An economical and quick method of joining plastic parts is by a snapfit joint. For the sake of brevity, this article will focus on one type. If youve ever built a plastic model kit, youve seen and know at least something about injection molding. Part design guidelines for injection molded thermoplastics. Injection molding process is the best way to manufacture plastic parts for high volumes and low cost. Whether you are just entering the field, or are a seasoned plastic parts designer, designing plastic parts for assembly is an excellent tool that will facilitate costeffec tive design decisions, and help to ensure that the plastic parts and products you design stand up under use. Plastic part design for injection molding hanser elibrary.
Jul 02, 2018 plastic parts are now commonplace in consumer product design, and for good reason. Plastic part design guidelines for injection molding. Without digital prototyping, youd need to use more budgetvaporizing physical prototypes, watch time slip away, and get to. Further, thin parts weigh less, using less plastic per part. The design of a plastic part and the selection of the plastics manufacturing process are extremely interdependent. The loctite design guide for bonding plastics, volume 6 3 recycling symbol illustrates the appropriate recycling symbol for the indicated plastic type, when appropriate.
The designers and engineers at api have over 250 combined years of experience in designing parts for plastic injection molding, selecting materials, and processing resins specializing in engineering and high performance resins. Read this article to know the advantages of injection molding. This creates higher contact pressure on the core surface and increases friction between the core and the part, thus making ejection of the part from the mold difficult. Aug 18, 2014 the essentials of better plastic part design cadimensions, inc.
The intersection of the base of the boss with the nominal wall is typically stressed and stress concentration increases if no radii are provided. Designing plastic parts and components involve implementing wide knowledge from different engineering areas. Design and manufacturing of plastic injection mould. It is particularly important to bear the following factors in mind when designing snap joints. However, not every plastic part design can be efficiently injection molded. We recommendedusing the guidelines in the table to the right as thicknesses vary by material. The detailed yet simplified discussion of material selection, manufacturing techniques, and assembly procedures enables the. Whenever you begin a design project involving plastic parts, where your end goal is to have the component injection molded, youll want to consider some things on the front end of your design process that will allow for time and money to be saved during the production phase of your project. There are many things that must be carefully considered and planned for. Structral engineering and geomechanics plastic versus elastic design of steel structures sutat leelataviwat, subhash c.
Several decades ago, plastic part design guidelines began to emerge that tried to address some of the more obvious problems in producing injection molded plastic parts. Design parts with a minimum of per side draft in order to accommodate easier ejection from the mold. So working with us early in the design process is important. Highly durable, endless color options and of course, an inexpensive option when manufactured in high volumes. Designing plastic parts is a little different from designing metal parts. Injection molding offers high repeatability and good design flexibility. Since plastics shrink when cooled, it is common for parts to shrink or grip tightly to cores. The designers and engineers at api have over 250 combined years of experience in designing parts for plastic injection molding, selecting materials, and. The injection molding process requires the injection molding machine, raw plastic, and the mold. Typical property table provides data on typical physical properties for each plastic. Injection molding is so popular, because of the dramatically low cost per unit when manufacturing high volumes. Designing plastic parts for assembly hanser publications. Metal parts are often designed with thick walls, while plastic parts should ideally maintain uniform wall thickness for uniform flow and less shrinkage.
This information can only be provided by raw materials suppliers, specialist plastics product designers and plastics processors but there is a need to get the basics of the product design right in the first. Design and engineering our engineering department begins with your design or concepts to develop a 3d part design. Design consideration for plastic part design and its. Plastic part design for injection molding hanser publications.
Plastic design issues injection molded plastic parts offer an important combination of flexibility, toughness, and chemical resistance for cost effective, longterm performance in a wide range of applications. Injection molding has various advantages compared to other plastic manufacturing process. Design considerations draft plastic parts are always designed with a taper or draft in the direction of mold movement to allow part ejection or removal from the mold. It is intended to give the product designer the basic guideline to design a product that is of high quality and easy to manufacture plastic parts. Plastic component design considerations to insure a quality final product, it is necessary to start out with quality components. Injection molding is one of the most widely used processes for fabrication of plastic parts. The ability to design plastic parts requires knowledge of material propertiesper formance indicators that are not design or geom etry dependentrather than. Once the use of plastic is assumed, the chapter provides support for the determination of which of the four major plastics manufacturing processes should be used. The strength of the snapfit joint depends on the material used, its geometry and the forces acting on the joint.
Trade names lists common suppliers of each resin and the trade names for their products. Coring and wall thickness resin material inches abs 0. This will ultimately reduce material and manufacturing costs. There are several styles of gates that are commonly used in molding. Design tips get quick advice on creating plastic, metal, and elastomeric parts for 3d printing, cnc machining, sheet metal fabrication, and injection molding. Because of shrinkage of plastic material, injection molded parts have a tendency to shrink onto a core. Variations and evolutions of these appear in nearly every plastic part design book, guide or reference. May 06, 2016 plastic is cheaper and easier to work with.
Designing with manufacturability in mind can accelerate production time and reduce production costs. Some general guidance is then provided about the design of plastic parts for stiffness and strength. Trantina, design with plastics, materials selection and design, volume 20, asm handbook, asm international, 1997, pages 639 to 647 the key to any successful part development is the proper choice of material, process, and design matched to the part performance requirements. On average, the wall thickness of an injection molded part ranges from 2mm to 4mm. The raw plastic is melted in the injection molding machine and then poured into the mold where it is allowed to cool and solidify.
Tres book isbn 9781569905555 hanser hanser publishers, munich hanser publications, cincinnati. Thick section thick section not recommended recommended prefered plastic design. Draft angle design is an important factor when designing plastic parts. May 30, 2012 new high performance plastics and innovative molding processes make this possible. A snapfit joint can be designed so it is easily separated or so that it is inseparable, without breaking one of its components. When designing plastic parts, your team should consist of diverse players, including conceptual designers, stylists, design engineers. May 23, 2015 these benefits in terms of cost reduction, ease of manufacturing through injection mold for the higher quantity and superior quality and the appearance of the parts contribute to extensive adoption of plastic in the product development by the industry. Processing conditions for plastic injection molding. Parts are specifically designed to meet thermoforming design specifications as well as yours.
For the engineering and design team at urbe, it was a no brainier to utilize plastic components for the fenders and battery hub in order to ramp up its. Goel, shihho chao encyclopedia of life support systems eolss central to the idea of all plastic analysis methods is an implicit assumption that the structure being analyzed is made from ductile materials. Injection molded parts can be molded to a high quality standard by focusing on these areas of plastic. Designing plastic parts for assembly hanser elibrary. Blow molding design guideline blow molding design guideline 3 radii corners material will freeze when it comes into contact with the mold, causing it to stretch into corners if parison is trapped pinched off at parting line, it must stretch into the cavity preblowing the parison prior to mold closure helps minimize stretch. Tres designing plastic parts for assembly book isbn. Thick section core out thick section not recommended recommended typical metal design. General input on the best molding method for the design concept should be sought early in the design process so the part shape can be optimized accordingly. Minimum radius at base of boss a fillet of a certain minimum radius should be provided at the base of a boss to reduce stress. The result is a digital prototype of your product, one you can explore in detail. Api is experienced in molding all thermoplastics, specializing in engineering, high performance, and glass reinforced resins. Detailed plastic product design will always require detailed knowledge of the application, the processing method and the selected plastic.
When designing moldedin threads, avoid feathered edges and include radiused roots in order to minimize stress concentrations p and to keep the walls uniform. Threads plastic threads used for joining parts can be machined or moldedin. Jul 20, 2016 rex plastics product development plastic part design fundamentals gates and parting lines. Request pdf design of plastic parts practical considerations for plastic part design are presented beginning with an overview of advantages of polymeric. Designing plastic parts for assembly sciencedirect. Injection molded plastic parts offer an important combination of flexibility, toughness, and chemical resistance for cost effective, longterm performance in a range of applications. Plastic part design guidelines for injection molding ensures good quality products. Each plastic part design must have a gate, or an opening that allows the molten plastic to be injected into the cavity of the mold. Almost every plastic part around you was manufactured using injection molding. Concept to finished part design process like a successful play in football, successful plastic product design and production requires team effort and a welldeveloped strategy. Plastic resin enters the mold through a sprue in the a plate, branches out between the two sides through channels called runners, and enters each part cavity through one or more specialized gates. Loctite design guide for bonding plastic ellsworth. The essentials of better plastic part design youtube.
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