押し出しダイのトラブルシューティング ガイド: 電気ゾーンとヒーター
時には、最も組織化された運用であっても、広範囲にわたるトラブルシューティングを必要とする予期しない生産開始の問題に直面することがあります。 体系的なアプローチを使用して問題を定義し、考えられる原因を整理し、解決策を開発することで、ダイ システムを正常にオンライン化できます。
当社のサービスと現場での テクニカルサポート の経験により、セットアップの問題の一般的な原因を特定し、トラブルシューティング プロセスを迅速に進めることができました。
ヒーターの点検
ダイやフィードブロックを 生産ライン に再インストールするたびに、ヒーターを確認することが重要です。 これは、機器が最近保管場所から取り出されたか、最近改修されたか、または 予防ンテナンス イベントのために単にシャットダウンされた場合に当てはまります。
設置プロセスを完了する前にヒーターを点検することで、ヒーターが適切に加熱され、生産開始時にさらなる問題が発生しないことが保証されます。
ヒーターを確認するときは、ダイまたはフィードブロックに付属の電気図面に記載されている情報を参照します。 電気図面には、ゾーンの数、各ゾーンにあるヒーターの数、各ゾーンのヒーターのワット数が示されます。
Example Electrical Drawing
- In this example drawing, we see the zones for the flex and non-flex bodies of an extrusion die (highlighted in orange). Each zone is labeled, for a total of 10.
- This diagram also shows that the end zones (1, 5, 6, and 10) have fewer heaters than the center zones (highlighted in green). This also means that these zones have a reduced number of total watts.
- Finally, at the center of the drawing (highlighted in blue), we see the pin designations, beginning on the left.
This information will be important to note as you begin checking heaters.
Once you’ve reviewed the information in your electrical drawing, you may begin testing the heater by checking the ohms in each zone using a multimeter, reading across the corresponding pins. We will use the information from the drawing above as an example, so Zone 1 is across from Pins 1 and 2.
First, we need to calculate the total number of ohms (Ω), using Ohm’s Law, in Zone 1:
Ohm’s Law: Ohms = Voltage (V) x Voltage (V) ÷ Watts (W)
240 V x 240 V = 57,600 Total Voltage
3 Heaters x 500 W Each = 1,500 Total Watts
57,600 ÷ 1,500 W = 38.4 Ω (± 10%)
The number of heaters differs for each zone in this die, so we will need to complete a similar exercise to find the total number of ohms for Zone 2, as well as any other zones with a different number of heaters:
Ohm’s Law: Ohms = Voltage (V) x Voltage (V) ÷ Watts (W)
240 V x 240 V = 57,600 Total Voltage
4 Heaters x 500 W Each = 2,000 Total Watts
57,600 ÷ 2,000 W = 28.8 Ω (± 10%)
Using an ohmmeter, check the value of the corresponding pins for each zone. If the measurements differ from the calculated value, then you’ll need to check each individual heater within the zone as there may be an issue. To do this, you will need to calculate the heater ohms (Ω) of the individual heater:
Ohm’s Law: Ohms = Voltage (V) x Voltage (V) ÷ Watts (W)
240 V x 240 V = 57,600 Total Voltage
Divide the Total Voltage by the Heater’s Wattage (500 W)
57,600 ÷ 500 W = 115.2 Ω (± 10%)
If your heater ohm reading differs from this value, verify that the installed heater has the correct voltage and wattage required (this information is engraved on the heater). If this information is correct, then the heater may be bad and should be replaced.
Checking Electrical Connections to the Die System Zones
Whether you are installing a brand-new die or feedblock, or one that’s been recently refurbished or pulled from storage, it’s important to ensure that all electrical components are in the proper position to function correctly. This process can be completed in a relatively short time and saves a lot of frustration later during start-up.
This procedure should be completed when your die or feedblock is at an ambient temperature. Starting from one end of the die, begin turning power on to one zone at a time. Once the temperature begins to climb for the activated zone (approximately 10°F), turn the power back off and move to the next zone to repeat the process.
While simple, this process ensures two things. First, you are confirming that the correct zone is heating once power is applied. Second, you are confirming that each thermocouple is installed in the correct location.
If you notice that a different zone is heating when power is applied, then there could be an issue related to wiring or thermocouple placement. If a zone does not turn on, check if there is a solid-state relay that needs to be replaced, if there is a fuse blown in the control panel, or if there is a loose or broken wire.
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