Nowadays 3D printing is also rapidly catching up to traditional manufacturing, but mainly are used in prototyping with smaller numbers to make a functional prototype.<\/p>\n
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The following are different 3D-printing methods:<\/span><\/p>\n<\/div>\n\n
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Stereolithography (SLA)<\/span><\/p>\n<\/li>\n- \n
Selective Laser Sintering (SLS)<\/span><\/p>\n<\/li>\n- \n
Fused Deposition Modeling (FDM)<\/span><\/p>\n<\/li>\n- \n
Digital Light Process (DLP)<\/span><\/p>\n<\/li>\n- \n
Multi Jet Fusion (MJF)<\/span><\/p>\n<\/li>\n- \n
PolyJet<\/span><\/p>\n<\/li>\n- \n
Direct Metal Laser Sintering (DMLS)<\/span><\/p>\n<\/li>\n- \n
Electron Beam Melting (EBM)<\/span><\/p>\n<\/li>\n<\/ul>\n<\/div>\n\n
The cheapest among them is FDM, which gives almost near functional prototypes for testing and verification.<\/span><\/p>\n<\/div>\nSelecting the Right Plastic Manufacturing Process<\/h2>\nWhen selecting a manufacturing process, keep these factors in mind:<\/div>\n
Form:<\/strong><\/div>\n\n
Do your parts have complex internal features or tight tolerances? The geometry of a design may limit manufacturing options, or it may require significant design for manufacturing (DFM) optimization to make it cost-effective to produce.<\/span><\/p>\n<\/div>\nVolume\/cost:<\/strong><\/div>\n\n
What is your planned annual production volume of parts? Despite high upfront costs for tooling and setup, some manufacturing processes produce parts that are inexpensive per unit.<\/span><\/p>\n<\/div>\nLead time:<\/strong><\/p>\nWhat is the turnaround time for parts or finished goods? While certain high-volume production processes create first parts within 24 hours, tooling and setup can take months.<\/p>\n
Material:<\/strong><\/p>\nWhat stresses and strains will your product have to withstand? A variety of factors determine the best material for a given application. Affordability must be weighed against aesthetics and functionality.<\/div>\n
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Consider the features that are suitable for your application and compare them to the options accessible in a given production process.<\/div>\n
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For mass production, we can choose any method of manufacturing, depending on the above factors. But to make them reproducible and increase repeatability, we need to optimize the design according to the manufacturing process chosen for Design for Manufacturing and Assembly (DFMA).<\/div>\n
What does DFMA \u2013 Design for Manufacturing and Assembly \u2013 mean?<\/h2>\nDFMA is an engineering methodology that promotes the ease of manufacturing the product\u2019s parts and its simplified assembly into the final product during the early phases of the product lifecycle. It reduces both time-to-market and total production costs.<\/div>\n
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DFMA used to be two distinct methodologies: Design for Manufacturing (DFM) and Design for Assembly (DFA). In DFM, we focus on selecting cost-effective raw materials and taking steps to reduce the complexity of manufacturing processes during the product design phase (the least disruptive and expensive time to handle these issues) in order to minimize product component manufacturing time and cost. Likewise, DFA is concerned with minimizing the number of individual components, assembly steps, and quality variability of a build by minimizing assembly time, costs, and complexities.<\/div>\n
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DfMA allows waste or inefficiency in product manufacturing and assembly to be identified, quantified, and eliminated.<\/div>\n
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As a benchmarking tool, it may also be used to analyze the products of competitors.<\/div>\n<\/div>\n
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DFMA core principles are:<\/span><\/strong><\/div>\nMinimize the number of components<\/div>\n
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This will decrease assembly costs, reduce work-in-process, and simplify automation.<\/span><\/p>\nDesign for ease of part-fabrication<\/h4>\n<\/div>\nPart geometry is simplified and pointless capabilities are avoided.<\/div>\n
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Tolerances of parts<\/span><\/h4>\n<\/div>\nParts should be designed so that they are within the capability of the process.<\/div>\n
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Clarity<\/h4>\n<\/div>\nIt is best for components to be designed so that only one assembly method can be used.<\/div>\n
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Limit the use of flexible components<\/h4>\n<\/div>\n\n
Parts made of rubber, gaskets, cables, etc., are generally more difficult to handle and assemble. As an example, design for ease of assembly, using snap-fits or adhesive bonding rather than threaded fasteners. An effective product is one that has a base component for locating other components quickly and accurately.<\/span><\/p>\n<\/div>\nDesign for\u00a0ease\u00a0of assembly<\/h4>\nEg: the usage of snap-fits and adhesive bonding instead of threaded fasteners together with nuts and bolts. A product should be developed with a basic component that can be used to quickly and precisely locate other components.<\/div>\n
Remove\u00a0or reduce required adjustments<\/h4>\nDesigning adjustments into a product leads to more out-of-adjustment situations.<\/div>\n
Advantages of DfMA:<\/h2>\nDFMA has a number of advantages, including:<\/div>\n
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Speed<\/h3>\n<\/div>\nThe use of prefabricated elements in DfMA construction reduces the program on-site significantly.<\/div>\n
Lower\u00a0assembly\u00a0cost<\/h3>\nDFMA lowers the cost of assembly by reducing labor requirements, using fewer parts, and reducing the number of unique parts.<\/div>\n
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Higher\u00a0quality\u00a0and\u00a0sustainability<\/h3>\nEach step can be made more efficient and quality by using an automated process. There may be less waste generated during construction, greater efficiency in site logistics, and fewer vehicles moving materials to the construction site.<\/div>\n<\/div>\n
Shorter assembly time<\/h3>\n\n
The DFMA uses standard assembly techniques such as vertical assembly and self-aligning parts to reduce assembly time. By ensuring a smooth transition from the design phase to the production phase, DFMA also ensures that the production process is as efficient and rapid as possible.<\/span><\/p>\n\n
Increased reliability<\/h3>\n<\/div>\n<\/div>\nDfMA increases reliability by reducing the number of parts, thereby reducing failures.<\/div>\n
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Safety<\/h3>\n<\/div>\nSafety can be improved substantially by removing construction activities from the site and placing them in a factory environment.<\/div>\n
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DFM Guidelines for Reducing Costs and Challenges in Manufacturing Plastic Components:<\/h2>\n<\/div>\n\n
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Before tooling begins, start DFM early in the design process<\/span><\/p>\n<\/li>\n- \n
Engineers, designers, the contract manufacturer, the mold maker, and the material supplier should meet to discuss the design<\/span><\/p>\n<\/li>\n- \n
Create the product in such a way that the number of parts is kept to a minimum.<\/span><\/p>\n<\/li>\n- \n
Build it with a modular design<\/span><\/p>\n<\/li>\n- \n
Limit the number of machine operations needed<\/span><\/p>\n<\/li>\n- \n
Use standard components<\/span><\/p>\n<\/li>\n- \n
Design parts to be multi-functional<\/span><\/p>\n<\/li>\n- \n
Design parts for multi-use<\/span><\/p>\n<\/li>\n- \n
Design for ease of fabrication<\/span><\/p>\n<\/li>\n- \n
Avoid separate fasteners<\/span><\/p>\n<\/li>\n- \n
Minimize assembly directions<\/span><\/p>\n<\/li>\n- \n
Maximize compliance<\/span><\/p>\n<\/li>\n- \n
Reduce handling and consider how a design affects part packaging and shipping.<\/span><\/p>\n<\/li>\n<\/ul>\n<\/div>\nWhy DFM is necessary for the Injection Molding Process<\/h2>\nBeyond estimating manufacturing costs, your injection moulding vendor should use DFM principles to reduce component costs, assembly costs, support production costs, and identify the impact of DFM decisions on other factors throughout the entire design and production process.<\/div>\n
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The increasing complexity of plastic injection moulded parts is another reason to choose a moulder who follows DFM principles. To meet the quality\/cost requirements of customers, tolerance, draft angles, undercuts, and other factors must be considered during the design stage.<\/div>\n
Critical Elements of Design Optimization<\/h2>\nBest DFM practices for plastic injection moulded parts include the following critical elements prior to the creation of a mould:<\/div>\n
Considering Material Shrink Rate:<\/h3>\n\n
Shrinkage is the contraction of a moulded part as it cools after injection. Depending on the resin (amorphous vs. crystalline materials) family, each material shrinks at a different rate. , mold design, and processing conditions. Depending on the direction of flow, the resin may also shrink differently. As a rule of thumb, a 10% change in mould temperature can result in a 5% change in original shrinkage. Furthermore, injection pressure has a direct impact on shrinkage rates. The lower the shrinkage rate, the higher the injection pressure.<\/span><\/p>\n<\/div>\nDraft:<\/h3>\nThe type of draft required is determined by how the features of a part are formed in a mould. Most bosses, ribs, and posts formed by blind holes or pockets should taper thinner as they extend into the mould. If the mould separates from the surface before ejection, surfaces formed by slides may not require a draft. Consider incorporating draft angles on product features such as walls, ribs, posts, and bosses that run along the direction of release from the mould, thereby facilitating part ejection.<\/div>\n
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For most materials, a draft angle of at least one-half degree is acceptable. One to two degrees of draft may be required for the high-heat and exotic resin. For every 0.0254 mm of texture depth, add one degree of draught.<\/span><\/p>\n<\/li>\n- \n
Draft all surfaces parallel to the mould separation direction.<\/span><\/p>\n<\/li>\n- \n
Angle walls and other part features are formed in both mould halves to aid ejection and keep wall thickness uniform.<\/span><\/p>\n<\/li>\n<\/ul>\n<\/div>\nUniform Wall Thickness:<\/h3>\n\n
To avoid thick sections, uniform wall thickness throughout a part (if possible) is essential. Non-uniform walls can cause warping of the part as the melted material cools.<\/span><\/p>\n<\/div>\nIf different thicknesses of sections are required, make sure the transition is as smooth as possible to make the material flow evenly inside the cavity. This ensures the entire mold will be completely filled, lowering the possibility of defects.. Thickness transitions that are rounded or tapered reduce molded-in stresses and stress concentrations caused by sudden changes in thickness. Incorporating the right wall thickness for your part can have a significant impact on the cost and speed of production. The least wall thickness that can be used is determined by the part\u2019s size and geometry, structural requirements, and resin flow behavior. Injection moulded parts typically have wall thicknesses ranging from 2mm to 4mm (0.080\u2033 to 0.160\u2033). Injection moulding with thin walls can produce walls as thin as 0.5mm (0.020\u2033). Work with an experienced injection moulder and design engineer to ensure that the proper wall thicknesses are used for the design and material selection of your part.<\/div>\n
Radii to Edges:<\/h3>\n\n
Aside from the main areas of a part, uniform wall thickness is an important design element for edges and corners. Adding generous radii to rounded corners will improve the design of a plastic part by reducing stress concentration and increasing the material\u2019s ability to flow. Parts with large radii are also more cost-effective and easier to manufacture, as well as having more strength.<\/span><\/p>\n\n
Ribs:<\/h3>\n<\/div>\n<\/div>\n\n
Many people think that by making the walls of an element thicker, the strength of the part will increase. When essentially, making walls too thick may lead to warpage, sinking, and other defects. The purpose of using ribs is that they increase the strength of an element without increasing the thickness of its walls. With less material required, ribs will be an economical solution for added strength. For increased stiffness, increase the amount of ribs instead of increasing height and space a minimum of double the nominal wall thickness except each other.<\/span><\/p>\n\n
Draft Angle:<\/h3>\n<\/div>\n<\/div>\n
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