. Before a trade shop commits to a layout, confirm:

Press and print station — the job must be tied to the machine that will run it.
Cylinder or sleeve ID — verify that the physical item exists and is available.
Gear system and tooth count — store CP or DP with the number of teeth.
Approved print repeat — keep the exact value in its native unit.
Usable face width — repeat answers the around dimension; face width limits the across dimension.
Plate and tape buildup — use the combination the cylinder undercut and distortion setup expect.

A generic chart can suggest a repeat. Only the press inventory can confirm it.

Why the cylinder record belongs on the job

Cylinder choice affects step-and-repeat, distortion compensation, plate dimensions, mounting, and the final plate area. If prepress receives only “12-inch repeat,” an operator can still choose the wrong press, gear standard, cylinder width, or buildup.

A flexo-native MIS should keep the press, cylinder or sleeve ID, gear teeth, pitch system, repeat, face width, plate gauge, tape, and distortion reference on one job record. That gives CSR, prepress, the plate room, and the customer’s press team the same cylinder specification—and makes a rerun reproducible.

The short version

Flexo cylinder size is not one diameter from a universal table. It is a press-specific combination of gear system, tooth count or sleeve repeat, usable width, and plate buildup. Select from the actual inventory, verify the repeat math, and preserve the approved cylinder specification with the job.

Flexo cylinder sizes FAQ

What are standard flexo cylinder sizes?

There is no universal standard set. Each press supports a defined repeat range and gear or sleeve system, and each printer owns a specific inventory within that range.

How do gear teeth determine repeat length?

For CP gears, multiply tooth count by circular pitch. On a 1/8-inch CP system, repeat in inches equals teeth divided by eight.

How do I calculate cylinder diameter from repeat?

Divide the print-surface repeat by π. Then account for plate and mounting-tape buildup when determining the bare cylinder diameter, following the press specification.

What should a flexo job ticket record?

Record the press, cylinder or sleeve ID, tooth count, pitch system, approved repeat, usable face width, plate and tape buildup, and distortion reference.

All Printing Resources: Gear Tooth Based Print Repeat & Distortion Calculator — definitions and formulas for circular pitch, diametral pitch, tooth count, and print repeat.
FlexoExchange: CP Versus DP — worked examples for converting gear systems and calculating available repeats.
Flexo Repeat Length & Cylinder Calculator — calculate repeat, print-surface diameter, buildup, and images around.
Flexo repeat length — the difference between gear pitch, cylinder OD, and effective print repeat.
Flexo plate distortion — why the approved repeat and plate gauge must use the same reference.