Summary
Durante l’imballaggio automatizzato di prodotti in rapido movimento in condizioni controllate, le linee di termoformatura producono basi di vaschette di plastica trasparenti da materiale continuo in bobina. Un piccolo sensore per oggetti trasparenti, con tecnologia UV brevettata, rileva la presenza di ogni set di vassoi trasparenti dopo la loro formatura, avviando un’operazione successiva e, facoltativamente, innescando un circuito di conteggio. Si evita l’intervento manuale, garantendo un funzionamento affidabile e senza contaminazioni con tempi di fermo ridotti o nulli.
Vantaggi per il cliente
- I sensori UV garantiscono il rilevamento affidabile di oggetti in plastica trasparenti e di forma irregolare
- Rilevamento sicuro dei materiali trasparenti più sottili
- Massima riserva operativa a grazie all'elevato fattore di assorbimento della luce UV da parte di plastiche trasparenti
- Eliminazione di commutazioni multiple su un singolo oggetto
- Funzionamento affidabile senza la necessità di intervento manuale
- Sensibilità molto bassa a polvere, vapore e spruzzi
- Ampia gamma di funzionamento adatta alle diverse dimensioni dei vassoi
- La semplice procedura di apprendimento a una o due fasi ottimizza l'impostazione iniziale del sensore
- I parametri di sensibilità sono richiamabili o aggiornabili da remoto tramite IO-Link
- L'allarme di stabilità evidenzia una sensibilità ridotta, evitando arresti non pianificati
Vantaggi specifici del prodotto
Sensori fotoelettrici a catarifrangente, con luce ultravioletta, per il rilevamento di oggetti trasparenti- Sensibilità molto bassa alla forma dell'oggetto
- Protocollo di connessione seriale IO-Link disponibile su versioni PNP, senza costi aggiuntivi
- Parametri di funzionamento archiviati nella memoria interna del sensore
- Recupero da remoto o aggiornamento dei parametri, tramite IO-Link
- Sensibilità molto bassa a polvere, gocce d’acqua e spruzzi
- Sensori robusti, certificati Ecolab, con custodia miniaturizzata in plastica con grado di protezione IP67
Applicazione del cliente
Production engineers rely on high-integrity process control to manage operations, particularly on high-volume packaging lines. Thermoforming equipment, frequently deployed in modern process manufacturing across a range of industries from pharmaceuticals to food and beverages, plays a key role in continuous production of plastic packaging, including blister packs and film-sealed trays.
Typically, this type of packaging comprises a recessed, semi-rigid tray base, vacuum-formed in-line from a clear thermoplastic material and sealed with a metal or plastic film after the desired products are loaded. Configurable thermoforming lines are ideal for high-speed production of tray bases from continuous reel-stock material.
After forming, continuous strips of trays pass through the machine towards a slitting and cutting station. Error-free control of trays is essential for managing throughput.
Sensors must detect the presence of the transparent trays as they pass through the machine, initiating subsequent operations, including filling and sealing. Optionally, a sensor must also increment a counter as each set of trays passes the sensing position.
Photoelectric sensors using visible-light sources are unsuitable as they require part-specific set-up to differentiate reliably between a range of different tray profiles. A solution is required that optimizes efficiency by avoiding manual intervention between batches.
Soluzione del cliente
The Contrinex C23 transparent-object reflex sensor with ultraviolet LED-light source is ideally suited to this application. One of these small cubic devices, mounted opposite a compact rectangular reflector, is positioned beside the strip of trays immediately after they are formed. As each set of trays breaks the reflected UV beam, it triggers the sensor, initiating downstream operations and, where required, incrementing the item count.
Contrinex transparent-object sensors utilize a patented reflex operating principle with polarized ultraviolet light at 275 nm. At this wavelength, absorption of the polarized UV light by a range of commonly used plastics is maximized. Sensor output is insensitive to target geometry, ensuring reliable detection of irregularly shaped targets, including those with ridged and grooved surfaces and those with complex formed shapes – something that cannot be guaranteed with visible-light sensors.
Custom-designed UV reflectors, using high-tech plastic materials with excellent reflective properties in the ultraviolet range, provide a range of sizes and profiles that simplify installation – even where space is limited. Positioning sensors and reflectors is simple thanks to a range of adjustable mounting brackets, and autocollimated optics ensure there are no blind zones.
An industry-standard PNP normally open output ensures optimum flexibility. Additionally, IO-Link, a standardized point-to-point serial connection protocol for sensors and actuators, is enabled on PNP versions at no additional cost. A second output provides a stability alarm in the event of reduced sensitivity, flagging the need for preventative maintenance before any performance degradation occurs.
Robust sensor construction, featuring small (20 mm x 30 mm x 10 mm) Ecolab-certified plastic housings with M8 connectors, ensures reliable operation. A sensing range up to 1200 mm, adjustable via a teach button or via IO-Link, accommodates a range of machine parameters. Sensitivity data is stored on the sensor’s inbuilt memory and may be retrieved or updated remotely via IO-Link, eliminating the need for manual adjustment.
These rugged small sensors meet the customer’s need for reliable operation with little or no manual intervention. The solution is highly cost-effective with minimal non-productive time; throughput is maintained at or above target levels.