The Ultimate Guide to Design for Assembly Processes

Design for Manufacturing Terminology

The terms "Design for Manufacturing" (DFM) and "Design for Assembly" (DFA) are often used in this industry. They refer to a set of procedures and guidelines that aim to adapt the conceptual and design stages of product development to the specified manufacturing method while ensuring the simplicity and efficiency of production and assembly.

Meanwhile, Design for manufacturing and assembly "DFMA" combines these two separate methodologies: design for assembly and manufacturing. While design for manufacturing concentrates on the materials selection and manufacturing procedures, design for assembly optimizes the product and assembly process.

In this post, we'll look more closely at the design for assembly principles and their significance to manufacturing procedures and design process. Let's jump straight into that.

What is Design for assembly?

Designing products and assemblies so they may be quickly and simply put together is known as design for assembly, or DFA. The reduction of assembly costs, assembly time, and part counts are the three main objectives of DFA. Design for assembly aims to increase productivity by making the production process more straightforward, quicker, and more A product is designed using the Design for Assembly (DFA) concept, which minimizes the number of parts and components needed to assemble.

A product may be put together more quickly and easily with fewer pieces, reducing assembly cost and labor expenses. DFA can improve the product's dependability and quality because it is made to last for a long time.

By minimizing the number of required assembly steps and reducing the number of component requirements, Design for Assembly (DFA) streamlines the final product's structure reliably.

Significance of Design for assembly

• It cuts down on production time

  Design for assembly significantly offers design optimization, removing the need for several design changes and revisions. As a result, it prevents production delays and enables the speedy production of new items - the shortened production processes facilitate quicker production and the entire assembly of new goods.

• Minimizes manufacturing costs

  DFA promises more cost-effective product designs. This is because it uses fewer components in product design. By using fewer parts in your design, DFA can assist you in creating superior goods at a cheaper cost.

• Assembling and disassembling the product is easier.

  To make things easier to assemble, design for assembly prioritizes modular designs., getting rid of unnecessary features. Additionally, it makes the disassembly process easier and faster. While the assembly procedure is intended to be simplified, less disassembly is required due to this design. This is crucial since it ensures that products will be maintained and fixed.

• Enhances automated assembly processes

  Assemblies are designed to be automated since machines or robots position the assembly elements throughout production. The self-aligning feature (automatic assembly) guarantees rapid and straightforward production. With the aid of DFA, assembly automation is made simpler, and machines or robots can align assembly components, boosting production efficiency.

• It contributes to the improvement of product reliability: 

  By using DFA, designers aim to make their products more dependable by minimizing the number of assembly components using modular assemblies, which lowers the risk of failure.

• Reduces material wastage

  By removing the need for numerous trials, DFA reduces material waste and helps production processes run more smoothly.

Design for Assembly Principles

There are numerous DFA key principles regarding design for assembly and its application to manufacturing processes. Adherence to these core assembly operations is crucial since they will speed up the prototyping process, reduce assembly time and costs, improve product quality, and satisfy more customers. We've listed a few below that are very significant:

Reduce part count

A product's part count is a crucial marker of its design excellence. The first DFA rule is 'wherever possible, combine parts, provided it doesn't affect the part's viability.' Lower part counts may accelerate final assembly times. Good products often have fewer parts, and those parts are typically more potent and easier to produce, fix, and maintain.

Minimizing the number of parts differs from removing essential components from the part. This method can help to cut down on the number of fasteners required and reduce wasteful labor expenditures. The design process can be streamlined by minimizing the amount of custom machining and fabrication required. This also makes finding enough inventory, raw materials, or parts easier. This gain is particularly beneficial for sections that could see future demand spikes.

Communication between designers and other departments is essential to choose the most cost-effective option while using Design for Assembly principles.

Integrate modular design

Designers should consider modular designs and incorporate modular assemblies to accomplish quick and effective assembly, which entails employing standardized components that are interchangeable with other parts in size and shape.

In addition, modular design provides several advantages. One of these advantages is that it increases a system's scalability. This implies that a system can be readily expanded or changed as necessary without requiring a total system overhaul. Additionally, a system's flexibility can be increased by modular design, enabling it to be adjusted to various settings or uses.

In general, symmetrical products are simpler to put together than asymmetrical ones. Engineers can create items that are cheaper to produce by designing the different components to be quicker and easier to assemble using symmetry principles.

Build-in fasteners

Fasteners are cheap, but the installation process takes a lot of time. Additionally, threaded fasteners are notorious for producing the majority of manufacturing flaws on the assembly line. By adding fasteners to the pieces themselves, the number of parts that need to be made and put together can be decreased. The assembling will go faster due to removing screws, bolts, and other additional components.

Another method is to create components that can be put together without needing adhesive fasteners like screws or nails. Snap-fit parts are those that snap together without the use of fasteners. Snap-fit and tabs components are more uncomplicated to put together and take apart and less likely to become loose with use.

Make symmetrical designs

Symmetry is frequently employed in product design and engineering to produce more aesthetically beautiful designs or to improve the functionality of designs. For instance, many items are created with symmetrical parts so they may be put together accurately and quickly. Avoid designing left- or right-handed parts, even if this results in obsolete or unneeded features that do not otherwise affect the part's functionality (since this could essentially double your tooling demands).

The time required for reorientation is decreased by making the design symmetric. So that the assembly worker does not have to waste time figuring out how to install a part or make components fit. If that isn't possible, make the asymmetry evident by going the other way around.

Utilize mistake-proofing (or Poka-Yoke)

Use physical barriers like poka-yoke principles to prevent improper component assembly. Designers can also apply Poka-Yoke manufacturing and assembly principles during the product design process. Making it harder to fit pieces incorrectly can prevent problems during the assembly process. Designing a product that makes it impossible to assemble it wrongly is known as mistake-proofing.

This can be accomplished in various methods, such as physically obstructing the part (by adding a notch, for example) or utilizing color coding or multiple forms for other portions. Mistake-proofing can help product development processes go much more quickly and smoothly while lowering the likelihood of mistakes and preventing complex assembly problems.

Maintain realistic tolerances 

Although it is possible to make parts with extremely precise tolerances using modern mechanical engineering equipment, this does not imply that it is always essential. A part's design is probably flawed if it cannot be put together within the required tolerances. The part can be redesigned often to allow for an assembly process within the necessary tolerances.

The following criteria should be taken into account when determining whether tolerance is realistic for assembly:

• The component's size and shape

• Which assembly methods will be used (manual assembly or automated assembly)

• The operators' level of expertise

• The kind of necessary production equipment being employed

If it turns out that tolerance is unrealistic, it should be changed. In rare circumstances, it might be possible to raise the tolerance to consider production variance slightly.

Using readily available standard parts

The use of standardized pieces in the assembly has numerous advantages. The number of pieces that must be handled, sorted, and assembled is decreased in the first place. The cost of labor may be significantly reduced as a result. Second, it can lessen the need for expensive production machinery, the time needed for assembly, and the likelihood of mistakes. As standardized pieces are more likely to fit together correctly and perform well, they can also raise the quality of the end product and ensure the smooth running of the design process.

Apply the same tools to all assemblies

It is possible to increase the energy, labor, and cost-effectiveness of both assembly and disassembly by using a single tool for the entire assembly operations required or, better yet, the entire product line.

A specific tool will be needed during the assembly process for every additional fastener type if an assembly uses various screw or fastener types in multiple regions. If one or the other hex head will work, avoid mixing socket and hex heads.

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