Prototype building of an Expansion Joint using 3D Printing

A prototype is an early sample, model, or release of a product built to test a concept or process or to act as a thing to be replicated or learned from. It helps customer to have an actual vision of the part and can alter specifications before the part is manufactured

It is generally used to evaluate a new design to enhance precision by system analysts and users.

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Benefits of Prototyping

Making a prototype improves the accuracy of final product. It also helps us to identify and address problems at early stage of design.

It can help us estimate development costs, timescale of production of final product, skills and production process required for manufacturing as well as potential resource requirements for the product.

Making a prototype can encourage us to Innovate the product and increase the potential abilities and efficiency of the product.

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Pressure balanced Expansion Joint

Pressure created by pumps or gravity is used to move fluids through the piping system

Fluids under pressure occupy the volume of their container. The unique concept of pressure balanced expansion joints is they are designed to maintain a constant volume by having balancing bellows compensate for volume changes in the bellows (line bellows) which is moved by the pipe.

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Design of Expansion Joint

Expansion Joint mainly consists of Five main components

Dimensions of these components were taken from a standard drawing of an Expansion Joint obtained online.

Following description shows the details of how each component was designed in PTC CREO

Since all the Pressure balanced Expansion Joint components are circular the best way to model them in CREO is by using the 'Revolve' command.

It basically allows you to make a sectioned sketch of the component and revolve it in 360 degrees to produce the model.

Following images show how each component was constructed using the 'Revolve' command.

1. Body

2. Pipe

3. Gland

The holes on the faces are done using 'Pattern' command, which allows you to pattern a feature over the face around an axis, along a length etc.

4. Gland Bush

5. Neck Bush

Final Assembly

The final assembly looks as shown below.

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Detailed drawings of each part of the Assembly in PDF format are provided below.

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3D Printing

The CAD model of the Main assembly is currently in a .prt file format which can be converted into .stl file format so that it can be read in Slic3r software used for 3D printing.

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Materials

Traditionally, 3D printing focused on polymers for printing, due to the ease of manufacturing and handling polymeric materials. The materials that can be used to 3D print this prototype are described as follows.

Resin It is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers

Thermoplastic

It is a plastic polymer material that becomes pliable or mold-able at a certain elevated temperature and solidifies upon cooling

Poly-carbonate

Poly-carbonates are a group of thermoplastic polymers containing carbonate groups in their chemical structures