Provide adaptable interfaces that permit several sizes, styles or lengths of screw. Traditional integral snapfit attachment design focuses almost exclusively on the individual locking features, such as cantilever hooks, bayonetfingers, compressive hooks and. A systematic approach to integral snapfit attachment design. Accordingly, the design of a snap fit joint is highly dependent on the polymeric materials. Designing for assembly and disassembly 1 thousands of parts are joined together in each automobile, such as the plastic metal hybrid grill opening reinforcement in this ford focus. General joint design rudimentary design is provided by the snap fit manufacturers such as basf basf 2007 or bayer bayer materialscience llc 2000. For the motor design, the lead angle on the stator was 35 and the coefficient of friction between the hytrel. Use of snapfit fasteners in the multilifecycle design of. They can be injection molded, extruded or produced downstream via machining or stamping. Bayer also offered some documents that are useful design guidelines. The snap fit design guide by basf 9 has designed snap fit calculator which utilizes all the beam formulas and calculates the stress or strain values induced by the deflection. The new part design must adhere to specific material and molding process guidelines. Design issues on living hinges living hinges also known as integral hinges in a plastic part can be defined as thin, flexible. I have designed parts which are snapfit using polypropylene.
The first snapfit handbook creating and managing attachments for plastic parts 2nd edition paul r. Lets assume that you understand the mechanics of how snap fit fasteners work maximum permissible deflection, mating force, stress and strain, etc. It lets you find information on our entire portfolio and browse the industries and applications where our products are used. Snap fit is formfitting joint which permits great design flexibility. Design guidelines for additive manufactured snapfit joints core.
They work well, but the best advice i can give make one or a few in one or more material and do some life testing to figure out which material performs the best. General joint design rudimentary design is provided by the snapfit manufacturers such as basf basf 2007 or bayer bayer materialscience llc 2000. Here you will find valuable information on how to design ribs, screw bosses, reduce cosmetic blemishes and in general, design parts that are optimized for fit, function and appearance. The specific name of the snapfit is usually named after the type of stress or strain it utilizes. Jones, short cantilever beam deflection analysis applied to thermoplastic snap fit design, 1987 spe. Based on the assumption of the eulerbernoulli beam theory, the design variables for the joints are the following. While in the past injection molding has been the only viable method for producing snap fit joints in plastics, 3d printing opens up new opportunities and challenges in their design. Pdf design guidelines for additive manufactured snapfit joints. Bayer materialscience llc, pittsburgh, pa, 2000 pp. Design and analysis of snap fit joint in plastic part. The design of the snapfit determines what it can be used for. Below is simple table for designing snap fit joints from bayer snap fit joints for plastics a design guide, please consult the pdf for more info. Aside i will try to check my own library to upload something. Snap fit latch design a snap fit latch is the simplest, quickest, and most costeffective method of assembling two or more parts.
Rudimentary design is provided by the snapfit manufacturers such as basf basf 2007 or bayer bayer materialscience llc. In general, the stiffness of the part to which the snapfit connects, isimportant. Design guidelines for additive manufactured snapfit joints. May 08, 2017 for a more indepth analysis of snap fit design and to dive deeper into the material properties, check out these guides below. Relationship between deflection force and mating force. Available formats pdf please select a format to send. Annular snap fits arent well understood but can be a handy means of making assemblies.
If high strength is not an issue, and it usually is not in a snap. Engineering tools are meant to serve as a guidance to the customers in the proper design and selection of materials on various applications that they are developingenhancing specially where it is still highly recommended to test the plastic grade prior to production. In order to understand the nature of the snapfit phenomenon, the large displacement but small deformation theory is used to model the insertion operation. The snap fit calculator employs basfs new algorithm for calculating stress and strength requirements. Jones, short cantilever beam deflection analysis applied to thermoplastic snapfit design, 1987 spe. Assembly is accomplished without the use of any additional components or fasteners. Height of the cantilever beam h, length of the cantilever l, width of the. Fundamentals of annular snapfit joints machine design. Snapfit assembly process with industrial robot including.
The snapfit phenomenon is experienced during the insertion of batteries into the battery holder. Snapfit joints for plastic a design guide, bayer materialscience ag, edition 0220. You should also check for spherical joint clearance should be y2. They have introduced magnification factor q which give more accurate prediction of total allowable deflection and strain value for short beams. This manual will guide you through the basics of snap fit design. To demonstrate the new concepts and the capabilities of additive manufactured snap fit joints a showcase is conceptualized, designed in detail and produced using fused deposition modeling and selective laser sintering. A good design tip is to diminish the cross section of cantilever beam over its length bottom image. Share share this awesome question with your friends. The classical threesection screw can be employed with adequate quality for the processing of many thermoplastics. This is a simple snapfit joints library based on snap fit joints for plastics a design guide by bayer materialscience llc.
As i understand your joint is c cross section with 1st type. Design calculations for snap fit joints in plastic parts, ticona, a business of celanese, florence, ky, 2009. The growing and increasingly aging world population requires improved medical care and an adequate supply of food. Contains the engineering formulas and worked examples showing how to design snapfit joints for bayer thermoplastic resins. In this contribution, the existing design guidelines for snapfit joints are challenged.
Dec 18, 2012 i am in the process of designing snap fit plastics. This chapter will give you a thumbnail sketch of the benefits of snapfits and the materials used to make them. The structural features of a snapfit joint are hooks, knobs, protrusions, or bulges on one of the parts to. Snapfit latch design a snapfit latch is the simplest, quickest, and most costeffective method of assembling two or more parts. Plastic component design considerations to insure a quality final product, it is necessary to start out with quality components.
How to design snapfit joints for 3d printing 3d hubs. When snap fit joints are being designed, it is important. I have no mechanical engineering background so i didnt even know the relevant terminology. Predicting and validating assembly forces of cylindrical. The solution center represents our combined polymers expertise. Our snapfit design calculator is a betatool that guides you through snap fit design. A basic distinction is drawn between a the snap arm joint flexural beam principle b the torsional snap joint torsion rod principle c the annular snap joint cylindrical profiles d the ringshaped snap joint regular polygon profiles. A thermoplastic with truly diverse applications, makrolon is used in medical devices, automotive headlamps, sporting equipment, electronics, eyewear, architectural glazing led lighting, and numerous other products. This manual is intended to help you successfully design and manufacture. Snapfit joints for plastics a design guide by bayer. Snap fit is used to fix two parts together in a certain position. The algorithm revises classical physics theory on cantilever stresses because of the unique performance of plastics in such applications. Bayers broad product portfolio includes many worldfamous brands which have shaped the iconic bayer brand.
The structural features of a snap fit joint are hooks, knobs, protrusions, or bulges on one of the parts to be joined,which after assembly engage in corresponding depressions undercuts, detents,or openings in the other part to be joined. To demonstrate the new concepts and the capabilities of additive manufactured snapfit joints a showcase is conceptualized, designed in detail and produced using fused deposition modeling and selective laser sintering. Torsion snap joint on a housing made of makrolon polycarbonate fig 6. If this is not entirely possible, then allowance can be made for. Design of snap joints and springs in plastics 1999. The snapfit calculator employs basfs new algorithm for calculating stress and strength requirements. How to design snap fit components fictiv hardware guide. Snap and press fits 24 snap fits 25 press fits heat welding and sealing 26 heat or hotplate welding 27 bar sealing 27 electromagnetic or induction welding. Design issues on living hinges living hinges also known as integral hinges in a plastic part can be defined as thin, flexible webs that connect two relatively rigid adjacent wall sections. Pdf cantilever snapfit performance analysis for haptic.
Snap fit joints for plastic a design guide, bayer materialscience ag, edition 0220. Bayers products for humans, animals and plants bayer. Bayer has now been acquired by covestro, and the online tools are very similar. This manual will guide you through the basics of snapfit design. Most all snap fit joint designs share the common design features of a protruding ledge and a snap foot.
This uses less material and results in a more even distribution of strain in the cantilever. Snap joints are classified according to the type of spring element and the separability of the joint. Guide gives general product design overview with a focus on plastic part design. This is a simple snapfit joints library based on snapfit joints for plastics a design guide by bayer materialscience llc. Pdf design guidelines for additive manufactured snapfit.
The complete part design handbook for injection molding of thermoplastics. A continuous annular snap joint offers a semihermetic seal and is better for single assembly applications a page 6 of 26 snapfit joints for plastics a design guide. The broad portfolio of makrolon polycarbonate resins from covestro includes general purpose, lighting, medical and food contact. Design support to assist you in designing parts for injection molding and to help avoid errors. Snap fits all snap fits are variations of two basic. The thickness of the optimal snap fit arm decreases linearly. Question asked by ricky barnett on feb 9, 2012 latest reply on feb 10. On this basis, a snapfit joint is a frictional, formfitting joint. Designing components with snap fits can save you time and money in production by reducing material costs and part quantities as well as improving ease of assembly. This utilization of snap fit joints for plastic molded.
Anyone know of a simple snap fit design calculator. Or is there some functionality within solidworks itself to design snaps. Other types of snapfits, which can be used, are the u or l shaped cantilever snaps see. When snapfit joints are being designed, it is important. Rudimentary design is provided by the snap fit manufacturers such as basf basf 2007 or bayer bayer materialscience llc 2000. Rudimentary design is provided by the snapfit manufacturers such as basf basf 2007 or bayer bayer material. Secant modulus for bayer engineering plastics at 23c 73f page 14 of 26 snap fit joints for plastics a design guide b fig. Indeed, incorporating a press or snap fit into a design to take advantage of the speed and economies it allows labor reduction and elimination of assembly fixtures, equipment andor inventories of separate fastenersmay be one of the more critical decision points in a successful product. Snap fit joints for plastics a design guide cantilever snap joints b fig. What plastic material is best for a snapfit design. A lid of a container, similar to a jar, is designed as an integrated single component. A cantilever snapfit latch basically consists of a protrusion some type of bead or hook at one end of the beam and a structural.
Be creative and dont be afraid to think outside the box. Below is simple table for designing snapfit joints from bayer snapfit joints for plastics a design guide, please consult the pdf for more info. Virtually all consumers and industrial products, utilizing plastic molded components, have multiple components attached together with some form of snap fits. Simple snapfit joints library by fpetrac thingiverse. Contains the engineering formulas and worked examples showing how to design snap fit joints for bayer thermoplastic resins. Covestro makes additive manufacturing fit for serial production.
Injection molded parts can be molded to a high quality standard by focusing on these areas of plastic. For a more indepth analysis of snap fit design and to dive deeper into the material properties, check out these guides below. Plastic component design considerations design guidelines for metal to plastic conversions there are several common mistakes made when replacing a metal product with a plastic molded part. I do strongly advise you to check basf, bayer and dupont web pages. Our innovative materials for wind turbine blades, towers and cables help support cleaner energy solutions. A design guide joining techniques engineering plastics. Dsm engineering plastics technical guidesnap fit designcantilever beam snapfitscantilever beam type snapfits can be calculated using a simplification of the general beam theory.
Snapfits are the simplest, quickest and most costeffective method of assembling two parts. After a bit of research i learned that one way to do this is with snapfit joints. A product of the bayer design engineering services group, this manual is primarily intended as a reference source for part designers and molding engineers working with bayer thermoplastic resins. For detail design guidelines, please refer engineering polymers joining techniques a design guide, bayer mater ialscience ag, edition 0220. Lets assume that you understand the mechanics of how snapfit fasteners work maximum permissible deflection, mating force, stress and strain, etc. Thats how we determined which material and geometry of the snapfit design worked the best. Cantilever snapfit performance analysis for haptic evaluation article pdf available in journal of mechanical design 312. Most snapfit joints have a common design of a protruding edge and a snapin area. Design guidelines for additive manufactured snap fit joints. Our snapfit design calculator is a betatool that guides you through snapfit design. A snapfit cantilever with constant cross section has an uneven distribution of strain top image. With our products, we are contributing to finding solutions to some of the major challenges of our time. And for more information, you can always visit our web site at. The paper emphasizes that unlike the design and use of conventional fasteners, every snap fit used in a product must be designed fiom scratch.
The advantages, drawbacks and general design considerations on snap fits are listed. A cantilever snap fit latch basically consists of a protrusion some type of bead or hook at one end of the beam and a structural. Selftapping screws for thermoplastics, bayer materialscience ag, edition 0220. Whether the snap joint is a cantilever or a cylindrical fit, they both function similarly. When designed properly, parts with snapfits can be assembled and disassembled numerous times without any adverse effect on. Pdf snapfit joints are one of the cheapest and fastest connectors available. April 2009 1 preface this set of hints and tips for plastics product designers is intended as a source book and an aide memoire for good design ideas and practices. Search them through for appropriate tutorials, there are plenty of them. This paper describes the design and the use of snap fit fasteners for the multilifecycle design of products. Snapfit joints for plastics a design guide by bayer mit fab lab.
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