Concurrent Engineering: How Overlapping Design and Manufacturing Phases Cuts Time-to-Market

The traditional approach to bringing a new product to market runs in a straight line: engineering completes the design, then hands it to manufacturing, which builds the tooling and processes, then hands it to production. This sequential model is intuitive, but it has a fatal flaw — every department discovers problems created by the previous department only after that department has moved on. Corrections cost time and money that compounds at each handoff. Concurrent engineering — also called simultaneous engineering or integrated product development — attacks this problem directly by running design, process planning, and production preparation in overlapping parallel streams rather than sequential queues.

What Concurrent Engineering Is and Where It Came From

Concurrent engineering as a formal methodology gained traction in the 1980s and 1990s in defense and automotive manufacturing, driven by the Defense Advanced Research Projects Agency (DARPA) and codified in the Institute for Defense Analyses Report R-338 in 1988. The core principle is simple: all disciplines involved in a product's life — design engineering, manufacturing engineering, quality, procurement, service — participate in the product development process simultaneously from the earliest stages, rather than receiving a finished design as a fait accompli.

The documented time-to-market improvements have been substantial. Boeing's 777 development program, which used concurrent engineering extensively, delivered the aircraft 40% faster than comparable previous programs. Automotive OEMs running concurrent engineering programs in the 1990s cut typical platform development cycles from 48-60 months to 24-36 months. For mid-size manufacturers, the gains are proportionally similar: a new product that previously took 18 months to reach production readiness can often be launched in 10-12 months with disciplined concurrent methods.

The Core Mechanism: Overlapping Rather Than Sequential Phases

In a traditional sequential development process, the project network looks like a chain — each link must close before the next opens. In concurrent engineering, the network looks more like an overlapping set of parallel swimlanes, where later phases begin working on the constraints and requirements they already know while the earlier phase resolves the remaining open items.

Consider a new machined assembly. Sequential development might look like this:

1. Design engineering: 12 weeks
2. Design review and release: 2 weeks
3. Manufacturing process planning: 8 weeks
4. Tooling design and procurement: 14 weeks
5. First article inspection: 4 weeks
6. Production readiness: 2 weeks Total: 42 weeks

A concurrent approach overlaps these phases based on what information is already stable:

• Manufacturing process planning begins at week 6 (when the major geometry is frozen) rather than week 14
• Tooling procurement for the items with the longest lead times begins at week 10, before process planning is complete, based on preliminary routing decisions
• First article inspection criteria are defined at week 8, enabling the quality team to prepare fixtures and measurement plans in parallel

Total with overlap: 26-28 weeks — a 35-40% reduction without any increase in resources.

The key enabling mechanism is the formal identification of what must be known before a downstream task can start (hard dependencies) versus what is merely conventional to know (soft dependencies where a prudent estimate can substitute for a final answer). Concurrent engineering is the practice of systematically eliminating soft dependencies from the critical path.

Design for Manufacturability as the Foundation

Concurrent engineering only delivers its time compression benefit if manufacturing knowledge is injected into the design process early enough to prevent costly late-stage changes. Design for manufacturability (DFM) is the set of practices that makes this injection systematic.

Effective DFM in a concurrent engineering context includes:

Process capability matching: Tolerances on the design should be checked against the actual Cpk values of the shop's machines or the supplier's documented capabilities before the drawing is released. A tolerance that is achievable with the target process at plus or minus 0.001 inches but currently only held at plus or minus 0.003 inches on available equipment will cause scrap or require process investment — information that is far cheaper to act on during design than during first article inspection.

Assembly sequence review: Manufacturing engineers walk through the assembly sequence with the design team while the CAD model is still parametric. Components that would require awkward fixturing, special tooling, or two-person assembly operations are identified and redesigned before the drawing is released.

Standard component selection: Preferring standard fasteners, bearings, seals, and electronic components over custom-specified items shortens material lead times, improves supplier competition, and leverages existing receiving inspection procedures. A concurrent team with access to the component library during design selection can often substitute a standard item for a custom specification at zero performance cost.

Make-or-buy analysis: Concurrent engineering programs surface make-or-buy decisions earlier, giving procurement more lead time to qualify suppliers. A component that requires a 20-week supplier qualification will not delay the program if the qualification begins in week 4 rather than week 16.

The Role of Integrated Product Teams

Concurrent engineering is an organizational model as much as a technical one. The structural mechanism that enables parallel workstreams is the integrated product team (IPT) — a cross-functional group with representatives from all relevant disciplines who share authority and accountability for a defined portion of the product.

An IPT for a new mechanical sub-assembly might include a design engineer, a manufacturing engineer, a quality engineer, a procurement specialist, and a production planner. This team owns the sub-assembly from concept through production readiness. Decisions that in a sequential model would require formal handoffs between departments are made within the team, in real time, which eliminates the wait time and communication latency that dominates sequential development cycles.

From a scheduling perspective, the production planner's presence on the IPT from day one is significant. Rather than receiving a completed routing from manufacturing engineering three months before production launch, the planner participates in routing development, identifies capacity conflicts with existing work before they become emergencies, and begins building tentative capacity reservations months earlier than would be possible in a sequential model.

How Production Scheduling Software Supports Concurrent Engineering

Concurrent engineering creates a specific scheduling challenge that sequential development does not: multiple partially-defined projects are sharing real production equipment and real engineering labor simultaneously, and the definition of each project is changing as the development process progresses. Standard ERP scheduling tools, which assume stable BOMs and routings, are often inadequate for this environment.

Production scheduling software that supports concurrent engineering programs should handle:

Multi-project capacity modeling: The scheduler must be able to model NPI prototype runs alongside regular production on the same machines and work centers, so that resource conflicts are visible before they become firefighting situations. This requires work orders to carry a project code that the scheduler can use to segregate and prioritize across programs.

Tentative routing support: Early in a concurrent program, the routing is not fully defined — cycle times are estimates, the sequence may change, and some operations may move between work centers as the process plan evolves. The scheduler should allow planners to enter preliminary routings with confidence intervals rather than requiring fully resolved routings before any scheduling can occur.

Rapid reschedule on design change: When a design change occurs mid-program — a common event in concurrent engineering — the scheduler must be able to quickly identify all affected open work orders, show the planner what the cascading schedule impact is, and rebuild the plan around the change. Manual reschedule on a complex concurrent program can take days; a tool like RMDB can recompute the constraint-based schedule in minutes.

Critical path visibility: The planner needs to see which tasks are on the critical path to production release at any given moment. In a concurrent program with 8-12 parallel workstreams, the critical path shifts as tasks complete or slip. Without automated critical path tracking, planners rely on intuition and weekly status meetings to identify path changes — by which time the slack is already consumed.

Integration with the smart manufacturing data layer: Modern concurrent programs increasingly generate real-time data from digital prototyping, simulation, and connected test equipment. Scheduling tools that can ingest this data — for example, automatically updating cycle time estimates when a production run generates actual measured times — can continuously refine the schedule as the program matures. See our guide to smart manufacturing and Industry 4.0 for more on building this data infrastructure.

Managing the Primary Risk: Rework from Design Changes

The most frequently cited risk in concurrent engineering is that downstream work done based on preliminary design information must be redone when the design changes. A process plan built on a preliminary drawing that is subsequently revised by 15% may require partial or complete rework. Tooling ordered before the design is frozen may not fit the released drawing.

Managing this risk requires three practices:

Design freeze milestones: Formal gates where specific elements of the design are declared frozen for downstream work purposes. The key insight is that not all design elements need to be frozen simultaneously. A concurrent program can freeze the interface dimensions and mounting hole patterns — the information manufacturing needs to design fixtures — while leaving surface finishes, internal geometry, and secondary features open for continued refinement.

Interface control documents: For complex assemblies with multiple concurrent design sub-teams, interface control documents (ICDs) define the boundaries between sub-assemblies that must be respected by all teams. ICDs create a contractual stability between workstreams that allows each team to proceed confidently without waiting for the adjacent team to complete its work.

Rework cost tracking: Teams should explicitly track the cost of rework caused by design changes to concurrent workstreams. This data creates visibility into whether the time savings from overlap are being offset by rework costs, and it informs future decisions about how early to start downstream work on similar programs.

Applying Concurrent Engineering to Custom and Configure-to-Order Manufacturers

Most of the published concurrent engineering literature addresses new product development for standard products — automotive, aerospace, consumer electronics. But the principles apply equally to custom and configure-to-order manufacturers who produce engineered-to-order (ETO) products.

For an ETO manufacturer building custom industrial equipment, each order is effectively a small product development program. Concurrent engineering applied to ETO means that while detail engineering is completing the final drawings for the mechanical sub-systems, procurement is already sourcing long-lead-time components based on the preliminary specifications, and the shop floor is preparing fixturing and routing plans based on the preliminary BOM.

RMDB is particularly well-suited to this pattern because it is designed for the high-mix, low-volume job shop environment where ETO manufacturers operate. The scheduling engine handles the variability of one-off routings, custom cycle times, and frequent repriorization that ETO work demands — the same capabilities that enable it to manage the overlapping workstreams of a concurrent engineering program. For more on production scheduling in complex job shop environments, see our production scheduling software guide.

Frequently Asked Questions

If your team is running concurrent development programs and struggling to keep NPI work visible alongside your production schedule, RMDB provides the multi-project finite capacity scheduling foundation to manage both streams without conflict. Contact us to see how it fits your development-to-production workflow.