S-WS450 Wave Soldering Process Parameters: A Setup Guide for Lead-Free THT Lines

Wave soldering is the high-volume process that solders through-hole (THT) components — connectors, transformers, relays, electrolytic capacitors and terminal blocks — to a PCB after SMT placement and reflow. If you are evaluating a 450 mm-class lead-free wave soldering machine for an EMS, ODM, automotive electronics, medical electronics or industrial control line, the machine model matters less than how its process parameters are set up. This guide explains the S-WS450 wave soldering machine from Southern Machinery (founded 2011 in Shenzhen, serving 237+ customers worldwide) through the parameters that determine solder joint quality: flux, preheat, conveyor speed and angle, and solder pot temperature. All specifications cited here are taken from the official product page at smthelp.com.

What is this machine used for?

The S-WS450 is a full-size, inline, lead-free wave soldering machine used to solder THT and DIP components onto PCBs up to 450 mm wide. A board enters on the conveyor, gets spray flux on its underside, is preheated in four zones, crosses one or two solder waves where molten solder wets the leads and pads, and exits to the next station (lead cutter, cleaning, or AOI). It is the soldering bridge between THT auto insertion upstream and post-solder processes downstream.

Two points matter when matching the machine to the job:

• Board size. The conveyor accepts boards from a minimum PCB size of 80 x 60 mm up to 450 mm width — large enough for industrial power supplies, LED drivers, appliance control boards and automotive modules.
• Dual-wave capability. In a dual-wave (turbulent + smooth) configuration, the first wave fills SMD pads and dense lead areas while the second, laminar wave finishes the through-hole joints. This is the standard configuration for mixed SMT/THT boards and lead-free alloys. Confirm the dual-wave layout with the supplier for your specific board mix.

Wave Soldering Process Parameters That Decide Joint Quality

The S-WS450 is controlled by a PLC + computer system, which means every process parameter below is programmable and repeatable — the real advantage of automation over manual soldering. The parameters work as a system; changing one usually requires re-balancing the others.

Flux: spray pressure and flow rate

Flux removes oxides and promotes wetting. The S-WS450 uses a spray fluxing system with adjustable spray pressure of 0.25–0.4 MPa and a flux flow of 10–100 ml/min. In process terms:

• Too little flux causes poor wetting, incomplete hole fill and icicles.
• Too much flux leaves residues that can attract contamination or require post-solder cleaning.
• Spray pressure and flow interact with conveyor speed: a faster line needs enough flux volume per board, which is why both parameters are adjustable rather than fixed.

Preheat: four zones with PID + SSR control

The S-WS450 provides 4 preheating zones over a total preheating length of 1800 mm, with PID + SSR temperature control from room temperature to 250 °C. IR tube heating is standard; hot air is available as an option. Preheating has three jobs: activate the flux, dry solvents, and raise board temperature gradually to reduce thermal shock when the board meets the wave. Warm-up time to a 150 °C setpoint is approximately 15 minutes.

For process engineers, the 1800 mm length matters because it defines how much time a board spends in preheat at a given conveyor speed — the practical lever for controlling ramp rate and top-side board temperature before the wave.

Conveyor speed and board angle

Conveyor speed is adjustable from 0 to 2000 mm/min, and the conveyor angle is adjustable between 4 and 7 degrees. The angle creates the peel-back effect that separates the board from the wave cleanly, reducing bridging and solder buildup. Conveyor height is 750 ± 50 mm so the machine can be aligned to the rest of the line, and width control is manual (a point to note for frequent width changes between jobs).

The combination of speed and angle sets contact time with the solder wave. Contact time that is too short leaves incomplete fill on thick multilayer boards; too long can wash solder away or overheat the board. There is no universal "correct" number — it depends on board thickness, copper weight, component thermal mass and alloy. This is why a machine with continuous speed adjustment and an angle range is preferable to a fixed-speed design.

Solder pot temperature and alloy

The solder pot is mechanical-motor-driven and made of full titanium as standard, with a lead-free capacity of approximately 450 kg. Pot temperature is controlled at up to 350 °C with a control precision of ±1–2 °C. Titanium construction matters for lead-free production because lead-free alloys (SAC family and others) are more aggressive to steel pots and require stable temperature control to avoid dross and inconsistent joints.

A ±1–2 °C control band around the setpoint is what keeps joint quality consistent across a full shift; larger swings produce dull joints, icicles and variable hole fill.

Conveyor fingers and PCB support

The S-WS450 transports boards on double-hook claw fingers (standard), with a brush-type finger cleaning system. Fingers hold the board edges through flux, preheat and the wave. Two setup points to verify with the supplier: finger pitch vs. your board edge clearance (components near the board edge can collide with fingers), and whether heavy boards or pallets need additional support tooling.

Verified S-WS450 Parameters at a Glance

System	Parameter	Value (official product page)
Machine	Model / dimensions	S-WS450A / L4500 x W1400 x H1650 mm, approx. 1500 kg
Power	Supply / operating consumption	3P5W, 380/220 V 50 Hz / approx. 10 kW
Control	System	PLC + computer
PCB	Size (L x W)	Min 80 x 60 mm; max width 50–450 mm
Conveyor	Speed / height / angle	0–2000 mm/min / 750 ± 50 mm / 4–7 degrees
Conveyor	Width control / fingers	Manual / double-hook claw (standard)
Flux	Spray pressure / flow	0.25–0.4 MPa / 10–100 ml/min
Preheat	Zones / length / control	4 zones / 1800 mm / PID + SSR
Preheat	Temperature range / warm-up	Room temp to 250 °C / approx. 15 min at 150 °C
Solder pot	Material / drive	Full titanium (standard) / mechanical motor
Solder pot	Temperature / capacity	Up to 350 °C, ±1–2 °C / lead-free approx. 450 kg
Exhaust	Duct diameter / capacity	Φ200 mm / 25 m³/min

Typical Application Scenarios

The S-WS450 suits factories that solder leaded components in volume on medium-to-wide boards:

• Power supply and energy-saving lighting — LED drivers, ballasts, street-lamp and floodlight power boards with large electrolytic capacitors, transformers and heat-sensitive layouts.
• Electrical appliances — air conditioner, TV, microwave, electric kettle and induction cooker control boards with a mix of SMD and THT components.
• Automotive and vehicle electronics — car audio, vehicle power supply and control modules where joint repeatability and traceability are required.
• Industrial control and instrumentation — PLC/relay boards, meters and general electronics with connectors and terminal blocks.
• EMS/ODM high-mix lines — when THT auto insertion (radial, axial or odd-form) already feeds the line and soldering must keep pace without manual touch-up.

How the S-WS450 Fits Into a Complete PCB Assembly Line

The S-WS450 is not a standalone tool; it is one station in a full PCB assembly flow:

1. Incoming — PCB loader and board handling conveyors feed the line.
2. SMT side — solder paste printing, Pick and Place, Reflow Oven (for the SMD portion of the board).
3. THT side — radial/axial/odd-form auto insertion machines place leaded components.
4. Wave soldering — the S-WS450 solders all THT joints in one pass.
5. Post-solder — auto lead cutting, PCBA cleaning if required, and AOI/AVI inspection.
6. Outgoing — unloader or magazine stacker.

Because the S-WS450 runs inline with SMEMA-style board handling, it can be linked to loader/unloader conveyors and other stations. When sizing the line, plan for the machine footprint (L4500 x W1400 x H1650 mm), the 3P5W 380/220 V 50 Hz supply, and the exhaust ducting (Φ200 mm, 25 m³/min) — these are the installation facts a factory layout team must confirm before quoting.

Southern Machinery supplies SMT, THT, wave soldering, board handling and inspection equipment as individual machines or as complete lines, which simplifies the integration question: one supplier can match conveyor heights, speeds and control interfaces across the line.

Key Selection Parameters to Confirm With Southern Machinery

Do not rely on a brochure alone. Before configuration, prepare these facts so the supplier can recommend the correct S-WS450 variant and line layout:

• Board dimensions — maximum width, minimum size, board thickness and edge clearance for conveyor fingers.
• Component mix — pure THT or mixed SMT/THT (dual-wave requirement), heaviest component, tallest component height.
• Solder alloy and flux — lead-free SAC305/SnCu or tin-lead; no-clean, water-soluble or rosin flux; whether post-solder cleaning is planned.
• Throughput target — boards per shift and conveyor speed range needed for your takt time.
• Facility constraints — available power (3P5W, 380/220 V 50 Hz), floor space, exhaust capacity (Φ200 mm duct, 25 m³/min) and conveyor height alignment (750 ± 50 mm).
• Pallet/fixture strategy — whether boards run bare or on wave-soldering pallets, and finger-cleaning needs for flux buildup.
• Special process requirements — nitrogen wave soldering if your quality targets demand it (Southern Machinery's wave soldering family includes nitrogen-capable platforms; confirm the option that fits your alloy and board type).

ROI, Quality, and Throughput Considerations

The economic case for an automated wave soldering machine is built on repeatability and throughput, not on a single headline number:

• Quality. A programmed process removes the operator-to-operator variation of hand soldering. The same flux, preheat and wave parameters produce the same joint every board, which reduces rework and field failures — the expensive end of quality cost.
• Throughput. Conveyorized soldering at 0–2000 mm/min keeps pace with auto insertion machines. Manual soldering becomes the bottleneck the moment a THT line has more than a few hundred insertions per board.
• Energy and footprint. At approximately 10 kW operating consumption with an integrated 1800 mm preheat section, the S-WS450 concentrates the whole soldering process in a single inline station rather than multiple benches.
• Payback inputs. For a realistic ROI model, compare current manual soldering labor, defect and rework rates against the machine price, installation (power, exhaust), alloy/flux consumption and maintenance. Ask Southern Machinery for a configuration and payback discussion based on your board mix — they will not give you a meaningful number without your real data.

Frequently Asked Questions

What is the S-WS450 wave soldering machine used for?
It solders through-hole components — connectors, transformers, relays, electrolytic capacitors and terminal blocks — onto PCBs up to 450 mm wide in a conveyorized lead-free process, after SMT placement and THT auto insertion.

What PCB sizes can the S-WS450 handle?
The conveyor accepts boards from a minimum of 80 x 60 mm up to 450 mm width. Conveyor width is adjusted manually.

Is the S-WS450 suitable for lead-free soldering?
Yes. It ships with a full-titanium solder pot (standard) with approximately 450 kg lead-free capacity, controllable up to 350 °C with ±1–2 °C precision.

What preheating does the S-WS450 have?
Four preheating zones over 1800 mm with PID + SSR control, heating from room temperature to 250 °C. IR tube heating is standard; hot air is an option.

What conveyor speed and angle does the S-WS450 support?
Speed is adjustable from 0 to 2000 mm/min and conveyor angle from 4 to 7 degrees, with conveyor height at 750 ± 50 mm for line alignment.

How do I choose between wave soldering and selective soldering?
Wave soldering is the right choice for high-volume boards where most THT joints can tolerate full-board contact. For high-mix, low-volume boards or assemblies with heat-sensitive or clearance-critical areas, Southern Machinery also offers selective soldering platforms — describe your board mix and they will recommend the process.

Get Configuration Advice from Southern Machinery

Southern Machinery was founded in 2011 in Shenzhen, China, and has served 237+ customers worldwide with SMT/THT PCB assembly automation equipment, including complete SMT, THT, wave soldering, board handling and inspection line solutions backed by spare parts, training and retrofit services.

• Request a configuration recommendation: contact Southern Machinery with your PCB dimensions, component mix, alloy and target throughput — email Jason Wu at jasonwu@smthelp.com, call/WhatsApp +86 13602562576, or use the inquiry form at https://www.smthelp.com.
• Download product catalogs and PDF datasheets: visit the file portal at https://file.autoinsertion.com.
• See real machine photos: browse the product photo album at https://ph.smthelp.com.
• Watch the machine in operation: the S-WS450 overview video (https://www.youtube.com/watch?v=dEeBOEpMoec) shows the machine running on the Southern Machinery YouTube channel.