Direct answer
Requirements, concept, detailed design, build, FAT, installation, SAT and validation. Buyers control cost and schedule mainly in the first two phases.
What this discipline delivers
- A user requirement specification (URS) defining what must be achieved, not how
- A concept with cycle-time budget and risk assessment
- Detailed mechanical, electrical and control design
- A build with documented factory testing
- Site installation, commissioning and validated handover
Method and stages
Phase 1 — Requirements
URS, product data, throughput, interfaces, acceptance criteria and constraints.
Phase 2 — Concept
Options, cycle-time budget, layout, preliminary risk assessment, budget estimate.
Phase 3 — Detailed design
Design freeze, drawings, schematics, software architecture, procurement of long-lead items.
Phase 4 — Build and FAT
Manufacture, assembly, software, factory acceptance test with real product.
Phase 5 — Install, SAT, validate
Site installation, commissioning, site acceptance and performance qualification.
Engineering and project considerations
- Changes after design freeze cost multiples of changes before it
- Real product samples must be available for concept and FAT
- Long-lead components should be ordered against the schedule, not the budget cycle
- Documentation and code ownership must be contractual
- Design reviews with buyer participation at each phase gate
What to prepare before engaging engineering companies
- URS in performance terms with measurable acceptance criteria
- Product samples spanning the full variability range
- Site constraints and interface data
- Phase-gate schedule with buyer decision dates
What to measure
Frequently asked questions
What is a URS?
A user requirement specification states what the machine must achieve — throughput, quality, interfaces, compliance — without prescribing the design. It is the buyer's most powerful document.
Who writes the specification?
The buyer, ideally with independent engineering support. Specifications written by the supplier tend to describe what that supplier already builds.
Related engineering knowledge
Solution Domain
Custom Industrial Machinery
Engineering Knowledge
Industrial Engineering Workflow
Engineering Knowledge
Factory Acceptance Testing (FAT)
Buyer Decision Brief
What To Prepare Before Contacting Engineering Companies
Solution Domain
OEM Engineering
Engineering Knowledge
Industrial Mechanical Design
Buyer Decision Brief
When Does A Custom Machine Make Sense?
Independent, buyer-side and supplier-neutral
Global B2B Group does not sell machines and does not represent equipment manufacturers. This material is published to help industrial organisations define the problem, prepare the specification and structure the investment before engineering partners are selected.