PCB Assembly / Through-Hole Assembly

PCBSync · Assembly engineering & project planning

Through-Hole Assembly: Plan the Insertion, Soldering and Inspection Route

Prepare a through-hole assembly request for leaded components, connectors and mixed-technology boards. Define the mechanical fit, soldering access and inspection requirements so PCBSync can review the appropriate build route.

Explore tools & budget Request a reviewed quote

Prototype through production · scope and schedule confirmed after file review

Populated control board with numerous wire-to-board connectors and mixed component sizes.

At a glance: Through-hole assembly places component leads into board holes and joins them using an appropriate soldering process; the route depends on layout, components, thermal demand and production scope.

Prepare a clearer project request

Through-Hole Assembly tools

Through-Hole Assembly workbench

PCBSync Engineering Tools · no account required · calculations run in your browser

Reference assembly processing and stencil costs only. Route-specific fixtures, press-fit tooling, process development and special inspection require a reviewed quotation.

PCBSync engineering tools

PCB assembly & stencil quote planner

Configure the build. See the scope behind the budget.

REFERENCE BUDGET · USD

Bare PCB planner →

Assembly processing + stencil

Choose a supply arrangement. Component procurement and PCB fabrication are reviewed separately from this processing budget.

How this reference budget works

The planner uses the existing PCBSync assembly processing model. Its stencil allowance is USD 35 for a one-side set or USD 60 for a both-side set, multiplied by the number of sets. These are uncalibrated planning allowances, not published selling prices. Frame size, apertures, coating and custom construction require review. Assembly quantity means individual boards, not panels.

The displayed ±12% spread is illustrative, not a validated accuracy claim. Special requirements are listed separately and do not silently enter the total. Turnkey selection does not price your BOM. A final quotation requires engineering review of the actual files and material availability.

Valid planner settings can be retained in this browser tab for up to two hours; assembly and fabrication planners share the board quantity. Contact details and uploaded design files are not stored by this planner.

Match the scope to the decision

Through-Hole Assembly: requirements that change the build

Decision / stage	What to define	Evidence or next action
Fit	Lead geometry, finished holes and thickness	Component drawing and fabrication tolerance
Route	Wave, selective or manual processing	Access, thermal demand and assembly sequence
Release	Orientation, solder joints and function	Agreed inspection and test requirements

Practical engineering and purchasing guidance

Plan the work before releasing the files

Start with the lead and finished-hole relationship

Provide the exact component part number, recommended footprint, lead geometry and finished-hole specification. Include tolerances and the board thickness relevant to insertion and soldering in the bare-board manufacturing specification.

Nominal drill size alone is insufficient for a plated hole. Distinguish the finished opening from the fabrication drill and identify non-plated mechanical holes separately from electrically connected solder joints.

Choose a route around the actual assembly

Wave, selective and manual soldering are different ways to process through-hole joints. Mixed boards also require attention to previously mounted surface-mount components and the order of operations.

State whether the design has bottom-side components, high thermal mass connections, inaccessible joints or heat-sensitive parts. These details influence equipment access, protection, fixtures and process-development work.

Control insertion and acceptance

Document orientation, seating, lead forming and any retention hardware. Define inspection against the applicable customer requirements and agreed workmanship criteria instead of assuming one numerical hole-fill rule fits every build.

For repeat production, identify the controlled program or work instruction, fixture revision and required records in the contract manufacturing brief. Use the readiness tool to list open requirements and request a quotation that distinguishes processing, tooling and special test costs.

Keep the review concrete

Include these requirements in your enquiry

Lead and finished-hole dimensions are defined

Component orientation and seating are shown

Bottom-side access and nearby components are reviewed

Heat-sensitive and high-mass joints are identified

Soldering and inspection requirements are specified

Fixtures and supplied-material responsibilities are assigned

Mark unresolved items explicitly. Ask the quotation to identify proposed exceptions, required customer approvals and any inspection or special-process charges that remain open.

See the physical construction

Assembly examples from the PCBSync media library

These physical examples highlight component density, access, interconnects and handling details. Identify the features relevant to your design so the engineering review can focus on your actual build requirements.

Complex motherboard assembly showing large packages, expansion connectors and mixed-height components.

Selective soldering equipment shown in the PCBSync media library.

Browse the supporting pages

Through-Hole Assembly guide library

Find a guide in this series

13 supporting guides

Mixed PCB Assembly SMT vs THT Assembly Through Hole vs SMD SMD vs Through-Hole Components Press-Fit Assembly PCB Press-Fit Connector Assembly Selective Soldering Selective Soldering Process Selective Wave Soldering Pin-in-Paste Assembly Wave Soldering Wave Solder Pallet Design Hand Soldering

Answers before requesting a quote

Through-Hole Assembly FAQ

Can through-hole and SMT components share a board?

Yes. Include the mixed-technology route in your PCB assembly request; the assembly needs a reviewed sequence and protection for parts already fitted.

Which soldering route should I request?

Provide the files and constraints, then ask for the proposed route and exceptions. The appropriate choice depends on the actual design and production scope.

Technical links checked 2 October 2026. Apply the current documentation and project-specific acceptance requirements. Planners do not certify manufacturability or validate uploaded design files.

From planning to a reviewed quotation

Discuss your Through-Hole Assembly requirements

Send the scope you want reviewed

Add a project brief or reference budget from the tools above. Include your assembly revision, requested quantity, required timing and open engineering questions.

For a quotation, prepare the fabrication files, BOM and placement data, plus the drawing and any test or programming instructions relevant to the work. Need an NDA or a specific file-transfer route? Contact us before sharing files.

Email: [email protected]
Phone: +86-755-23203480

Review the message and attachments before sending. An enquiry does not place an order.

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Through-Hole Assembly: Plan the Insertion, Soldering and Inspection Route