STEM Pneumatics

Model 1: Functional model - experience compressed air

Topic: Produce compressed air with a self-built pump and learn how it works in a pneumatic cylinder. Controlling a pneumatic cylinder using a valve.
Learning objectives:

• Compressed air allows a pneumatic cylinder to extend or retract. However, blocking the exhaust air prevents this, so it must be able to flow out on the other side of the cylinder.
• Non-return valves only allow compressed air to pass in one direction and can be used, for example, to build a compressed air pump.

Time required: 45 min

Model 2: Extended functional model - compressor, pressure gauge, exhaust air throttling

Topic: We generate compressed air using an electrically operated compressor, measure the air pressure using a pressure gauge and take a closer look at the throttling of compressed air.
Learning objectives:

• Compressors generate compressed air in continuous operation, A pressure gauge is a measuring device for the pressure of air (or gases in general). It provides valuable insights into how pneumatic systems work.
• In order to move cylinders slowly, their exhaust air is throttled. Throttling the supply air is inappropriate.

Time required: two task sheets, 45 min each

Model 3: Barrier with single-acting cylinder - Single-acting cylinder, solenoid valve

Topic: We use pneumatics in a self-built barrier. We get to know the "single-acting" cylinder and the electromagnetic valve. In further tasks we will modify the barrier - so ideally the model should remain constructed.
Learning objectives:

• To learn about the mode of operation and areas of application of a single-acting cylinder
• Establish the connection between electrics and pneumatics via push-button and solenoid valve

Time required: 45 min, more depending on the speed of assembly and willingness to experiment

Model 4: Barrier with double-acting cylinder

Topic: We show how the movement of a double-acting cylinder can be throttled in only one direction or to different degrees in both directions.

Learning objectives:

• Effects of connecting a throttle and a non-return valve in parallel
• This allows compressed air to be throttled in only one flow direction, while it flows practically freely in the other.
• In this way, we can throttle the exhaust air on one side of the cylinder, but leave the supply air unthrottled in the cylinder. We obtain direction-dependent throttling.

Time required: 45 min, if the barrier from the previous task was still in place

Model 5: Vacuum gripper - generating and working with negative pressure

Topic: We generate air pressure that is lower than that of the ambient air and use this in a suction gripper.
Learning objectives:

• A mechanically operated cylinder, as in the home-made hand pump, can generate not only positive pressure but also negative pressure at the other connection.
• With this and a suitable flexible suction cup, light parts with a smooth surface can be held, lifted and moved.

Time required: 45 min for construction and thematic tasks, more depending on the implementation of the optional tasks

Model 6: Electropneumatic air motor

Topics: We construct a compressed air motor that works in a similar way to a steam engine.
Learning objectives:

• In the functional model of the air motor, the combination of several disciplines leads to success: pneumatics, electrics and mechanics/kinematics.
• Only the correct interaction of all sub-areas leads to a solution.

Time required: 45 min

Model 7: Scissor lift tables - pneumatic lifting platform

Topic: We construct a lifting platform - a so-called "scissor lift" - and have it pneumatically driven.
Learning objectives:

• The mechanics of the scissor lift and the care required for precise construction,
• To increase the achievable force by pairing two pneumatic cylinders in parallel,
• the increase in the achievable sliding distance by placing two pneumatic cylinders in series

Time required: 90 min

Model 8: Project model - negative pressure backlash

Topic: This model represents pneumatics in the context of a slightly more complex model - a pneumatic positioning unit that can also be used as a clearance.
Learning objectives:

• Design techniques from mechanical engineering
• Conversion of a linear movement into a rotary movement
• Suitable supply of compressed air to a rotating machine part

Time required: This model is structurally complex and will take several units of e.g. 45 minutes.