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Fareed Mohmed · Engineering

Clamp Cylinder Selector

Clamp force · Arm length · Arm inertia · Part number

Choose a pneumatic clamp cylinder to hold a workpiece in a fixture. A clamp is chosen by the force it must give and by how long and heavy its arm is.

Mindman catalogue data only (other makers are not loaded yet). Curves in the catalogue were read off its graphs, so allow about 5 %. Confirm every part against the maker’s catalogue before you order. See also the Pneumatic Component Selector for ordinary cylinders.

00

Start Here: The Selection Process

Seven steps from the machining force to the order. Read this once, then use sections 01 and 02. Steps with a button link to where you enter or read that step.

1

Find the force on the part

The largest force that will try to move the workpiece, for example the cutting force of a mill or the push of a press. In N.

Enter it in section 01 →
2

Choose the safety factor

2 for a steady force, 3 or more for interrupted cuts or shock. The theoretical clamp force has no friction loss in it, so the factor also covers this.

3

Count the clamps

Divide the force over the clamps that share it. Required force each = safety factor × force ÷ number of clamps.

4

Check the clamp force

The clamp force at your air pressure must be at least the required force. The tool uses the smaller (rod-side) area of the swing clamp, which is on the safe side.

See the result in section 02 →
5

Check the arm

A long arm puts a bending moment on the rod, so each bore has a longest arm that falls as the pressure rises. A heavy arm swung fast carries inertia, so each bore also has a largest inertia for the piston speed. Slow the swing with a speed controller if the inertia is too high.

Rule: keep the arm short and light; a long arm with a heavy block at the tip is the usual cause of a failed clamp.
6

Pick the clamp type

MCKC swing clamp: the arm swings aside to load the part, then clamps straight down. MCKB lever clamp: a lever gives a stroke and a force from a smaller cylinder. MCKA: a plain pin-mounted cylinder, for a direct push.

7

Order and check what the tool does not

  • Clamp stroke, swing direction and arm in the order code
  • Sensor, and mounting and fixture details
  • Clamp only in the straight stroke, never in the swing; mount vertically
  • The exact part number from the Mindman catalogue

Common mistakes

Sizing on cylinder force aloneA strong enough cylinder can still fail if the arm is too long or too heavy. Check the arm limits.
Clamping during the swingA swing clamp holds only in the straight clamp stroke. Set the stroke so the part is clamped after the swing.
Side load on the rodThe rod must not take a side or turning force from the workpiece. Keep the workpiece face square to the axis.
No margin on interrupted cutsUse a factor of 3 or more when the cut is interrupted or the tool can snatch.
Pressure falling in useClamp force and the allowed arm length both depend on pressure. Check them at the lowest pressure you will see.

Brands that make this product

Outlined gold: loaded with series and part numbers. Grey dashed: not loaded yet. Confirm every part against the maker’s catalogue before you order.

Mindmanpart numbersSMCnot yetFestonot yetAirTACnot yetParkernot yetCamozzinot yetNorgrennot yetAventicsnot yet
See all hardware and brand coverage

Brand names and logos are trademarks of their owners and are shown only to identify catalogues.

01

Your Clamping Job

clamp cylinderworkpiecearm length Lclamp forcecutting force
N, the largest that tries to move it
sharing the force
2 steady, 3 or more for interrupted cuts
bar
mm, rod axis to clamp point
kg, used to estimate the inertia
kg·m², leave 0 to estimate
mm/s (50 to 200)
mm: clamp stroke, or stroke for the pin type
seen from the arm end
02

Clamp Cylinders That Pass

03

How It Is Calculated

Force each clamp must give

Required force = safety factor × force on the part ÷ number of clamps. The clamp force at your pressure must be at least that.

Which force is used

Swing clamp (MCKC): the rod-side area, the smaller one, because the catalogue does not say which of its two force columns is the clamping direction. Lever clamp (MCKB): cylinder force × lever ratio L1 ÷ L2. Pin type (MCKA): push force of a plain cylinder only. Forces are theoretical.

Arm length and inertia

Each MCKC bore has a longest arm for the pressure and a largest inertia for the piston speed, read from the catalogue graphs. With only the arm mass given, inertia is estimated as for a uniform bar, mass × length² ÷ 3; a heavy block at the tip is worse, so enter the real inertia if you know it.

Limits of this tool

Curves were read off the catalogue graphs, so allow about 3 to 5 %. The catalogue does not say which force column is the clamp direction, and MCKA has no force graph. Confirm stroke, arm and sensor against the catalogue before you order.