Extrusions Flashcards
Extrusions are Ideal for making metal _________ that can be a variety of shapes, solid, hollow, and with tight tolerances
profiles
Extrusions requires relatively _______investment ($___-$___) and have a ______ time to market (_________)
cheap, 1-5, fast, 6 weeks
About _______of metal extrusions are ___________(most of which are __________)
90%, aluminum, 6000 series
The extrusion process is:
o Preheated __________ placed inside ____________
o Pressed by a ________ through the ___________
o __________ shape comes out the _________
Billet, ram, casting, extruded, die
Billets are ______________ bars made by __________
cylindrical bars, casting
Billet diameters can be as large as ___________ and must be _________ than the _________
350mm, larger, profile
Profiles are typically ________ of the billet diameter and the Cross-sectional ratio between _______ and
________ is known as _____________, R
20-80%, billet, profile, extrusion ratio
About ____________ of billet goes through the die in a single pass and the __________ can be recycled
80-90%, offcut
A _______________________ is when a second billet is place behind another which can produce ___________ in extrusion
Billet-to-Billet Extrusion, weak spots
To allow time to load subsequent billets, manufacturers aim for about _____________________
80% effective press time
Sometimes billets are heated with a “__________________” where the die end is __________ than the ram
end which allows the material near the ram end and sides of the material to be heated to optimal temperature via __________ and _____________
temperature taper, hotter, friction, deformation
The Flow of metal through die is similar to ______________from a larger channel to a
smaller one where metal funnels toward the ____________, with the largest deformations occurring in in
a _____________ region. Downstream of this region are wedge shaped “________________” where material does not pass through the die and is ______________
fluid, cone shaped, dead metal zones, scrapped
The Extrusion diagram shows the ________________that material can be extruded vs. __________________
o Ignores _____________
Initial billet temp, temperature taper
Line 1 of the Extrusion Diagram relates to the _________ where the _______ the billet, the ________ the ram will be able to extrude the billet
ram force, hotter, faster
Line 2 of the Extrusion Diagram relates to the ___________of the material where as the velocity goes up, material will __________, causing _____________(aka ______________)
melting, heat up, hot cracking, hot shortness
Line 3 of the Extrusion Diagram begins at the ______________ and increases with velocity again because material ___________ as velocity increases
cold cracking temperature, heats up
The __________________ is the temperature below which the material will crack because it cannot ______________ to fit through die
cold cracking temperature, deform enough
Overall, the Extrusion diagram shows the viable ______________ of initial billet temperature and exit velocity
combinations
In general, extruders will want the velocity to be as __________ as possible
high
Considering a Y- shaped profile:
The Die is a ________ made of ___________ and the material only makes contact with the die
over the ______________
flat disk, tool steel, bearing surfaces
Determining bearing surface lengths is a highly case-specific process and is often done by ________________
Trial and Error
Considering a Y- shaped profile:
You wish to distribute material evenly over profile but the material will want to flow ___________
near the center of the extrusion so the bearing surfaces are made ________
to increase the ________ and promote ___________ flow speed through the die
faster, thicker, friction, uniform
When creating profiles with slots the ratio between the slot depth, H, to width, B, is _____________
Limited
If H/B gets too _________, shear stresses in the die could be enough to break the ______________
high, tongue
