Dice are made by forming a material into a controlled shape, adding or reproducing markings, finishing the surfaces and inspecting the result. The route depends on the material: plastic can be injection molded, liquid resin can be cast in a mold, and metal can be cast or machined. There is no single process behind every die.
This overview explains those routes and the terms used in product descriptions. It is a guide to understanding manufacturing, not a material-specific workshop recipe.
Start with the design
A die needs more than an outline. A design specifies its faces, dimensions, edge profile, markings and how a player identifies the result. A maker also has to decide how the object will leave its mold or be held during machining. Lettering must remain readable after finishing.
A design can be represented digitally or by a physical master used to make a mold. A 3D-printed master and a finished 3D-printed die are different things: the first is tooling for later copies; the second is the playing object itself. Product records should state which is meant. Compare polyhedral dice, dice dimensions and numbering layouts.
Route 1: injection-molded plastic
In thermoplastic injection molding, heated material fills a tool cavity, cools and is released as a solid part. Reusable tooling supports repeated production. The chosen polymer, geometry and tooling affect the process; a generic label such as “plastic” does not identify all of them.
Protolabs describes injection molding as a repeatable production method and lists acrylic among its available thermoplastics. Its manufacturing documentation provides the process background here, rather than evidence about a particular dice brand. Chessex’s own catalog discusses plastic dice molding and the tooling costs involved in custom designs. Protolabs: injection molding; Chessex: catalog and custom dice.
After molding, an entry point or parting line may need attention. A visible manufacturing trace can explain how an object was produced, but its presence alone is not a measurement of rolling bias. See common dice materials for the difference between a material family and a marketing label.
Route 2: cast resin
In resin casting, a liquid casting material is mixed as specified by its manufacturer, introduced into a mold and allowed to cure. Flexible rubber molds can reproduce the details of a master. Pigment or embedded decoration may be part of a particular design, but the exact resin chemistry and compatibility need to be confirmed by the maker.
“Resin” is a broad term. It does not by itself tell you whether a product is epoxy, polyurethane or another formulation, nor whether its production was manual or industrial. Smooth-On’s mold-making and casting tutorials describe several molding and casting approaches. For the terminology used in dice listings, see resin dice.
Why makers manage bubbles
Air can be trapped during mixing and molding. Smooth-On distinguishes vacuum degassing, which removes trapped air from mixed material, from pressure casting, which reduces remaining bubbles during cure. They are different operations and are not interchangeable labels. A clear surface is a visual result; it does not certify the statistical fairness of a die. Smooth-On: vacuum versus pressure.
Actual workshop practice must follow the material’s technical bulletin and safety data sheet, including mixing, ventilation, protection and curing requirements. Pressure casting requires suitable rated equipment and its manufacturer’s instructions; it is not a reason to improvise a pressure vessel. Smooth-On: pressure casting guidance.
Route 3: metal casting and machining
Cast and machined metal dice should not be treated as the same manufacturing claim. Casting forms material in a mold; machining removes material from stock to form the required shape. Protolabs describes CNC milling as cutting plastic or metal blocks to a digital design. These process definitions do not establish which route a particular product uses. Protolabs: manufacturing process overview.
Die Hard Dice provides a useful example of why the base metal and appearance need separate fields: its Raw Finishes page describes die-cast zinc alloy with an electroplated finish that resembles raw steel. The visual name is not a declaration that the die is solid steel. Die Hard Dice: Raw Finishes.
For a product record, capture the stated alloy, whether the maker identifies casting or machining, and the coating separately. Do not infer a process from price, weight or a photograph. Read more about metal dice.
Finishing: surfaces and edges
Finishing may remove production traces, smooth faces, polish surfaces or add a coating. The chosen operation should be recorded when the manufacturer identifies it. “Gloss,” “matte” and “metallic” describe appearance; none is a complete manufacturing specification.
Gamescience describes its own approach in contrast with tumbled dice. Its statements about rolling performance are a manufacturer’s position, not independent proof that one edge style is always fairer. A rounded die and a sharp-edged die are different physical designs; comparing their outcome distributions requires a defined test. Gamescience: maker explanation.
See finishes and surfaces, sharp-edge dice and rounded-edge dice for more precise descriptions.
Adding numbers, pips and symbols
Markings can be reproduced by the mold, cut or engraved later, printed on the surface, or filled with a contrasting color. These are separate steps: a recessed number may be molded rather than engraved, and “inked” describes coloring rather than the original way the recess was formed.
Chessex discusses engraving as a route for custom dice, while Protolabs lists pad printing, laser engraving and painting among finishing options for manufactured parts. Those examples illustrate available methods without implying that every die uses them. Protolabs: secondary finishing operations.
For readability, inspect contrast, complete markings and any convention used to distinguish 6 from 9. A decorative font is useful only if players can interpret it consistently. See dice markings and engraving.
Inspection is different from proving fairness
A useful inspection checklist records face shape, visible defects, dimensions, legibility and the completeness of the set. These observations can identify obvious problems, but do not prove that each outcome has the same probability. Nor does a material name, a high price or “precision” in a product title.
Rolling evidence needs a stated sample size, method, surface and interpretation. A handful of throws is not enough to establish small differences. For the distinction between a mathematical fair-die model and a physical object, read fair dice and physical testing.
What to record when documenting a die
- Material: the stated polymer, resin or alloy; mark it unknown if unspecified.
- Forming method: molded, cast, machined or printed, only when supported.
- Finish: surface texture, coating and edge profile.
- Markings: molded, engraved or printed; color fill recorded separately.
- Evidence: link the maker’s specification and distinguish it from your own observations.
- Testing: report the method and limits instead of treating appearance as proof.
To follow the wider story, read the history of dice. To document an individual object, browse dice products or contribute a sourced record.
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