design considerations:
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shape design considerations

The extrusion of Brass, Bronze and Nickel Silver shapes is carried out at elevated temperatures and relatively high pressures. The ability to extrude a particular shape is dependent on the choice of alloy and the cross sectional area of the shape; therefore our technical sales staff will consult with the client when a new shape is required.

The following factors will have a bearing on the final shape design: -

1. Generally, shapes having thin metal thickness are more difficult to extrude.

2. Solid shapes are more easily extruded that hollow shapes and are therefore less expensive to produce. With hollow shapes the wall thickness may need to be increased to facilitate extrusion.

3. Uniform metal flow is the key to successful production of copper based extrusions, therefore careful consideration should be given to both shape and tolerance requirements.

4. Symmetry and balance assist in the achievement of uniform metal flow during the extrusion process and consequently leads to optimum extrusion conditions. The achievement of uniform metal flow is also desirable to enhance the attainment of relatively close extrusion tolerances, given that the extrusion of copper based alloys is a hot working process.

5. It is important to consider various shape design elements to enable the extruder to produce material to customer requirements in an economical manner with a short lead-time.

manufacturing considerations

1. Size limitations of solid shapes vary with press capacity and associated handling equipment. A solid shape having a circumscribing circle of up to 170mm diameter can be extruded.

(The circumscribing circle is the smallest circle, which completely encloses the shape.)

2. In determining the feasibility of a particular shape the ratio of circumscribing circle diameter / metal thickness of 40:1 maximum is applied. Another factor is minimum cross-sectional area that can be extruded.

Providing both criteria are met it usually means that the shape is acceptable as far as extrusion is concerned. Nevertheless the configuration of the shape must also be considered, with long narrow tongues and balance or distribution of metal needing to be taken into account.

3. Hollow shapes have additional size limitations in comparison to solid shapes, due to different types of tooling used for hollow extrusion.

4. Cars should be exercised in the interpretation of these statements as other factors such as post extrusion processing may be involved. Direct technical advise should be obtained from a Deeco Metals representative or agent in order that each shape inquiry is treated on its merits.

5. When very large complex shapes are required it is often necessary to extrude two or more sections which may be joined by various means to giver the desired configuration.

6. Shapes are supplied in standard 3.6 meter lengths (12ft) however up to 20ft lengths may be supplied on request.

Certain shapes do not lend themselves to production on long length, particularly complex sections, which have to be matched with other sections.