IMA Schelling Woodworking Door production
Cost-effective and efficient throughfeed production of doors
Cost-effective and efficient throughfeed production of doors
Doors come in a wide variety of styles and designs. Whether plain square edge style door, internal rebated door with the door top face having a straight edge profile or another edge profile, postformed doors or functional door - they are all different, and so are the demands placed on the machine and unit design for the edge processing operations. As a specialist for innovative woodworking machines and workcells, the IMA Schelling Group offers individualized edge processing cells for throughfeed door construction tailored to the specific needs of the user.
Normally doors, which can be 30 up to 90 mm in thickness, are slightly thicker than typical raw panels for furniture production. Furthermore, a solid wood door or a skeleton-core hardwood door differs from a faced chipboard panel or MDF panel. Hence, the sizing process of door leafs requires router and hogger units having much higher motor power and solid machines. Other values for comparison: The sizing units for chipboard or MDF panels typically have a motor power of between 4.5 and 8 kW. In contrast, the machining units of door leafs need hogging units that have motor power ratings of 18 to 30 kW. The extremely robust, rigid fabricated and low-vibration structure of an IMA Schelling machine is another essential factor for the cost-effective and at the same time highly accurate routing & milling operations with excellent repeatability for the complete lifecycle of the machine.
In addition to the higher power of the sizing motors, the sizing and edge banding operations on door leafs differ in other ways from those on conventional furniture components. Different from these components, the first pass operation of door leafs is usually transverse processing and the second pass operation is longitudinal processing. This is a relatively minor change, the main aspect of which is that the vertical edges of the door extend along the entire length of the door and hence are not interrupted by the glue joint of the transverse edge.
Depending on the complexity of the production, throughfeed door construction utilizes the full bandwidth of edge processing and fine finishing units from the IMA Schelling portfolio. The result is project and application specific workcell and unit constellations. They are based on a machine technology that uses single-side, 1.5-side and double-side machines. The customer-specific designs range from semiautomatic single machines for edge processing through fully automatic production lines, to manufacturing cells for door linings and architraves.
As a general rule, door manufacturing is the supreme discipline of throughfeed edge processing machines. Hence, the core of door production typically consists of IMA machines of the Combima series configured to meet specific customer needs. They combine format machining operations – i.e. panel sizing, rebating and profile milling of the door blanks – and edge banding and fine finishing operations. In this process, common units for processing furniture components as well as special units for door construction are used. For door manufacturers who produce doors of different thickness, a segmentation of the top pressure track is practical because the machines won't need to be emptied completely when the door thickness is changed. Moreover, our workpiece infeed systems specifically developed for door blanks are perfect substitutes for upstream double end tenoning or edge jointing, making these machines obsolete.
Different from conventional furniture component manufacturing, on door production machines, the format processing area alone can be longer than a complete edge processing machine for furniture components. Door machine lengths may range from 40 m to 60 m. These extremely long machines with uninterrupted feed chain are made possible by special drive systems with two pinwheel drives (master & slave). In special cases, very long machines can also be equipped with power transmission (two separate feed chains). This is an advantage, for example, in cases where the door production is combined with paint finishing equipment which can cause contamination so that the chain will need replacing. In that case, not the entire chain but only one of the two chains needs to be replaced, simultaneously reducing both maintenance work and costs significantly.
In addition to throughfeed processing, also CNC machines for various machining operations such as making all the cuts for the lights, latch bolts, handles, mortise cuts for lock cases & lock faceplates, drilling the holes for the door hinges, etc., are required.
A seamless edge is one of the typical characteristics of high-end furniture. Today this is achieved through laser edge banding. In this process, the activation of the functional layer of the edging tape – which occurs directly before the tape and workpiece are joined together – is a crucial factor that influences the edge quality. For straight edges, the activation poses no problem because the edging tape is applied in one go. However, when edgebanding rebated doors, you need to perform several steps to bend and press the edging tape into the profiled section. On rebated doors, the edging tape is first applied to the door top face, then – during the second pass – the longitudinal edging is slotted to lay flush against the transverse face, and eventually the tape is bent and pressed into the rebated sections. In this process, the edging tape is pre-scored along the bending lines to reduce the material strength at these points.
Laser edge banding of such profiled side faces was previously considered infeasible. But IMA Schelling has now demonstrated that this assumption was false. Based on the established high-end Laser Edging process, the company developed an innovative solution that allows furniture manufacturers to use the process advantages of the zero-joint technology also for rebated doors.
In addition to the classical thin edgings for rebate edge banding, also up to 2 mm thick PVC edgings have made inroads in the world of doors. The integration of additional edge processing steps upstream of the edge banding operation allows the thick edgings to be bent, pressed and glued into the rebated sections. To optimize the fine-finishing quality, additional units such as profile scrapers, contour trimming and corner rounding units can be frictionlessly integrated into the machines. The advantages of thick edgings are improvements in visual and tactile design. They can also improve product functionality since they are more resistant to wear and tear and less sensitive to shock than thin edgings. With small radiused edges, door design conforms to the trend of small radii in furniture design. Furthermore, doors with thick edgings can be an inexpensive alternative to functional doors with cast PU edging.
The globally unique postforming line for the production of architrave angles from surfaced panels, developed by IMA Schelling for and in cooperation with the door manufacturer HUGA KG, is a typical example of a fully individualized door manufacturing process. The process substantially simplifies the production of architraves angles and moreover enables throughfeed fabrication of round angle trims from wear and shock resistant Durat®-surfaced panels. The heart of the approximately 54 metres long work cell for particularly narrow boards and finished parts (min. finished size: 56 mm) consists of two double-side Combimas arranged spatially offset from one another.
The Durat-surfaced raw panels are cut into narrow strips before they enter the sizing zone of the door processing machine. A special workpiece infeed system feeds these strips into the area between the chain and top pressure track without applying stress. The double-side sizing produces a parallel edged component that can pass at 28 m/min through the machine where it is folded to form an architrave angle with rebated lining and wall junction. In addition, the Combimas are equipped with various conventional format machining units to produce a specific self-supporting profile for the bending point and with automatically regulated heating zones which make sure that every part will have the right processing temperature.
Thanks to the new process, the decorative lining and rebated lining from HUGA have exactly the same colour and surface structure as the door leaf and door lining. Moreover the possibility to cut a surfaced panel into architrave angle strips of any desired width eliminates the need for film changes and stock-keeping of film reels in different widths. All necessary adjustments are carried out automatically.
The new panel processing installation, which replaces two old manufacturing cells, currently processes workpieces having lengths of 2000 mm, 2200 mm, 2600 mm and 3000 mm at a feed speed of 28 m/min and with a workpiece spacing of 500 mm.