1.4 Wave Solder Setup

Wave soldering is the original mass production technique, and its effectiveness is determined by the harmonious, disciplined alignment of four critical mechanical and thermal steps. This chapter details the non-negotiable setup parameters—from setting the conveyor angle for optimal drainage to balancing the turbulent chip wave with the smooth main wave—that ensures every single THT joint achieves a uniform, clean fillet without creating bridges or icicles.

1.4.1 What the Wave Must Achieve

Wave soldering is the original mass soldering process,process. and itsIts reliability depends on everysequential, stagerepeatable doingprocess its job in sequence.control. The fluxerwave's functional goal is simple: to achieve a complete, high-quality fillet on every THT joint with a clean, dripless exit.

Wave Process Flow

1. Preparation: Fingers and preheaterrails sethold the conditions,PCB at a fixed conveyor angle and speed.
2. Fluxing and Preheat (Chapter 1.2): Chemically clean the chipboard and bring the top-side temperature into the required range.
3. Chip Wave (Turbulence): The first wave scrubs solder into tight gaps,pin-to-pin the main wave builds clean fillets,gaps and theplated peel-off trims the joint without disturbance. When conveyor angle, wave height, and dwell times are tuned to the board’s mass, the flow looks more like a calm river than chaotic whitewater.

   1.4.1 What the wave must dothrough-holes (in factory words)

   • Carry fluxed copper into clean solder,PTHs).
   • WetMain everyWave barrel(Laminar): The second wave forms the final, smooth fillet and leadcontrols the peel-off,.
   • Leave quietlyExit:—no bridges, no icicles, no burns.
      Everything you set—fingers/rails,Peel-off flux & preheat, chip wave → main wave, peel-off/air knives, palletsbars—either helps that quiet exit or fightsair it.knives trim excess solder, preventing
     bridges and icicles.

   
   

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1.4.2 TheEssential hardwareHardware piecesComponents

(know

Understanding yourthe actors)mechanical actors is key to tuning the process.

• Conveyor &and fingersFingers:: titanium/Titanium or stainless fingers holdtransport the panelboard (or pallet) at a fixed anglespeed and speed. Finger health = surface quality.
• Fluxerangle: foam or spray (see 13.2). FluxCleanliness coverageis +paramount; preheatdirty makesfingers lead to poor wetting and solder wicking along the waveboard predictable.
• Preheaters: IR/hot air zones raise top-side into the right band before solder.edge.
• Chip Wave (Turbulent): A high-energy wave (turbulent): scrubs between tight leads,that pushes solder upstream into holes.challenging gaps. Necessary for achieving barrel fill and clearing small bridges in the middle of pin rows.
• Main/Lambda waveWave (laminar)Laminar):: smoothA “sheet”smooth, continuous flow that finishesprovides filletsthe final, controlled contact to finish the fillet and givesensure thea clean peeldrainage.
• Peel control: mechanical peel-off bar, air knife, or nitrogen knife breaks the solder film onupon exit.
• Pallets (Fixtures): (composite):Custom composite fixtures that expose only THT windows;windows protectwhile shielding surrounding SMT andcomponents maskfrom solder splash.

Think: turbulence to enter, laminar to leave.

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1.4.3 Starter Settings and Profiling

Wave profile settings (tunemust frombe here)adjusted based on the alloy and the board's thermal mass.

Parameter	Lead-freeFree (SAC)	SnPb	Notes
Pot tempTemperature	260–260 – 275 °C	245–245 – 255 °C	GoHigher hottertemperatures increase dross formation; only raise if designwetting demands—fixis prep firstpoor.
Conveyor angleAngle	6–6 – 8°	6–6 – 8°	Helps gravity assist in drainage and peel;peel-off tooupon exit. Too flat →promotes bridgesbridging.
Contact timeTime (totalTotal in solder)Dwell)	2.0–0 – 4.0 sseconds	1.5–5 – 3.0 sseconds	Thicker/heavierTime =in contact with solder; longer
Chip wave dwell for thick boards	or 0.5–1.5heavy scopper	0.5–1.0 s	Enough scrub; don’t overcook
Main wave dwell	1.0–2.5 s	1.0–2.0 s	Where fillets are finished.
Wave heightHeight	1–1 – 2 mm rise above board	1 – 2 mm rise above board	same	JustShould kissjust "kiss" the bottom;bottom floodingsurface; splashesexcessive height leads to uncontrolled splash.
Top-sideSide tempTemp at entryEntry	110–110 – 140 °C (VOC-Lead-free)	100 /– 90–120130 °C (alcohol)Lead)	Must meet the minimum 100–130flux °Cactivation temperature	See 12.2(Chapter for flux-specific bands1.2).

Orientation: PutBoards must be positioned so fine-pitchlong & densepin rows leadingare intoperpendicular to the chip wave firstdirection where possible. Parallel rows create channels that trap solder, inviting bridging.

1.4.4 Peel Control: The Quiet Exit

The (soprimary function of the scrubexit doesarea itsis job)to cleanly separate the board from the molten solder, minimizing solder tails and long rows exit lasticicles (so peel is clean).

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1.4.4 Fingers, rails & support (bridges start here)

• Finger spacing: close enough to keep panels flat; add center support pins for thin or heavy-copper panels.
• Cleanliness: brown, sticky fingers → solder won’t wet uniformly under them. Wipe and run finger-cleaner coupons as scheduled.
• Edge clearance: leave ≥ 3–4 mm from copper to conveyor finger path; avoid solder wicking along copper right to the finger.
• Lubrication: use approved high-temp minimal films if required; over-lube = flux contamination.

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1.4.5 Peelers, air knives & the quiet exit

• Peel-offOff barBar:: smallA stationary bar (often titanium) set just downstream of the main wavewave. thatIt lightlycreates wipes/deflectsa controlled point of contact to mechanically deflect and break the solder filmfilm. asSet the board exits.
• • Set height to justlightly touchwipe the freshfreshly formed fillet meniscus; too high = gouges, too low = useless.meniscus.
• Air/N₂Nitrogen knifeKnife:: A narrow jet blowing along the direction of travel rightimmediately after the main wave.
• • Low, evenThis flowuses trimsgas icicles;pressure tooto muchgently createstrim ripplesicicles. → bridges.
• Timing: a brief dwell after the main wave before the knife lets fillets finish; then a short, sharp assist.

Use the smallest intervention that givesachieves a clean peel—don’tpeel; sandblastexcessive yourair joints.flow creates ripples that can cause bridges.

Timing:

A

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small

pause

(1.4.6dwell) Chipafter vsthe main wave (howallows theythe workfillet together)to stabilize before the air knife applies pressure.

1.4.5 Maintenance and Consistency

Wave soldering rewards routine maintenance. Process consistency depends on the physical health of the machine and the purity of the solder.

• ChipDross wave:Management: high-energy,Dross small(oxidized crestsolder) throwsmust be skimmed on a scheduled basis. Excessive dross interferes with pump stability and contaminates the working alloy.
• Solder Level: Keep the solder pot level precisely in spec. A low solder level fakes a upstreamshort wave height, leading to non-fills.
• Flux System Cleanliness: intoRegularly gapsclean spray heads or foam stones and holes—greatlog for 0.8–2.0 mm pitches, DIP rows, and uneven masses.
   Main wave: smooth sheet that levels and drains.

  Tuning sequence

  1. Provethe flux & preheatdensity (13.2).
  2. Sete.g., chipspecific wavegravity heightor & dwell until bridges between fine pins disappear.
  3. Set main wave height & dwell until exit icicles disappear and fillets look even.
  4. Add peel-off/knife only if small tails persist.

  If you try to make the main wave do chip wave’s job, you’ll crank it too high and invite splash/bridges.

  
  

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  1.4.7 Pallet aperture tricks (cheap geometry, big wins)

  • Dams: leave 2.5–3.0 mm mask/pallet land around openings—seals stop leaks and wave undercut.
  • Directional windows: taper the entry edge slightly (ramp) so solder meets copper gently; keep exit edge sharp°Bé) to encourageensure peel.consistent chemical activity.
  • LabyrinthsFinger Health:: forConveyor tight,fingers parallelmust rows,be addregularly acleaned to prevent flux residue and solder build-up, which causes narrowsolder throatwicking at entry and a wider exit—reduces local turbulence but lets solder drain.
  • Built-in thieves: a tiny downstream island after fine-pitch rows pulls bridges offalong the lastPCB pin.edge.
  • Step-downs: thinning pallet locally around hungry pins lets them see a bit more wave height without flooding neighbors.
  • Titanium fences/inserts: drop-in guards near tall SMT as a reversible trial before you cut a new pallet.
    

  
  

  Final

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  Checklist:

  
  

  Wave

  1.4.8Solder FastSetup symptom → small fix (don’t turn five knobs)📝

  SymptomParameter	FirstOptimization moveMandate	IfDefect stillPrevention there…Focus
  BridgingConveyor in fine rowsProfile	Angle 6 – 8°Raise; speed set to meet chip2.0 wave– 4.0 seconds 0.2–0.5total mmcontact or dwell +0.3 stime.	IncreaseControls conveyordrainage angleand 1–2°;prevents addlarge thief / pallet throaticicles.
  BridgingThermal at exitPrep	AddTop-side peel-offtemperature contactconfirmed orin lightflux activation range (air/N₂110 – 140 °C knifefor lead-free).	LowerPrevents solder balls (due to solvent flash-boil) and non-fills.
  Wave Dynamics	Chip wave set to maximize scrub; main wave 0.2–0.5set mm;for shortenlaminar mainexit.	Prevents dwellbridging in fine-pitch rows and ensures fillet quality.
  Icicles/spearsPeel Control	Peel-off barSlightly or fasterair exitknife +set small knife	+5 °C pot;to trim dwell;tails checkwithout leadcreating protrusion (12.1)
  Poor top-side fill	Verify flux & top-side temp; slow belt (longer contact)ripples.	RaiseEliminates chipicicles waveand orbridging potat +5the °C;trailing second pass on stubborn rowsedge.
  Solder balls/spittingHealth	MorePot temperature in spec; preheatdross dryskimmed; solder level (not hotter last zone)maintained.	LowerEnsures chipconsistent wavewetting aand touch;alloy confirm flux dose uniform
  Dull joints/de-wet	+5 °C pot or +0.3 s main dwell	Check finish age/oxidation; consider N₂ over waves
  Shadow non-fill (under shields)	Angle board to wave; add micro flux access or second attack	Pallet step-down or partial re-route so wave sees the pinspurity.

  Always re-check flux UV pattern and top-side temp before you crank pot temperature.

  
  

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  1.4.9 First-article setup (10–15 minutes that saves a day)

  1. Flux proof: UV or weight coupon—coverage even on exposed THT windows.
  2. Preheat profile: TCs near the densest THT; hit your top-side band.
  3. Waves idle: set chip and main to starter heights; verify angle and conveyor speed.
  4. Single pass: run one panel; watch contact lines and peel.
  5. Inspect: bridges, icicles, top-side fill at the worst rows.
  6. Adjust one knob: chip dwell/height → main dwell/height → peel/knife.
  7. Lock recipe with a comment (“chip +0.3 s dwell; main −0.2 mm; knife 10%”).

  Take two clear photos (before/after) of the same row—add to the Golden Recipe.

  
  

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  1.4.10 Maintenance & health (waves go bad slowly)

  • Dross & level: skim on schedule; keep solder level in spec—low level fakes a short wave.
  • Pumps/impellers: worn pumps pulse → random bridges; listen/feel each start of shift.
  • Nozzles: nicks change flow; dress or replace.
  • Heaters & sensors: calibrate; a lying thermocouple drives “mystery” defects.
  • Flux system: clean spray heads/foam stones; log °Bé / acid number; keep lids closed.
  • Finger cleaner: run a cleaner coupon; wipe rails; grime = de-wet lines.
    

  
  

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  1.4.11 Pocket checklists

  Setup (per product)

  • Flux pattern even; dose logged
  • Top-side temp at entry in band (per flux)
  • Angle 6–8°; conveyor speed to meet 2–4 s contact
  • Chip wave height/dwell set; main wave set; waves centered to pallet windows
  • Peel-off/knife off (start clean), enable only if needed

  First article

  • No bridges after chip tuning; clean peel after main
  • Top-side fill on test header/critical holes
  • Photos saved; recipe rev + notes updated

  If defects rise mid-run

  • Re-check flux & preheat before touching pot
  • Change one of: chip dwell/height, main dwell/height, peel/knife
  • Record change; verify on next panel

  Daily care

  • Skim dross; verify solder level
  • Inspect nozzles & pumps; finger path clean
  • Flux °Bé/acid number within band; spray pattern verified
    

  
  

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  With disciplined setup and small, targeted adjustments, wave soldering delivers uniform joints without splatter or rework. The process rewards consistency: clean hardware, measured tweaks, and pallets that guide the solder stream make every pass stable and repeatable.