Views: 28 Author: Site Editor Publish Time: 2026-08-27 Origin: Site
In a candy factory, the last 15 minutes of a shift determine the first 15 minutes of the next. Rushing through shutdown to get the team out the door on time is one of the most expensive habits in confectionery manufacturing. Residual syrup that hardens overnight, a vacuum seal left unrelieved, or a cooling tunnel belt parked wet will greet you the next morning with downtime, scrap, and a frustrated crew.
At Sweets Machinery, every machine we build—from the SWM-AFD dissolving system to the SWM-HCD and SWM-JCD depositing lines—is designed so that daily shutdown maintenance is fast, logical, and thorough. Below is a comprehensive, equipment-by-equipment shutdown checklist that plant supervisors can implement immediately to protect their investment and ensure a smooth start every morning.
The dissolving tank is where sugar meets water and heat. After the final batch, syrup film and acid residues remain on the tank walls and agitator shaft. If left overnight, they crystallize into a rock-hard crust that takes hours to remove.
Shutdown sequence:
From the HMI, initiate the End-of-Day Rinse cycle. The CIP spray ball flushes the 280 L weighing tank and 320 L dissolving tank with 60–70°C water for 8–10 minutes.
If the day included citric or malic acid recipes, follow with a 1–2% food-grade NaOH circulation for 5 minutes, then a soft-water rinse to pH neutral.
Release the single hand knob at the screw feeder inlet. Remove the auger and rinse under a hose. Inspect the 316L mirror-polished surface (Ra ≤ 0.4 µm) for any burnt syrup spots near the heating jacket inlet—if found, wipe with a soft nylon pad while the surface is still warm.
Leave the tank lid slightly ajar to allow air circulation and prevent condensation buildup overnight.
Why it matters: A clean, dry dissolving tank prevents microbial growth and eliminates the "sugar rock" that can clog the screw feeder on next morning's startup.
The SWM-MC (300/500 kg/h) operates at 150–160°C under vacuum. After shutdown, residual syrup coats the microfilm heating cylinder and vacuum chamber. If the vacuum is left engaged, the door seals compress permanently and the pump oil degrades.
Shutdown sequence:
· On the HMI, select Cooker Shutdown → Auto Purge. The system reverses steam briefly to blow out residual syrup, then opens internal spray nozzles for a 70°C hot-water flush (10 minutes).
· Open the vacuum chamber access door (quarter-turn latch, no tools). Wipe the chamber walls with a food-grade sanitizing cloth. Check the sight glass—if cloudy, clean with a non-scratch pad.
· Check the vacuum pump oil sight glass. If the oil appears milky (water ingress from condensation), drain and replace. If clear and amber, leave it. Always release the vacuum before leaving the plant—never store the cooker under negative pressure overnight.
· Inspect the scraper blades. If buildup exceeds 1 mm, note it in the maintenance log for replacement during the next scheduled service. Do not attempt blade removal during shutdown—this is a scheduled maintenance task.
Why it matters: Releasing vacuum protects door seals from permanent compression set. Fresh pump oil prevents corrosion inside the pump housing. A clean heating cylinder ensures consistent heat transfer on the next startup.
The SWM-JC600 handles pectin, gelatin, and carrageenan slurries at 600 kg/h. Gelatin residues are protein-based and will spoil overnight if not properly flushed.
Shutdown sequence:
Select CIP → JC600 End-of-Day on the HMI. The system flushes with 50°C warm water to remove loose gel, then circulates 1.5% NaOH at 60°C for 12 minutes through the cooker and evaporator cone.
Rinse with acidified water (0.5% nitric, 55°C, 5 minutes) to neutralize and passivate the 316L surfaces.
Open the inspection port. Check the evaporator cone for gel buildup. If any remains, use the supplied Teflon scraper—never metal tools that could scratch the passive layer.
Drain the condensate receiver completely. Close the drain valve. If condensate smells sour, run an extra sanitizer cycle before the next production day.
Why it matters: Protein residues left overnight become a bacterial breeding ground. Proper alkaline cleaning followed by acid passivation keeps the 316L surfaces passive and corrosion-resistant, extending equipment life by years.
The SWM-HCD (300–600 kg/h, 40–55 strokes/min) features a servo-driven depositor head, nozzle plate, and precision mold alignment system. Sugar strings and burnt droplets harden quickly once the machine stops.
Shutdown sequence:
From the HMI, select Nozzle Purge → Hot Water Flush. The depositor cycles shut-off valves three times to clear internal syrup paths, then flushes the nozzle plate with 75°C water for 3 minutes.
Tilt open the hopper (gas-spring assisted, no tools). Spray the hopper interior and rotor pump body with hot water. Swing the pump head away on its hinge for full access.
Release the quarter-turn cam locks and remove the nozzle plate. Soak in warm water with mild detergent. Use a soft-bristle brush to clear micro-holes.
Wipe the mold alignment rails with a sanitizing cloth. Check the ±0.3 mm alignment pins for sugar buildup—clean with a cotton swab if needed.
If equipped with a cooling tunnel, wipe the belt surface with a food-grade belt cleaner. Ensure no syrup drips have pooled under the frame. Leave the tunnel fans running for 5 minutes after belt wipe to evaporate residual moisture.
Why it matters: Hardened sugar on nozzle plates requires mechanical scraping that can damage micro-holes. A clean, dry cooling tunnel belt prevents mold growth and sticky spots on the next day's candy.
The SWM-JCD (150–600 kg/h) runs solid, striped, layered, and center-filled jelly on metal molds. Gel residues are stickier and more prone to bacterial growth than hard candy syrup.
Shutdown sequence:
Select CIP → JCD End-of-Day on the HMI. The system flushes the blend tank with 55°C water, then circulates 1.5% NaOH at 60°C for 15 minutes through the depositor head and product pipes.
Rinse with acidified water (0.5% nitric, 55°C) for 5 minutes to passivate 316L surfaces.
Detach nozzles (quarter-turn release). Soak in warm caustic for 10 minutes, then rinse. For center-filled nozzles, use the supplied micro-brush to clean the inner filling channel.
Wipe metal molds with a sanitizing wipe. Check demolding pins for gelatin film—if present, spray with a mild enzyme cleaner and wipe clean.
For the SWM-JCD-S40 compact line (40 kg/h, 9×1.3×2.55 m), the same routine applies. Its smaller footprint means the entire shutdown takes about 20 minutes instead of 30.
Why it matters: Gelatin film left on molds overnight becomes a sticky, rancid layer that transfers off-flavors to the next batch. Clean molds and nozzles ensure consistent deposit weight and product appearance.
The SWM-LD50 (30 kg/h, 3 kW, four wheels) is used for R&D and small-batch testing. Its compact size makes shutdown fast—but skipping it causes cross-flavor contamination between trials.
Shutdown sequence:
On the HMI, select CIP → LD50 Shutdown. The system flushes the 15 L dissolving tank and depositor head with 60°C water for 5 minutes.
Remove the hopper by releasing the single hand knob. Rinse under a tap.
Detach the nozzle (quarter-turn) and soak in warm water.
Wipe the machine exterior with a sanitizing cloth. The stainless steel panels (Ra ≤ 0.8 µm) clean easily with a single pass.
If the unit will not be used for several days, leave the electrical cabinet door slightly open to allow ventilation and prevent humidity buildup around the PLC.
Why it matters: In R&D, flavor purity is everything. A properly cleaned LD50 ensures that today's strawberry trial does not taint tomorrow's mint formulation.
After the core machines are flushed, finish with the peripherals that support product flow.
Cooling tunnel belts: Wipe with food-grade belt cleaner. Check for pooled condensate under the belt—if present, adjust the dehumidification setting (target 45–55% RH for gummy lines). Leave the tunnel fans running for 5 minutes after wiping to dry the belt completely.
Conveyor frames: Spray with hot water and wipe. Check for sugar drips on frame rails—common near the depositor exit. A dry frame prevents ants and other pests from establishing a path.
Air knives and blowers: Remove any sugar dust from the air knife slots with a soft brush. Blocked slots cause uneven drying and sticky candy on the next run.
Utility isolation: Close all compressed air valves (0.4–0.6 MPa range). Shut the main steam valve. Drain any residual water from glycol lines to prevent freezing overnight. If the plant temperature drops below 5°C, ensure the glycol concentration is adequate for freeze protection.
Electrical check: Verify that all VFDs show "Ready" status with no active faults. Note any alarm history in the logbook for review at the next shift start.
Equipment Module | Shutdown Time | Key Action | Overnight Risk if Skipped |
SWM-AFD dissolving tank | 10 min | CIP rinse + auger removal | Sugar crystallization, clogged feeder |
SWM-MC cooker | 12 min | Auto purge + vacuum release | Seal compression, pump oil degradation |
SWM-JC600 cooker | 18 min | Alkali + acid flush | Bacterial growth, protein spoilage |
SWM-HCD depositor | 15 min | Nozzle purge + hopper tilt | Hardened sugar, damaged micro-holes |
SWM-JCD depositor | 20 min | NaOH + acid CIP | Gelatin film, off-flavors |
SWM-LD50 lab unit | 8 min | CIP + hopper removal | Cross-flavor contamination |
Cooling tunnel & conveyors | 10 min | Belt wipe + drain check | Mold growth, pest attraction |
Total daily shutdown time: 20–35 minutes for a full line. One person. A systematic routine. No surprises the next morning.
At Sweets Machinery, we engineer our equipment so that daily shutdown maintenance is not a burden—it is a 20-minute investment that protects your next 10 hours of production. The SWM-AFD, SWM-MC, SWM-JC600, SWM-HCD, SWM-JCD, and SWM-LD50 are all designed with tool-free access, HMI-guided CIP, and clear visual indicators so your team knows exactly what to do when the last batch is done.
