From: Converter-Flessibili-Carta-Cartone

Providing a second lease of life for a flexo (or gravure) press or a coater/laminator

Ever wondered what happens to equipment when a company is subject to consolidation and the contents of a plant are sold off? Ever wondered what happened to the flexographic packaging press that you decided to sell?

In the case of the former the equipment may be shipped off to another plant within the group, perhaps a satellite plant in Central Europe. Quite likely, in the case of the latter, the press that you may have thought was no longer up to scratch or no longer fitted in with the new type of work that your company was handling found its way on to the second hand machinery market or was sold in auction. Again, there is a reasonable possibility that the machine found its way to some other corner of the world. In each case the machine would have been unpacked, evaluated and after some deliberation experts would be called in and the flexo or gravure press, or the coater/laminator would be subject to an upgrade or a re-build.
Danarota Technic’s Managing Director Bjorn Olesen says that the company, perhaps better known as being the European Division of North American headquartered Montalvo have undertaken a number of projects recently for companies around the world, including most recently a company in Saudi Arabia and another in Bulgaria. In each case Danarota’s mechanical and electrical engineers provided on site inspection, which in turn resulted in the production of a project plan with a time line for completion mapped out.

Projects undertaken by Danarota have been both straightforward and complex. At the plant in Bulgaria for instance, a stack type flexo press was subject to a tension control upgrade whereby the existing dancer control was replaced with a tension-sensing load cell based method of closed-loop control Other aspects associated with the upgrade included the replacement of the web guiding system with a more responsive and accurate system.
Other upgrade projects have involved replacing drives, improving the performance of turret type unwind/rewinds – from semi-automatic to automatic flying splice, as well as various other aspects associated with web handling and controllability that enhanced functionality.
Bjorn Olesen says that controls upgrade (including tension control) causes the least potential disruption to operations, while having a significant impact on machine capability. Continuing he says that new control schemes can provide economic benefits not available with the present system. It may be that your company is spending too much time on eBay looking for parts, and that management wants/needs information (such as job set up and storage data) that is not available or possible with the existing machine. On the production side it may be that downtime is increasing and there is loss of production, or that there are fewer resources to support older systems. Most likely, especially with tension control and drives, that the older machine now needs to process a greater range of materials and with greater accuracy.

Amongst the equipment and systems shown to provide real performance improvements include drives (AC), supervisory systems, material treatment, i.e. corona treaters and servo-systems; improving digital communication via embedded communicative protocols, i.e. Profibus, DeviceNet, CanOpen and wireless diagnostics; installing web tension control modules that integrate seamlessly with machine control logic such as Montalvo’s X-3400ce tension control with digital parameter handling, and devices that measure ‘actual’ direct tension in the moving web, i.e. Montalvo tension-sensing load cells.
“In evaluating and deciding upon a course of action, we analyse a machine’s current performance, the machine’s strengths and weaknesses; we also look at other areas that are pertinent to operations, such as whether or not the company has an experienced workforce. Often we provide operator training. In the case of developing countries where the workforce may have little operating experience, we try to minimise operator involvement by seeking semi or fully automatic solutions, and this is where load cell based systems and highly responsive automatic controllers are a boon. The controllers compare tension measurements against set point and then make automatic adjustment to regulate web tension via drives and pneumatic brakes,” concludes Bjorn Olesen.