Successful CAD Product Designs & Appropriate Design Approach

Jul 5, 2017 -- Every product design engineer struggles, sooner or later; in deciding to adopt a design approach that is sound for their manufacturers during production. Also they need to keep a check of enhancing the product design cycle. Theoretically, it is said and advised to have a bottom-up CAD design approach for new product development since it lends more experimentalism. But in reality, most product design engineers employ top-down design approach for improving the existing designs



Most design engineers are of the opinion, and also often insist; that the assembly components need to be released before the sub-assembly they go into whenever a new product is to be designed. However, that isn’t necessary and often also not even desirable. In fact, most designs either utilize top-down approach or bottom-up approach; however, this is feasible only when requirements are known and when the designs make use of some standard components.



Frame-to-component VS Component-to-frame Design Approach



While majority design engineers insist on following a bottom-up approach in CAD systems, there also are engineers who are in favor of top-down CAD design approach. Practically, each of these approaches has their own merits and demerits and is characterized by their application.



For instance for a sheet metal design engineer, working on large scale assembly designs such as a pump casing, they need to look at the larger view. When working with large assemblies, if engineers cannot step back and have a holistic view of their designs, integrating systems and components becomes even tough. Thus, while designing components of larger assemblies and industrial automation products, design engineers usually go for a top-down approach. One can say that top-down design approach is the one that is led by extensive research leading to the development of the entire product and allows multiple engineers work cohesively on a single product.



On the other hand, with a bottom-up approach, what design engineers do is, attain the outline of the component first and then proceed with the assembly. A system by system and often iterative approach for assembly gives wider scope for detailed design research. As a result, the bottom-up approach is preferred when the product is experimental and sufficient time is allotted to design cycle. The secret door to success with the bottom-up design approach is a concrete testing of components and sub-systems for a verified design.

Design Parameter Top-Down Approach Bottom-Up Approach Permitted time for extensive planning and research Y N Experimental product design N Y Flexible approach to higher complexity of product designs Y N Need to address value addition from each division for collaborative design approach N Y Adaptive design for unconstrained features N Y Enabled executive design decision making Y N Development of design workforce deployment strategy N Y Control over tight budget plans Y N

Blended Design Approach



Although both these approaches are very distinctive, no product design approach will fall into either of these, obediently. As a result, design engineers today adopt a blend of both these approaches, for those most successful designs. The blend only means, product design engineers start with a top-down approach, having an outline of the assembly, and then proceed towards an optimal solution, to what we call middle-out design approach.



The middle-out approach essentially means that it is a combination of both, which means that some files will be designed inside the assembly while some are designed outside of it. Since the designer can address the components as adaptive and leave them un-dimensioned while creating the base assembly, it allows the designers to reuse the part of it in future as well.



With middle-out approach, product design engineers can easily expedite the design cycle time since it gives a strong case for product design engineer who is looking to reduce design data recreation, free-up the time for design innovation. It essentially creates fidelity approaches for downstream engineering processes of manufacturing and marketing.



Since this design approach addresses the top-level requirements and functions, it keeps the legacy of adding new features, intact. Middle-out design is rationally based on the iterative nature of the fundamental systems of engineering.



Conclusion



It might seem that when we have followed the legacy of adopting an efficient bottom-up approach, there isn’t a need for transition. However, there are times when engineers face challenges with the bottom-up approach in the wake of rising design complexity. As a result some product design engineers will advocate that one is better than the other. While those who are dedicatedly invested in product design tasks will know that it is wise to adopt the blend of two; a middle-out approach for staying successful.

About Author:

Usha B. Trivedi is a Technical Writer at Hitech CADD Services - CAD Design Services. She is a qualified mechanical engineer and contributes in-depth articles for industrial equipment, processing plants and fabrication sector. Her contributions are primarily focused on enabling engineering professionals, fabricators and plant owners to accelerate design and improve project efficiencies through BIM, 3D CAD and CAE tools.