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What is Turnkey PCB Assembly Service ?

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Turnkey PCB Assembly

Turnkey PCB assembly refers to outsourced manufacturing services where the PCB fabricator or assembly contractor provides complete end-to-end production of printed circuit boards. This differs from just bare PCB fabrication or loose component placement, which still requires significant time and effort from the customer.

A reliable turnkey service handles all aspects of assembly from component procurement to post-production support. The PCBs are delivered to the customer fully assembled, programmed, and tested – ready to be integrated into products. Turnkey assembly allows OEMs to shorten development cycles and achieve faster time-to-market for new electronics.

This article provides an in-depth understanding of turnkey PCB assembly services, benefits, key factors impacting reliability, and tips for selecting the right turnkey partner.

What is Turnkey PCB Assembly?

PCB Assembly Control Board

Turnkey PCB assembly provides a seamless solution covering these stages:

Design Support

  • DFM analysis – Design for Manufacturability inputs to optimize assembly and efficiency.
  • BOM review – Ensure part selections meet cost, availability, and lifecycle needs.
  • Fabrication liaison – Smoothen handoff from PCB layout to fabrication.

Supply Chain Management

  • Procurement – Sourcing and purchasing required components and bills of materials.
  • Vendor management – Coordinating with suppliers and tracking orders.
  • Inventory – Maintaining optimum inventory levels for production needs.

SMT Assembly

  • Solder paste printing – Precisely deposit solder paste on pads.
  • Pick and placeHigh speed component mounting using surface mount technologies.
  • Reflow soldering – Solder paste reflow in ovens to permanently bond components.
  • Inspection – Automated optical inspection (AOI) to check assembly quality.

Post SMT Assembly

  • Conformal coating – Protect PCBs from environmental damage.
  • Press-fit connectors – Press-fit board edge connectors.
  • Box build – Enclosure integration and wiring.
  • End-of-line testing – validate assembly quality and functionality.

Programming and Functional Test

  • ICT test – In-circuit test to verify shorts, opens, values.
  • Boundary scan – Detect defects in BGA assemblies.
  • Firmware loading – Program firmware like power-on self tests.
  • Functional test – Exercise system functions based on test specifications.

Post Production Support

  • Repair and rework – Correcting component or design issues.
  • Upgrades – Component replacements, firmware updates, enhancements.
  • Warranty – Managing returns and replacing defective units.
  • End-of-life – Redesigns, replacements for obsolete parts.

The comprehensive scope reduces the workload on internal engineering teams and accelerates new product introductions.

Benefits of Turnkey PCB Assembly


OEMs stand to gain the following advantages from partnering with turnkey assembly service providers:

  • Faster time-to-market – Eliminates delays in finding suppliers, procurement, assembly learning curves, etc.
  • Improved quality – Leverage assembly house process capabilities, expertise, certifications.
  • Lower costs – Specialized assemblers enjoy economies of scale.
  • Focus on core competencies – Redirect internal resources to design, engineering, and software.
  • On-demand flexibility – Ability to scale production up or down rapidly.
  • One-stop service – Simpler to manage single supplier instead of multi-vendor coordination.
  • Proactive support – Assistance with design, component engineering, obsolescence mitigation.

Key Factors Impacting Reliability

Reliability is a key benchmark of any turnkey assembly service. Below are some important factors that contribute to consistent, defect-free assembly quality:

Stringent Quality Processes

  • ISO certified facilities – Assembly houses that are ISO 9001 and ISO 13485 certified have established quality systems.
  • Automation – Automated optical inspection, solder paste inspection, and pick-and-place reduce human errors.
  • Process control – Statistical process control, defect tracking, root cause analysis ensure continuous improvements.
  • ESD control – Use of wrist straps, heel straps, ESD-safe tables prevent static discharge damage.
  • Cleanliness – Assembly done in cleanrooms along with cleaning processes prevent contamination.
  • Traceability – Part serialization, date stamping allows tracking of each component.
  • Testing – Comprehensive testing protocols – ICT, boundary scan, burn-in, HASS/HALT provide reliability screening.

State of the Art Equipment

  • SMT assembly lines – High accuracy, multi-head chip shooters, and advanced soldering processes ensure repeatable quality.
  • Inspection – Automated optical, x-ray provide superior inspection over visual checks.
  • Testers – Investment in test fixtures, boundary scan provide thorough fault coverage.
  • Materials – Use of proven solder masks, solder pastes, fluxes, underfills chosen for reliability.
  • Handling – ESD-safe hand tools, boards, packaging materials prevent static and physical damage.

Skilled Engineering Team

through-hole assembly process
  • Certified engineers – IPC certification for soldering, inspection, repair indicates thorough training.
  • Experienced technicians – Repair and rework specialists that can quickly diagnose and fix issues.
  • Subject matter expertise – Extensive component level knowledge to make smart substitutions.
  • Domain capabilities – Specialized know-how in assembly standards for automotive, medical, industrial applications.

Responsible Supply Chain Practices

  • Qualified suppliers – Suppliers are carefully selected and regularly audited.
  • Traceability – Reel-to-reel traceability in inventory and WIP ensures quality parts are used.
  • Counterfeit avoidance – Procured parts are independently validated and tested.
  • Continuity planning – Backup sources, die banks for at-risk components prevent shortages.
  • Lifecycle management – Monitor end-of-life notices and make last time buys appropriately.


Reliable turnkey PCB assembly enables OEM engineers to minimize time spent on manufacturing coordination and focus innovation efforts on product features and software. Careful selection of the right assembly partner and collaborative engagement early in the design process ensures high-quality, defect-free board assemblies delivered on schedule. Investing in the upfront DFM review and testing validation stages of turnkey assembly improves time-to-market and reduces costs associated with field failures. Ultimately, turnkey assembly allows brands to gain competitive advantages through well-built, durable, and cutting edge electronic products.


What are the key factors to look for in a turnkey PCB assembly provider?

Some key factors to evaluate in a turnkey PCB assembly provider include: technical capabilities matching your product needs, certifications such as ISO and IPC Class 3, proven track record with years in business and customer testimonials, global footprint for supply chain resilience, customer focus with design support and transparency, and financial stability.

What cost savings can be expected from turnkey vs in-house assembly?

Turnkey assembly is estimated to save around 30-50% in costs compared to in-house assembly. Savings result from economies of scale in procurement, optimized SMT lines, avoiding capital investments, and leveraging assembly expertise.

How can turnkey assembly reduce time-to-market for new products?

By eliminating assembly process development, supply chain selection, purchasing, and staffing requirements, turnkey assembly can cut weeks to months off new product launch times. The capabilities are ready on day one versus taking months to set up in-house.

What level of quality can be expected from turnkey vs in-house assembly?

Specialist turnkey assemblers often exceed in-house quality levels by utilizing the latest automated inspection equipment, statistical process control, certified operators, and reliability testing capabilities that are cost-prohibitive for smaller OEMs. Their institutional expertise also results in repeatable processes.

Does the OEM have less control or visibility with outsourced turnkey assembly?

No, a turnkey partner should provide complete transparency and embed the OEM’s engineers into every process step including reviews of component selection, inspection protocols, quality procedures, reliability tests and failure analysis. This close collaboration ensures OEM expectations are met.