2. Tutorial: Engineering technology Topic: Volume forging – Extrusion Prepared by: Ing. Elena Nová Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

3. Volume forging – Extrusion

4.  Extrusion is a technology which can be used at higher, medium and cold temperatures. Forged material is moved in directions determined by the tool’s construction- extrusion die.  Product is called  extrusion punch.

5. Extrusion technology: Metals with low forging strength as is aluminum and its alloys can be extruded in one operation. Steel and other metals use more operations.

6.  It is necessary to treat the material by straitening and cutting before actual extrusion. After that follows surface cleaning and phosphate.  Extrusion die consists of extrusion punch and extrusion die.  Lubricant for extrusion at higher temperatures is glass.  Cold extrusion uses oil.

7.  Extrusion is divided:  Hot extrusion  Is used for full and hollow profiles with difficult cross sections which cannot be made by rolling. Cold extrusion  Is used for thin walled products, cartridges, tubes, spray cans.  Production is very economic.

8.  Extrusion is divided according to direction on:  Forward  Backward  Combined  Sidewise  Radial

9. At forward (direct) extrusion is material moving in the same direction as extrusion punch. It is used for forging pivots, bolts, bushes, products with constant cross section.  Princip dopředného protlačování (1, 3 – die, 2, 4 - punch, a, – punch,  b – wiper, c – die, d – ejector)

10.  At backwards extrusion, material moves in opposite direction. It is used for manufacturing of hollow extrusions where wall thickness is very thin compared to its diameter.  Princip zpětného protlačování  1, 3 – die, 2, 4 - punch,  a, – punch, b – wiper, c – die,  d - ejector

11.  Combined (compounded) extrusion  Very stressed, profiled products are made in this manner. Principle of combined extrusion 1, 3 – die, 2, 4 - punch, a, – punch, b – wiper, c – die, d – ejector)

12.  Side and radial extrusion  At side extrusion is material moving perpendicularly to direction of extrusion punch.  Radial extrusion is a forging where material and tool parts are moving in radial direction to axis of extruded product.  Principle of side (left and middle) and radial extrusion

13.  Hydrostatic extrusion, semi-finished product is inserted in liquid of very high pressure. By the all- dimensional tension is material ductility increased.

14.  What kinds of extrusion do you know?  Divide extrusions in accordance to flow direction.  Describe construction of extrusion tool.  What material and method do we use for cold extrusion?  What material and method do we use for hot extrusion?

15.  Translate and describe:

16.  http://www.ksp.tul.cz/cz/kpt/obsah/vyuka/s kripta_tkp/sekce/04.htm