Sanding & Polishing
Sanding & polishing for industrial woodworking
Sanding and polishing for sizing and surfacing
The CNC mills and lathes of today already achieve outstanding dimensional accuracy and precision. However: highly glossy and precise workpieces (down to the closest ten thousandth of a millimetre) are no longer created by means of cutting. The modern approach is to use specialist finishing machines that do not operate with chisels and blades, but rather by means of abrasion. This is where sanding, polishing and lapping machines come into play and a wide range of machines have been developed for use in the woodworking industry.
Wood sanding machines and polishing machines
Within the woodworking industry, sanding and polishing machines play a similar role as the machines used in the metal industry. Despite being referred to as grinding machines when it comes to metal, sanders and polishers are also used for dimensional accuracy, surface finishing and preparation for coatings on wooden materials. A variety of interesting devices have been developed for the woodworking machinery sector which are used for many specific applications on this delicate material.
Typical sanding machines and polishing machines in the wood industry include:
Fladder sanders
Veneer sanders
Edge sanding machines
Strip sanding machines
Profile sanders
Rod sanding machines
Cylinder sanding machines
Belt- and wide belt sanding machines
Belt- and wide belt sanding machines are used to level out surfaces and work using a looped sanding belt which is tensioned between two rollers – the driver roller and tensioning roller.
The drive roller is linked to an electrical motor via a gear and the necessary tension is created using the other belt. This level of tension enables the belt to be placed under a high level of strain without slipping. When switched on, the belt moves in a circular motion ready to accept the wooden workpiece.
The advantage of belt sanding machines is that they offer a very wide sanding surface. They are particularly suited to levelling out uneven surfaces, but where surfaces are already even, belt sanders can still be used to remove old, unwanted coatings and veneers.
Table-top belt sanders are produced by FALKEN, UVM and BINI. Wide belt wood sanders are available from LISSMAC, CASADEI, TAGLIABUE and HEESEMANN.
Fladder sanders
Belt sanders are highly efficiency devices but are generally only used for occasional applications since the sanding belt is not very durable and requires frequent replacement. Those looking for more productive methods of sanding often select Fladder machines. Instead of a sanding belt, these machines use rotating rollers to which are applied strips with a sanding function. This makes the rollers more resilient than belts and enables fladder machines to be used in demanding applications such as deburring metals, as well as pre-sanding roughly sawn surfaces on wooden materials.
Major manufacturers of fladder and deburring machines include FLADDER and SORBINI.
Veneer sanding machines
After peeling and steaming, sheets of veneer are still curvy and aesthetically unpleasing. The veneer is re-sanded, before or after it is adhered to the base item (depending on the process) and there is a whole range of industrial sanders on offer specially designed for processing veneers. These machines work using the conventional sanding process: sanding rollers, sanding belt or eccentric sander.
Edge sanding machines
Applying veneers to edges is a very demanding application and the machines used count amongst the most complex and expensive machines in the woodworking industry. Edge presses are often fitted with soft- and post-forming machines as well as a sanding station, which sands and polishes the edge and produces excellent results. Integrated belt or eccentric sanders are the primary choice but there are also stand-alone edge sanding machines available.
Major manufacturers of this type of machinery include: ARMINIUS, REHNEN, HAPFO BSM, BOERE and LOEWER.
Long belt sanders
Long belt sanders are an even more efficient way of processing edges and surfaces. The longer the sanding belt, the longer (or broader) the profile/board that can be machined. This is where long belt sanding machines are used. They have a "floating" sanding belt arranged above the work table and the workpiece is guided under the belt via a sliding carriage.
Well-known manufacturers of long belt sanding machines include: JOHANNSEN, SAMCO, HEESEMANN, HÖFER and COMAS.
Strip sanding machines and profile sanders
Strip sanding machines, often known as brush sanders, serve to finish and smooth long wooden materials of every type. They use brush rollers as standard and are ideal for creating the widest variety of contours and shapes. Despite this, they are very simple in technical terms and parts are easy to replace. Strip sanding machines feature an integrated conveyor unit, which slides the workpiece under a sanding roller during an automated sanding cycle. This helps prevent excessive amounts of material being sanded off.
Well-known manufacturers of strip sanding machines and profile sanders include: LOEWER, VEMJAKOB, RECKMANN, STEMAS and STAEHLE.
Frame sanding machines
A key feature of frame sanding machines is that they possess two tensioning rollers, in contrast to the single roller found in most belt sanders. They can therefore generate a triangular tensioning path in which the sanding belt is clamped. This means a wide range of sanding surfaces can be created through pressing them down vertically onto the frames passing through. Frame sanding machines are thus capable of achieving the consistently high-quality results demanded by window-making applications.
Popular manufacturers of such devices include KED KED, SAMCO, MAWEG, MEBLO, ELU and DEWALT.
Rod sanding machines
Rods play a special role in the woodworking industry and are used in the construction of wooden items or simply as decorative elements. When sawn and shortened, rods become useful in tenon joints that are used to securely connect components.
The quality and dimensional accuracy required becomes much stricter if the rods are intended for use as structural elements, which is where rod sanding machines come into play. They consist of one or two belt sanding stations arranged vertically. The wooden rod is pressed against the sanding belt by press rollers that rotate in the opposite direction to the belt, which ensures the rod stays in the same position and is consistently machined around its length and circumference.
Well-known manufacturers of rod sanding machines include: EHEMANN, SCHUMAG, LOCATELLI, HEMPEL, CAMAM and WINTER.
Cylinder sanding machines
Cylinder sanding machines use a combination of roller and belt: a sanding cylinder. This is a cylinder with defined dimensions that is adhered to a sanding belt. The machines are technically simpler than belt sanding machines and more precise in operation than fladder machines.
The advantage of this design is that the cylinder can be as wide as needed (almost limitlessly) and it is thus more reliable at machining large boards than belt sanders, whose belt is prone to ripping, especially where there are large workpieces. With cylinder sanding machines, this is simply not possible.
Well-known manufacturers of cylinder sanding machines include: DANKERT, HOLZMANN, JET and ZIMMERMANN.
What to be aware of when buying a sander for wood?
Machine frame
The main benefit of sanding machines for wood is that they are technically simple which, when combined with a sturdy design intended for industrial use, means that there is little to no wear on key components. The machine table, frame and guidance mechanisms are generally very robust and intended for indefinite use.
Wear parts
When it comes to wear parts, however, there is great deal of wear and tear with which to contend: the bearings, in particular, are in need of frequent replacement. The electrical components as well (primarily the motors and switches) are not intended for continual use over many years. The use of extraction, however, can help extend the life of electrical components in wood polishing machines since, if left to accumulate, the fine dust created can cause short-circuits and clog up the machine.
Maintenance
Those looking for a used sanding machine or polishing machine for sale can look forward to low maintenance expenditure and minimal down-time. Thorough cleaning and replacement of critical components is generally sufficient for transforming an old, used machine into a perfectly serviceable device.
