Tooling Terminology Glossary
Boot Core- A core used to form a casting feature away from the
parting line. The boot is used to connect the core with the parting line to
fix the core's position.
Cast Iron Corebox- Used for either hotbox processes or blow
processes. Cast iron boxes are either cast from a master pattern and then
polished, machined from a block of stock or both.
Core Strippers- Templates that strip the fins off a core after it is
cured.
Core Setting Fixtures- Used to set several cores into a mold at once.
Coreboxes- Tooling used to form cores. Coreboxes for oilsand and cold
box processes are usually made of wood or plastic. Because they are not
heated and not under extreme abrasion, wood is usually sufficient. Often
strike surfaces where the excess sand is struck away with a metal bar are
coated with metal strips to enhance the life of the box. In processes where
the boxes are heated metal must be used. Cast iron is the best choice for
this. It is more wear resistant and dimensionally stable under heat.
Aluminum, having a high coefficient of thermal expansion, tends to move too
much when heat is applied. In core processes where sand is blown or injected
into a box, it is good to use metal unless the quantities are low. The
blowing is very abrasive and will wear out a wooden box very quickly.
Cover Cores- Cores used to form a complex shape in order to avoid
using a matchplate.
Flatback- A mounted pattern that is not split because the shape is
conducive to mounting a flat feature against the pattern board.
Follow-board- Used to help a molder make a part that would otherwise
not lay flat against the split line. A follow-board follows the complex
contour of a part.
Gauges (Gages)- Used to check castings for dimensional accuracy.
Paste Corebox- A paste box is used to make a portion of a core that
will be pasted to one or more additional sections to form a whole assembly
that can be placed in the mold.
Loose Pieces- Used in both molds and coreboxes to form an undercut.
Loose pieces remain with the core or mold when it is drawn and are then
removed. Loose pieces should be avoided when possible.
Loose pattern- One that is not mounted on a board. Often loose
patterns are used in floor molding where a pattern is rammed up in the sand
by hand on the floor.
Master patterns- Temporary patterns used as an intermediate step in
making metal patterns or coreboxes. They are usually made of wood. A master
pattern will have double shrinkage. Double shrinkage is necessary because
the metal tooling will shrink once when it is cast and the casting will
shrink a second time when it is cast.
Matchplates- Metal tooling that has been cast from a master with all
of the impressions integrated into one, homogenous pattern. Usually made of
aluminum although cast iron and bronze are sometimes used. Matchplates are
necessary when the quantities to be made in the life of a part are high or
when an offset parting line is required because of a complex configuration.
A matchplate will last for many thousands of impressions.
Mold- A mold is what molten metal is poured into. It is not a
pattern. See pattern.
Pattern- In the sand casting business tooling is commonly referred to
as patterns and coreboxes. When sand is packed around it a pattern forms the
cavity in the mold that will receive the metal. Patterns can be made of
wood, metal, plastic or composites. Occasionally one will hear someone refer
to a pattern as a mold. A mold is what the metal is poured into. It is not a
pattern.
Patternmaker's Shrinkage- Before a patternmaker starts building a
pattern he must calculate shrinkage. When metal cools from the point at
which it became a solid to room temperature it contracts. Different metals
contract at different rates. Ductile iron shrinks less than one sixteenth of
an inch per foot. Stainless steel shrinks five sixteenths of an inch per
foot. Most other metals shrink somewhere in between those extremes. To
compensate for this, patternmakers have to make a pattern oversized. A table
of shrinkage factors for various metals is provided at the end of the design
section in this book.
Patternmaking- Patternmaking is a very old art. It goes back to the
days of the guilds and artisans. Until recently patternmaking was learned as
a trade. An aspiring patternmaker began as an apprentice, became a
journeyman and, if good enough and persistent enough, became a master. There
are very few masters left. Most of the new patternmakers come out of
vocational schools today. The quality of the education is excellent.
Patternmaking is very good profession for an individual with the necessary
skills. It has become a technically oriented profession with today's
computerized design and manufacturing methods.
Permanent Mold- A permanent mold is a metal or composite mold into
which metal is poured directly. It will last for many cycles.
Plastic Pattern- Many patterns today are being made from composite
materials. They are often referred to as plastic patterns. The most common
plastic used is urethane although there are many. Often the resins are
reinforced with glass or steel fibers to give the pattern more strength and
wear resistance. Plastic is often a cost effective way to duplicate a shape.
It is midway between wood and matchplates in both cost and durability.
Rigging- Rigging is the gates, runners, risers, traps, filters etc.
that are designed by the foundry and built as part of a pattern.
Shell Corebox- A corebox used to make a shell core. It is a blow type
box and normally is made of cast iron.
Shrink Rule- A special ruler used by
patternmakers. It has linear (patternmaker's) shrinkage already calculated.
A different shrink-rule is required for every increment of shrinkage.
Split Wood Pattern- Normally mounted with one half of the pattern on
one side of a board and the other half on the other side.
Split Wood Corebox- A corebox split through a line from which a core
can be drawn. The box is pinned to assure proper alignment and clamped
together during filling.
Sweep Corebox- A somewhat crude method of forming a core by rotating
a template about an axis to shave away sand in the shape desired.
Tooling- Foundry tooling includes all those pieces of equipment which
are used in the manufacture of a specific casting. While patterns and
coreboxes are the most common types of tooling, there are many others
including core setting fixtures, core strippers, trim dies and gauges.
Trim Dies- Used to remove gating from the casting after it is shaken
out.
Wood Patterns- The most common and most cost effective patterns are
made of wood. They are usually durable enough to stand up for at least 1000
impressions and sometimes many more. Wood patterns are usually made of
mahogany because of its tight grain, resistance to cracking, hardness and
dimensional stability. A good patternmaker will glue together many pieces of
wood to make a pattern in order to get the grain running the right direction
for a given shape.
See also loose and split patterns.
Wood Corebox- A corebox made of wood.