A manufacturer of wood fibre insulation panels wanted a pit saw for the accurate cutting of their panels. The saw should, on the one hand, be mobile, but on the other hand it should also handle large plate thicknesses not only in the case of 90° cuts, but also in angled and mitred cuts, as is often the case with energy-oriented refurbishment of existing buildings. Such a tool did not exist. After all, the insulation panels cannot be sawn well or even sawn at all with conventional saws due to the fibres, certainly not in thicknesses of 200 millimetres or more, and not at all in mitred and complex double mitred cuts.
One of the challenges was the accurate and torsion-free traversing of the saw blade at any desired angle. The insulation layers of the building envelope are always getting thicker: 180 millimetres are the standard. This is not only due to the thickness, but also because of the precise and joint-free laying of the insulation panels on site. Otherwise, cold bridges are created which greatly impair the insulating effect and favour the growth of mildew. All bearing elements must be lubrication-free, because sawdust settles on the guide and results in jamming in combination with lubricants.
The metalworking shop Manfred Bader GmbH in Kißlegg / Allgäu developed the first prototype of an insulation pulling saw, which consisted of a simple trestle with saw and stop-dog and was already equipped with igus bearings. This saw was made available to various companies. The pilot series was well received by users: The saw delivers very clean cuts at high speed It is easy to use. The extraction system, the development of which involved a great deal of effort, ensures clean work and use in closed rooms. For example in wall prefabrication and in element construction. An optimisation followed on the basis of the feedback from these practical tests. This included an angular stop and the integration of a line laser. Now the saw with the designation HDZ 720 is ready for volume production. It allows the cutting of insulation panels with a maximum length of 2,000 millimetres and a thickness of 260 millimetres (with angled cuts) or 200 millimetres with a 45° inclination. A single roller lubrication-free linear bearing of type drylin WJRM-01-20 is used for this purpose. In addition, the single-roller guide element is cost-efficient. And it fulfills its task also from the operator's point of view: a tensile force of only 3 to 4 kilograms is necessary for moving the saw unit that weighs 35 to 40 kilograms. In the meantime, the locksmithery with its easy to use insulation pull saw has received several awards for its innovative product, which creates a new business area: the Bavarian State Prize 2015, the Innovation Award of the Economic and Innovative Promotion Corporation of Ravensburg (WIR) and the VR-innovations Preis Mittelstand regional 2015.
Manfred Bader also made use of the igus® construction kit for other bearing elements, which he already knew from the original product range – the doors and gates with sash windows. They have always had good experience with the igus bearings, even in adverse environmental conditions. Thus the protective hood in front of the saw blade, which descends automatically, is also guided via a linear bearing from the drylin product range. The inclination of the saw blade is adjusted by means of a trapezoidal nut, the mitre angle is adjusted by means of an igus lead screw drive, and the igus tribo-tape ensures a simple movement of the stop on the rotatable stop-dog. An energy chain is used for the energy supply from the base frame to the saw blade drive.
Even complex cuts can be done well with the pit saw, even for large material thicknesses. The igus energy chain can be seen on the top of the machine frame.
View of the drylin guidance of igus in the saw unit.
The drylin guidance makes it easier for the operator to work on the pit saw: he has to apply only three to four kilograms of force to move the saw blade unit weighing almost 40 kilograms.
The protective hood of the saw unit is also guided by a drylin® linear bearing.
The adjustment of the mitre angle is made by means of an igus lead screw drive.