Glossary - Design & Molding Terms
Glossary - Special DefinitionsPlanet Proto is focused on providing Quality Prototypes. Prototyping Technologies improve and new technologies emerge. The Planet only provides its customers with the processes needed to make the best parts in the business. We say “You Design, We Proto.” The following is a list of terms we think will be helpful to you as an engineer or designer. They are listed in the order of most inquiries.
Abrasion Resistance: The ability of a material to withstand mechanical actions such as rubbing, scraping, or erosion can progressively remove material from its surface.
ABS or acrylonitrile butadiene styrene (a co-polymer or mixture of compounds used for everything from Lego parts to electronics housings), nylon (chemically resistant, heat resistant, tough and flexible – used for combs).
Aspect Ratio: Ratio of total flow length to average wall thickness. This is a very significant issue in designing for injection molding but is less critical in the Planet Cast process.
Back Pressure: The resistance of the molten plastic material to forward flow. In injection molding, back pressure increases the temperature of the melt, and contributes to better mixing of colors and homogeneity of the material. However, as back pressure increases, so does cycle time. This is not a significant issue in Planet Cast parts.
Bosses: Sometimes thought of as the people in charge, in this case a boss is a cylindrical protrusion within a part, often designed to accept fasteners or to locate product inner components. Bosses generally require draft. In plastic part design and prototyping, Plastite screws are recommended for reliable function.
Clearance Holes: A gap that allows relative movement between two components in an assembly as applied to a hole. Generally found in a reference table alongside information with tap drill size and threaded fastener diameter. Depending on the exact interface geometry, at least one or more dimensions would be considered as critical clearances for the assembly to function as intended.
Chamfer: Also known as a bevel, it is a flat, truncated corner.
CAD (Computer Aided Design): Software developed to leverage reuse of designs, create a Product Life Cycle Management Systems and rapid prototype processes commonly used. A designer or engineer needs to operate a 3D CAD program with high user-centered features to leverage the rapid time to market opportunities presented by PlanetProto. Common 3D Design Packages include: Solid Edge, NX5 by UGS, Solid Works, ProEngineer-WindChill, Mechanica, Catia and others.
Casting: The process of forming solid or hollow articles from fluid plastic compounds or resins by pouring or injecting the fluid into a mold or against a substrate with little or no pressure, followed by solidification and removal of the formed object. This is part of what we do at Planet Proto. Our Planet Cast process allows customers to go to trade shows sooner, be first in the marketplace, and possibly take dozens and dozens of parts with them for the big product rollout.
Computer Numerical Control Machining: CNC machining refers specifically to a computer “controller” that reads G-code instructions and drives the machine tool, a powered mechanical device typically used to fabricate metal components by the selective removal of metal. CNC does numerically directed interpolation of a cutting tool in the work envelope of a machine. The operating parameters of the CNC can be altered via software load program. CNC machines today are controlled directly from files created by CAM software packages, so a part or assembly can go directly from design to manufacturing without the need of producing a drafted paper drawing of the manufactured component.
Commodity Resin: A class of injection moldable resins that are traded as a commodity and are used in products with generally low performance requirements. Basic Styrene, Basic Polyethylene, Basic Polypropylene and low-end ABS are considered commodity resins.
Custom Color: Custom Color swatches are small, easily mailed panels of a sample color. These panels may be paper, card stock or sheet metal. Color swatches are used by Planet Proto to as a reference to a custom mixed resin color or custom paint color. Custom Color watches are mailed to Planet Proto.
Custom color requires an additional charge.
Draft: The taper of features. It allows deeper features to be produced in three-axis milling machines.
Draft Angle: Taper or draft required in Injection Molded and Cast Parts perpendicular to the parting line. Draft angle in mold side wall surfaces permit ejection of a cooling part from a mold. Draft allows the part to break free by creating a clearance as soon as the mold starts to open.
Thermoplastics shrink as they cool. This part shrink causes the mold to grip cores or male forms in the mold making normal ejection from the mold difficult or impossible if draft has not included these features in the design. Careful consideration of draft and shutoff are required at the beginning of the engineering process.
Refer to Mold Tech or ASME texture plaques early in the design and engineering process. Different depth textures require different draft angles to successfully mold parts without Drag Marks. Rule of Thumb examples follow. Plastic part designers are responsible for selecting their own draft angles.www.mold-tech.com | www.asme.org
Drag Marks: A form of deep scratch or scratches on the surface of the component usually caused by the ejection of the part. This is not a problem in soft tooled Planet Cast parts.
Durometer: A measure of the hardness of a resin. It is measured on a numeric scale with numbers ranging from lower (i.e., softer) to higher (i.e., harder). Durometer indicates the hardness of a material, defined as the material's resistance to permanent indentation. It is named for instrument maker Albert F. Shore, who developed a measurement device called a durometer in the 1920s. Durometer is typically used as a measure of hardness in polymers, elastomers and rubbers. Planet Proto offers FLEX polyurethane resins in the soft durometer range of Shore A 25, 40, 60, 80 & 90
Elastomer: A rubber-like material that at room temperature can be stretched repeatedly to at least twice its original length and, upon immediate release of the stress, will return with force to its approximate original length. Planet Cast Flex Resins have many elastomeric properties. Few materials referred to as elastomers actually stretch to twice their original length.
Engineering Plastics: Engineering Plastics or resins – A class of polymers, based on aromatic backbones, having high strength, stiffness and toughness together with high thermal and oxidative stability, low creep and the ability to be processed by standard techniques for thermoplastics: samples include polyacetal, polyamide, polycarbonate and polysulfone resins. Engineering Plastics are commonly referred to and engineering resins and have improved mechanical, chemical and thermal properties over commodity grades of resins.
Fillets: In mechanical engineering, a concave easing of an interior corner of a part used to reduce stress concentration (pronounced “fill-it”).
Flame Retardant: 1) A resin formulated to resist burning. Planet Cast Flame Retardant resins are designated with an “FR”; 2) Having the ability to resist combustion (a flame retardant plastic is considered to be one that will not continue to burn or glow after the source of ignition has been removed.) Some of the Planet Cast Ultimate resins are Flame Retardant carrying the designation of FR.
Flubber: A plastic-like material with exceptional kinetic energy storage and energy release capacity. It is closely related to Unobtanium. Actual Flubber cannot be molded in the Planet Proto system and is not readily available. Flubber is not available through Planet Proto.
Hardness: The resistance of a material to compression, indentation and scratching.
Haze: The cloudy appearance in a transparent or translucent material caused by light scattered from within the specimen or from its surfaces.
Hygroscopic: readily absorbs moisture.
Industrial Designer: The person with a funny shirt at the conference room table presenting the board mounted product images responsible for increasing product sales independent of product performance, marketing or cost improvements. Industrial Designers establish the aesthetics, new function, customer appeal, perception and usability of products. They work closely with product engineers, user research, user-related experience and marketing executives to meet common goals. The positioning of the product is many times driven by these improvements into a product concept and is another primary responsibility of industrial designers. They may be the most beneficially creative people in an organization. Their incredible curiosity and drive for finding new methods and materials is surprising.
Industrial Design may include the art of creating overall shape of the object, the location of details with respect to one another, proportions, colors, texture, sounds, product feel and other aspects concerning the product ergonomics. Additionally, the industrial designer may specify aspects of the product concerning the production process and choice of materials. Industrial Designers may also design the way the product is presented to the end user/customer at the point of sale.
Industrial Designers are responsible for reflecting the full value of the corporate brand in each product concept. Industrial Designers are committed to a better product related experience and a brighter future through the use of products they have designed. Industrial Designers should play nice with all engineers. Industrial Designers are the core developers of Planet Proto.
Injection Molded Materials: Commonly used thermoplastic materials.
Injection Pressure: The pressure on the face of the injection screw or ram when injecting material into the mold, usually expressed in PSI.
Knit Lines: Where melted material flows together to form a line or lines that may cause weakening or breaking of the component. Because of the longer “open” time of the catalyzed Planet Cast resin do not have this same issue.
Liquid Injection Molding (LIM): The process that involves an integrated system for proportioning, mixing, and dispensing two component liquid resin formulations and directly injecting the resultant mix into a mold that is clamped under pressure.
Memory: The tendency of a plastic article to revert in dimension to a size previously existing at some stage in its manufacture. Planet Cast parts are manufactured using a low pressure process. This low pressure approach produces parts with very little internal stress.
Mold Texture: Planet Proto surface textures combine the skill of trained technicians and specialized materials to produce 3D decorative and functional finish on the surfaces of our soft tools and the resulting Planet Cast parts.
In injection molding, achieving the texture is dependent on draft angle, shut-off and rib location, as well as resin selection and gloss level. All these features have a very significant impact on the final appearance of the texture in both injection molding and Planet Cast processes. Texture is an integral component of the product design and should be decided early in the design process. Surface textures achievable in Planet Proto molding may not be achievable in injection molding. Planet Proto surface textures include: Glass smooth, smooth, medium, heavy. Glass smooth is always required to make clear parts see-through.
Molding Pressure: The pressure applied to the ram of an injection machine or press to force the softened plastic completely to fill the mold cavities. Planet Cast parts are manufactured using a low-pressure process. This low-pressure approach produces parts with very little internal stress.
The Objet Eden500V is the primary Rapid Prototyping system used by Planet Proto. The 500V provides an easy to use, fast and clean solution for the precise building of any geometry. This shortens product development cycles and decreases time to market for the new products and parts of Planet Proto customers. Rapid Prototypes produced on the Eden500V have smooth and durable surfaces, with exceptionally fine details and an outstanding surface finish.
The Eden500V offers high resolution in the y-axis of up to 600 dpi – the highest in the market. A choice of High Speed (HS) or High Quality (HQ) printing modes gives The Planet maximum flexibility to achieve the quality required in different timeframes. The Objet 500V provides high-quality 3D models and parts. The system works similar to an ink-jet printer but cures the PolyJet FullCureT material with UV light and resolution to .0006”. Single parts sizes can be up to 18” x 14” x 8.25”.
Orange Peel: A surface finish on a molded part that is rough and splotchy. OP is usually caused by moisture in the mold cavity or poor heat transfer properties. In painted parts orange peel is caused by incorrect reducer ratio or moisture in the mixture.
Packing: The filling of the mold cavity or cavities as full as possible without causing undue stress on the molds or causing flash to appear on the finished parts. Over- or under-packing results in less than optimum fill. This is not a problem with Planet Cast parts. Low pressure is our approach to making quality plastic parts quickly.
Parting line: Also referred to as parting surface. A parting line appears as a vector upon the face of the plastic part. This vector line is a witness of the two parting surfaces contacting each other when the mold is closed. Draft must fall away from the parting lines on ALL vertical faces in the plastic part. The widest point on the part is thus the parting line. The location of parting line and subsequent application of draft to the plastic part are design decisions that affect both the aesthetics and functionality of the part. Industrial Designers and Product Engineers decide the placement and shape of a parting line.
Pellets: In injection molding, tablets or granules of uniform size, consisting of resins or mixtures of resins with compounding additives that have been prepared for molding operations by extrusion and chopping into short segments.
PET has good barrier properties against oxygen and carbon dioxide. Therefore, it is utilized in bottles for mineral water. Other applications include food trays for oven use, roasting bags and audio/video tapes as well as mechanical components.
PET exists both as an amorphous (transparent) and as a semi-crystalline (opaque and white) thermoplastic material. Generally, it has good resistance to mineral oils, solvents and acids but not to bases. In its clear form it is very clear and holds a glossy surface well.
Pigment (also know as Colorant, Color Concentrate): A plastic compound that contains a high percentage of pigment, to be blended in appropriate amounts with the base resin so that the correct final color is achieved. The color of the base resin may have a significant effect on the color range that can be achieved.
Plastic: a substance; specifically : any of numerous organic synthetic or processed materials that are mostly thermoplastic or thermosetting polymers of high molecular weight and that can be made into objects, films, or filaments.
Also, the way you probably pay for your Planet Proto order – credit cards used for payment.
Plastite Screws: Planet Proto recommends Plastite for Planet Cast parts and injection molded parts. PLASTITE™ TRILOBULAR™ thread-rolling screws were developed specifically for use in plastics. They combine a unique TRILOBULAR™ cross-sectional form with deep, wide, spaced threads.
The three-lobed design of PLASTITE™ screws use the cold flow characteristics of many plastics by allowing plastic material to recover and fill in between the lobes, which establishes maximum resistance to vibrational loosening. In addition, the screws’ deep, coarsely spaced threads provide a heavier shear area and deeper thread engagement in the plastic, further enhancing holding capabilities.
PLASTITE™ screws’ TRILOBULAR™ design reduces hoop stress and the friction of root interference, which can frequently cause the bursting of thin-walled bosses. Bursting a boss with hoop stress is a drag.
PMS Color (Pantone Color Matching System): Pantone was the first color matching system released in 1963. (the lesson to product developers is: first into the market earns the best brand recognition and gains “staying power” – Get to market first – get to market fast – send prototypes to the show). Planet Proto uses the PMS system as a color reference tool. If a customer specifies a PMS color it is considered a custom color and there is a custom color match charge.
The Pantone system was originally developed for cosmetics. The system is used to specify colors in printing, but also used in the manufacture of colored paint, fabric and plastics. Most of the Pantone system colors are beyond the printed CMYK gamut, those that are possible to simulate through the CMYK process are labeled as such within the company's guides.
Pantone colors are described by their number. PMS allows designers to ‘color match’ specific colors when a design enters production stage – regardless of the equipment used to produce the color. This system has been widely adopted by Graphic Designers, Industrial Designers, Engineers and others. Note: Pantone recommends that PMS Color Guides be purchased annually as their inks become more yellow over time. Your grandfather's Pantone fan will not work.
Polycarbonates provide temperature resistance, impact resistance and optical properties. Most polycarbonates are considered engineering plastics. lighting lenses, sunglass/eyeglass lenses, safety glasses, automotive headlamp lenses, compact discs, DVDs and lab equipment.
Polyethylene: Used in can and bottle handling machine parts, moving parts on weaving machines, bearings, gears, artificial joints, milk cartons, edge protection on ice rinks, butchers' chopping boards.
Polypropylene (tough and flexible – used for containers) in a wide variety of applications, including food packaging, ropes, textiles, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes and thermal underwear.
Polystyrene (low cost, lacking the strength and longevity of other materials) many toys, inexpensive items.
Polyurethane: Used in flexible and rigid foams, durable elastomers and high performance adhesives and sealants, fibers, seals, gaskets, carpet underlay, automotive components and hard plastic parts.
Polyvinyl chloride or PVC: As a hard plastic, it is used as vinyl siding, magnetic stripe cards, window profiles, gramophone records (which is the source of the name for vinyl records), pipe, plumbing and conduit fixtures and better pool floats.
Product Engineer: A difficult-to-find and specialized engineer who designs a product to meet timeframe, performance, technical, cost and marketing goals. Product engineers usually work closely with industrial designers and manufacturing engineers in the development of products. The products and components designed by a product engineer are expected to be reliable as planned, bringing profit to the employer or client company.
A qualified product engineer applies in-depth knowledge of manufacturing techniques, processes and materials. Their expertise is essential in successful product development. Exceptional understanding of causes of product and material failure, kinematics and engineering analysis methods is required. Experienced product engineers know that holding and inspecting a product in prototype form is more valuable to the product development process than the best view in.
Production vs. Prototyping: Creating a product or product components always involves a decision about how many units may be required. Low volumes – 1 to 400 usually rely on prototype processes tooling and lead times. Higher volumes – 300 to multiple millions are considered production volumes requiring production tooling and lead times.
Prototype requirements vary from product to product. Technologies change with time and affect where prototyping ends and production volumes begin. Time, access and material to excellent prototypes are the key factors that feed the decision about when to move from one to the other.
Injection molding is a manufacturing process for making parts from thermoplastic material and usually most economical in high volume production. Molten plastic is injected at high pressure into a mold cavity, which is the inverse of the product’s shape. After a product is designed by an Industrial Designer or a Product Engineer, molds are made by a moldmaker (or toolmaker) from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars. Injection molding is the most common method of production, with some commonly made items including electronic enclosures, small appliances, toys, handheld devices and outdoor furniture.
Prototype: A prototype is an early approximation of a final system or product. Prototypes are built, tested, and then reworked or refined by designers and engineers as necessary until an acceptable prototype is achieved. CAD systems, rapid prototyping and quantity (from 2 to 400 units) prototyping methods have accelerated the later stages of the product development process.
Quality prototypes are commonly used for photo shoots, trade show product releases and early sales samples. Quality prototypes are presented to corporate executives ahead of a product release so that the executive has the latest and greatest to review with other executives and corporate guests.
Quality prototypes allow products to be shown and sold before conventional tooling is ready or even ordered. Quality prototypes are used in focus groups and other types of user research. A comprehensive understanding of product users and the environment in which the product is used is many times best facilitated by prototypes.
Planet Proto makes Quantity Prototypes with molded in color and texture in quantities from 2 to 400-plus units. Some special features can only be achieved through resin casting systems like Planet Cast. Imbedded metals, antennas, in-wall circuit boards and thick-wall parts are some examples of parts that cannot normally be made in quantity using injection molding techniques. To have Planet Proto quote these unique approaches, please upload design documentation and fill out the customer comment form. A Planet Proto technician will call to discuss your specific needs.
Prototype Tool: A preliminary mold built upon which the final mold will be based.
Radiused: An external edge or vertex that has been rounded.
Reinforced Plastic: A plastic composition in which fibrous reinforcements are imbedded, with strength properties greatly superior to those of the base resin.
Release agent: A material sprayed on the mold which facilitates removing the part. We use release agents.
Resin (synthetic): The term is use to designate any polymer that is a basic material for plastics.
Rib: A linear reinforcing member of a part. Draft is required for molded Planet Cast and production plastic parts.
Short Shot (also known as Non-Fill): Failure to completely fill the mold or cavities of the mold. Edges may appear melted. Planet Cast parts can rarely have a similar problem to partial fill.
Sink Mark: An indentation on the surface of the part as a result of significant local change in wall section. The mark will occur in the thicker area. In injection molding with irregular thickness the thicker section of a part cools much slower and shrinks at a different rate from the rest of the part. It is sometimes considered a cosmetic problem. If sink marks are going to be an issue in the design of a part consider hiding the area with another part, nameplate, warning or texture. Planet Cast parts do not have sink marks under normal circumstances.
Soft Tooling: In a common Planet Cast process, soft or silicone tools are made. A pattern of the part to be cast is placed on a panel. The pattern or master is hand-finished and textured Planet PolyJet parts of the desired casting. Silicone rubber is poured over the pattern or master until the model is covered by a few inches of rubber. The silicone settles to level with the top edge of the cope or mold box. The silicone then cures. The other side of the tool is set up in a similar way. A second mold box is placed on the backside of the cured half tool.
Silicone is cast into the second mold box. Dowels (or pins) are placed in the silicone to make holes for the sprue and risers. The silicone cures. The risers and sprue are then carefully pulled out of the silicone. The critical part of the operation is to separate the cope and drag safely removing the pattern. The pattern is lifted from the silicone tool halves, leaving a molding cavity. The sprue hole leads to the void left by the master pattern.
Multi Part Tools are the key component of creating quick-turn molds for complex cast resin components. Cores are made (hand-formed, machined or grown as a Planet PolyJet part) to achieve what may be considered “actions” or “pulls” in an injection molding environment. There is a special art and technique required in making these cores in a production environment.
Soft Touch: Is a tactile applied finish originally developed for surfaces of vehicle interiors which are often touched. Soft Touch coatings provide a desired leather-like and grippy feel. These coatings are often two component in chemistry offering scratch/mar and chemical resistance (to things such as sunscreen and insect repellent).
These coatings also are available in various gloss levels ranging from extremely flat to high gloss. Some Soft Touch-type coatings have the desired soft feel property while providing excellent scratch/mar and chemical resistance. Both VelvaShield™ and Aqua~DekoSoft™ are available with Teflon™, for superior cleanability, or with antimicrobial agents designed to minimize the growth of microbials such as E. coli and other bacteria and fungi. If you need these kind of performance coatings applied to your Planet Proto prototype, please make note in the Comments section.
STL (Standard Tessellation Language): A file type that is the output of CAD software. The original flavor of .stl was created by 3D Systems. STL files are exported by many CAD systems such as Solid Edge, Solid Works, NX, Catia, Unigraphics, ProEngineer Alibre, Mechanica, Alias, Rhino, 3D Studio and others. Some CAD packages create better .stl files than others. The .stl file recommendations that follow this information are to be considered best starting settings for your CAD package.
STL files describe only the surface geometry of a 3D object. The files carry no representation of color, material type, specific material weight or other CAD model features. The .stl format specifies both ASCII and binary representations. The more compact binary files are more commonly used in prototyping.
An .stl file describes a raw unstructured triangulated surface by the unit normal and vertices (ordered by the right-hand rule) of the triangles using a 3D Cartesian coordinate system.
Stiffness: The capacity of a material to resist elastic displacement under stress.
Tensile Modulus (Also called modulus of elasticity): The ratio of nominal stress compared to the corresponding strain below the proportional limit of a material.
Tensile Strength: The maximum tensile stress sustained by the specimen during a tension test.
Tensile Strength, Break: The maximum stress that a material can withstand without breaking when subjected to a stretching load.
Tensile Strength, Yield: The maximum stress that a material can withstand without yielding when subjected to a stretching load.
Thermal Conductivity: Ability of a material to conduct heat.
Thermal Degradation: Deterioration of the material by heat, characterized by molecular scission.
Thermoset: A polymer that doesn’t melt when heated. Thermoset polymers “set” into a given shape when first made and afterward do not flow or melt, but rather decompose upon heating. They are often highly cross-linked polymers, with properties similar to those of network covalent solids, i.e., hard and strong or soft and elastic. Planet Cast Ultimate and Flex resins are thermosets.
Undercut: A protuberance or indentation that impedes withdrawal from a two-piece rigid mold.
We have ways to make this issue go away. It may require more hands-on work by our technicians.
Unobtanium: An exotic metallic material having excellent electrical conduction, an insulator, rare as gold, inexpensive, light weight, appropriate for use as a boat anchor. It is most commonly used in aerospace assemblies. It is not a hazardous material. It may or may not be recycled. Unobtanium is not available at Planet Proto.
Warpage: Distortion caused by nonuniform internal stresses. Warpage can be a Planet Cast issue in parts with inconsistent or unevenly thick wall sections. Generally the result of poorly designed part files.
Water Absorption: The amount of water absorbed by a plastic article when immersed in water for a stipulated period of time. All plastics will absorb moisture to some extent. Nylon is notable for water absorbsion.