The emerging trend in sheet materials is towards larger board sizes to accommodate market demands for architectural or interior fitting applications. It’s also a trend that allows the features of the latest generation of large table CNC routers, which have dramatically improved optimisation performance, to be used to the full, giving more efficient cutting, routing and shaping of individually nested components.
To take full advantage of the opportunities this presents, panel specialists need to have the right production machinery and one company that has had the foresight to do so is Huddersfield-based Decorative Panels. The company has been involved with paper foil lamination in the UK since the early 70s and has enjoyed significant year-on-year corporate growth.
Decorative Panels is now taking the paper foil lamination process onto another level with the installation of the latest generation of lamination lines from Hymmen of Germany.
The new line, 2.3m wide by 90m long, has been installed in a new 100,000ft² factory on the outskirts of Huddersfield and is expected to be fully operational by the end of the year. Hymmen has been involved in continuous process manufacturing for more than 100 years and is therefore ideally positioned to build a state-of-the-art line such as this. But, according to David Miller, of Hymmen Miller Ltd, ‘the way people like Hymmen stay ahead of the game is by working with companies who dominate their own market niches in the different countries in which they operate. To that extent Decorative Panels has been a pleasure to work with, for me and for Hymmen, which has been able to adapt and develop the core lamination technology with the benefit of the best hands-on experience from a market leader’.
This new line has been designed in conjunction with Decorative Panels and is based on Hymmen’s latest heavy-duty technology, recently installed in other new plants in Sweden and Norway. Sophistication of electronic controls is the key to the level and scope of precision they can now confer on operators in controlling mechanical functions like board preparation, temperature control, adhesive application, bonding, texturing, finishing and packing.
In overall terms, the new line is significantly faster than existing technology – approaching double the speed of the largest of the company’s three existing Hymmen lines. But it isn’t the speed relationship between the old and the new lines that determines the ultimate potential for increased productivity overall. Decorative Panels managing director Guy Metcalfe estimates that the new line will virtually double throughput from the outset.
More critically, though, the new line should significantly reduce rejection rates through more precise temperature controls. It will speed throughput by faster and superior quality trimming too, sort output by customer order and stack for packing more precisely. It will also dramatically reduce downtime during paper foil changes allowing greater flexibility in finishing to individual customer specifications.
The new line is split into three distinct sections from a control point of view and each is fully interactive so that the system overall reacts automatically to fluctuations at any point in the continuous production process. Temperature fluctuations for example, either from one board to the next or even within a single board, will adjust the temperature appropriately at the infra red heating phase and will maintain the change until instructed otherwise by the linked sensors.
Infeed is now double sided – from both sides of the transport line – to ensure continuity of flow to the board preparation section. Nip clamps on one side draw panels into position on the tracking while push feeders on the other each ensure a continuous, uninterrupted flow.
Each of the three sections has its own temperature sensor monitor which is fully interactive with running speed controls, pressure controls, adhesive application rollers, and trim stations. Dimensionally, from a board throughput point of view, the new line is the equal of Decorative Panels’ existing largest capacity laminating line at 2.3m width. The company also runs a 1.3m line more in common with central European paper lamination traditions among manufacturers that laminate individual pre-cut panel components.
Optimum bonding of decorative paper foils to wood based panel substrate materials is, in part, a product of the thinnest glue line achievable. Excess application weight of adhesive can result in blistering, tearing and a range of other undesirable side effects, whereas a very fine glue line, coupled with optimum board preparation and pre-heating, yields a theoretically perfect job.
A new system of ‘double brush’ board preparation on the latest Decorative Panels line improves the quality of the board surface presented to the first of the pre-heated calender rollers by some margin, compared with existing technology. The board surface is first scoured and then fine brushed and the first of the pre-heated calender rollers brings the resins inherent in the core of the board to the surface to enhance adhesion before presentation to the first catalyst, or hardener, material spreader.
Hymmen have moved a step closer to presentational ideals with the incorporation of ‘dancing rollers’ which raise the exposure time of paper to roller by 70% in order to compensate for increased running speeds and to generate the perfect application temperature in the foil itself. To reduce the thickness of the glue line, Hymmen has also developed contra-rotation of the application rollers for optimum bonding performance.
Roller pressure has been increased by 50% at the foil application and bonding stage and also at the secondary roller phase, which combines the texturing calender with smoothing rollers. Decorative Panels has specified two stage rollers at this point, rather than the single roller option on its existing number one press line, in order to maximise flexibility.
The secondary heated pressure roller station is necessary for perfect bonding but also for the application of texturing – to impart a wood grain ‘touch’ to the finished board. Through doubling up, the texturing roller can now be lifted out of service at any phase of throughput, in line with customer order specifications, while not compromising bond quality or finish.
Trimming of boards has been upgraded on the new line to handle faster running speeds and virtually eliminates overhang of the foil material on long edges. Diagonal trim controls have been similarly upgraded to part individual boards along short edges at the higher running speeds and to leave a foil material overhang of as little at 10mm between boards.
The scope and efficiency of quality controls at this stage of the lamination process have been improved to Decorative Panels’ specification with the addition of a permanent inspection station in a specially constructed pit under the transport line which will be attended by quality control staff on a three shift 24-hour cycle. There will be no more mirrors for the two QA controllers at shop floor level, both of whom will remain in position on the new line to increase the QA strength from two to three. The stop/ start controls at their disposal permit instantaneous sideways rejection of any single substandard panel with the minimum of disruption.
Quality checked panels then proceed to a newly engineered assembly station, at which the required number of boards will be calculated automatically by the system controls for stacking on a card or other suitable base board. Pre-scored folded sections provide full panel edge protection and a second station then facilitates the addition of a protective top board and all round secure strapping.
Included within the finished product package is a delivery note printed in-line with full content details – board sizes, finish, customer destination and order references. The addition of a tracking chip to extend full logistical monitoring to the final delivery destination would be a simple future addition, says David Miller Finished board packs will then be fork-lifted from the output end of the line for direct transfer to the distribution vehicles. A goods in/goods out ‘tunnel’ has been incorporated down the full length of the new factory so that incoming lorries can offload raw board at one end of the building before proceeding to the other end for reloading with laminated packs for departure.
The PC TOP control system that has been developed by Hymmen Germany is a Windows-based package that takes in all elements including temperature controls. Full modem diagnostics are a part of the package allowing for Hymmen engineers in Bielefeld to adjust the glue line if necessary.
The existing 2.3m-wide line at the company’s Crosland Road factory in the town is to be installed alongside the new Hymmen line and the combined production of the two will, according to Guy Metcalfe, greatly improve order-to-delivery performance. ‘This is a big step forward for us,’ he says, ‘and, as part of an overall inward investment package of around £7m, will extend our lead in the foil finished board materials sector significantly.’
