Often we discuss tooling development with our customers when they require new pattern and corebox equipment. Many of the descriptive terms are quite unique to the foundry industry. Listed below are definitions of tooling terms.
| PATTERN | A replica of the part to be cast. Normally made in wood by a patternmaker. |
| MOUNTED PATTERNS | One or more identical patterns (IMPRESSIONS) attached to a molding board (PLATE), which forms the PARTING LINE. Can be made from wood, plastic, or aluminum. |
| PARTING LINE | The junction between the upper flask (cope) and lower flask (drag), required for pattern removal. |
| FLASK | A frame with which a pattern plate or matchplate is mounted onto or sandwiched between. This frame is split in half by the pattern forming the cope & drag. Each cope & drag flask is filled with sand to form the cope & drag mould. |
| LOOSE MOUNTABLE PATTERNS | Wood, plastic, or aluminum pattern(s) supplied loose, which permits mounting by foundry; i.e. positioning within flask perimeter to allow for gating/risering. |
| RIGGING | Term associated to the application of gating and risering. |
| GATING | Term that refers to the passageways through which the molten metal flows into the mold cavity. Requires precise calculations and or experience to design. |
| RISER OR FEEDER | Reservoir from which additional hot/molten metal flows into the casting to provide for contraction, lack of which can cause internal porosity/shrinkage defects. |
| MATCHPLATE | Pattern and mold plate is one integral aluminum casting. Expensive, but lasts longer and can produce a more precise casting. Made normally from a master pattern. |
| MASTER | Loose pattern from which the matchplate is cast. Normally made by a pattern maker in wood, or by rapid prototyping (i.e. stereolithography). |
| PATTERN PLATE | A panel (usually aluminum) to which a pattern(s) is mounted to facilitate the molding process. Forms the parting line of the mold. The pattern(s) are either on separate cope and drag boards or back to back on the same plate, depending on molding method. |
| SHIFT BUTTON | Inserted into or applied onto the mold board to control mis-match (offset) between cope and drag molds. |
| DRAFT | Taper on the pattern, which allows it to be drawn from the tightly packed sand mould (varies from 1° to 7°). |
| CORE | Sand form placed in the mold cavity to create a hollow section in a casting. Cores are made ahead of time in coreboxes. |
| COREPRINTS | Part of the pattern that anchors the core in the mold. |
| SHELL CORES | Medium production hollow sand cores made in something like an injection molding die. Expensive tooling yielding very precise core dimensions and the smoothest cored surfaces of any core process. |
| COLD SET CORES | High production cores made on an automated core machine with either vertical or horizontal parting lines. |
| GREENSAND CORES | Cavity formed by the mould (not a separately made core). A cavity can be made through a section by just allowing the cope (UPPER) sand and drag (LOWER) sand to meet (KISS). The most economical but least accurate method to make a "cored" feature. |
| CORE CLEARANCE | The difference in size between a core and core print. |
| CERAMIC GATE FILTER | A thermal resistant slab of ceramic with small holes through it. Installed in the gating system, it filters slag and sand from the metal preventing inclusions in the casting. |
| RAPID PROTOTYPING | Computer 3D modeling to create master patterns by stereo-lithography or other rapid prototyping process (not made conventionally by a pattern maker). |
PATTERN SHRINK
ALLOWANCE
Pattern shrinkage allowance is needed so that when iron solidifies
and takes shape in the mold, the metal is still at a temperature
of about 2000 F (1090 C), depending on metal composition. As it
cools down to room temperature, the casting contracts (or "shrinks").
Therefore, to obtain a casting of desired size, the pattern is
made slightly oversize. This addition to the dimensions is called
a patternmaker's shrink rule. Different metals require different
shrink factors. Below are standards that Lethbridge Iron Works
applies.
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MOLD FLASK
SIZES
Lethbridge Iron Works has three sizes of molds that parts can
be made in. Anywhere from one to twenty parts may be cast in a
single mold.
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