Engineering Expertise

Most automation projects that miss their timeline or budget targets do not fail because of bad engineering. They fail because the engineering process was poorly structured. The machine design process, the sequence of stages from initial requirements through final commissioning, determines the outcome of a project more than any individual design decision. A well-run process catches problems at the stage where they cost the least to fix. A poorly run process delivers those same problems at the stage where they cost the most.

This guide breaks down each stage of the machine design process, explains what it should produce, and identifies where the process most commonly breaks down. Whether you are scoping your first custom automation project or evaluating a partner for a complex multi-discipline system, understanding the process is the first step toward a successful outcome.

What Is the Machine Design Process?

The machine design process is the structured sequence of engineering stages used to take an automated system from a defined need to a validated, production-ready machine. It integrates mechanical, electrical, controls, and software disciplines through a series of checkpoints designed to catch and resolve problems at the lowest possible cost. Each stage builds on the previous one, and each produces documented outputs that the next stage depends on.

At Bravo Team, this process underpins every machine and system design engagement, from standalone automation cells to fully integrated production systems spanning multiple disciplines. For a broader overview of the discipline, see our complete guide to custom machine design and automation.

The Machine Design Process: Stage by Stage

1. Requirements Definition

Every machine design project begins with requirements: throughput targets, tolerance specifications, cycle time, environmental conditions, safety classifications, and integration requirements with existing equipment. Requirements that are vague at the start of a project do not clarify themselves later. They become scope disputes. The engineering team’s job at this stage is to push for specificity, document what is agreed, and flag what is not yet known.

Good requirements are measurable and traceable to a real production need. They define what the system must do, not how it must do it. A requirement that says ‘the system shall process 60 parts per minute with a reject rate below 0.5%’ is useful. A requirement that says ‘the system shall be fast and accurate’ is not. The engineering team should be able to point to every requirement and explain how it will be verified during acceptance testing. If it cannot be tested, it should be rewritten until it can.

2. Concept Development

With requirements defined, the engineering team develops and evaluates multiple conceptual approaches. This is where interdisciplinary collaboration delivers the most leverage. Mechanical, electrical, controls, and software engineers working together at the concept stage surface constraints and opportunities that sequential handoffs miss entirely. The output is a selected concept with a documented rationale, not just a sketch.

An analysis of alternatives at this stage is not overhead. It is insurance. A mechanical concept that looks elegant on its own may require an unnecessarily complex control architecture. A simpler mechanical approach, surfaced through cross-disciplinary review, might achieve the same result with a fraction of the software complexity. These tradeoffs only become visible when all disciplines are in the room at the same time.

3. Proof of Concept

High-risk elements of the design are physically validated before the team commits to a full build. This is one of the most valuable investments in the entire process. Our research and development capabilities support rapid proof-of-concept development using SLA and FDM 3D printing, benchtop prototypes, and finite element analysis. Catching a flawed assumption at this stage costs a fraction of what it costs after fabrication.

Not every element of a design needs a proof of concept. The judgment call is identifying which assumptions carry the most risk if they are wrong. Novel actuation approaches, tight tolerance stackups, untested sensor configurations, and new material applications are all candidates. Validated components and proven subsystems can move directly to detailed design. The goal is to de-risk the unknowns, not to prototype the entire machine before designing it.

4. Detailed Design

Validated concepts are developed into complete engineering packages: 3D models in SolidWorks, electrical schematics, pneumatic and vacuum diagrams, wiring layouts, and controls architecture documentation. Design for manufacturability (DFM) reviews happen at this stage to confirm the design can be produced to specification within project constraints. Client-partners review and approve the full design before fabrication begins.

This is also where safety architecture is formally designed into the system. Machine safety cannot be retrofitted cleanly. Guarding layouts, E-Stop circuit architecture, safety PLC logic, and risk assessment documentation all need to be part of the detailed design package, not an afterthought addressed during commissioning. Teams that treat safety as a checklist item at the end of the project routinely incur costly redesigns when the system fails to meet applicable ANSI or ISO standards.

5. Fabrication

In-house machining and fabrication capabilities, including 5-axis CNC milling, 4-axis live tooling lathes, welding, and a 13-printer 3D print farm, allow the team to build and iterate without waiting on outside suppliers. The integration of design and fabrication under one roof is one of the most significant factors in compressing project timelines and catching fit-up issues early.

When fabrication and design are separated, fit-up issues discovered during assembly require a formal engineering change request, a supplier communication, a revised drawing, and a new production run. When the same team that designed the part can also machine a revised version the same day, that loop closes in hours rather than weeks. This is not a minor operational convenience. On complex builds with many custom components, it is often the difference between an on-time project and a late one.

6. System Integration

Mechanical, electrical, controls, and software systems are brought together and tested as a complete assembly. Integration is where the coordination quality of the earlier stages becomes visible. Teams that work concurrently through design produce systems that integrate cleanly. Teams that worked in silos discover their interfaces do not match.

Common integration issues on poorly structured projects include cable routing conflicts with mechanical structure, sensor mounting positions that were not reflected in the CAD model, PLC I/O counts that do not match the final wiring layout, and software that was developed against an earlier version of the controls architecture. None of these are difficult to resolve individually. The problem is that they tend to appear all at once during integration, compressing the schedule at exactly the stage when there is the least margin left.

7. Acceptance Testing and Commissioning

The completed system is validated against the original requirements through a Factory Acceptance Test (FAT) before it leaves the facility. Where required, a Site Acceptance Test (SAT) is performed at the client-partner’s location following installation. The system is not released to production until it meets the documented acceptance criteria. FMEA analysis and long-term monitoring support validation in applications where regulatory or quality requirements demand additional rigor.

The FAT is not a formality. It is the contractual and engineering checkpoint where every requirement is verified against a defined test. A well-structured FAT catches the gap between what the system does and what it was specified to do while the engineering team is still on-site and equipped to address it. Systems that skip formal acceptance testing and go straight to production commissioning tend to surface those same gaps in the client-partner’s facility, at the worst possible time.

Where Machine Design Projects Go Wrong

Most machine design failures trace back to one of three root causes. Understanding them is useful whether you are managing the project yourself or evaluating a partner who will manage it for you.

The first is vague requirements. When the engineering team does not have clear, documented performance targets at the start, every downstream decision is made against an undefined standard. The result is rework, scope creep, and schedule pressure. The most reliable signal that a project has vague requirements is a team that jumps to concept development without asking hard questions about what the acceptance criteria will look like. A good engineering partner will slow down at the requirements stage, even when the client-partner is eager to move quickly.

The second is late-stage discipline handoffs. When mechanical design is completed before the controls team is engaged, or when software development begins after fabrication is done, the integration problems that result are expensive and time-consuming to resolve. Concurrent multi-discipline collaboration from the concept stage forward is not a process preference; it is a risk control measure. The coordination cost of running disciplines in parallel is always lower than the rework cost of integrating them in sequence.

The third is skipping proof of concept. The pressure to move quickly to detailed design and fabrication is real, but teams that skip POC validation on high-risk elements routinely spend more time recovering from failures during integration than they saved by shortcutting the process. Our engineering team is structured specifically to run these stages concurrently and efficiently, without creating the coordination gaps that slow projects down and drive up cost.

Frequently Asked Questions

What are the stages of the machine design process?

The core stages of the machine design process are requirements definition, concept development, proof of concept, detailed design, fabrication, system integration, and acceptance testing. Each stage produces documented outputs that feed the next. Skipping or compressing stages, particularly proof of concept and requirements definition, is the most common driver of project overruns.

How do you write machine design requirements?

Effective machine design requirements are specific, measurable, and traceable to a real production need. They define what the system must do, not how it must do it. Key elements include throughput targets, dimensional tolerances, cycle time, environmental operating conditions, safety classifications, and integration requirements with existing equipment. Every requirement should be written so that it can be verified during acceptance testing. If a requirement cannot be tested, it needs to be rewritten until it can.

What is a Factory Acceptance Test?

A Factory Acceptance Test (FAT) is a structured validation process performed at the engineering firm’s facility before the system is shipped to the client-partner. The FAT verifies that the completed machine meets the agreed performance requirements under documented test conditions. It is the last checkpoint before commissioning and the point at which any remaining discrepancies between the delivered system and the acceptance criteria are identified and resolved while the team is still best positioned to address them.

How long does each stage of the machine design process take?

Stage durations vary significantly by project complexity. Requirements definition and concept development for a straightforward system might take two to three weeks. For a multi-discipline system with novel technical elements, those same stages could take six to eight weeks and produce substantially more value. Proof of concept can run concurrently with early detailed design in many cases, which compresses the overall timeline without reducing rigor. The full project schedule is established during the scoping process once requirements are documented and the engineering approach is defined. Contact us to start that conversation.

What is the difference between a FAT and a SAT?

A Factory Acceptance Test (FAT) is conducted at the engineering firm’s facility before the system ships. A Site Acceptance Test (SAT) is conducted at the client-partner’s facility after installation. The FAT verifies that the system meets its performance requirements in a controlled environment. The SAT verifies that it continues to meet those requirements after transportation, installation, and integration with the client-partner’s production infrastructure. For complex systems or regulated environments, both are standard project deliverables.

Ready to Start Your Machine Design Project?

A well-run machine design process is the difference between a system that performs on day one and a system that spends its first months in remediation. Every stage has a purpose, and every stage produces something that the next one depends on. The teams that consistently deliver on time and on spec are not the ones that move the fastest through the process. They are the ones who run each stage with the most discipline.

If you are scoping a custom automation project and want to understand what the process looks like for your specific application, our engineers are ready to dig in. Explore our machine and system design services, or learn directly from our machine design experts about our process.