Automated width adjustment: High reproducibility saves time and material
Precise, autonomous, mechatronic – this triad is behind the PAM option from Reifenhäuser Cast Sheet Coating. It allows settings in coextrusion lines to be controlled precisely and reproducibly via the line's control panel. Adjustments to the die and feed block are made fully automatically and mechatronically, based on the data stored in the recipe management system. This makes it easier and significantly faster to start up the line and change products. In addition, machine operators no longer have to make adjustments manually, which increases occupational safety.
Automation ensures high reproducibility and product quality
The PAM principle has now proven itself in the design of dies and feed blocks. Reifenhäuser is now also offering this automation solution for width adjustment in flat film lines. “Our goal was to consistently automate the systems involved in width adjustment and thus achieve complete automation of the line,” says Lucas Rieming, application engineer at Reifenhäuser Cast Sheet Coating. “From now on, our customers can control all quality-critical adjustments mechatronically. The advantages are obvious: occupational safety, product quality, and the reproducibility of the process steps are significantly increased.”
PAM Option 2.0 – the biggest advantages for automated width adjustment:
- Time savings during width changes
- High reproducibility of the product
- Optimized waste reduction through automated edge pinning
- High optical film properties through optimized combination of air knife and vacuum box
- Minimized potential for errors through reduced complexity in application
- Increased safety for plant operating personnel
- System can be retrofitted into existing plants (including third-party plants)
Excellent film transparency and precise cutting
The automation of the width change covers four areas of the system: edge pinning (electromagnetic attachment), vacuum box, pre-trim, and final trim. While the latter two systems are relevant for cutting the film, the first two ensure the all-important contact between the film coming out of the die and the chill roll. This is an important process step, not only to minimize unwanted constriction of the edge areas, but also to achieve high optical film properties, especially in terms of transparency. In principle, each of the four systems can be automated individually. However, in order to achieve the greatest added value, retrofitting from edge pinning to final trimming is recommended. In principle, every Reifenhäuser coextrusion line is suitable for this. The automation solution can also be integrated into third-party systems.
But what exactly does the PAM package for width adjustment look like?
Video: deckling, pinning and vacuum box
Edge pinning: less neck-in
As soon as PP and PE films emerge from the die, the relaxation of the molecular chains causes a constriction (neck-in) to form at the edges. Edge pinning reduces this effect by electromagnetically charging the film edges. This causes the film to adhere immediately to the roller. A flexibly adjustable air flow also ensures that neck-in is reduced and the film remains as wide as possible. With automated edge pinning, the difference between the exit width of the film at the die and what ends up on the winder remains as small as possible. The result: less material consumption and significantly less waste.
Vacuum Box: accelerated cooling process and system start-up
To achieve excellent film transparency, the film must cool quickly. This is achieved by pressing it completely onto the casting roller. Reifenhäuser optimizes this process with its automated solution. It combines the best of two methods: On the one hand, the strong air flow from the air knife presses the film onto the cooling roller from above. At the same time, vacuum chambers in the edge areas create a vacuum under the film so that the film rests completely on the roller at both edges. The interaction between the air knife and the vacuum box ensures very stable process control, promotes rapid cooling, and guarantees high film transparency. In addition, the use of the vacuum box allows the system to ramp up quickly to 350 meters/minute.
Video: pre-trimming
Pre-trim: high reproducibility
During pre-trimming, the edge areas with the remaining constrictions (neck-in) are separated. They are immediately extracted and returned to the production process. The automation of pre-trimming guarantees high reproducibility of the trim. This is an advantage when the same film is produced on many machines and fluctuations in width must be prevented. PAM ensures that the knives are always positioned identically.
Video: final trimming
Final trim: space- and cost-saving large housing
The automated Reifenhäuser solution integrates the final trimming into the winder. This allows the films to be cut to exactly the width required by the customer. Reifenhäuser has designed a 3D-printed large housing for this purpose, in which all the necessary components are integrated. A solution that is as simple as it is space- and cost-saving. Not least because all of the pneumatically controlled knives for cross and longitudinal cuts are driven by a single electric motor. A plus point in terms of energy efficiency.
Reduced error rate through continuously available process knowledge
The PAM option also alleviates a significant pain point for manufacturers: “Many companies are now experiencing difficulties finding experienced machine operators for their systems,” explains application engineer Rieming. “With automated width adjustment, we are transferring the necessary process knowledge to the machine.” In this respect, PAM ensures a high degree of reproducibility, which makes it much easier to control the machines. The result is significantly fewer application errors in production and thus lower costs. In addition, automation helps to restart systems more quickly after width or product changes.
Would you like to automate key process steps in your plant? Then get in touch with us. We will present you with suitable solutions:
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