SMC MGPM40-25Z Compact Guide Cylinder 40 mm Bore

A guide cylinder that carries its own side loads

MGPM40-25Z is a double-acting compact guide cylinder from the SMC MGP series. A standard round or compact cylinder pushes and pulls but cannot resist twisting; here the piston rod is paired with two guide rods and a front plate, so the cylinder body and the guide unit are one assembly. That makes it a common choice for pick-and-place heads, lifting stoppers, pushers and small transfer stations where the load is mounted to the plate and must not rotate.

The order code breaks down as follows: MGP is the series, M is the slide bearing type (L is ball bushing, A is high-precision ball bushing), 40 is the 40 mm bore, 25 is the 25 mm stroke and Z is the current design suffix. No port-thread letter is shown; the catalogue lists separate port-thread letters (TN for NPT, TF for G) and notes that only M5 x 0.8 is available for the 12 and 16 mm bores, so confirm the port thread you need. No auto-switch code is appended, so the cylinder is ordered without switches, but the piston carries a built-in magnet.

Technical specifications

Slide bearing, ball bushing or high-precision: choosing the type

The three bearing types share the same mounting dimensions in the catalogue, so the choice is about accuracy and load. The slide-bearing MGPM used here is the economical, rugged option; the ball-bushing MGPL has lower friction and a tighter non-rotating accuracy (+/-0.03 deg at this bore); the MGPA high-precision version is tighter again, at +/-0.01 deg for 32 mm bore and above. Comparing weights, the MGPM40-25 is 1.64 kg while the equivalent ball-bushing MGPL40-25 is 1.59 kg, so the choice makes little difference to the moving mass at this size.

Because the plate overhangs the cylinder, the load must be checked against the catalogue model-selection graphs on allowable lateral load and rotational torque, not just the thrust figures. Fit the cylinder with the load centre as close to the plate as possible and use the rubber bumpers only for light loads; heavy or fast masses need an external shock absorber or a deceleration circuit.

Mounting, piping and options

The catalogue shows four mounting arrangements, including top, bottom and T-slot bottom mounting, with knock-pin holes on each mounting surface for repeatable positioning, and the ports can be taken from the top or the side. Small solid-state or reed auto switches and magnetic-field-resistant switches can be mounted directly on two surfaces. The catalogue lists made-to-order suffixes such as -XB6 for a heat-resistant version to 150 deg C, -XC6 stainless steel, -XC22 fluororubber seals and -XC82 bottom mounting, but these are different part numbers and are not included in MGPM40-25Z.

In Oman and Gulf plants the usual points to confirm are a dry, filtered supply (non-lube operation depends on clean air, typically from an air-preparation line) and whether coolant, dust or wash-down water is present; the catalogue shows dust-resistant and water-resistant variants for those cases.

Key features of the MGPM40-25Z

• Cylinder, guide rods and plate in one compact body, so no external linear guides or anti-rotation brackets need to be designed and aligned.
• Slide bearing guides that tolerate shock and lateral loads well, making them suited to stopper and pusher duties.
• Built-in magnet for auto switch position sensing, with switches mounted directly in the body grooves.
• Rubber bumpers at both ends to absorb end-of-stroke impact on light loads.
• Knock-pin holes on the mounting surfaces for repeatable positioning when a cylinder is replaced.

Sizing the force for your load

The theoretical output of 628 N extending and 551 N retracting at 0.5 MPa is a static figure. For a moving load, engineers normally apply a load factor: a common rule of thumb is to use no more than about 50 to 70 percent of theoretical force for dynamic motion, leaving margin for friction, acceleration and pressure drops in the line. For vertical lifting, remember that the load acts against the extend stroke and assists the retract stroke, and check the plate’s allowable load in the SMC selection graphs for the chosen speed.

Applications

• Lift-and-stop units on conveyor lines in bottling, packaging and food plants
• Pushers and ejectors that divert products between lanes
• Clamping and positioning of workpieces in assembly and test fixtures
• Vertical axes of small pick-and-place units combined with a gripper

Maintenance in Gulf plants

Most cylinder failures come from contaminated air rather than wear. In Oman and the Gulf, compressors draw in hot, humid and dusty air, and condensate forms in the lines as the air cools. Fit a filter, regulator and, where necessary, a refrigerated dryer upstream, drain receivers regularly, and keep the guide rods clean. Check flow controls are set so the cylinder does not hit the bumpers hard, and inspect the guide rods for scoring that may indicate excessive lateral load.

What to include in your RFQ

Give the full code MGPM40-25Z with any port thread letter, auto switch type and lead wire length if required, made-to-order suffixes, quantity and the delivery location. If you are replacing an installed unit, a photograph of the nameplate helps confirm the exact version.

Documents and quotation

The linked SMC catalogue covers how-to-order, specifications, model selection graphs and dimensions for the MGP series. Please confirm bore, stroke, port thread, bearing type, switch needs and any made-to-order option before ordering. Other cylinders are listed under Pneumatic Cylinders. Seven Star LLC is an independent supplier and can quote this exact code on request.