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Choosing a Builder: Design-Build vs. Build-to-Print for Custom Machinery

A buyer of a custom machine can either state what the machine must do and let the builder design it, or hand the builder a finished design and pay it to build exactly that. UTEC Industrial designs, engineers, machines, fabricates, and installs custom material handling systems for aerospace and heavy industry from its Spokane Valley, WA facility, integrating Allen-Bradley PLC and motion control with in-house CNC machining, heat treating, and stress relief. This article explains the two models for a project engineer, engineering manager, or OEM engineering team: where the terms come from, how performance and detail specifications differ, how US government contracts allocate design risk under each, and what changes in warranty, verification, and controls scope. The choice decides who owns each link of the build chain, design → engineering → parts machining → fabrication → assembly → weld fatigue → stress relief → drives → controls → tuning → monitoring, and who answers for it when the machine does not do its job.

What do "design-build" and "build-to-print" mean for custom machinery?​

Neither term has a machinery-specific definition in the public sources used here, and both are borrowed. "Design-build" is defined in construction sources. The Federal Acquisition Regulation, in its part on federal construction and architect-engineer contracts, defines design-build as "combining design and construction in a single contract with one contractor", and design-bid-build as "the traditional delivery method where design and construction are sequential and contracted for separately with two contracts and two contractors". The Design-Build Institute of America (DBIA), a construction association, says the single contract for both design and construction "is the fundamental difference between design-build and other project delivery systems". The FAR is cited here as codified in 48 CFR, using the eCFR text current as of September 28, 2026; it is being rewritten under an overhaul led by the Office of Federal Procurement Policy and the FAR Council (the RFO), and provision numbers may change.

"Build-to-print" is a term used in defense and space practice. The Defense Standardization Program's Guide for Performance Specifications (SD-15) says, "Sometimes detail specifications are referred to as 'build-to-print' specifications." The NASA Systems Engineering Handbook says a product is implemented by purchase, by making or coding it, or by reuse, and that in some cases implementing a product "may have aspects of more than one of these forms (such as a build-to-print)".

As engineering reasoning, applied to machinery: in a design-build order the builder designs the machine against the buyer's performance requirements and then builds it, and in a build-to-print order the buyer, or the buyer's engineer, furnishes the detail design and the builder makes it to the drawings (48 CFR Part 36, 2008, 36.102; Design-Build Institute of America, 2026; Office of Federal Procurement Policy and FAR Council, RFO deviation guidance, 2026; SD-15, 2009, p. 3; NASA/SP-2016-6105 Rev2, §5.1.1.2).

How do performance specifications and detail specifications differ?​

SD-15 gives the two definitions the models rest on. A performance specification "states requirements in terms of the required results and the criteria for verifying compliance, without specifically stating how the results are to be achieved". It describes the functional requirements for an item, its capabilities, the environment in which it must operate, and any interface, interoperability, or compatibility requirements, and it "does not present a preconceived solution to a requirement". A detail specification "provides preconceived solutions to requirements and describes exactly how an item is to be produced", identifying materials, specific parts and components, and how the item is to be fabricated and assembled.

The FAR addresses the same choice for US federal agencies. Under 48 CFR 11.002(a)(2)(i), agencies shall, to the maximum extent practicable, ensure that acquisition officials state requirements in terms of functions to be performed, performance required, or essential physical characteristics. Under 11.101(a), agencies select requirements documents consistent with an order of precedence: documents mandated for use by law; performance-oriented documents; detailed design-oriented documents; and standards, specifications and related publications issued by the Government outside the Defense or Federal series for the non-repetitive acquisition of items. The FAR ranks the document types; it does not say which is better for a given machine.

As engineering reasoning, for a coil car in an aluminum mill, performance requirements are the coil weight, travel distance, cycle time, stopping accuracy, and interfaces to the mill, and detail requirements are the frame section, wheel diameter and material, gearbox, and weld details. A URS can hold both kinds, and the URS article covers how to write each requirement so it can be verified (SD-15, 2009, pp. 2-3; 48 CFR Part 11, 2024, 11.002 and 11.101).

Who carries design risk under each model in US government contracts?​

The public statements on design risk come from the US government, describing how it allocates that risk in its own contracts. They are not legal advice for a private contract, whose own terms govern. SD-15 states that "Using performance specifications also shifts the design risk to the contractor since the Government is not telling the contractor how to meet a requirement." It adds that detail specifications place "a greater risk on the government if the item fails to satisfy the required purpose because the government has specified the materials, parts, components, and fabrication and assembly processes."

The FAR's warranty guidelines make a related distinction. Among the guidelines a contracting officer shall consider under 48 CFR 46.706(b)(1)(ii): "If the Government specifies the design of the end item and its measurements, tolerances, materials, tests, or inspection requirements, the contractor's obligations for correction of defects shall usually be limited to defects in material and workmanship or failure to conform to specifications. If the Government does not specify the design, the warranty extends also to the usefulness of the design."

The Supreme Court addressed owner-furnished plans in United States v. Spearin (1918), which concerned a lump-sum contract to build a Navy Yard dry-dock to plans and specifications the Government prepared. The Supreme Court held that "if the contractor is bound to build according to plans and specifications prepared by the owner, the contractor will not be responsible for the consequences of defects in the plans and specifications", and that this responsibility of the owner is not overcome by the usual clauses requiring builders to visit the site, check the plans, and inform themselves of the requirements of the work. The case concerned a federal construction contract. As engineering reasoning, the three sources point the same way within their own settings: the party that specifies the design carries more of the risk that the design fails to serve its purpose, subject to the FAR's "usually" and to the terms of the contract (SD-15, 2009, p. 3; 48 CFR Part 46, 2021, 46.706; Supreme Court of the United States, United States v. Spearin, 248 U.S. 132, 1918, pp. 136-137).

Which warranty terms follow from each model?​

The FAR has a warranty clause written for equipment bought to performance specifications or design criteria. Under 48 CFR 46.710(c)(1), the contracting officer may insert FAR 52.246-19 when three conditions all hold: performance specifications or design are of major importance; a fixed-price supply, service, or research and development contract for systems and equipment is contemplated; and the use of a warranty clause has been approved under agency procedures.

The clause defines a defect as "any condition or characteristic in any supplies or services furnished by the Contractor under the contract that is not in compliance with the requirements of the contract". The contractor shall promptly comply with timely written direction from the contracting officer to correct or partially correct it "at no increase in the contract price". A corrected or replaced item carries a warranty equal in duration to the original, running from the date the corrected item is delivered. The contractor is not responsible under the clause for correcting defects in Government-furnished property, except for defects in installation, unless it performs or is obligated to perform modifications or other work on that property. The clause also excludes all implied warranties of merchantability and fitness for a particular purpose.

FAR 46.702(a) gives the principal purposes of a warranty in a Government contract as delineating the rights and obligations of the contractor and the Government for defective items and services, and fostering quality performance. As engineering reasoning for a private buyer, the Government-furnished-property rule has a build-to-print parallel: if the buyer furnishes the drawings, or a part the builder installs, the warranty terms should say which defects belong to the builder's workmanship and which to the furnished design (FAR 52.246-19, 2001, paragraphs a and b; 48 CFR Part 46, 2021, 46.702).

When does a design-build order fit a custom machine?​

SD-15 states that, generally, "it is considered preferable to state requirements in performance terms", and that it is "especially important to use performance specifications when stating requirements during the pre-production phases of systems or product development in order to keep technical options open". It adds that performance specifications can broaden the number of potential suppliers, since the requirements are not built around specific solutions. The FAR says, in 11.002(c), that requiring agencies "should not dictate detailed design solutions prematurely", and that potential offerors should, to the extent practicable, be given an opportunity to comment on agency requirements or to recommend alternative approaches.

DBIA, which promotes the method for construction, lists benefits it claims for design-build, including "Allocation of risk to those who can best manage it" and "Earlier knowledge of firm costs". It also states that "Research over decades has consistently shown" faster project delivery, more reliable performance, and less cost and schedule growth; the page names no specific study for that statement. These are DBIA's claims about construction projects, not findings about machinery. DBIA describes two variations: two-step best-value design-build, which first identifies the most highly qualified design-builders and then seeks design and cost proposals, and progressive design-build, where the design-builder is selected primarily on qualifications and the owner and design-builder then progressively advance the design and cost model toward a mutually agreeable design concept and contract price.

As engineering reasoning, design-build fits a machine whose duty the buyer can state but whose mechanism is not yet chosen. Examples are a first-of-a-kind positioner for a spacecraft structure or a liner handler for a mining concentrator. In both, the buyer knows the load, envelope, and cycle, and the builder's design and fabrication knowledge shapes the answer (SD-15, 2009, p. 3; 48 CFR Part 11, 2024, 11.002; Design-Build Institute of America, 2026).

When does a build-to-print order fit a custom machine?​

SD-15 says that while a performance specification should be considered first, "there are many examples of when it is preferable to develop and use a detail specification". It describes products the DoD has invested substantial resources to research and develop that are unique to the military, have no commercial potential, and are likely to have very few specialized suppliers, and says their specifications would often be detail specifications. It also describes situations where the nature of the requirement makes it essential to mandate a specific solution, such as a decoration whose appearance, size, and materials are specified so that each one is identical. It adds that as the product baseline matures and stabilizes to a "build to" description, the specifications will likely be a mix of performance and detail specifications.

In the NASA life cycle, two design reviews approve the baselines. After a successful preliminary design review, "the design-to baseline is approved", and after a successful critical design review, "the build-to baseline, production, and verification plans are approved". The FAR's contract-type factors make a related point in 48 CFR 16.104: as a requirement recurs or as quantity production begins, the cost risk should shift to the contractor, and contractor risk usually decreases as the requirement is repetitively acquired.

As engineering reasoning, build-to-print fits a second unit of an existing machine, a rebuild to original drawings, or a design an owner's engineering group has already taken through its own critical design review. It also fits when the buyer must keep design authority, as an OEM does when the machine is part of its own product line. UTEC Industrial machines to tolerances of ±0.001 in, has a 48 in lathe swing, and performs NDT and CMM inspection, the capabilities a build-to-print order tests directly (SD-15, 2009, pp. 3-4; NASA/SP-2016-6105 Rev2, Table 6.7-1; 48 CFR Part 16, 2021, 16.104).

What should a build-to-print package contain?​

As engineering reasoning, a build-to-print order is only as complete as the package behind it. FAR 46.706(b)(1)(ii) shows what "specifies the design" covers in the Government's own warranty guidance: the design of the end item "and its measurements, tolerances, materials, tests, or inspection requirements". ASME Y14.100-2017 establishes the essential requirements and reference documents applicable to the preparation and revision of manual or computer-generated engineering drawings and associated lists, unless tailored by a specialty standard.

As UTEC engineering practice, a build-to-print package for a custom handling machine includes:

  • released drawings and parts lists, with revision letters, to ASME Y14.100-2017 or the owner's drawing standard;
  • material specifications, including plate, bar, and casting grades and any required material test reports;
  • weld symbols and joint details, the weld procedure requirements, and the weld inspection method and acceptance criteria;
  • the stress-relief requirement for welded structures, and whether it precedes final machining;
  • tolerances on bores, fits, and datum faces, and the dimensional inspection plan;
  • electrical schematics, panel layouts, and the I/O list if the controls are part of the order;
  • the tests the builder runs before shipment, and who witnesses them.

In that practice, anything not in the package is either a question for the buyer or a design decision the builder makes. As engineering reasoning, the second case turns a build-to-print order into a partial design-build order without the contract saying so. For witnessed testing, FAR 52.209-3 has the contractor notify the contracting officer in writing of the time and location of first article tests so that the Government may witness them (48 CFR Part 46, 2021, 46.706; ASME Y14.100-2017; FAR 52.209-3, 1989).

How is verification different under each model?​

SD-15 describes the difference in the Government's verification practice. With detail specifications, verification "often relies more on examination and demonstration to ensure compliance with the 'build-to-print' requirements for specific and extensive lists of materials and parts in the end item". Since performance specifications do not require specific materials, parts, designs, and processes, "there is usually less emphasis on examination and demonstration and more emphasis on test and evaluation, simulation and modeling, and analysis", and there is usually a one-for-one correlation between requirements and verification. Because performance specifications allow different designs and approaches, SD-15 says, it is desirable to have a first article inspection or qualification provision to verify compliance with all of the specification requirements prior to production.

The NASA handbook adds who does the work. For major end products purchased from a vendor, the responsibilities of the Government and contractor team should be documented in the SEMP and Integration Plan, which will define, for example, "whether NASA expects the vendor to provide a fully verified and validated product or whether the NASA technical team will be performing those duties".

As engineering reasoning, a build-to-print order is verified against the drawings: dimensions, materials, weld inspection, and certificates. A design-build order is verified against the requirements: rated load, cycle time, positioning accuracy, and interlocks, proven by test. IEC 62381:2024 defines requirements and checklists for the FAT, FIT, SAT and SIT of automation systems in the process industry; the project lifecycle article covers where each test falls (SD-15, 2009, pp. 39-40; NASA/SP-2016-6105 Rev2, §5.1.1.2.2; IEC 62381:2024).

How should controls and sensing be split between buyer and builder?​

As engineering reasoning, the controls are one place where a build-to-print order can become a hybrid, because a drawing package can fix the steel and still leave the sequence, the interlocks, and the tuning to the builder, which fits the NASA handbook's note that implementing a product may have aspects of more than one implementation form. As engineering practice, the order states for each item below whether the buyer furnishes it or the builder designs it:

  • the risk assessment and the list of safety functions, with the required performance level of each;
  • the electrical design: schematics, panel layout, and the controller, I/O, and network;
  • the sensing: encoders, load cells, limit and position sensing, and zone interlocks with adjacent equipment;
  • the drives: VFD or servo for each axis, and their sizing basis;
  • the PLC and HMI program, and who owns and edits it after handover;
  • tuning under load, and condition monitoring once the machine is in service.

Three standards frame the split, cited at the level of scope. ISO 12100:2010 specifies principles of risk assessment and risk reduction to help designers achieve safety in the design of machinery. ISO 13849-1:2023 specifies a methodology and provides related requirements, recommendations and guidance for the design and integration of safety-related parts of control systems (SRP/CS) that perform safety functions; it applies to SRP/CS for high demand and continuous modes of operation and does not apply to low demand mode of operation. IEC 60204-1:2016 applies to electrical, electronic and programmable electronic equipment and systems to machines not portable by hand while working. As engineering reasoning, if the buyer furnishes the mechanical design and the builder designs the safety functions, the builder is the designer of that part of the machine. UTEC Industrial is a Rockwell Automation Recognized System Integrator and builds UL 508A control panels, work a buyer can assign to the builder item by item from that list (NASA/SP-2016-6105 Rev2, §5.1.1.2; ISO 12100:2010; ISO 13849-1:2023; IEC 60204-1:2016).

What should a buyer ask before choosing a builder and a model?​

The Construction Industry Institute publishes an owner's tool, IR165-2, whose page describes a procedure for selecting an integrated project delivery and contract strategy for capital projects that "is used on a project-by-project basis", with a spreadsheet-based decision support tool as its central component. It is cited here at the level of that description; it was written for capital projects, not machinery, and its use for a custom machine is engineering reasoning.

As UTEC engineering practice, the questions to settle before choosing include:

  • Who holds design authority, and who approves a deviation from the drawings or the requirements?
  • Who owns the drawings, native CAD files, and PLC programs after delivery?
  • How is a design change priced once fabrication has started?
  • Which steps does the builder perform in its own shop, and which are subcontracted, including machining, welding, stress relief, and controls?
  • Which inspection records and test reports are delivered with the machine?
  • Which quality-system standard, if any, does the order invoke?

On the last point, the federal clause FAR 52.246-11 has the contractor comply with the higher-level quality standards the contracting officer lists, and flow them down, as applicable, to subcontracts for critical and complex items, or where a subcontract's technical requirements call for control of such things as design, work operations, in-process control, testing, and inspection, or attention to such factors as organization, planning, work instructions, documentation control, and advanced metrology. An aerospace buyer can name SAE AS9100D, the quality management system requirements for aviation, space, and defense organizations, as such a standard (Construction Industry Institute, IR165-2, 2003; FAR 52.246-11, 2014; SAE AS9100D, 2016).

Where does each model sit along the design-to-monitoring chain?​

As engineering reasoning, the two models divide the chain at different points:

  • Design-build: the builder owns design, engineering, parts machining, fabrication, assembly, weld fatigue, stress relief, drives, controls, and tuning, and the buyer owns the requirements and acceptance. Monitoring is specified in the requirements.
  • Build-to-print: the buyer's package fixes design and engineering, and the builder owns execution from parts machining through assembly. Weld fatigue is settled in the buyer's joint details, stress relief in the buyer's notes, and drives, controls, and tuning in whatever the package states.
  • Hybrid: the buyer furnishes the mechanical design, and the builder designs the controls, safety functions, and tuning, or completes a partial design under the buyer's review.

In the NASA life cycle, the design-to baseline is approved at preliminary design review and the build-to baseline at critical design review. As engineering reasoning, a buyer who wants build-to-print pricing on a design-build project can hold a design phase through that review and then order the build against the approved baseline. UTEC Industrial stress-relieves welded structures, including by automated vibratory stress relief. As engineering reasoning, where that step falls relative to final machining belongs in the drawings of a build-to-print order and in the builder's plan of a design-build order (NASA/SP-2016-6105 Rev2, Table 6.7-1; SD-15, 2009, p. 3).

Related Articles

References​

  • 48 CFR Part 36: Construction and Architect-Engineer Contracts. GSA, DoD and NASA (FAR), as amended 2008.
  • Design-Build Institute of America. What Is Design-Build? (undated web documentation, accessed September 2026). DBIA, 2026.
  • Office of Federal Procurement Policy and FAR Council. Revolutionary FAR Overhaul: FAR Part Deviation Guidance. Acquisition.GOV, 2026 (web documentation, accessed September 2026).
  • SD-15: Guide for Performance Specifications. Defense Standardization Program, U.S. Department of Defense, 2009.
  • NASA. NASA Systems Engineering Handbook, NASA/SP-2016-6105 Rev2. National Aeronautics and Space Administration, 2016.
  • 48 CFR Part 11: Describing Agency Needs. GSA, DoD and NASA (FAR), as amended 2024.
  • 48 CFR Part 46: Quality Assurance. GSA, DoD and NASA (FAR), as amended 2021.
  • Supreme Court of the United States. United States v. Spearin, 248 U.S. 132 (1918).
  • FAR 52.246-19: Warranty of Systems and Equipment under Performance Specifications or Design Criteria (MAY 2001). GSA, DoD and NASA, 2001.
  • 48 CFR Part 16: Types of Contracts. GSA, DoD and NASA (FAR), as amended 2021.
  • ASME Y14.100-2017: Engineering Drawing Practices. ASME, 2017.
  • FAR 52.209-3 (SEP 1989): First Article Approval—Contractor Testing. U.S. General Services Administration, 1989.
  • IEC 62381:2024: Automation systems in the process industry — FAT, SAT, FIT and SIT. IEC, 2024 (Ed.3).
  • ISO 12100:2010: Safety of machinery — General principles for design — Risk assessment and risk reduction. ISO, 2010.
  • ISO 13849-1:2023: Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design. International Organization for Standardization, 2023.
  • IEC 60204-1:2016 (Ed. 6.0): Safety of Machinery -- Electrical Equipment of Machines -- Part 1: General Requirements. International Electrotechnical Commission, 2016.
  • Construction Industry Institute. Owner's Tool for Project Delivery and Contract Strategy Selection User's Guide, 2nd ed. (IR165-2). CII, 2003.
  • FAR 52.246-11 (DEC 2014): Higher-Level Contract Quality Requirement. U.S. General Services Administration, 2014.
  • SAE AS9100D: Quality Management Systems -- Requirements for Aviation, Space, and Defense Organizations. SAE International, 2016.

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