What are the most important mechanical design considerations for easy assembly and disassembly?

Minimizing parts is a significant consideration for easy assembly and disassembly. This reduces errors and simplifies the process. Additionally, Design for Manufacturing (DFM) is crucial even with fewer parts, ensuring better manufacturability. In summary, keeping the number of parts to a minimum while optimizing their manufacturability is key for easy assembly and disassembly.

An example of designing assemblies to reduce assembly time is by reducing the number of fasteners or different tools needed to assemble the components. Reducing the number of fasteners or eliminating hardware by using alternatives like rivets and clips can reduce assembly time while maintaining strong connections. Using the same hardware in multiple spots can eliminate tool changes.

Every assemblies are made for the purpose of performance. Design can not compromise them for ease in assembly or disassembly. Tolerance and fits are the best parameters to be considered for ease. Balancing efficiency, performance, life, ease in repairs, repairability, reliability after reassemblies are the factors to be considered first. Reducing components is a good idea but should not cost the performance and reliability. With best tolerances and fits if you achieve 95% efficiency and with little open tolerance if you achieve 92% efficiency and life, why should you spend more. One can use equation, Eff 1 * LCC (Life cycle cost) 1 = Eff 2 * LCC (Life cycle cost) 2. Above equation answers all aspects of a good design.

The other school of thought is to design your parts so they only fit together correctly. This way it is not possible to incorrectly assemble parts. An example is using different bore sizes for a flexible and rigid side of a shaft coupling.

In my point of view as a construction lead, make it simple and efficient. This way will allow disassemble / modification if necessary.

Modular design and Integral design are the two strategies for design . When the functional elements of an assembly dont require to assembled and disassembled in service then integral design can be used considering the design for manufacturing and assembly aspects. But when flexibility and replacement is required modular design is better. There is always a trade off and reasoning for each unique situation on which approach to use.

Snapfits and press fits are great for low duty applications when the operating forces and moments are much lower than the forces required for separation of joint . High loads require bonding and fastening . Before deciding on fastening methods its important to do a simple static force analysis to know the range of forces and moments generated.

Make it so the assembly or the disassembly is used by few tools. Design it so the nuts and bolts or screws use the same size or few sizes for minimal need for different tool sizes.

Single sided fasteners, where access is restricted. Commonality of fasteners. For example if using M6 socket head cap screws, try to minimise the number of lengths to avoid confusion. Rather than using M6x10, M6x12, M6x20, etc. I disagree that screws are complex! Snap fits and press fit parts can be prone to damage when disassembling.

Design for Assembly (DFA) can be used to overcoming the challenges associated with mating intricate and inadequately complex parts. However, it is important to acknowledge that this design methodology requires additional effort in tolerance design. For instance, opting for fit tolerance instead of interference tolerance can prove effective, particularly in applications that are not subjected to high levels of vibration or dynamic loads. Incorporating geometrical tolerance based on the standards outlined in the ASME code becomes imperative when preparing shop drawings for such designs. By adhering to these guidelines, manufacturers can ensure accurate and precise assembly, facilitating the successful realization of the intended design.

DFA works on simplifying the manufacturing and maintenance processes by reducing the number of parts, optimising component shapes, and decrease the need for custom tools.

One very useful principle which I have found impactful in design is Exact constraint design . Making the design in such a way that the degrees of freedom of the joining components get constrained automatically through the process of assembly just enough for function but not more making it redundant . Using 10 bolts to joining one plate to another when only 3 can suffice is one way of thinking about it.

Incorporating Design for Disassembly (DFD) principles has a significant impact on mechanical design considerations for easy assembly and disassembly. DFD focuses on designing products with end-of-life recycling or reuse in mind. This reduces waste and environmental impact. By considering DFD, products become more sustainable, and disassembly becomes more straightforward, facilitating the recycling process and contributing to a more eco-friendly approach to design and manufacturing.

Generic Requirement: Question the requirements along the PLC development: still designing in the right direction? Meaning, is the current design status still verifiable and valid with respect to the requirements? Is there any advantage to gain through modification of one or more requirements? Specific Requirement: Manual Handling/Tooling Required space/volume, a technical derived requirement, in order to satisfy the necessity of accessibility for assemblage and installation, and vis versa.

when assembling a product it is important to be mindful the client might need to disassemble for x reason (s). So you should make it logical process of disassembly, not easy mind you! That might take a few versions after the prototype phase. Try not to use welds and rivets but this is not possible all the time.

Utilize “poke yoke” or mistake proofing in your design. This means design your assembly so that parts cannot be assembled wrong. A common poke yoke is designing the part to fit only one way by mechanically blocking the other orientations. A good part only goes on one way: the right way.

Like we know, making a prototype a much easier to proceed the mass production manufacturing. It also means you need to consider all the human factors inside your product design, tooling design, and process design. The best mechanical engineer is to design a product which can let anyone to produce every product with same quality level through your drawings and procedures.

Design assembly procedure to be foolproof so that even if the assembler didn't read the instructions carefully the assembly will not be achieved without exposing either the assembler, operator, or the machine to danger.

Use Appropriate GD & T During Part Design make easy manufacturing and easy assembly if you don't do this so many problems occur in the process that's why in the design field use experience guys.

Usage of error-proofing, incorporating Poka Yoka principles to make sure it is impossible to assemble the part in the wrong way is must and also creates a good environment for the worker.

Access for commonly available commercial tooling. Assume the maintenance engineer will need to use a standard combination spanner and allen key/torx bit. Model them up in 3D and make sure you have access to get them into the area and can turn one fastener whilst holding the nut or vice versa!