Focusing on pain point of "repeatedly adjusting temperature parameters for same material (such as PC/ABS alloy) on different machines," this section dissects differences in temperature control hardware, algorithm logic, and configuration environment between FANUC/Sumitomo/Haitian machines. It establishes a penetrating analysis model of "temperature setting→actual conduction→material response" to help machine engineers master "temperature compensation strategies based on equipment characteristics" and solve problem of "set temperature meeting standards but process results fluctuating."

 

Temperature is "invisible commander" of injection molding process—it directly affects material viscosity, melt flowability, and mold thermal balance. However, due to differences in technical approaches, three machines exhibit significant differences in the entire temperature control chain (setting → conduction → feedback), resulting in vastly different actual effects of same temperature setpoint on different machines.
1. Temperature Control Hardware: Inherent Difference Between Sensor Accuracy and Heating/Cooling Systems
- FANUC (ROBOSHOT series): Employs high-precision thermocouples (accuracy ±0.5℃) + ceramic heating coils (thermal response time <1s), paired with a closed-loop PID temperature control module (control cycle 100ms). Temperature difference between different sections of barrel can be stably controlled within ±1℃, and hot runner temperature fluctuation is <±0.3℃.
- Sumitomo (DE series): Standard configuration includes molybdenum wire heating coils (thermal response time ≈2s), and temperature control sensor is a platinum resistance thermometer (accuracy ±0.3℃), but hot runner is finely divided (up to 12 sections in some models). Advantage lies in its multi-region independent compensation capability, but due to slow response of heating coils, barrel front temperature is prone to drift (±2℃/h) during long-cycle production.
- Haitian (MA series): Employs electromagnetic induction heating (thermal response time ≈ 5s), sensor accuracy ±1℃, but has weak interface compatibility with mold temperature controllers (common pressure drops cause actual mold temperature to be ±2℃~±3℃ lower than set temperature). While low in cost, it suffers from poor temperature uniformity, and thick-walled parts are prone to shrinkage cavities due to localized overcooling.
Key Conflict: Hardware differences determine "temperature-sensitive scenarios" for three machines—Fanuc needs to withstand minor fluctuations (e.g., a ±0.5℃ deviation affects thin rib filling), Sumitomo needs to compensate for heating lag (e.g., front-end cooling after prolonged production), and Haitian needs to resist external interference (e.g., mold temperature controller pressure drops).
2. Control Logic: Differences in "Active-Passive" Temperature Regulation Modes
- Fanuc: Employs a "predictive-corrective" algorithm. Based on parameters such as material melt index and injection speed, it calculates required heat in advance and dynamically adjusts heating power. For example, when injection speed increases by 20%, system automatically increases heating power at the front of barrel by 1.5% to compensate for insufficient melt shear heating.
- Sumitomo: Based on "segmented compensation" logic. Barrel is divided into three sections: preheating, melting, and metering. Each section has an independently set target temperature, but in actual adjustment, priority is given to ensuring stability of metering section temperature (because metering accuracy directly affects injection volume). For example, when preheating section temperature fluctuates, system will prioritize maintaining metering section within ±1℃, sacrificing consistency of preheating section.
- Haitian: Simplified to a "single-point following" mode. Only nozzle temperature is core adjustment object, and temperatures of other sections of barrel passively follow (e.g., setting rear section at 210℃, actual temperature may only be 205℃ due to heating coil aging). This logic is suitable for general-purpose parts, but for precision parts (such as optical lenses), uneven local temperature can easily lead to warping.
Key conflict: "Optimal flow temperature" of same material (e.g., 280℃ for PC/ABS alloy) needs to be achieved by three machines using different logics—Fanuc relies on predictive compensation, Sumitomo relies on segmented locking, Haitian relies on single-point strong control.
3. Environmental Interference: Differences in "Heat Exchange Inertia" between Mold and Machine
- FANUC: Standard configuration includes high-precision mold positioning rings (tolerance ±0.02mm), resulting in a large contact area between mold and machine, leading to high heat transfer efficiency (mold heating time reduced by 30%). Engineers regularly clean oil stains from mold surface (once a week) to reduce thermal resistance.
- Sumitomo: Slightly larger mold interface tolerance (±0.05mm), leading to accumulation of residual thermal grease between mold and machine after long-term production, resulting in decreased heat transfer efficiency (mold cooling time extended by 20%). Regular grease replacement is required (every two weeks).
- Haitian: Significant pressure drop issues at mold temperature controller interface (common ΔP = 0.5~1 bar), with actual mold temperature 2℃~3℃ lower than set temperature. Additional mold heating rods are needed for compensation (e.g., adding a 300W heating element to fixed mold side), but this can easily lead to localized overheating.
Key Conflict: Environmental interference amplified discrepancy between "set temperature" and "actual mold temperature"—FANUC needed to prevent oil contamination, Sumitomo needed to resist silicone grease aging, and Haitian needed to address inadequacy of its mold temperature controller.

 

Background and Known Conditions
- Product: A brand of PC/ABS mobile phone case (size 150×75×8mm, average wall thickness 1.5mm, single-slider injection);
- Material: PC/ABS alloy (melt flow index 18g/10min, recommended barrel temperature 270℃~290℃, mold temperature 80℃±2℃);
- Objective: All three machines must achieve "no shrinkage cavities, no weld lines, and surface gloss ≥85°".
Case 1: FANUC → Sumitomo: "Heating Hysteresis Trap" of Frequent Weld Lines
FANUC Initial Parameters (Stable Production):
- Barrel Temperature: Rear Section 260℃ → Middle Section 280℃ → Front Section 290℃ → Nozzle 285℃;
- Mold Temperature: 80℃ (Stable control via mold temperature controller);
- Injection Speed: 80mm/s;
- Result: 1000 molds produced continuously, smooth surface without weld lines, gloss level 88° achieved.
Problems when directly replicating to Sumitomo DE-40:
- After 500 molds, a noticeable weld line appeared in the middle of shell (0.3mm width, gloss level reduced to 75°);
- Actual temperature fluctuation in the front section of barrel (288℃~292℃, exceeding FANUC's ±1℃ range).
Engineer Analysis and Adjustments:
Sumitomo's heating coil response was slow (2 seconds vs. FANUC's 1 second). Original initial setting of 290℃ resulted in heat loss during production, with actual temperatures fluctuating only between 288℃ and 292℃, leading to decreased PC component fluidity and increased weld lines. Therefore, initial temperature was increased from 290℃ to 295℃ (compensating for lag), and Sumitomo's "segmented compensation" function was enabled, locking metering section temperature at 290℃ ± 0.5℃.
Simultaneously, Sumitomo's mold interface tolerance was slightly large (±0.05mm), reducing heat transfer efficiency between mold and machine. Mold preheating time needed to be increased (from 10 minutes to 15 minutes) to ensure initial mold temperature stabilized at 80℃ ± 1℃.
After adjustments, 1000 molds were produced, with weld line width < 0.1mm and gloss level of 86° meeting the standard.
Case 2: FANUC → Haitian: "Insufficient Mold Temperature Trap" with Frequent Shrinkage
FANUC initial parameters (same as above stable parameters).
Issues encountered when directly copying design to Haitian MA3000:
- Shrinkage cavities (0.2mm~0.3mm in diameter) appear in thick-walled areas of product (such as at the base of reinforcing ribs);
- Actual mold temperature is only 75℃ (Fanuc is stable at 80℃), with PC/ABS cooling too quickly, resulting in insufficient shrinkage compensation.
Engineer Analysis and Adjustments:
Pressure drop at Haitian mold temperature controller interface causes actual mold temperature to be lower than set (75℃ vs. 80℃). A 300W heating rod needs to be added to fixed mold side for compensation (to stabilize mold temperature at 78℃±1℃).
Simultaneously, Haitian's "single-point following" temperature control logic only focuses on nozzle temperature (285℃), while actual temperature of rear section of barrel is only 255℃ (set at 260℃), indicating that PC components are not fully melted. Therefore, rear section temperature was increased from 260℃ to 265℃ (to compensate for heating coil aging).
Furthermore, Haitian's hydraulic system has weak pressure stability (±1 bar), requiring injection pressure to be increased from 80MPa to 85MPa to ensure full melt filling.
After adjustment, 1000 molds were produced, shrinkage cavities disappeared, and surface gloss reached standard of 85°.

Core Conclusions
Essence of temperature parameter failure across different machines is:
- Hardware inherent characteristics determine temperature control accuracy: Fanuc is sensitive to small fluctuations (±0.5℃ is considered sensitive), Sumitomo is sensitive to heating lag (requiring segmented compensation), and Haitian is sensitive to external interference (mold temperature controller pressure drop requires additional heating);
- Control logic determines direction of adjustment: predictive compensation requires anticipating material demand, segmented locking requires prioritizing metering segment, and strong single-point control requires compensating for barrel temperature differences;
- Environmental interference amplifies deviations: "Small details" such as mold cleanliness, interface tolerances, and mold temperature controller performance can directly lead to temperature runaway.
Core Competency Requirements for Machine Adjustment Engineers:
1. Temperature Control Logic Penetration: Ability to select appropriate temperature regulation strategies (predictive compensation/segmented locking/single-point strong control) based on machine type (FANUC/Sumitomo/Haitian);
2. Multi-Dimensional Compensation Awareness: Thorough investigation of the entire temperature deviation chain, from "heating coil response → mold heat conduction → mold temperature controller pressure drop," rather than simply adjusting setpoints;
3. Verification Tool Proficiency: Mastery of tools such as infrared thermometers (for measuring actual mold temperature) and hot runner temperature recorders (for monitoring segmented fluctuations) to achieve dual-dimensional verification of "setpoint-actual."