A new design for 3D-printed pistons uses latex gloves as a flexible seal. The design comes from YouTuber Robert Murray-Smith and enables the construction of functional pistons without time-consuming post-processing.
Conventional 3D-printed pistons usually require time-consuming grinding to achieve the necessary accuracy of fit. The new design avoids this problem by using an elastic latex jacket between the piston and cylinder wall. The design is based on the principle of the roller piston, in which a flexible sleeve unrolls and rolls up like a stocking.
The system consists of four 3D-printed components: a spherical piston, two holders and a cylinder. A finger of a latex glove serves as a seal. Graphite powder is applied to the latex surface to reduce friction. Wet lubricants are unsuitable as they cause the latex to swell.
Assembly is carried out by placing the latex finger over the piston and attaching it to the brackets. Optionally, the seal can be reinforced with silicone sealant. The finished piston moves with very little resistance and responds to low pressures.
The design is suitable for various applications such as pumps, compressors or air motors. A particular advantage is the low hysteresis – the delay between pressure change and piston movement.
The STL files for the replica are available on Thingiverse. Murray-Smith demonstrates the construction and assembly of the system in a video.
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