Design Guidelines for Manufacturing And Assembly Minimize The Number And Variety of Fasteners.

Did you know that a component doesn't add value but is crucial and essential for products? That component is the fastener. In a product, a fastener's role is simply to hold parts together and has little impact on functionality. However, producing fasteners like bolts and nuts can be time-consuming and costly. Additionally, tools are needed to install them. Therefore, it's important to minimize the number and variety of fasteners in product design.

1. Using Fasteners Of Same Kind

As shown in Figure 1-1, the original design used four types of bolts with varying lengths, head shapes, and thread forms. In the optimized design, these were simplified to a single standard bolt, M3x6, which can be used in various positions throughout the product.

2. Using Snap Joint Assemblies Or Edge Fold Instead Of Fasteners

Snap joint assembly is one of the most economical and eco-friendly methods. Compared to traditional bolt assembly, snap joints enable faster, more time-efficient, and cost-effective assembly.

As shown in Figure 1-2, two plastic parts are secured using a snap joint. In sheet metal, a compressed edge fold can be used to further reduce the number of fasteners needed.

As shown in Figure 1-3, the original design uses four bolts to secure two sheet metal parts. In the optimized design, the number of bolts is reduced to two by adding a compressed edge fold to the sheet metal, similar to how a snap joint functions in plastic parts.

3. Avoiding The Disconnected Fastener Design

Using an integrated part instead of two separate parts can reduce the number of fasteners, shorten assembly time, and increase efficiency. Refer to Figure 1-4 for details.

4. Using Tapping Screw Instead Of Machine Screw

Using a tapping screw instead of a machine screw in metal components eliminates the need for expensive tapping processes. For plastic components, tapping screws can replace machine screws, avoiding the need for embedded nuts in injection molding and reducing both the quantity and cost of parts. However, tapping screws are best suited for products that don't require frequent disassembly or have lower fastening requirements.

5. Bolts And Nuts Are The Last Choice

Compared to other assembly methods, using bolts and nuts results in the highest production and assembly costs while offering the lowest efficiency. Therefore, reserve bolts and nuts as a last resort, unless the assembly demands exceptionally high precision.