Arena PLM

BOM Mistakes Every CAD Designer Makes

As a CAD designer, have you ever asked yourself why BOMs are so complex to understand? The term BOM (Bill of Materials) is used to define a list of raw materials, sub-assemblies, intermediate assemblies, sub-components, parts, and the quantities of each one of these inputs required in the manufacturing of a product. Essentially, it is the blueprint of a product which is typically its lifeblood right from procurement and production control, to logistics and inventory management. A BOM can range from a small to a huge assembly line that could have multiple mini-BOMs within.

Most products today require model and option configurations among others. However, the management of these configurations in a CAD system can be too complex and complicated. If one tries to apply these configurations to a structure transformation, they would get lost. The best solutions could be reached if an appropriate tool used to manage the BOMs is tailored with the exact order to follow. Unfortunately, this rarely happens and companies end up with a load of complicated spreadsheets.

Modern manufacturing trends such as globalization, contract manufacturing, mass customization, Internet of Things, etc. continue increasing product complexity. They demand more complicated tools to help engineering and manufacturing companies work together. Having details about the components, availability, cost and other frameworks such as regulation is crucial. Duplicating this information in the BOM system is possible, but not reliable or adaptable.


Managing and maintaining any BOM is a challenging task for organisations. This is due to the different variables applied such as program execution, complexity, design changes, communication and process flow. Here are some of the BOM mistakes every CAD designer makes:

Losing Control of the Development Costs

When teams are about to commence their project, the project scope and set of requirements usually seem well-defined. Targets are well allocated and the mission and goals are clear. However, a few months into the project, the project engineer runs the projected cost of the bill of materials and gets shocked over how it has exceeded the target cost.

In this situation, the team lost focus on the projected cost in the course of executing technical decisions. One way to avoid this from happening is by starting with a sub-system and key component cost budgets early enough.

CAD designers solving complex product design projects need to establish early budget targets for electronic and mechanical components, or the expected cost determinants. The figures might change in the course of the project but regular monitoring will enable assessments to be done in a timely manner. The sooner variants are calculated, the lower the impact to project cost.

Forgetting Project Requirements

While the project is ongoing, it is easy to lose the focus of the objectives and requirements needed to be driven into developing the final product. Unfortunately, these oversights are not realized until late in the development process. It may be too late even for any missing features to be incorporated back in the ongoing process. Correcting the missing steps can be too costly in terms of wasted time and budgeting. They may become disastrous when trying to configure product cost projects.

Inadequately Resourced ERPs

A well-designed project has defined requirements and features with projections of budget costs and scheduling. Once it is given a go-ahead, CAD designers are ready to start the project.

ERP (Enterprise Resource Planning) is more of a people project at its core. The biggest challenge before and after the implementation is not technology, but the biggest issues are related to people. At every stage, organisations strive to manage change, communicate with and educate their team. Human resource issues are related to change management, training and dealing with staff adequacy.

Implementation of ERP is a costly, complex and lengthy project. The initial budgets are often exceeded with many hidden costs in the implementation of the ERP. While doing budget preparation and allocating resources, CAD designer should ensure all the factors that could affect the costs, skill requirements and tools needed during implementation are properly looked into.

Failing to Execute the Full Set of Deliverables

Many products are comprised of a core product with an array of complementary accessories. A good project is well-staffed and works to specific, well-defined requirements. The need for accessories in the requirements is usually well established but, unfortunately, these accessories are not defined or properly staffed until it’s too late in the project. The product cannot be launched if the required design accessories are not available.

Failure to Monitor Schedule

Teams often lose sight of the project schedule. It takes a lot of effort to monitor and track schedules up to completion. Some organisations have dedicated tools that monitor estimates to completion (ETC).

Managing huge projects may demand constantly keeping up with the ETC. In smaller organisations, projects or startups, such controls may not be available or even frequently monitored if there was. Losing control over the schedule makes smaller projects to grossly over-run in schedule. Time is money and projects that take longer accrue more costs.

Wrong Team

No matter the size, there is no project too small to be messed. Assuming a design project of low priority or low complexity can be handled without senior designers or an incompetent team with performance issues is doomed for failure.

Parting Shot

A project should always start out with a targeted BOM cost and always ensure that business goals are realistic and achievable. The BOM budget target should be broken down into subsystem targets. Team members should make early and frequent updates and avoid fixing things at the end of the project.