China & Thailand PCBA manufacturing support
Through-hole assembly production line

A planned route for leaded components

Through-Hole Assembly with Defined Fit and Soldering Access

Provide hole and lead data, insertion details and component thermal limits. Review wave, selective or manual soldering with the SMT sequence, mechanical support and inspection criteria for your board.

KeepBest company photograph

Start with lead fit and mechanical seating

Review component insertion alongside wave, selective and manual soldering. Each method needs a review of access, support and thermal requirements rather than a blanket assumption about suitability.

Project scope and review plan · Use these fields to define the requested review. Example entries are illustrative; the order confirms the accepted scope and records.

Compare columns · swipe or scroll on smaller screens

Layout or component concernClarification requiredMethod and output to review
Crowded solder sideSMT exposure, nozzle access and masking drawingAssess wave / selective suitability and the protection / support plan.
Thermal-sensitive connectorManufacturer limits, seating height and allowed exposureAssess selective / manual operation; agree first-unit seating and joint checks.
Heavy ground planeHole / lead dimensions, thermal mass and accessReview soldering approach and tooling; define the joint acceptance evidence.
Detailed engineering considerations

Through-hole components remain relevant where the design needs leaded connectors, larger devices or mechanical support through the board. KeepBest reviews THT and mixed technology assemblies using the component drawings, hole data and soldering requirements. The right route may involve wave, selective or manual soldering, depending on board access, thermal limits and the agreed build scope.

KeepBest company photograph · visible production reference

Component and hole fit

Compare finished hole dimensions, lead geometry and component tolerances before insertion. Connector height, polarity, lead forming and board seating matter to both electrical assembly and the mechanical fit of the finished product.

Compare wave, selective and manual soldering

Access, thermal limits, masking and quantity determine the suitable operation.

KeepBest company photograph · visible production reference

Wave soldering assessment

Review the solder side, exposed SMT parts, masks and support needs before selecting a wave route. Identify components or areas that must be protected, and agree the intended soldering and inspection conditions.

KeepBest company photograph · visible production reference

Selective soldering access

Assess nozzle access, nearby components and the board's thermal mass for local soldering. Keepouts and processing requirements depend on the actual layout and tooling; generic clearance values should not replace project review.

Manual and sensitive operations

Some devices, wires or low-quantity assemblies need manual operations. Define the soldering instructions, lead preparation, strain relief and inspection criteria, particularly where thermal exposure or access makes automation unsuitable.

Sequence SMT and through-hole operations

Resolve support, connector and access constraints before another operation closes them off.

Mixed technology coordination

Plan through-hole insertion and soldering alongside SMT placement and reflow. A clear sequence avoids leaving sensitive parts, restricted access or mechanical interference to be discovered after another operation has already been completed.

Inputs, decisions & outputs

From lead fit to accepted connections

  1. 01

    Review insertion requirements

    Check the fabrication and component drawings together to understand lead fit and seating. Resolve polarity, connector height and lead-forming instructions before materials and the insertion route are prepared.

  2. 02

    Assess a suitable soldering method

    Review wave, selective or manual options against board access, component restrictions and quantity. Confirm the proposed route and required supports or masks as part of the manufacturing scope.

  3. 03

    Insert and solder to the release

    Use the approved assembly drawing and process instructions for the intended component positions. Special manual tasks, wire attachments and protected areas follow the agreed requirements for the released design.

  4. 04

    Inspect the completed connections

    Review insertion, polarity, component seating and solder workmanship under the agreed criteria. Electrical or functional checks follow separately where specified, with any rework or nonconformance handled through the approved disposition process.

Your project

Prepare insertion and soldering instructions

Select the items you want to carry into the project brief.

Before release

Questions about through-hole soldering

When is through-hole assembly useful?

Leaded connectors, larger components and mechanically loaded parts can make THT relevant. The design must still address hole fit, retention and electrical requirements; through-hole mounting alone does not prove the reliability of a product.

Do all THT boards use wave soldering?

No. The layout, component temperature limits, solder-side access and quantity influence the route. Selective or manual soldering may be more suitable for particular areas or devices, subject to engineering review.

Can you assemble a board with SMT on both sides and THT parts?

Provide the complete populated-side information and THT instructions. Engineering needs to assess access, protection and thermal sequence for the mixed assembly before confirming the process and inspection plan.

Is a fixed selective-soldering clearance guaranteed?

No fixed clearance is presented as a capability here. Nozzle access, neighboring parts, supports and thermal demands vary by design. Review the actual drawings and proposed tooling with engineering.

Can component sourcing be included?

Component sourcing can be requested in the reviewed order scope. Provide manufacturer part numbers and mark consigned parts, approved alternatives and any supplier requirements so purchasing and incoming inspection responsibilities are explicit.

A planned route for leaded components

Prepare your project brief.

Tell us what you are building and what you need reviewed. Include the current revision, quantities and any open questions. The project scope and acceptance criteria are agreed from your requirements.

Review the required files →

Submit your details and files for project review. A saved reference confirms receipt; notification delivery is tracked separately.

Send a project enquiry

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    ZIP, Gerber/drill, CSV, XLSX or PDF · up to 10 files, 10 MB each, 20 MB total.
    Files are stored privately for project review.

    Get A Quote

    Fill in your requirement information and upload Gerber and BOM files, we will give you a quote within 24 hours.

    Get A quote

    Fill in your requirement information and upload Gerber and BOM files, we will give you a quote within 24 hours.