When outdoor temperature drops below 10 degrees Celsius, the failure mode of a plastic blow molding machine shifts away from wear and toward fluid behavior. The single most common winter breakdown across extrusion blow molding and injection blow molding lines is hydraulic oil that has thickened to the point of near solidification, forcing the pump to cavitate, the valves to lag, and the clamping system to crawl. This guide explains why low temperature destabilizes every subsystem of a blow molding machine, then gives a graded, repeatable maintenance and cold-start procedure that plant engineers can apply directly on the floor.
Wanplas is the main brand of a plastic machinery group that spans blow molding, extrusion, injection, and recycling equipment through specialized factories. The group operates more than 300 employees, serves 100 plus exported regions, and has accumulated an average of 10 plus years of experience per equipment type. Within the blow molding category, the Wanplas group builds extrusion blow molding machines through its Apollo factory and injection blow molding machines through its Aibim factory, both of which are referenced throughout this article with real model families. The maintenance principles below apply to conventional hydraulic machines and to the hybrid and fully electric lines used in colder export markets.
The Cold-Weather Impact Map for Blow Molding Machines
Low temperature does not attack a blow molding machine in one place. It changes the physical state of fluids and elastomers across six interconnected subsystems, and a problem in one quickly propagates to the others. Understanding the map is the first step to a winter maintenance plan that prevents oil solidification rather than reacting to the breakdowns it causes.
The hydraulic system is the primary victim. Mineral hydraulic oil is a non-Newtonian fluid whose viscosity rises steeply as temperature falls. At minus 5 degrees Celsius a standard grade can be several times more viscous than at 40 degrees Celsius, so the pump cannot draw enough oil and the servo and proportional valves cannot shift at the commanded speed. The pneumatic system suffers from condensate that freezes inside the lines and valves, blocking actuation of blow pins, pre-blow, and parison transfer. The cooling water circuit can freeze and crack the mold water channels, the head water jacket, and the chiller or cooling tower piping. The electrical cabinet accumulates condensation when a cold machine is brought into a warm room, risking short circuits and inverter trips. Mechanical guide members, tie bars, and slides lose their lubricating film when grease thickens, increasing friction and wear. Finally, the resin and the process itself drift: cold pellets hold surface moisture, the barrel cold zone resists heating, and the parison cools faster, changing wall thickness and shrinkage.
Cold-weather failure is fluid failure first. If the oil, the air, and the water are kept in their correct physical state, most winter breakdowns of a blow molding machine simply do not occur.
Mapping these subsystems lets a maintenance team assign ownership. The hydraulic and lubrication tasks belong to the machinery technician, the pneumatic and water tasks to the utilities operator, and the resin and process tasks to the production supervisor. A winter plan that lists each subsystem with its temperature limit, its inspection frequency, and its responsible role is far more reliable than a single generic “keep it warm” instruction.
How Hydraulic Oil Behaves at Low Temperature
The heart of winter maintenance is understanding viscosity. Viscosity is the internal resistance of the oil to flow, measured in centistokes at a reference temperature, most often 40 degrees Celsius. As temperature falls, viscosity rises; the relationship is not linear but exponential, which is why a small drop from plus 5 to minus 5 degrees Celsius produces a large jump in thickness. A blow molding machine designed around an oil viscosity of roughly 46 centistokes at 40 degrees Celsius may be pushing 400 to 600 centistokes at sub-zero temperature, and at that point the pump suction line cannot fill fast enough.
Hydraulic Oil Classification by Viscosity Grade
The viscosity index, shortened as VI, describes how much the viscosity changes with temperature. A higher VI means the oil stays thinner when cold and thicker when hot, which is exactly what a seasonal climate demands. The ISO VG scale defines grade by the mid-point viscosity at 40 degrees Celsius, so ISO VG 32 is thinner, ISO VG 46 is medium, and ISO VG 68 is thicker. The HM and HV designations come from ISO 6743-4, the classification of industrial lubricants: HM is an anti-wear hydraulic oil with a standard viscosity index around 95, while HV is a high-viscosity-index hydraulic oil, typically VI 140 or above, blended to stay fluid in a wide temperature range. DIN 51524 defines the German equivalent families, with Part 2 covering HM and Part 3 covering HVLP, the high-VI version with added corrosion and aging protection.
| Grade (ISO 6743-4 / DIN 51524) | Typical viscosity at 40 C (cSt) | Viscosity index | Approx. pour point | Best use on a blow molding line |
|---|---|---|---|---|
| ISO VG 32 HM | 32 | ~95 | ~ -6 C | Light-load circuits, mild winter, southern plants |
| ISO VG 46 HM | 46 | ~95 | ~ -9 C | General-purpose hydraulic, temperate climate |
| ISO VG 68 HM | 68 | ~95 | ~ -6 C | Heavier clamping loads, warm climate only |
| ISO VG 32 / 46 / 68 HV | 32 / 46 / 68 | >=140 | down to ~ -30 C | Cold climates, northern export markets, seasonal plants |
The pour point is the temperature at which the oil stops flowing under a defined test, and it is the single most important number for winter planning. It is not the lowest start temperature: a machine should be brought to operating viscosity well above the pour point. A practical rule is to keep the minimum oil temperature at least 10 to 15 degrees Celsius above the pour point before allowing load. With a standard HM oil around minus 9 degrees Celsius pour point, that means avoiding load below about zero Celsius without heating. An HV grade with a pour point near minus 30 degrees Celsius gives far more margin for unheated halls.
Wax precipitation is the other cold mechanism. Mineral oils contain paraffinic fractions that can crystallize as temperature falls, forming a waxy network that thickens the fluid and can clog fine servo valves and filter elements. Synthetic and severely hydrotreated base stocks reduce this risk, but the practical defense is correct grade selection plus tank heating that keeps the bulk oil above the waxing threshold. Multi-grade hydraulic oils, analogous to multi-grade engine oils, use viscosity-index improvers to flatten the viscosity curve; they are appropriate where the machine sees both cold startup and hot running, which describes almost every seasonal blow molding plant.
Concrete Hazards of Cold Start
Starting a blow molding machine with cold, thickened oil produces a cascade of damage that is easy to prevent and expensive to repair. The first event is pump suction starvation and cavitation. The pump draws oil from the tank through a suction line sized for warm viscosity; when the oil is thick, the line cannot fill the pump chambers, so vapor pockets form and collapse inside the pump, pitting the vanes or gears and generating noise and heat. Cavitation within the first minutes of a cold start can remove more material than weeks of normal operation.
The second hazard is pressure shock. Hydraulic accumulators and long lines are full of cold, incompressible-but-stiff fluid. When a directional valve shifts at full command while the oil is still thick, the pressure spike is sharper than at temperature because the fluid and the elastomer seals are less compliant. Repeated spikes fatigue fittings and can burst a hose. The third hazard is servo and proportional valve lag. These valves meter flow by moving a spool against the oil; cold oil resists spool motion, so the parison programming, the clamp stroke, and the blow timing all drift. On an extrusion blow molding line this shows up as uneven parison wall and late transfer; on an injection blow molding line it shows as incomplete core pinch and flash.
Cold also hardens every elastomer. Oil seals, rod seals, and hydraulic hoses lose flexibility below their glass transition region and crack when the machine finally moves, so a cold start that succeeds can still cause a leak that appears hours later. The filter bypass valve is forced open when the thick oil cannot pass the element at rated flow, which means unfiltered oil circulates and carries wear particles into servo valves. System efficiency falls because the pump works harder against internal leakage and the motor draws higher current to move stiff fluid, yet delivers less flow. Finally, the clamping and carriage systems crawl: the mold does not close fully, the parison is cut at the wrong moment, and the container wall thickness becomes inconsistent. These are not separate faults; they are one cold-oil event expressed through different components.
Low-Temperature Startup SOP by Ambient Grade
A single warm-up instruction cannot cover every climate. The procedure must scale with the ambient temperature, because the physical state of the oil at plus 8 degrees Celsius is completely different from its state at minus 15 degrees Celsius. The table below grades the ambient environment and defines the warm-up path, the minimum circulation time, and the oil temperature at which load is permitted. These are engineering guidelines; the exact ramp should follow the machine manual and the factory commissioning report.
| Ambient temperature | Warm-up method | Min. circulation time | Pressure ramp | Load permitted at oil temp |
|---|---|---|---|---|
| Above 10 C | Low-pressure idle circulation, tank heater standby | 5 to 10 minutes | Direct to working pressure | 25 to 30 C |
| 5 to 10 C | Low-pressure circulation plus tank heater | 15 to 20 minutes | Stepwise to working pressure | 25 to 30 C |
| 0 to 5 C | Tank heater preheat plus low-pressure circulation | 30 to 45 minutes | Stepwise 0-25-50-75-100 percent | 30 C minimum |
| Below 0 C | Self-acting tank heater preheat, extended circulation, line tracing | 45 to 90 minutes | Stepwise, hold at 50 percent longer | 30 to 35 C |
The procedure is the same in shape at every grade: never apply load until the oil reaches 25 to 30 degrees Celsius, ramp pressure in steps rather than all at once, and keep the working oil in the 40 to 55 degrees Celsius window during production, with an alarm set at 60 degrees Celsius so overheating is caught as quickly as cold is. The operator should record the start time, the ambient temperature, the oil temperature at load, and the first good container time, because that log is what lets a plant prove the warm-up is working and tune the duration for its own climate.
Oil Temperature Management Hardware Solutions
Warm-up is faster and safer when the machine is equipped to manage oil temperature instead of relying on the pump to churn the fluid warm. The first device is a tank immersion heater sized by power density, not just combined watts. A power density above about 1.5 watts per square centimeter creates a local hot spot that carbonizes the oil against the heater sheath and eventually shorts the element. The correct design spreads the wattage across a larger surface or uses a lower-density element with thermostatic control so the sheath temperature stays moderate.
Thermostatic control requires a sensor placed in the tank return zone, not just at the heater, because the bulk temperature lags the heater zone. A good layout uses two sensors: one at the heater to prevent local overheating and one near the pump suction to confirm the oil the pump sees is warm. Coolers need attention too: in winter the chiller or plate cooler should run on a bypass or a three-way temperature-control valve so the return oil is not over-cooled below the 40 degree Celsius floor, which would force the heater to fight the cooler. Tank insulation, a heated cabinet or a heated machine room, and pipe tracing on long suction and return lines all reduce the warm-up time and the risk of the oil solidifying in a dead leg.
For plants in genuinely cold regions, an oil temperature controller can be added to circulate warm oil through the tank and the manifold before the main pump starts, reaching the 25 to 30 degrees Celsius threshold without loading the hydraulic pump at all. This is the configuration Wanplas specifies for blow molding lines exported to northern and sub-zero markets, where the machine may sit cold for twelve hours overnight and must start reliably the next morning.
Seasonal Oil Change Strategy and Oil Analysis
Winter is the right moment to verify, not assume, the condition of the hydraulic oil. Before any seasonal change of grade, sample and analyze the existing oil so the decision is based on data. The core tests are viscosity at 40 degrees Celsius, water content by Karl Fischer expressed in parts per million, acid number or TAN for oxidation, particle count by ISO 4406 for cleanliness, and a check for the presence of glycol or other contaminants. A cleanliness target in the range of ISO 4406 20/18/15 or better, often described by a NAS class such as NAS 8, keeps servo valves alive through the stress of cold starts.
Oil Analysis Parameters Before Seasonal Change
- Viscosity at 40 C – confirms the oil still matches its grade and has not sheared or thickened from oxidation.
- Water content (Karl Fischer, ppm) – free and dissolved water below a few hundred ppm; higher values demand dehydration before winter.
- Acid number, TAN – rising TAN signals oxidation that accelerates at temperature swings.
- Particle count, ISO 4406 – tracks wear debris and confirms the filter strategy is working.
- Glycol and elemental metals – reveals coolant ingress or component wear early.
The decision to change grade versus change oil is separate. If the oil is clean and within grade but the climate demands better cold flow, switch to an HV grade of the same viscosity class; if the oil is degraded, change it entirely. Mixing oils is dangerous: different additive packages can react, form sludge, or drop out rust inhibitors, so a full drain and flush is required when switching families. Flushing means circulating a compatible low-viscosity fluid through the system, then purging it completely, not simply topping the new oil on top of the old. The breather and the filter elements should be replaced at the same time, because the old breather may have loaded with moisture that will condense into the new oil, and the filter media holds the particles the analysis just measured. Finally, drain the water that collects at the bottom of the tank, because that free water freezes and rusts the tank first.
Pneumatic System Winter Problems
The pneumatic side of a blow molding machine is where low temperature causes the most visible winter stoppages, and they are almost always about water turning to ice. Compressed air leaving a dryer still carries vapor that condenses as it cools in the plant, and in winter the lines, the tri-unit filters, and the valves can drop below zero locally. Ice plugs a blow pin, freezes a pilot valve, or locks a pre-blow cylinder, and the machine faults on a missing action. The defense is a dryer sized for a low pressure dew point well below the coldest line temperature, with the refrigeration or adsorption dryer set colder in winter than in summer.
The tri-unit at the machine should be drained far more often in winter: daily at minimum, and several times per shift in sub-zero operation. Where freezing is likely, an electric trace or a small heater on the drain bowl prevents ice from welding the bowl shut. Pneumatic tubing also becomes brittle in the cold, so lines routed near external walls or unheated zones should use low-temperature-rated polymer or be relocated, and the air receiver drain frequency should be increased because more free water separates when the receiver is cold. These are purely low-temperature issues; the broader solenoid, cylinder, and leak-diagnosis work belongs to a separate pneumatic troubleshooting article and is intentionally not repeated here.
Coolant System Freeze Protection
The cooling water circuit must not be forgotten, because a frozen mold water channel is a cracked mold. In winter the cooling tower and the chiller behave differently: the tower may ice over and the chiller refrigerant loop can struggle at low ambient, so both need their low-temperature operating mode and antifreeze plan. The mold water circuits and the die head water jacket are the most exposed, and any water left inside them at a hard freeze will expand and split the steel.
| Antifreeze volume concentration (ethylene-glycol based) | Approximate freezing point | Note for blow molding lines |
|---|---|---|
| 20 percent by volume | about -8 C | Mild frost protection only |
| 30 percent by volume | about -15 C | Common winter setting |
| 40 percent by volume | about -25 C | Cold-region and northern export |
| 50 percent by volume | about -35 C | Extreme climate only; check heat-transfer loss |
The concentration must be matched to the lowest expected temperature and confirmed against the additive data sheet, because over-concentration reduces heat transfer and under-concentration freezes. Pumps should be protected with trace heating or drained when idle for long periods, and the mold and head water must be fully blown out with compressed air at shutdown. Hard water scale interacts badly with cold: scale insulates the channel wall, so the localized freezing stress concentrates and cracks the mold more easily, which is why water treatment and periodic descaling matter more in cold plants than in temperate ones.
Electrical and Drive Systems in Cold Weather
The control cabinet is a hidden winter risk. A cold machine moved into a warm room, or a cold hall that warms during the day, throws condensation onto drives, relays, and terminals. That moisture causes nuisance trips, inverter faults, and in the worst case short circuits. A cabinet heater with a condensation set-point, or a small dehumidifier in the cabinet, keeps the internal temperature a few degrees above the room dew point and prevents the film from forming. Inverters themselves dislike cold start: many will fault or limit output until their internal temperature rises, so a brief preheat or a cabinet heater avoids a failed first cycle.
Mechanical drives thicken too. Servo motors and planetary or helical reducers carry grease that stiffens at low temperature, raising starting torque and possibly tripping the drive on over-current. Guide rails, tie bars, and sliding platens use grease chosen by NLGI grade and base-oil viscosity; a summer NLGI 2 grease may be too stiff in winter, while a lower NLGI grade or a synthetic base oil flows at sub-zero temperature. Chains and ball screws need a lubricant that does not channel or stiffen, because a thick film starves the contact and accelerates wear on the first cold strokes. The cure is to specify低温-grade greases for cold plants and to let the machine idle through the warm-up before demanding full-speed motion.
Resin and Process-Side Adjustments
Winter changes the plastic as much as the machine. Pellets stored in a cold, sometimes damp warehouse absorb surface moisture and, when brought into the warm hopper, can condense water that causes splay and silver streaks in the parison. Resin drying and the feed hopper should be insulated or heated, and the hopper dryer set and verified rather than assumed. The barrel cold zone, the rear section nearest the feed throat, resists heating when the surrounding air is cold, so the temperature ramp to setpoint must be extended; a cold barrel zone under-feeds the screw and produces an unstable melt.
The parison and the container cool faster in a cold mold and a cold room, so the mold temperature controller setpoint may need to rise, and the cooling time may need to shorten to keep cycle stable while avoiding over-cooling that stresses the part. Shrinkage and post-shrinkage shift with temperature, so dimensions drift if the process window is not re-validated seasonally. For the materials most common on Wanplas blow molding lines, HDPE and PP, low temperature raises impact strength in the finished article but also makes the melt stiffer during forming; the practical effect is that drop-test and impact-test results measured in a warm lab will differ from field performance in a cold distribution chain, so cold-region customers should validate their containers at the temperatures they will actually see. This is why seasonal process re-qualification belongs in the winter plan, not just mechanical maintenance.
Recommended Wanplas Blow Molding Models for Cold Climates
When a blow molding line must run reliably through winter, the model choice and its cold-region configuration matter as much as the maintenance routine. The Wanplas group builds both extrusion blow molding and injection blow molding machines, and both families can be specified with tank heating, insulated lines, cabinet heating, dryers, and cold-grade hydraulic oil so they start predictably in northern and cold-export markets. The specification tables below use representative engineering ranges for each series; exact values are confirmed against the ordered configuration and the factory standard offer.
Apollo ABLB Series – Extrusion Blow Molding (hydraulic)
| Representative model | Container volume range | Clamping force (representative) | Hydraulic system type | Oil tank volume (representative) | Installed power (representative) |
|---|---|---|---|---|---|
| ABLB 55 | 2 to 3 L | approx. 40 to 60 kN | Hydraulic, proportional valve | approx. 300 L | approx. 22 kW |
| ABLB 75 | 5 to 10 L | approx. 80 to 120 kN | Hydraulic, servo-proportional | approx. 450 L | approx. 37 kW |
| ABLB 90 | 10 to 20 L | approx. 120 to 180 kN | Hydraulic, servo-proportional | approx. 600 L | approx. 55 kW |
The Apollo ABLB series is a standard hydraulic extrusion blow molding line covering containers from 200 milliliters up to 20 liters, with eight models in the family and processable materials including PE, PP, PVC, PA, PC, ABS, PS, EVA, TPU, and PETG. For cold climates the hydraulic tank heater, insulated lines, and an HV grade oil are the recommended additions, because the larger tank volumes above mean a longer warm-up that heating shortens substantially.
Aibim IBM Series – Injection Blow Molding (hydraulic with PREFILL)
| Model | Container volume range | Clamping force (representative) | Hydraulic system type | Oil tank volume (representative) | Installed power (representative) |
|---|---|---|---|---|---|
| IBM55 Hybrid | 3 to 250 mL | approx. 55 kN | PREFILL plus variable displacement pump, hybrid electric | approx. 150 L | approx. 15 kW |
| IBM65 | 50 to 500 mL | approx. 65 kN | PREFILL plus variable displacement pump | approx. 200 L | approx. 20 kW |
| IBM75 | 100 to 1000 mL | approx. 75 kN | PREFILL plus variable displacement pump | approx. 250 L | approx. 28 kW |
The Aibim IBM series runs the three-station, one-step injection blow molding process for containers from 3 milliliters to 1000 milliliters, using a unique PREFILL technology and variable displacement pump pressurizing in the hydraulic system that saves at least 35 percent energy. Because the hydraulic demand is lower than on a large extrusion line, the smaller oil volume warms faster, but the same HV grade and tank heater rule applies, especially on the IBM55 Hybrid where the electric axes share the hydraulic clamp.
Requirement to Model Selection with Cold-Region Configuration
| Customer requirement | Recommended model | Low-temperature region recommended configuration |
|---|---|---|
| Pharma or cosmetic vials, 3 to 250 mL | Aibim IBM55 Hybrid | Tank heater, ISO VG 46 HV, cabinet heater, dry indoor air supply |
| Food and daily-chemical bottles, 2 to 5 L | Apollo ABLB 55 or ABLB 75 | Tank heater, insulated lines, air dryer, ISO VG 46 HV |
| Chemical drums and jerry cans, 20 to 200 L | Apollo ABLD heavy-duty series | Dual tank heaters, line tracing, insulated manifold, ISO VG 46 HV |
| Extra-large containers up to 1500 L | Apollo ABLD large series | High-power heater, extended warm-up SOP, heated room |
| High-volume PET bottles | YuDa high-speed PET blow series | Oven and pneumatic heating maintained, dryer dew point control |
Long Holiday and Extended Shutdown Winter Care
Many blow molding plants in cold regions stop for a winter holiday, and the shutdown itself is where damage happens if done carelessly. Before stopping, drain every water circuit completely and blow it out with air so no pocket remains to freeze and crack a mold or a head. Purge the screw and barrel with a purge compound so residual melt does not degrade and seize the screw; for long stops a dedicated purging grade protects the metal better than the production resin. Apply rust preventive to mold cavities, cores, and the blow pins, and store molds in a dry, dehumidified space.
The hydraulic system should be kept sealed to exclude moist air, or lightly pressurized with dry nitrogen through the breather so condensation cannot form inside the tank during the cold weeks. Before restart, run the checklist: verify oil analysis is current, test the tank heater, confirm the ambient and oil sensors read correctly, perform the graded warm-up, and only then ramp to pressure. A plant that documents this checklist avoids the classic post-holiday failure where the first cold start cracks a seal or freezes a water line that was thought to be empty.
Winter Inspection Checklist
A winter maintenance plan is only as good as its inspection discipline. The table below separates daily, weekly, and monthly tasks so nothing is left until it breaks. Each item should be recorded; the log is what turns winter maintenance from advice into a managed process.
| Inspection item | Daily | Weekly | Monthly |
|---|---|---|---|
| Oil temperature at load | Record start and load temp | Trend check | Compare to alarm setpoint |
| Oil level and appearance | Check sight glass | Sample color and cloud | Lab analysis if suspect |
| Leak points (seals, hoses, fittings) | Visual walk-around | Torque check on joints | Replace aged hoses |
| Pneumatic drain and dew point | Drain several times per shift | Verify dryer setting | Service dryer filters |
| Water circuit antifreeze | Confirm no freeze alarm | Check concentration | Refractometer test |
| Cabinet condensation | Check heater status | Inspect for moisture | Dehumidifier service |
| Cold-start duration | Log warm-up minutes | Adjust by ambient | Review SOP fit |
Common Myths and Mistakes
Four mistakes account for most winter hydraulic failures, and all four are avoidable. The first is direct load start: an operator arrives cold, flips the machine on, and runs the first container immediately. Without the graded warm-up the pump cavitates and the valves lag, and the damage is done in the first minutes. The second mistake is arbitrarily swapping to a much thinner oil, such as dropping from ISO VG 46 to ISO VG 32, to “fix” cold start. A thinner grade lowers viscosity everywhere, not only at startup, and under load at normal temperature the film may be too thin, increasing wear and internal leakage; the correct fix is an HV grade plus heating.
The third mistake is running the tank heater while the oil level is low, so the element is partly exposed and dry-burns, carbonizing the oil and destroying the sheath. The heater must be interlocked to the level switch and the power density kept at or below 1.5 watts per square centimeter. The fourth mistake is ignoring the breather: a saturated breather lets moist plant air into the tank, where it condenses onto cold metal and rusts the system from inside, and it also restricts flow so the pump starves. A desiccant breather replaced on schedule is one of the cheapest winter insurance measures available.
Quantified Results of Standardized Warm-Up
Plants that implement the graded warm-up and the HV grade typically see measurable improvement, expressed here without any cost figures. Cold-start related faults, measured as startup-stage failures per hundred starts, commonly fall by 40 to 60 percent once the oil is held at 25 to 30 degrees Celsius before load and the working window is kept at 40 to 55 degrees Celsius. Action repeatability, tracked as the standard deviation of clamp close position or parison cut timing, improves by roughly 30 to 50 percent because the servo and proportional valves respond at their designed rate instead of fighting stiff oil.
Energy per unit, measured as kilowatt-hours per 1000 pieces, drops because the pump no longer churns thick fluid at high current during an extended uncontrolled warm-up; reductions in the range of 5 to 12 percent are typical when the warm-up is time-bounded by sensor confirmation rather than left to operator habit. Filter bypass events, counted through differential pressure logs, decline sharply once the oil flows at design viscosity, which protects the servo valves and extends element life. None of these gains require new machinery; they come from controlling the physical state of the oil, the air, and the water that are already in the machine.
Applications Across Industries and Cold-Region Export Markets
The Wanplas blow molding range serves a wide set of industries, and winter maintenance matters most where the end product lives in a cold chain. Apollo extrusion blow molding lines produce containers for food and beverage, daily chemical products, the chemical industry, building material, medical and pharmaceutical, automotive production, transportation, and cultural and sports goods; the typical end articles are jerry cans for detergent, drums for industrial chemicals, pharmaceutical and cosmetic bottles, and automotive fluid reservoirs. Aibim injection blow molding lines target pharmaceutics, food, drink, and cosmetic containers in the 3 milliliter to 1000 milliliter range, where wall uniformity and cleanliness are critical.
Northern and cold-climate export markets add a specific requirement: the container must survive not only the machine but the distribution and use environment. A HDPE detergent bottle filled in a temperate plant and shipped to a sub-zero region can become brittle if its impact performance was validated only at room temperature, and the drop-test result shifts with the storage temperature. This is why Wanplas recommends cold-region customers specify the tank heater and HV oil configuration and re-qualify their containers at the field temperature, so the winter maintenance plan covers the product as well as the machine. The group’s blow molding factories, with 4000 plus Apollo machines running in over 90 countries and Aibim lines in over 40 countries, have supplied precisely these cold-export scenarios.
Wanplas Service and Support
Wanplas backs every blow molding line with a service structure designed for plants that cannot afford a cold-season breakdown. Each machine is run through testing before shipment so the hydraulic, pneumatic, and electrical systems are verified under load, not just visually inspected. Engineers perform on-site installation and commissioning, setting the warm-up parameters and the oil and air specifications to the local climate during the first run rather than leaving them at factory default.
The group’s shared policy includes USD 500 free parts per year for the covered line, free replacement of damaged parts within the warranty, and a production capacity and quality standard guarantee. Training is provided for operators and maintenance staff so the graded warm-up and the inspection log become routine, and remote monitoring lets the factory check PLC data and flag abnormal trends before they become stoppages. Wanplas also operates an open factory policy and welcomes customer visits to review the build, the test, and the winter configuration options in person. For blow molding specifically, the Apollo and Aibim factories bring over 20 years and over 12 years of focused experience respectively, and the group’s average of 10 plus years per equipment type supports the broader extrusion, recycling, and molding portfolio.
Frequently Asked Questions
What oil viscosity grade should I use in winter for a blow molding machine?
In cold climates choose a higher viscosity index grade such as ISO VG 46 HV, which holds a stable viscosity across the temperature swing and keeps a low pour point near minus 30 degrees Celsius. Conventional HM oils with a standard viscosity index around 95 thicken more sharply and raise cold-start load on the pump and valves.
At what oil temperature can I start production after a cold start?
Idle low-pressure circulation until the oil reaches 25 to 30 degrees Celsius, then ramp pressure stepwise. Full load is only permitted above 30 degrees Celsius, and the normal working window is 40 to 55 degrees Celsius with an alarm at 60 degrees Celsius to catch overheating as quickly as cold.
Can I just swap to a thinner oil like ISO VG 32 to solve cold start?
No. A thinner grade lowers viscosity everywhere, not only at startup, and can thin the film enough to increase wear and leakage under load at normal temperature. The correct fix is a high viscosity index HV grade plus tank heating and a graded warm-up procedure, not a permanent grade reduction.
Why does my blow molding machine produce uneven wall thickness only in winter?
Cold oil makes servo and proportional valves respond late and the clamping and parison systems crawl, so the mold does not close fully and the parison is not cut at the right moment. Standardized warm-up and a stable 40 to 55 degrees Celsius oil window restore repeatability and wall uniformity.
How often should I drain condensate from the pneumatic system in winter?
Increase drain frequency in winter: daily at minimum, and several times per shift in sub-zero operation, because cold compressed air drops more free water that can freeze inside valves and lines. A refrigeration or adsorption dryer with a low dew point setting is recommended for cold halls.
What antifreeze concentration should I use for the cooling water circuit?
Use an ethylene-glycol-based additive and match concentration to the local lowest expected temperature, commonly 30 to 40 percent by volume for a freezing point near minus 15 to minus 25 degrees Celsius. Always confirm against the product data sheet and bleed the circuit fully before long shutdown.
Do Wanplas blow molding machines support cold-region configuration?
Yes. Apollo extrusion blow molding lines and Aibim injection blow molding lines can be specified with tank heaters, insulated lines, cabinet heating, dryers, and cold-grade oils so they start reliably in northern and cold-export markets. Configuration is confirmed per order with the factory.
What should I do before a long winter production stop?
Drain water circuits, purge the screw and barrel with purge compound, apply rust preventive to molds, keep the hydraulic system sealed or lightly pressurized, and build a restart checklist covering oil analysis, heater test, and gradual warm-up before load.
Conclusion
Winter failure of a plastic blow molding machine is, in most cases, the predictable result of hydraulic oil moving toward solidification while the rest of the system is asked to run at summer settings. The defense is not a single trick but a system: choose a high viscosity index HV grade, manage oil temperature with correctly sized and controlled heating, follow a graded cold-start procedure that never loads until the oil reaches 25 to 30 degrees Celsius, protect the pneumatic and water circuits from freezing, and keep the electrical cabinet dry. Plants that adopt this routine cut cold-start faults by 40 to 60 percent and improve action repeatability by 30 to 50 percent without buying new machinery.
Wanplas, through its Apollo extrusion blow molding and Aibim injection blow molding factories, supplies the ABLB, ABLD, and IBM series with cold-region configurations that include tank heating, insulated lines, cabinet heating, and dryers, supported by pre-shipment testing, on-site commissioning, USD 500 free parts per year, training, and remote monitoring. If your line runs in a cold or seasonal climate, contact the Wanplas team with your container size, material, and ambient temperature range, and we will recommend a model and a winter configuration tuned to your plant, and welcome you to visit the factory to review the build and the test in person.
