Product size quickly adjusted using special rulers by moving the right and upper spindles (the left and lower spindles are adjusted within a small range to compensate for tool wear)
Innings blanks occurs through a powerful gearbox using two pairs of upper and lower, grooved, spaced apart from each other. This solution makes it possible to increase the reliability and accuracy of supply of workpieces of insufficiently good quality and high humidity (unlike the grouse located nearby).
Four-sided machine "START 5x210" complete with system of continuously variable feed speed control, allowing you to optimally adapt to the available material for work.
Exact workpiece position in two planes is provided by special support plates running almost the entire length of the desktop and paired spring-loaded rollers. The pressing force of each roller is independently adjustable over a wide range. The paired design of the rollers allows the pressing force to be evenly distributed.
Precision grinding of working shafts four-sided machine "START 5x210" guarantee the complete absence of axial and radial runout of the tool.
High spindle speed(4500 rpm) allows you to achieve high quality finishing surface. Optionally, it is possible to install one or two upper spindles with a rotation speed of 6000 rpm.
Four-sided planing machine "START 5x210" equipped protection system from reverse ejection of the workpiece.
The bed is designed in such a way that it provides easy access to all important components of the machine, while having the necessary rigidity to eliminate vibration during operation.
Working surface The table is made of especially strong steel, which increases its service life, and is also additionally ground to minimize feed resistance and increase processing accuracy.
Working surface service life amounts to at least 10-15 years However, if necessary, this part can be replaced separately from the rest of the equipment. Replaceable work surface makes the service life of the machine practically unlimited, unlike analogues, where the machine frame and its working surface form a single whole.
The electrical systems of the machine are controlled by an independent mobile console.
The machine can be equipped with a special reception table, with precise height adjustment. Correctly selected height of the receiving table will avoid “undercutting” at the end of the workpiece.
The compact dimensions and light weight of the machine make it quite mobile and easy to install.
The most simplified, but well-thought-out design ensures its high reliability.
Multi-spindle machines are very efficient in saving time when processing wood in large volumes.
Wooden blanks, after sawing, have defects, such as surface unevenness, cracks, etc., which must be eliminated before proceeding with their further processing.
To eliminate these defects, milling machines are used, through which each of the four surfaces of the workpiece is processed separately.
When the volume of wood being processed is large enough, it is easier, more convenient and more economical to use multi-spindle woodworking machines.
Such machines are also called. As the name suggests, all four planes of the workpiece are machined, or gouged, simultaneously.
It can have from 4 to 10 spindles, depending on the requirements for the final type of your product. Simply put, the number of spindles depends on the complexity of the profile of the product that you want to obtain at the output of the machine.
consists of the following main parts:
- Working and serving tables;- Feed and eject rollers;
- Lower and upper spindles;
- Right and left spindles;
- Additional spindles for creating complex profile shapes;
- Universal spindle.
The feeding table has clamping elements and the ability to adjust the frame vertically, which allows you to pass workpieces of various thicknesses through the machine.
For example, in order to make a heavily deformed surface smooth, it is necessary to remove a large number of wood, on the other hand, direct wood harvesting requires the removal of very little material (removing only band saw marks is sufficient).
In a situation where it is necessary to straighten a piece of wood entering the machine, a pressure roller is used, located in front of the first upper spindle. An additional pressure block located in front of the first lower spindle is used for thin material that does not need straightening. This option can be disabled via the machine control panel.
At the initial stage of the material passing through, it is very important to achieve smoothness on the bottom and right sides of the workpiece, which are the basis for further operations to give the desired shape to your product.
Another method of straightening wood, using a grooved table, is most suitable for processing hard wood. In this case, the first lower cutting block forms grooves on the underside of the workpiece, shaped like the pattern of a grooved table, which reduces friction between the workpiece and the tabletop and evenly feeds the material for further processing.
But this method of straightening wood requires the four-sided machine to have another lower spindle, the cutting unit of which will remove the intermediate grooves and level the lower surface of the product. The work table can be equipped with a manual or automatic feeding system for waxilite, a resin-dissolving lubricant, to facilitate feeding of the workpiece. In the case of processing resinous wood, the presence of an additional lower spindle is also necessary to remove waxilite from the underside of the workpiece.
Feed rollers of four-sided planer
Feed rollers can be equipped with spring or pneumatic cylinders. The rollers must be properly designed to provide maximum traction and minimum wear.
Vertical spindles of four-sided planer:
Vertical spindles require a high-quality and flexible adjustment system, otherwise it will take a lot of time to change the type of profile and, accordingly, the diameter of the tool.
Quick adjustment of the vertical spindles allows for optimal contact between the workpiece and the work table.
When the vertical spindles of the four-sided planer are in a clearly fixed position, the diameter and working height of the cutting tool, as well as the feed speed and pressure of the feed rollers are adjusted simultaneously through the digital control panel. High-quality adjustment of the left vertical spindle guarantees high quality gouging, and is especially important when working with hardwood.
Top spindle of four-sided planer
The top spindle is the first right vertical spindle of the machine. The cutting tool located at the top position can be used both for planing the surface and for profiling the workpiece. A good four-sided machine should produce up to 40 mm of profiling on the top horizontal/vertical spindle.
Universal Spindle for Four Side Planer
The planer can be equipped with an additional universal spindle to achieve greater profiling flexibility.
Four Side Planer Options
The four-sided planer can be equipped with additional optional devices, such as: an additional feed device after the upper horizontal spindle, a grooved work table for processing hardwood, extended feed and work tables, increased power of spindle motors and others.
Table. Characteristics of some four-sided machines (characteristics - selling company, model, number of spindles, width of the workpiece being processed, height of the workpiece being processed, minimum length of the workpiece, spindle diameter, rotation speed, feed speed, loading table length, presence of a jointing support, motor power 1 and 4 spindles, motor power 2 and 3 spindles, presence of a molding support, possible positions of the molding support, motor power of the molding support, power of the feed motor, power of the traverse lifting motor, total power of the machine motors, dimensions of the machine, weight of the base machine; manufacturer - BZDS S23-4, Winner, Nortec, Gau Jing Machinery Industrial Co. Ltd GA-623H, Nortec, Machinery Industrial Co. Ltd GN-6S23, Griggio S.p.A. G 240/5, Griggio S.p.A. G 240/6, BZDS S25-5a Pro, SCM Group Superset NT Plus, High Point M-180, High Point MX-180/5, Ledinek Superles 4V-S150, REX Bigmaster 310-K, SCM Group Topset Master, REX Timbermaster Type U-41-K, MIDA Alfa-500)
Figure 1. Diagrams of feed mechanisms
Figure 2. Scheme of the cardan drive of the feed rollers using worm gears
Figure 3. Options for spindle placement in four-sided machines
See the table and figures in
And the quality of the processed parts largely depends on how uniform this movement is.
Feed mechanisms on four-sided machines
The feed mechanisms of four-sided machines refer to devices with a frictional connection between the workpiece and the elements that feed it. The movement of workpieces occurs due to the adhesion of their surface to the moving working elements of the feed conveyor. In this case, resistance in the form of friction forces applied to them and longitudinal components of cutting forces is overcome.
In four-sided machines, concentrated feed mechanisms of three types were and are used: tracked, roller-tracked, roller - and distributed - roller (Fig. 1).
Tracked feed mechanisms are distinguished by reliable grip of workpieces moved along the table, which eliminates their slipping, and uniform distribution of vertical force, which reduces the straightening of warped workpieces. Such mechanisms are used for feeding short workpieces (for example, in domestic machines of the PARK-8 and PARK-9 models, designed for processing parquet staves) and in many modern four-sided machines based on double-sided jointer-thicknessers - in the area of the jointer support.
Roller-caterpillar mechanisms are also distinguished by reliable grip and high feed force of workpieces. They are used primarily in machines for processing heavy workpieces with large cross-sections, for example, wall beams.
Roller machines, consisting of rollers (rollers are a pair of parallel drive shafts rotating towards each other), were originally used in four-sided machines. These mechanisms are distinguished by their simple design, reliability and low sensitivity to differences in thickness of the workpieces being advanced.
A common disadvantage of concentrated feed mechanisms of all three named types is the advancement of short workpieces end to end; with obliquely cut ends, workpieces can be squeezed to the side and upward, which leads to the need to increase the force of the upper and side clamps in the machine, leading to an increase in the required feed force.
Therefore, the design of most four-sided machines produced today uses a distributed feed mechanism in the form of a set of drive rollers located one behind the other along the entire length of the work table.
The first four-sided machine with such a distributed feed mechanism was introduced in 1960 by the German company Harbs, and today the vast majority of four-sided machines are equipped with them. The advantage of the roller mechanism is the ability to feed workpieces with an inter-end gap and process only one workpiece, which, without being pushed by others following it, is freely carried by drive rollers through the entire machine. Moreover, even when feeding workpieces end to end, the last loaded workpiece does not remain clamped in the machine.
The rollers of such a feed mechanism are installed on a single beam on swinging arms and at the same time play the role of upper clamps. In older machine models, these rollers were pressed against the workpieces by springs, but today pneumatic cylinders are used for these purposes. The beam is lifted along with all the rollers and clamps for adjustment to the processing size using a motorized drive, which also allows free access to the machine’s work table and its spindles for inspection and replacement of cutters.
The working surface of the feed rollers in machines is corrugated. The drive rollers installed behind the finishing cutter are coated with a layer of wear-resistant plastic.
Feed drive on four-sided machines
Rice. 2. Scheme of the cardan drive of the feed rollers with
using worm gears:
1 - beam;
2 - swinging lever;
3 - feed roller;
4 - feed roller spindle;
5 - axis of rotation of gearbox worms;
6 - worm gearbox;
7 - cardan shaft;
8 - machine desktop;
9 - guide ruler
Initially, the rotation of the rollers of such feed mechanisms was driven by a common shaft passing through the entire lifting beam, using bevel gears and chain drives.
But in 1970, the German company Gubisch developed a four-sided longitudinal milling machine
Maud. GN14, in which the cardan drive of the feed rollers was first used, which is used today in the designs of almost all similar machines. In such a drive, each of the feed rollers is connected through a cardan transmission to the output shaft of its worm gearbox, and the worms of all these gearboxes located on the same axis are connected by couplings and rotate simultaneously by one drive (Fig. 2), which is also mounted on the beam and rises with it .
Electric motors with variators of various designs were initially used as such a drive to rotate the rollers, providing stepless control of the feed speed. In modern machines, instead of variators, frequency control of the rotation speed of the electric motor of the feed mechanism is used using electronic converters.
Supports on four-sided machines
Any four-sided machine is equipped with at least four supports: horizontal (lower and upper) and vertical (left and right). In this case, the left calipers can be tilted. In the so-called moulders, an additional universal support is used - moulder.
For the sake of unification, each equipment manufacturer tries to make all these calipers the same. However, their design is significantly influenced by the need for adjustment movements. Thus, for the lower and right-hand feed spindles, radial adjustment is required, and its value is minimal, since it is only necessary to regulate the allowance removed by the cutter installed on them. At the same time, all left and upper spindles, when adjusted to the size of the workpiece being processed, must move within significant limits. All spindles usually also have the ability to move axially to adjust the position of the profile cutters.
Depending on the design developed by the machine manufacturer, the spindle is either an electric motor shaft (motor spindles) or a shaft mounted in bearings and driven into rotation by an electric motor through a belt drive. In the simplest and cheapest machines, one electric motor can simultaneously rotate two vertical spindles.
To transmit the rotation of the electric motor to the spindle, outdated models use V-belts, while modern ones use thin synthetic ones.
The accuracy and rigidity of spindles is largely determined by the bearings in which they are installed. Many manufacturers use conventional bearings to reduce the cost of their machines, while high-precision bearings are used in expensive and high-quality machines.
It is believed that the use of machines with motor spindles is ineffective, since when replacing bearings in them, the rotor balance may be disrupted, which can lead to a decrease in the quality of processing. In addition, in belt-driven calipers, the belt serves as a damper, which prevents engine overload; Replacing it in case of failure will cost less than replacing the motor spindle.
To carry out adjustment movements, the calipers are mounted on dovetail guides or on parallel rolling pins. The movement of the supports along them is carried out by means of a “screw-nut” pair, rotated manually, with position control on a ruler with a vernier scale, or, in machines equipped with an electronic control system, by servomotors controlled by it.
Moulder support for four-sided machine
This name arose from the concept of “kalevka” - a profile cut on the edge of a workpiece. A certain Armin Berner designed his first molding machine in Germany in 1920. And in 1954, the German company Weinig announced that it had received a patent for a multi-purpose four-sided machine with a molding slide that could be rearranged into different positions.
Such a support, depending on the design and model of the four-sided machine, can work in relation to the workpiece only from below, below and left, below and above, below and right, as well as below, above, left, right, or tilt at any angle.
The choice of technological capabilities of this support depends on the cross-sectional profiles of the parts produced by the company.
In most cases, molding supports at domestic enterprises are usually used for making a longitudinal recess on the underside of a machined part, for example, a platband, or for longitudinal cutting of milled blanks into narrow parts.
There is one more nuance: when choosing a machine, many production workers do not even think about the required power of this spindle, which leads to errors when processing parts. Thus, for simplicity of calculations, it is believed that when cutting with saws, making one cut requires engine power at the rate of 1 kW per 1 cm of workpiece thickness. That is, if a molding spindle is used to cut a 40 mm thick workpiece into three parts (with two saws), then the power of its engine must be at least 8 kW.
Power of other spindles on four-sided machines
If we conduct a simple analysis of commercial offers for four-sided machines, transmitted by our machine tool trading companies to their potential buyers, it turns out that for some reason the drive power of the spindles in this equipment is very often the same.
At the same time, the first lower cutter in the machine, which creates the basis for further processing of the part, removes a rather small allowance from the workpiece, and the required power of its drive is lower than what sellers offer. The power of the electric motor of the right cutter may also be insufficient, since it removes the allowance on the edge of the workpiece, which is always obviously narrower than the largest width of the face.
The most powerful of all of these should be the drive of the upper horizontal cutter, which removes the increased allowance, which includes all the inaccuracies in the dimensions of the workpiece in thickness and width. Experience has shown that its engine power should be at least 11 kW. Moreover, this may not be enough if deep profiles are to be processed.
Lack of power in at least one spindle leads to the need to reduce the feed speed, which reduces the productivity of the machine.
Composition and arrangement of spindles of four-sided machines
In Fig. Figure 3 shows, as an example, some of the possible options for the relative arrangement of spindles in four-sided machines. Manufacturers must select them in advance, before purchasing a machine, based on the required profile of the workpiece.
So, with the arrangement of the spindles shown in Fig. 3.1, it is possible to process parts with a rectangular profile or shallow profiling on four sides. The composition of the spindles shown in Fig. 3.2 makes it possible to mill a deep profile on the bottom surface of the part, and the spindle configuration shown in Fig. 3.3, - on the right (feed) edge.
If the composition of the machine components corresponds to that shown on
rice. 3.4, with the help of a molding support placed in various positions, it is possible to make deep profiles on all surfaces of the part and carry out its longitudinal cutting.
An additional lower spindle, as in the diagram shown in Fig. 3.5, makes it possible, for example, when jointing using a comb work table, to level the surface of the lower surface of the part and mill a profile on it using a molding spindle.
To sample a deep profile along the left edge and other surfaces of the part, additional vertical and molding spindles are used (diagram 3.6).
The arrangement of the spindles, corresponding to diagram 3.7, makes it possible to obtain U-shaped profiles, and that shown in diagram 3.8 - H-shaped ones.
The arrangement of spindles shown in Fig. 3.9, makes it possible to mill K-shaped profiles, and the diagram shown in Fig. 3.10, - even more complex, with additional longitudinal grooves.
On machines in which the spindles are located in accordance with the diagrams in Fig. 3.11 and 3.12, it is possible to obtain X-shaped profiles.
The spindles can be sequentially arranged in a different order, for example, in one that allows the allowance removed when forming the profile to be distributed over two or even three cutters. In addition, some profiles cannot be obtained without tilting at least one spindle.
Therefore, leading machine tool manufacturers, at the request of a particular consumer, can produce four-sided machines that have ten or more spindles. Today, machines with non-standard spindle arrangements are often found on the market for refurbished, used equipment.
Noise from four-sided machines
In many countries, the maximum permissible noise level in the workplace is legally set at 85 decibels (dB). Where noise levels exceed this value, protective equipment must be used. In fact, 85 dB is the maximum noise level that a person can be exposed to for eight hours without damaging their hearing. An increase in this noise level by 3 dB corresponds to a doubling of the intensity of exposure and a halving of the permissible time of exposure to sound. At a level of 88 dB, the permissible exposure time will be four hours, at 91 dB - two hours, etc. This means that the ear can tolerate noise of 110 dB for only a few minutes.
But this noise level is typical for all working four-sided machines. And even the presence of noise-absorbing casings on the equipment, which, as a rule, are open at the rear of the machine and have a decorative rather than protective purpose, does not help to reduce it. Therefore, such machines in production should be placed in a special soundproof cabin (Fig. 4), and machine operators must wear antiphons while working.
Four-sided machines are one of the main types of equipment at any woodworking enterprise, and not only the quality of the product, but also the productivity of the enterprise often depends on their correct choice. This means that when choosing a machine, you should pay attention not only to its price, you also need to carefully study the design of such equipment and the offers of potential suppliers, in particular, comparing them with the needs of the enterprise, and only then make the final decision on purchase.
Andrey MOROZOV,
"Media Technologies" company,
commissioned by LesPromInform magazine
Rice. 1. Four-sided machine with belt drive of all units from a single transmission shaft
And indeed, when hewing and shaping a log, a carpenter uses an axe, an adze and a scraper - a simple and imprecise tool. But the carpenter holds in his hands such wonderful plows as a plane, sherhebel, jointer, zenzubel, folded hebel, tongue and groove, molder and others, with the help of which you can not only plan the surface of a board or block, but also shape it with high precision along their entire length profile section. Another thing is how much manual labor and what qualifications this work will require...
Planing or milling?
They knew how to plan wood three thousand years ago, back in Ancient Egypt, and during the excavations of the city of Pompeii, which died in 79 AD. e., planes were found that were very similar to modern ones.
Throughout the long centuries that have passed since then, attempts have been made to mechanize the planing process. And if the first lathe was created by Diodorus Siculus back in the 650s BC. e., then there is no such thing that could be 100% called planing today. Instead, humanity has only milling machines that replace it - jointers, surface planers, milling machines with a vertical spindle (upper or lower) and four-sided ones - in the form of a combination of the previously mentioned ones, which allow processing the workpiece in one pass sequentially on all four sides. But since their use made it possible to abandon manual planing, at the end of the 19th century they were mistakenly called planing by carpenters. And when, after a hundred years, Russian scientists began to understand the classification of woodworking equipment, it turned out that these machines were not planing, but longitudinal milling.
The fact is that planing is the process of cutting wood with a knife, the blade of which moves parallel to the surface being processed. Planing as a technological process involves producing one chip of constant thickness per pass of the knife, for example, flowing curls of chips when planing with a hand plane or planing veneer on special machines when the knife moves in a straight line.
And milling is the process of cutting wood with a rotating cutter, the cutters of which perform cutting while moving along a circular path, while a rectilinear translational feed motion can be performed either by the workpiece or the entire tool. In this case, the processing allowance is divided by cutters (knives) turning along cycloids into a large number of chips, which, due to the kinematics of the process, have a variable cross-section and are shaped like an elongated comma.
The main difference between these two types of processing is that, from the point of view of the geometry of the processed surface, when planing it turns out to be flat, and when milling it turns out to be wavy, formed at the tops of the cycloid trajectories of the milling knives by alternating depressions and ridges.
But the term “planing” has already become firmly established in professional vocabulary, technical literature, and even in woodworking textbooks. And when developing our first GOST for these machines, its creators back in the early 1970s, in order not to make a revolution, were forced to take the term “longitudinal milling” into brackets in its name, leaving the usual “planing” as the main one. Of course, over time it was planned to correct this mistake, but then this good intention was somehow forgotten...
Nevertheless, four-sided are called “longitudinal milling machines designed for flat and profile longitudinal milling of wood blanks in one pass from all four sides along the cross section.”
History of the Quadrilaterals
It is believed that the inventor of the milling machine for metal processing was the Englishman Eli (Eli) Whitney, who received the corresponding patent in 1818. But soon such machines began to spread in woodworking. The first "planing and molding" machine - the forerunner of modern four-sided longitudinal milling machines - was patented in 1827.
The spread of such machines was hampered by the lack of an individual drive. The drive was group, that is, common and unified for all machines, and was carried out from the shaft of a water wheel, and later from the shaft of a steam engine, passed through the entire workshop, and from it came separate belt drives for each rotating unit. It is clear that it was very difficult to connect several drive belts to all four spindles located in a four-sided machine both vertically and horizontally, as well as to the feed mechanism (Fig. 1).
The victorious march of woodworking machines driven by their own electric motor began in 1907 with the creation of the DC Pattern Miller machine by the English company Wadkin. And 20 years later, in 1928 in Germany, the last large enterprises completed the replacement of the group transmission drive of machine tools with an individual one - from individual electric motors. The era of industrial woodworking began, in the development of technology in which four-sided machines played one of the main roles.
Classification of four-sided machines
Rice. 2. Classic arrangement of spindles for a four-sided machine:
1 - lower horizontal spindle;
2 - right vertical spindle;
3 - left vertical spindle;
4 - upper horizontal spindle
The purpose of four-sided longitudinal milling machines is to mill bars, boards or beams to produce blanks and parts that have a rectangular or profile section that is constant along the entire length.
Area of application: woodworking and furniture enterprises producing molded joinery and construction products and semi-finished products, as well as furniture parts made from solid solid wood.
Over the many years that have passed since their invention, four-sided machines have retained the entire composition of components originally incorporated in them, although they have seriously changed due to improved design.
Any such machine today includes a bed with tables located on it (working and jointing); longitudinal guide rulers; feed mechanism (concentrated or distributed); clamps for workpieces (lateral and vertical); milling units (horizontal and vertical) and control system.
Based on their design, four-sided machines are conventionally divided into three main groups. The first category includes light ones, with a processing width of up to 180 mm. They are intended primarily for the production of molded joinery and construction products (platbands, skirting boards, etc.). The feed speed of such machines is from 6 to 36 m/min (kinematic), the number of spindles is 4-6. The machines of the second group are medium-sized, with a processing width of up to 250 mm. They are used for the production of construction moldings, beams, boards, etc. The feed speed of machines in this group is 8-60 m/min, and for machines for calibrating lumber - 150 m/min and higher with the number of spindles no more than five. The third group is heavy machines with a processing width of up to 600 mm. They are used for processing construction beams, laminated veneer lumber and other similar parts with a large cross-section. There are also extra-heavy four-sided machines with a milling width of up to 2600 mm, used when processing wide laminated boards and beams.
Several decades ago, the first group of machines also included machines with a processing width of 60-100 mm, but recently the demand for such equipment has decreased and its mass production has almost ceased.
There is also a division of four-sided machines according to technological purpose. Typically, machines have, as a rule, only four spindles for processing the workpiece from below, from both sides and from above.
If four-sided machines are equipped with devices and milling units to eliminate curvature (warping) of the original workpieces, then, by analogy with a manual jointer, in professional language they can be called jointers. They have at the input an elongated working (planing) table and units that ensure the creation of a flat base surface on the lower surface and edge of the initial workpieces.
Machines equipped at the output with an additional, fifth, spindle, designed for cutting a deep longitudinal profile on workpieces or cutting them longitudinally with saws into workpieces, are called moulders - by analogy with a moulder plane. Machines that combine the functions of jointing and profile selection and are equipped with appropriate components and assemblies are called jointing-moulders.
The first moulding machine was designed in 1920 in Germany by Armin Berner. While working at Gubisch, he improved the design of the machine and expanded the range of its functions, resulting in the creation of the first four-sided jointing and moulding machine.
Technological diagrams of four-sided machines
Any four-sided machine can be considered as a combination of milling machine mechanisms, grouped on one bed in the order of the sequence of operations for processing parts.
With the classic arrangement of spindles (Fig. 2), the first in feed is the lower horizontal one, which, like the spindle of a jointing machine, creates a rectilinear flat base surface on the lower surface of the workpiece.
Then the first vertical spindle is installed in the machine (usually on the right of the feed), the task of which is to create a flat, rectilinear base surface on the edge of the workpiece, which will be strictly perpendicular to the base formed on its lower surface. The operation of this spindle is similar to the operation of a vertical milling machine with a lower spindle position, which performs the function of edge jointing.
In classical machines, the first vertical spindle is followed by a similar one, but it performs the function of thicknessing to obtain the specified width of the workpiece. The same spindle can simultaneously form a profile on the edge.
The thickness is formed by the upper horizontal spindle by removing the allowance from the upper surface of the workpiece - similar to processing on a single-sided thickness planer. With the same spindle, when installing the appropriate tool, you can also form a profile on the upper surface of the workpiece.
Thus, on a four-sided machine, all four longitudinal surfaces of the part are sequentially processed, which, in fact, predetermined the name of the equipment.
However, in some cases, the sequence of arrangement and the number of spindles in a four-sided machine may differ from those adopted in the classical scheme.
The main importance in this case is the cross-sectional shape of the processed profile. It may have, for example, a large depth of allowance that cannot be removed with one cutter due to the need to greatly increase the diameter of the cutter. The size (depth) of the allowance may be limited by the drive power of one spindle, which will not allow the allowance to be removed completely in one pass. The profile may also have some undercuts that are inaccessible to horizontal or vertical cutters.
In addition, when moving the workpiece through the machine, strict uniformity of this movement must be ensured through reliable contact with the elements of the feed mechanism. But, say, when manufacturing parts with a triangular or similar cross-section, there are simply no surfaces left on the workpiece suitable for contact with the rollers of the feed mechanism, and the final formation of the profile must be carried out by several cutters mounted on supports, which are located as close as possible to the output side of the machine .
All this may lead to the need to use additional horizontal and vertical spindles in the machine, including tilting ones.
But most often, in four-sided molding machines, a fifth, additional spindle is used to form relatively simple profiles, the support of which allows it to be placed above, below, left or right of the workpiece or tilted at any given angle.
A patent for such a universal molding support, adjustable to various positions, was received in 1954 by the German company Weinig.
The number of spindles, compared to the classical scheme, also increases in four-sided jointing machines. The operating principle of this equipment and jointing methods will be discussed in the next publication.
Andrey MOROZOV,
"Media Technologies" company
commissioned by LesPromInform magazine
Improvement of technological processes complicates the equipment and increases the productivity of an individual unit. In carpentry, the four-sided wood lathe combined previously separate operations on one table with a single pass of the workpiece. Cleanliness and precision of processing meets established quality standards.
Possible processing methods
Various heads with blades of different profiles can cut the layer from 4 sides of the blank:
- milling Performs only longitudinal cutting of wood under the groove. A disk-type cutter performs the task of cutting the board. To do this, clamps for the outgoing strips are placed on the receiving side of the table;
- planing;
- jointer
Most industrial models combine several types of cutting simultaneously. Round and square material is processed. Thin sheets of material undergo 2-sided milling and jointing.
Design specifics
The design of a four-sided woodworking machine includes 3 main parts:
- workpiece feeding device;
- spindle section with cutting elements;
- system for setting operating parameters, adjustment, control.
There are models that have several cutting mechanisms installed sequentially along one side of the part (multiple processing).
The speed of the knife shafts is 5000-6000 per minute. In machines of the latest designs, knife shafts are made up to 9000 rpm.
Processing area
The basic setup includes 2 horizontal shafts (top/bottom) and 2 vertical spindles. A head with a straight or shaped knife is placed on the spindle. The shaft rotation is in the range of 5000 - 9000 rpm.
The specified dimensions of the product are set by corresponding horizontal movement of the spindle, seating/raising of the cutting edge, and tilting the longitudinal axis at an angle of up to 25°. The thickness of the board is set by moving the upper shaft vertically.
The assembly layout may include the installation of a 5th planing shaft in order to obtain a profile along the bottom plane of the part.
Additionally, ironing knives are designed to eliminate waves on the surface of the wood from rotating heads. A block of fixed blades located at an angle of 45° to the table plane removes 0.02 -0.2 mm of wood with each edge. The wave crests from the jointer are cut to a specified cleanliness.
Control
Reducing human influence in the mechanical woodworking process increases its functions for accurate measurement, calculation of parameters for software, control of each phase of equipment operation, and the urgent need to correct deviations.
The control points are:
- calculation of the speed of movement of raw materials to maintain the specified processing accuracy;
- placing each individual node in calculated coordinates;
- synchronization of the complex operation;
- cleaning, removal of generated waste.
In individual production this requires a significant investment of time. In continuous production, it provides a significant gain in productivity and standardization of the quality of finished wood products.
Specialization
Installations for multilateral wood processing are complex enough in design to make one universal unit. Woodworking shops use varieties that are sufficient to quickly and accurately produce a certain range of products.
Having chosen a four-sided machine for profiling the timber, they produce a profile with a groove-tenon connection, two even (semicircular) sides. The planing operation can be combined on one machine after cutting the profile. The variety of beam cross-section geometry options is determined by the configuration of cutting attachments.
A carpenter using a four-sided longitudinal milling machine simplifies the work of producing wooden beams for door and window frames, baseboards, cabinet parts, and flooring.
Lumber after a circular saw has a poor surface quality. At the same time, a four-sided planing machine with the required performance allows you to achieve the required dimensional accuracy. It has from 4 to 10 spindles, on which, if necessary, a knife with a grooved blade for wood is placed. This makes it possible to operate the equipment as a machine for the production of profiled timber, based on production tasks.
Choice
Technical characteristics, electrical circuit, operating modes, equipment, programming - all this must be studied according to the manufacturer’s declared data. Features of automation operation, requirements for personnel qualifications, raw materials, and maintenance must be taken into account when organizing the production process, drawing up technological maps. Availability service four-sided milling machine, spare parts for it, will affect the smooth operation.