Detailed plastic part design principles, mold design practices and manufacturing procedures are well documented in many other books and standards and that. Design by analysis of a snapfit linking system between plastic parts. The design of the snapfit determines what it can be used for. New equations make fastening plastic components a snap. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Snapfit joints are classified according to their spring element and by separability of the joint. 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. Contains the engineering formulas and worked examples showing how to design snap fit joints for bayer thermoplastic resins.
When snapfit joints are being designed, it is important. Photo books make a book custom photo books snapfish. As i understand your joint is c cross section with 1st type. Snapfit joints for plastics a design guide by bayer mit fab lab. Tress book designing plastic parts for assembly 2nd, revised edition. Therefore, it is advantageous to have a good understanding of snap fit design. Entire books have been written like here and here about different snap joint design, but the cantilever style and its variations is both the easiest to design and. Torsion snap joint on a housing made of makrolon polycarbonate fig 6. Photobooks are perfect for documenting all your milestone moments and lifes firsts. Snap fits best practices product information center 3d systems. Creating a photo book is easy and there are 2 ways to start one. Press fits have so many great features, you might wonder why they dont replace all other connections.
This book explains the attachment level approach to snapfit design and, within the framework of the method, will provide a stepbystep description of the snapfit development process. Specific guidelines on designing snapfit joints is. It presents a stepbystep description of the snapfit development process and includes many illustrations to show what kinds of snapfit features are available to the designer. This book organizes and presents all design aspects of snap fits with an emphasis on the systems level thinking required to create worldclass attachments. This space constraint means that each topic is only covered to.
Develop a deep understanding of snapfit attachments and gain the knowledge to develop snapfit applications optimized for reliability, manufacturing, assembly and customer usage. One of the most common causes of snapfit failure is stress concentration at the sharp inside corner between the beam and wall to which it is attached. Alliedsignal plastics modulus snapfit design manual. If high strength is not an issue, and it usually is not in a snap. Bonenberger creating and managing attachments for plastics parts isbn 3446227539 vorwort weitere informationen oder bestellungen unter.
Jones, short cantilever beam deflection analysis applied to thermoplastic snap fit design, 1987 spe. Below is simple table for designing snapfit joints from bayer snapfit joints for plastics a design guide, please consult the pdf for more info. How to design snap fit components fictiv hardware guide. The program provides a workspace for the designer to test different scenarios by adjusting various input parameters and selecting different engineering materials for the snapfit design. 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.
Provide adaptable interfaces that permit several sizes, styles or lengths of screw. Most all snapfit joint designs share the common design features of a protruding ledge and a snap foot. In general, the stiffness of the part to which the snapfit connects, isimportant. The thickness of the optimal snap fit arm decreases linearly. A cantilever snapfit latch basically consists of a protrusion some type of bead or hook at one end of the beam and a structural. This book is a very good reference for designing plastic snapfit features. Adapting to many situations, holding parts in perfect alignment, easily introduced but forming a lasting bondi could either be describing press fits or your favorite pair of jeans. After reading this book i immediately recognized poor snapfit designs on products i. This book organizes and presents all design aspects of snapfits with an emphasis on the systems level thinking required to. After the joining operation, the snapfit fea tures should return to a stressfree condition. Snapfit latch design a snapfit latch is the simplest, quickest, and most costeffective method of assembling two or more parts. 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. Figures 1 through 3 show examples of annular snap fits. Design of a constantforce snapfit mechanism for minimal.
The snapfit design program is a webbased application that serves as an engineering tool in snapfit design. The book covers each topic in a single page to provide a basic reference to each topic. This book focuses exclusively on the plastic part attachment technology commonly called snapfits or sometimes integral attachments. Snap fit design snap fits are commonly used as an assembly method for injection molded parts. Read, highlight, and take notes, across web, tablet, and phone. New designers of plastic parts wishing to use snapfit had nowhere to turn unless they were fortunate enough to have access to an experienced snapfit designer.
It includes formula for calculating all of the important functions i wanted to predict in a design. It discusses snap fit mechanisms, locators, locating schemes and overconstraints, design forassembly, and the snap fit function from the end user pointofview. Our snapfit design calculator is a betatool that guides you through snapfit design. Beginning, as well as experienced, product designers will find the information they need to develop snapfits more efficiently and avoid many common snapfit. The snapfit calculator employs basfs new algorithm for calculating stress and strength requirements. A product of the bayer design engineering services group, this manual is primarily intended as a reference source for part designers and molding. Beginning as well as experienced product designers will find the information they need to develop snap fits more efficiently and avoid many common snap fit problems. Written by americas leading authority and creator of the attachment level approach, this book provides the tools needed to masterfully implement snapfit design. See more ideas about plastic design, design and 3d printing. As with ribs, add a draft angle to your snapfit joints and use a minimum thickness of 0. Figure 4 shows four different methods of designing snap fits for disassembly. Designing components with snap fits can save time and money in production by. Beginning, as well as experienced, product designers will find the information they need to develop snap fits more efficiently and avoid many common snap fit problems.
The joints are generally stronger, but require greater assembly force than cantilevered joints. The algorithm revises classical physics theory on cantilever stresses because of the unique performance of plastics in such applications. Paul r bonenberger this book organizes and presents all design aspects of snapfits with an emphasis on the systems level thinking required to create worldclass attachments. Jones, short cantilever beam deflection analysis applied to thermoplastic snapfit design, 1987 spe. A snapfit cantilever with constant cross section has an uneven distribution of strain top image.
First snapfit handbook creating attachments for plastic. In the example above, the most common snapfit joint design known as the cantilever snapfit joint is shown. For a more indepth analysis of snap fit design and to dive deeper into the material properties, check out these guides below. They have introduced magnification factor q which give more accurate prediction of total allowable deflection and strain value for short beams. In many cases, its the cheapest way to join 2 parts together. The truth is, press fits arent for every applicationjust like skinny jeans, there are pros and cons. This book organizes and presents all design aspects of snapfits with an emphasis on the systems level thinking required to create worldclass attachments.
The joint may be separable or inseparable depending on the shape of the. Design and analysis of snap fit joint in plastic part. Aircraft airframe structural design premium membership required to view documentbook. Snap fit design by neeraj kumar jha linkedin slideshare. A good design tip is to diminish the cross section of cantilever beam over its length bottom image. Snapfit assemblies also require more engineering calculations and analysis. It discusses snap fit mechanisms, locators, locating schemes and overconstraints, design. This takes you to where you can select photos from one or more albums you need at least 22 photos for a single photo per page and covers, but you can select as many as. This uses less material and results in a more even distribution of strain in. Beginning as well as experienced product designers will find the information they need to develop snapfits more efficiently and avoid many common snapfit.
The annular snap fit utilizes hoopstrain to hold a pressed part in place. Snap fits and hinges plastics product design wiley. The designer should be aware that the assembly may have some play due to tolerance stackup of the two mating parts. All publications the first snapfit handbook advanced search deutsche version the first snapfit handbook. It discusses snap fit mechanisms, locators, locating schemes and overconstraints, designforassembly, and the snapfit function from the end user pointofview.
A cantilever snap fit on a 3d printed enclosure cantilever snap fits are easy to design and intuitive for the user during assembly and disassembly. Strength, constraint, compatibility, and robustness have been identified as the key requirements of snapfit design. You should also check for spherical joint clearance should be y2. The specific name of the snapfit is usually named after the type of stress or strain it utilizes. The first snapfit handbook creating and managing attachments for plastic parts 2nd edition paul r.
This design uses 17% more material and exhibits 46% higher strain than the opti mal design. Snap fits are very useful because they eliminate screws, clips, adhesives, or other joining methods. Seminar 1 presentation on snap fit design preparedby. Most snapfit joints have a common design of a protruding edge and a snapin area. Contains the engineering formulas and worked examples showing how to design snapfit joints for bayer thermoplastic resins. Select the book type, size and design you want, and click make this photobook. If you continue browsing the site, you agree to the use of cookies on this website. Design of cantilever snaps using classical beam theory. To illustrate how these revised cantileverbeam equations can be used, the maximum deflection of a snap before failure and the mating force values will be calculated on a plastic snapfit design.
Although they have been around for many years, they have recently become more important in an attempt to simplify assembly and its associated costs. It discusses snap fit mechanisms, locators, locating schemes and overconstraints, designforassembly, and the snap. For microelectromechanical systems for which no other joining methods have been devised, micro snapfit connectors have been developed to join micro 3d structures. 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. It discusses snap fit mechanisms, locators, locating schemes and overconstraints. I have no hesitation in recommending the third edition of this book to anyone interested in optimizing the design of snapfit plastic assemblies. How to design snapfit joints for 3d printing 3d hubs. My initial test included trying to create a cantilever snapfit mechanism. Which appears to be a traditionally accepted approach to joining plastics. Dsm engineering plastics technical guidesnap fit designcantilever beam snapfitscantilever beam type snapfits can be calculated using a simplification of the general beam theory. With reallife observations, sample parts and a copy of the instructors book, the first snapfit handbook, you gain the tools necessary to master the snap. 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. Snap fits all snap fits are variations of two basic. Assembly is accomplished without the use of any additional components or fasteners.