News & Event
ELD - ELECTRONIC LEAK DETECTOR
An innovative system to identify hot runner system leakage.
(Close monitoring of all hot runner zones and production shutdown prior to any potential irreversible damage being caused.)
Product description
The INglass-HRS Automation Division is pleased to present its latest system to detect hot runner leakage from plastic materials or other liquids such as water and oil.
In the event of leakage, the E.L.D., Electronic Leak Detector, automatically shuts down the injection machine. LED lights positioned on the front panel of the E.L.D. signal the leakage and display the zone(s) where leakage has occurred.
Moreover, the E.L.D. carries out real-time system temperature monitoring and prevents the machine from starting the molding process until the hot runner has reached the correct working temperature. This avoids the machine being subject to mechanical stress in the event that material has not reached optimal fluidity.
E.L.D. installation is straightforward. The temperature controller and hot runner system are connected in series via the standard power and thermocouple cables. The E.L.D. interfaces with the machine, receiving information regarding injection processes underway and activating machine shutdown when a signal warns that material leakage has occurred.
Installation and connections
Working performance
- Real-time detection of any leakage.
- Automatic identification of the zone where leakage has occurred.
- Warning siren and LED lights signal leakage.
- Production cycle shutdown in the event of irregularity.
Advantages
- Reduces potential cost of production shutdown:
- Reduced machine idle time.
- Reduced mold maintenance costs.
- Reduced spare part costs (heaters and thermocouples).
- Cost-effectiveness: zero installation and/or maintenance cost.
- Adaptability: can be used with any injection molding machine/hot runner system.
- Ease-of-use: no set-up, calibration or machine adjustments required.
Operating principle
The E.L.D. control unit performs a heat and energy profile analysis of the hot runner system and employs complex mathematical algorithms to automatically calculate the energy consumption allowance for each heating zone. This allowance is used to control any variation or deviation from average consumption levels during normal production conditions and, as a consequence, identify any irregularities. Numerous tests and trials carried out by our Automation Division in partnership with the R&D team at laboratories and production centres have identified a close association between material leakage from the machine and variations in energy consumption. The presence of material between the machine surface and mold results in additional heat loss in the direction of the mold, which registers an average temperature in the region of 200°C lower than that of the hot runner system. To compensate for this heat loss, the heaters require higher energy consumption levels to keep the working temperature constant. The diagram below shows a typical example of production irregularities resulting from plastic material leakage (average power levels shown in black, instantaneous power consumption in green and the tolerance band allowance shown in red).
Technical features
Electrical
Mains voltage Single-circuit 230 V ±15%Frequency 50/60 Hz
Max, power input 16 VA
Thermocouple input/output 12 self-configurating (Types J, K, R, S, T)
Heater input/output 12 (Max 16 A - 240 Vac)
Alarm relay contacts RS-485 line (optional)
"Injection underway" input Volt free contact
Working temperature 5 °C ÷ 50 °C
Relative humidity 0÷95 % non-condensing
Connections Max 3 A 250 VAC exchange
Mechanical
Dimensions (Length x Height x Depth) IP30
Weight 10.5 Kg
Level of protection 365 x 235 x 350 mm
CASE STUDIES
No. 1 example of leakage: M-series nozzle
Mold type: M series
Material: PMMA
Mold temp.: 50 °C
Hot runner temp.: 220 °C
Injection P: 100 bar
Holding point: 35 bar
Cycle time: 40 seconds
The production cycle was started up in automatic after having inserted the required injection parameters. Monitoring of finished piece quality indicated no potential material leakage in the system. The E.L.D control unit signalled leakage in zone 2 and automatically shut down production after approx. 25 minutes. As a result, the mold was opened to assess the extent of the leakage and overall system conditions. As can be seen below, leakage was promptly identified before any significant damage had been caused to either machine or system.
Fig. 2 - Real-time warning alert of plastic material leaking from the nozzle.
Analysis of nozzle power input during the production cycle clearly shows how average consumption levels increase as the cycle progresses until exceeding the max. power allowance threshold (automatically calculated by the E.L.D. control unit).
Once the max. consumption level has been exceeded, and average consumption levels continue to rise, the E.L.D. control unit immediately signals the presence of material leakage.
Fig. 2 - Energy consumption increase in zone 2 (nozzle), affected by material leakage.
No. 2 example of leakage: M-series hot runner manifold
Mold type: G series
Material: Bayblend (PMMA)
Mold temp.: 80 °C
Hot runner temp.: 260 °C
Injection P: 100 bar
Holding point: 40 bar
Cycle time: 35 seconds
System leakage, in this case, was signalled by the E.L.D. control unit after approximately 35 minutes' production time.
Leakage was due to the incorrect fitting of hot runner nozzle and manifold.
The situation below was reported following the subsequent disassembly of the mold, after the E.L.D. control unit had shut down production.
Fig. 3 - The E.L.D. warning signals plastic material leaking from the hot runner system
As can be seen from an analysis of power consumption in the zone affected by the material leakage, there is a significant increase in power required in order to keep working temperature constant. The E.L.D. control unit promptly signals any leakage before the amount of material involved can cause significant damage to the system.
Fig. 2 - Energy consumption increase in zone 1 (hot runner system manifold), affected by material leakage.
MAIN ADVANTAGES: COST-REDUCTION FOR CUSTOMERS
How much can it cost to fill a mold?
|
PRODUCTION DOWNTIME |
ACTION |
COST |
|
1. Production downtime |
Average injection molding machine |
|
|
2. Mold disassembly |
20 man-hours (€60/hour) |
€1,200 |
|
3. System cleaning and resetting/readjustment |
Spare parts (heaters, thermocouples) |
|
|
4. Re-assembly |
12 man-hours |
€720 |
|
5. Production start-up |
Scrap - not quantifiable |
|
|
|
|
€13,520** |
E.L.D. control unit technology avoids unnecessary, yet costly, production downtime when warning signals arrive too late to prevent the system from overloading with material and short-circuiting the system. In such circumstances, a complete system overhaul would be required.
On the contrary, systems equipped with E.L.D. control units are able to intervene when minimum damage has been caused and, furthermore, avoid additional complications during the molding cycle that, otherwise, would result in production scrap.
This technology also allows users to identify related production problems, such as water loss or machine installation faults.
** Not including production downtime - a non-quantifiable cost.
