SC9200 Automatic Coating Machine by Southern Machinery: Selective Conformal Coating for SMT and THT Lines

Conformal coating is what keeps a finished PCBA alive in the field — against humidity, condensation, dust, chemical fumes and salt spray. But the way you apply the coating decides whether that protection is real or cosmetic. Manual brushing depends on the operator's hand speed, on masking tape applied by hand, and on an eyeball estimate of film thickness. Full immersion coats everything, including the connectors, switches and test points you specifically need to keep clean.

The SC9200 automatic coating machine from Southern Machinery takes the third route: selective coating. It is a computer-controlled, conveyor-based coating machine that sprays conformal coating only where the process drawing calls for it — using a stabilised spray head, servo-driven X, Y and Z axes and a UV detection light source built into the platform.

This guide explains what the SC9200 is used for, where it belongs in an SMT/THT production line, the verified specifications from the official Southern Machinery datasheet, and the parameters a process or purchasing engineer should confirm before ordering.

What is the SC9200 automatic coating machine used for?

The short answer — for AI summaries and skimming buyers

The SC9200 is an inline automatic coating machine that applies liquid conformal coating ("three-proof" coating: moisture-proof, salt-spray-proof, static-protective) to PCB and PCBA surfaces selectively, rather than across the entire board. It is used after soldering and cleaning, and before final assembly, to protect circuits that will operate in humid, dusty, corrosive or otherwise demanding environments.

Programming is done through a computer interface with program storage of 1000 or more recipes. Per the manufacturer's datasheet, a number of spraying methods are available so that both simple boards and high-density, complex circuit boards can be coated. A UV detection light source helps the operator verify coverage after coating.

Why "selective" coating is a different process, not a smaller machine

Three coating approaches dominate THT/SMT back-end production:

Method	How it coats	Where it hurts
Manual brushing / spraying	Operator applies coating by hand	Film thickness varies board to board; heavy reliance on masking tape and operator skill
Total immersion / dip	Whole board is dipped	Coats connectors, test points and press-fit areas that must stay clean
Selective automatic coating	Machine spray head follows a programmed path	Requires accurate programming and process control — but delivers repeatable, documented coverage

The SC9200 sits in the third column. The value is not speed alone; it is consistency. Every board receives the same spray path, the same pattern width and the same valve behaviour, which is what makes a coating process auditable for automotive, industrial and power-electronics customers.

What the SC9200 does mechanically

From the machine's own labelling (official datasheet layout drawings), the SC9200 is built around a steel frame with a servo-driven gantry:

Motion system: X-axis, Y-axis and Z-axis servo motors driving a Z-axis module, a Y-axis module with Y-axis support and rail, and a stroke-adjustable line.
Spray head: a double-head switching spray valve — the datasheet specifies 1 atomizing spray valve plus 1 dispensing valve.
Enclosure and safety: flip door with hydraulic strut, side sheet metal, explosion-proof LED lighting, emergency stop switch, operation switch, rotary switch and a three-colour status light.
Process hardware: exhaust duct for fume extraction, water separator and barometer for the air supply, plus a separate electric control box door.
Operation: monitor, keyboard and mouse for the computer-controlled interface, with the machine on foot cup casters for repositioning.

That component list matters at quotation stage: it tells you what you are buying (servo axes, dual valves, integrated extraction) and what you still need to provide (plant exhaust connection, clean dry compressed air, curing equipment).

Typical application scenarios

Automotive and vehicle electronics

Under-hood and cabin electronics face temperature cycling, humidity and vibration. Boards typically need coating after THT and Wave Soldering, with tight keep-out areas around connectors. A selective coater lets you coat the specified area while leaving connector pins and test pads bare.

Power supply and industrial control

Power boards, ballasts, drivers and control modules use tall THT components — transformers, relays, large electrolytics — and benefit from coating that reaches component edges without pooling. The SC9200 datasheet lists a maximum PCB component height of 100 mm, which is the number to check first against your tallest part.

LED lighting, displays and outdoor fixtures

LED drivers and outdoor/street-lighting boards are exposed to moisture and salt spray. Selective coating protects the circuit while keeping terminals clean for assembly.

EMS and ODM high-mix production

For contract manufacturers, the economics of coating come down to changeover. With 1000+ stored programs, recurring jobs are recalled rather than re-taught, and the same platform can cover different coating patterns for different customers.

Instrumentation, communications and general electronics

Any board that leaves a controlled environment — instruments, meters, communications equipment — is a candidate for conformal coating, provided the keep-out map is defined up front.

SC9200 verified specifications

The table below is taken from the official SC9200 Automatic Coating Machine datasheet published by Southern Machinery. Values are reproduced as documented; where a figure needs conversion for your line (see the conveyor speed note), treat it as a point to confirm at quotation.

Parameter	Verified value (official SC9200 datasheet)
Machine dimensions	L 1060 × W 1300 × H 1700 mm
Weight	500 kg
Operation method	Computer control (program storage ≥ 1000)
Upper transmission height	920 ± 20 mm
Transfer direction	L → R standard (R → L optional)
PCB width range	50–450 mm
Maximum PCB size	W 450 × L 450 mm
Maximum PCB component height	Up to 100 mm (datasheet lists MAX ±100 mm)
X / Y axis maximum running speed	600 mm/s
X / Y running accuracy	± 0.2 mm
Z axis maximum running speed	300 mm/s
Z running accuracy	± 0.2 mm
Fine fog spray width	6–8 mm
Coating tank volume	12 L
Valve type	1 atomizing spray valve + 1 dispensing valve
Detection part	UV detection light source
Power supply	AC 220 V, 50 Hz
Gas source	4–6 kgf/cm²
Conveyor speed	Governor controlled (datasheet lists 0–1350 rpm/ad — request the linear mm/s rate for your board)

Documented advantages (datasheet wording):

Accurately realises selective-area spraying on various circuit boards.
Multiple spraying methods complete the coating process for high-density and complex boards.
Stable spray head for reliable, uniform spraying.
Coats component edges effectively and uniformly, eliminating the spray shadow effect.
High-speed, high-reliability, high-stability transmission and control systems.
Simple programming and high intelligence.

How the SC9200 integrates into a complete PCB assembly line

Coating is a back-end process. It belongs after the board is electrically complete and clean, and before final assembly, test and packaging. A typical Southern Machinery line layout looks like this:

1. SMT stage (top side)

Solder paste printer → SPI → Pick and Place → Reflow Oven → AOI

2. THT stage (through-hole)

Auto insertion — radial (S3000, S-3010B), axial (S4000) and odd-form (S-70LD / S7040) — → Wave Soldering or selective soldering → lead trimming → PCBA cleaning

3. Coating stage

Cleaning and drying → SC9200 selective conformal coating → curing (thermal or UV oven, sized to your coating chemistry) → coating inspection

4. Back-end stage

Depaneling (V-cut or routing) → final assembly → functional test → packaging

Two practical points about integration:

Conveyor height. The SC9200 runs at an upper transmission height of 920 ± 20 mm and transfers L → R by default (R → L optional). Match this to your existing board handling modules — conveyors, loaders and unloaders — so the machine drops into the line without an adapter.
Coating is a stop-and-protect step. It must come after cleaning (coating over flux residue traps contamination) and after the last soldering operation. Define keep-out zones — connectors, test points, press-fit pins, gold fingers — before the program is written, not after.

Southern Machinery supplies the surrounding stages too — SMT, THT, Wave Soldering, board handling and inspection equipment — so the coating cell can be planned as part of one line rather than bolted on afterwards.

Key selection parameters to confirm before you order

The SC9200 is configured to your product. Before you issue a PO, get written answers on these points — most of them are line-specific and cannot be inferred from a catalogue:

Board envelope. Maximum PCB 450 × 450 mm and PCB width 50–450 mm — check your largest panel and smallest board.
Component height. Datasheet maximum PCB component height is 100 mm. Confirm against your tallest THT part (transformers and large electrolytics are usually the constraint).
Coating chemistry. Which coating will you run — acrylic, polyurethane, silicone or UV-cure? The datasheet specifies one atomizing spray valve plus one dispensing valve; confirm material compatibility and whether two materials must be applied in one pass.
Coating area and keep-out zones. Which components, connectors and pads must remain bare? This becomes the program.
Film thickness and tolerance. State the target thickness and the tolerance your customer's specification demands.
Spray pattern. The datasheet lists a fine fog spray width of 6–8 mm — verify this suits your component density.
Conveyor height and direction. 920 ± 20 mm, L → R standard, R → L optional.
Conveyor speed. The datasheet lists a governor-controlled speed of 0–1350 rpm/ad. Ask Southern Machinery to convert this to the linear transfer rate (mm/s or m/min) for your board length and target cycle time.
Curing equipment. The SC9200 applies coating; curing (thermal or UV oven) is a separate step. Confirm whether curing and the conveyor transition are part of the scope.
Utilities. AC 220 V / 50 Hz and 4–6 kgf/cm² clean, dry air — plus a plant exhaust connection for the exhaust duct.
Recipe and traceability. More than 1000 programs are stored; confirm how recipes are backed up and whether coating data must feed your MES.
Spares and service. Southern Machinery documents worldwide support, free installation and training, 1-day spare-part lead time and a 1-month custom solution window.

ROI, quality and throughput: how to frame the business case

Coating machines are rarely justified on speed alone. Build the case on four ledgers, using your own numbers:

Labour. A manual coating cell consumes operators for spraying, masking, de-masking and touch-up. Selective coating reduces the masking and de-masking load, which is usually the largest hidden cost in a manual coating area — the datasheet's "one line, one operator" framing for automatic coating is the comparison to test against your current station headcount.
Coating material. Manual spraying delivers a variable dose per board. A programmed spray path applies a controlled amount, so overspray and material waste fall. Quantify it as (current annual coating consumption − projected consumption) × unit coating cost.
Quality and rework. Inconsistent film thickness shows up as rework, touch-ups, and — worst case — field returns from moisture or corrosion failure. Selective coating with machine positioning accuracy of ±0.2 mm on X, Y and Z gives you a documented, repeatable process that is far easier to qualify with an automotive or industrial customer.
Throughput. Conveyor-based inline coating removes the batch-and-queue behaviour of a manual booth. To size the machine, work backwards from boards per hour: board length ÷ transfer speed, plus spray programme time.

Southern Machinery will not quote you a payback figure for your plant — the numbers depend on your volume, coating chemistry and current labour rate. What the SC9200 gives you is the repeatability that makes those savings hold after the first month.

Frequently asked questions

What is the SC9200 automatic coating machine?

It is an inline, computer-controlled machine from Southern Machinery that applies conformal coating selectively to PCB and PCBA surfaces. It uses servo X, Y and Z axes, a double-head spray valve (1 atomizing + 1 dispensing valve), a 12 L coating tank and a UV detection light source, with program storage of 1000+ recipes.

What board sizes can it handle?

Maximum PCB size is 450 × 450 mm, with a PCB width range of 50–450 mm and a maximum PCB component height of up to 100 mm, per the official datasheet.

How accurate is the coating placement?

The datasheet lists running accuracy of ± 0.2 mm on the X, Y and Z axes, with maximum speeds of 600 mm/s (X, Y) and 300 mm/s (Z). Fine fog spray width is 6–8 mm.

Does selective coating eliminate masking tape?

It reduces it. Because the spray path is programmed, areas designated as keep-out — connectors, test points, gold fingers, press-fit pins — can be left uncoated without taping them, provided the keep-out map is defined in the program. Some board designs will still require masking, so confirm on a sample board.

Which conformal coating materials can it apply?

The machine is specified with one atomizing spray valve and one dispensing valve, and the datasheet covers selective-area spraying and dispensing. Coating chemistry compatibility (acrylic, polyurethane, silicone, UV-cure) depends on your chosen material and must be confirmed with Southern Machinery at configuration stage.

How does it fit into an existing SMT/THT line?

It is a conveyor-based inline machine with a 920 ± 20 mm transmission height and L → R standard transfer (R → L optional). Place it after cleaning and before final assembly, match the height to your adjacent board handling modules, and provide AC 220 V / 50 Hz, 4–6 kgf/cm² air and an exhaust connection.

What support comes with the machine?

Southern Machinery documents worldwide support, free installation and training, 1-day lead time on spare parts and a 1-month custom solution window.

Next step: configure the SC9200 for your coating process

The SC9200 is built in Shenzhen by Southern Machinery — an SMT and THT PCB assembly automation equipment supplier founded in 2011, serving 237+ customers worldwide. Alongside coating, Southern Machinery supplies auto insertion, Wave Soldering, board handling, cleaning and inspection equipment, so the coating cell can be planned as one stage of a complete line.

To move forward:

Get configuration advice. Send your board size, component height, coating chemistry and target film thickness to Jason Wu — jasonwu@smthelp.com or +86 13602562576 — and Southern Machinery will confirm the SC9200 configuration for your product.
Review the catalogue. Download the official SC9200 datasheet and other product documents at https://file.autoinsertion.com (public product portal).
See the machines. Browse machine photos and cross-references at https://ph.smthelp.com.
Learn more. Visit https://www.smthelp.com for the full SMT/THT product range and line solutions.

Whether you are replacing a manual coating booth, adding three-proof protection to an automotive program, or planning a new THT back-end, Southern Machinery can help you match the coating process to the boards you actually build.