Timber band saw
Saw drive power
4 KW Elektrisch
for sawlogs up to 50 cm in diameter
SERRA FE 50
Mini sawmill for sawlogs up to 50 cm in diameter
Sawmill for less than 5.000 €? It’s not a mistake! The purchase of this machine for those who are going to process a small amount of wood from time to time is absolutely the right decision. Farmers, small carpentry and furniture workshops successfully use these machines on their farm.
During the development of this machine, special attention was paid to the ease of operation and ease of maintenance. These important points, combined with high performance and low price, have been successfully implemented.
machine lengthening possible
depending on the diameter of the log, the size of the lumber and the number of auxiliary workers
depending on the configuration of the machine
The machine bed is delivered to the customer disassembled. Thanks to the use of new, high-precision technologies for manufacturing the components of the bed, its installation does not take much time. Standard sawing lengths of 3.60 m, using 2.25 m long extension sections, virtually unlimited cutting length. Log installation, clamping, tilting. everything is done manually.
The saw motor power (narrow band) of 4 kW is sufficient for sawing logs with a diameter of up to 50 cm, while the maximum cutting width can be up to 40 cm. Saw tension and saw guide feed (carried out) manually. The use of carbide in the saw guide system has reduced data wear to almost zero. The water supply system for the kerf prevents wood-resin hardening on the saw body and working pulleys.
Machine control is built on an intuitive level and operator training does not take much time. Thanks to the manual feed of the saw unit, the operator always knows how fast he can cut. The operator is moved from the opposite side of the sawdust discharge, which distinguishes this machine from almost all machines of this class and significantly reduces the cleaning time at the end of the working day. The use of special, disposable, bimetallic saw blades eliminated the need for sharpening. After cutting 8. 10 cubic meters of wood, the saw is simply disposed of.
Saw band selection
Today, band sawmills are very widespread, due to their affordable price and quite acceptable cutting quality. It’s no secret that the quality of lumber obtained when sawing with a band sawmill and productivity in general depend on both the design of the sawmill and the band saws that are used on it. One of the main problems associated with band sawing is the relative fragility of band saws. When studying the properties of tape blades during the period of operation, it was found that the breakage of the saw is preceded by the formation of cracks in the interdental cavities, caused by metal fatigue under alternating loads. This significantly reduces the performance of the band sawmill, increases the financial costs of repair and preparation of saws, creates a danger for the frame operator and auxiliary workers. To achieve the maximum performance of your saw band, the following rules must be followed:
- clean logs before sawing
- sort the logs
- observe the rules of installation and tension of the saw band
- follow the manufacturer’s recommendations
As practice shows, frame operators do not always adhere to the recommendations of band saw manufacturers. Therefore, for the normal operation of the sawmill, it is necessary to select a band saw that would be able to work in the most severe conditions, including continuously during the shift, without removing the sawmill from the pulleys.
So how do you choose a band saw? To begin with, it is worth deciding on the type of saw, paying special attention to its operating parameters. Currently, the Russian market offers a wide variety of band saws from various manufacturers. Saws made of carbon steel are widely represented, there are saws with a hardened tooth. The performance of this category of saws is very dependent on the manufacturer and can vary widely. Band saws of some unscrupulous manufacturers are cracked in the first hours of operation.
The best choice for today. these are bimetallic band saws, it is they who are able to withstand prolonged loads and frame errors. On average, a bimetallic saw cuts about 50 cubic meters of wood, which in terms of their cost will be 50.75 cents per cubic meter of wood. Very high resistance to cracking, allows some frames to cut up to 100 cubic meters of wood with one saw! The bimetal saw can grind from 34 mm to 18 mm and still work without breaks! It is known that the smaller the diameter of the pulleys and the thicker the saw blade, the higher the likelihood of cracking. Bimetallic band saws are very beneficial in this regard, they are also selected depending on the type of sawmill and the type of wood being cut, but at the same time their resistance to cracking is an order of magnitude higher than that of conventional carbon steel saws. When choosing a bimetallic saw, as well as conventional saws, you should pay special attention to the thickness and width of the blade.
Saws can be installed on the sawmill, the blades of which are equal in width, the width of the pulleys, and re-sharpened, that is, narrower. In practice, narrower saws are used much more often than saws of equal width to the pulleys. Therefore, in most band sawmills, structurally, the upper point of the convexity of the pulley rim is displaced by 0.25 from the center of the rim to its leading edge. Right choice. the width of the saw coincides with the width of the pulleys, increased by the depth of the cavity, approximately 1-3 mm. The saw band is positioned so that the tooth valleys protrude 2-4 mm beyond the pulleys. On sawmills with rubberized pulleys, these dependencies are less important. After you select the band saw in width and thickness according to your sawmill, the next thing to pay attention to. this is the step of the tooth. Today, the most versatile band saws are with a pitch of 19 mm and 22 mm. The selection of the pitch depends on what kind of wood you will cut and on its hardness. Strips with a pitch of 19 mm allow sawing both hard and frozen wood, and freshly cut wood, with a slight increase in the set of teeth. It should be noted that for sawing large diameter logs, traditional pitch blades are better suited. 22 mm. Regarding the step of the band saw, framers often have difficulties in connection with the imperfect design of the sharpening device.
Sharpeners used for sharpening band saws are adjustable and non-adjustable. Non-adjustable ones are designed for sharpening saws with a certain pitch, for example, 22 mm and do not allow sharpening the blade with a different pitch. In this regard, many frames are forced to use band saws with a certain tooth pitch when cutting any wood, under any conditions.
When buying welded band saws, you should make sure that there is no change in the tooth pitch at the place of the weld, which is quite common on narrow saws. Therefore, it is better to start sharpening the canvases from the place of welding, and ending with it. Quality band saws should not have bulges at the weld.
Band saw for sawing wood
The utility model relates to the sawmill and woodworking industries, in particular to band saws for sawing wood. The task of the utility model is to expand the arsenal of band saws for sawing different types of wood in different climatic conditions in summer and winter. The technical result consists in the implementation of this purpose, as well as in increasing the cutting speed while improving the cutting quality, in reducing the power consumption, i.e. saving energy and extending the life of the saw band. The technical result is achieved by improving the band saw, including a band saw blade with teeth made with sharpening angles of the front angle of 4 ° or 7 ° or 9 ° or 10 ° or 13 °, the rear angle of 32 ° or 34 ° or 39 ° or 29 ° or 30 ° and a tooth pitch of 22, 225 mm, defining the tooth profile 4 ° / 32 °; 7 ° / 34 °; 7 ° / 39 °; 9 ° / 29 °; 10 ° / 30 °; 13 ° / 29 °, with a 90 ° cutting edge angle, formed by a tooth height of 5.6-7.6 mm, and with a set of teeth to the left. to the right. straight.
The utility model relates to the woodworking industry, in particular to band saws for sawing wood.
A useful model is known (Patent RU 108732, published: 09/27/2011), including a blade with teeth made with sharpening angles of the front and rear edges of the teeth, respectively, 10 ° and 30 ° and setting the teeth according to the right-left scheme with the setting value on the side 0, 38-0.50 mm. The saw is used with a width of 32-40 mm with a tooth pitch of 22 mm.
This saw is intended only for fine cutting of frozen wood and does not provide the achievable removal of sawdust in other applications.
Known utility model (Patent UA 81004, published: 09/27/2011), including a blade with at least one tooth, made with sharpening angles of the front and rear edges of the teeth, respectively, 10 ° and 30 ° and the setting of the teeth according to the scheme. The toothing scheme is carried out according to the scheme to the right. to the left. directly with the value of the tooth opening towards 0.52 ± 0.70 mm. The radius at the junction of the blade with the tooth is 1.24 ± 0.2 mm, the height of the tooth is 6.25 ± 0.05 mm. The cutting edge of the tooth tip, like the entire edge of the tooth profile, is formed strictly perpendicular to the body of the blade.
This technical solution eliminates the disadvantages of the above technical solution. Achieved the ability to cut a limited type of wood.
The disadvantage of this saw is the implementation of this saw of one tooth profile and this does not give a wide range of possibilities to use it for sawing different types of wood with different hardness and density in different climatic conditions, on different sawing machines and the possibility of increasing the cutting speed.
This utility model is the closest analogue to the claimed solution, i.e. prototype.
The technical result consists in the implementation of this purpose, as well as in increasing the cutting speed while improving the cutting quality, in reducing the power consumption, i.e. saving energy and extending the life of the saw band.
The technical result is achieved by improving the band saw, including a band saw blade with teeth made with sharpening angles of the front angle of 4 ° or 7 ° or 9 ° or 10 ° or 13 °, the rear angle of 32 ° or 34 ° or 39 ° or 29 ° or 30 ° and a tooth pitch of 22, 225 mm, defining the tooth profile 4 ° / 32 °; 7 ° / 34 °; 7 ° / 39 °; 9 ° / 29 °; 10 ° / 30 °; 13 ° / 29 ° with a 90 ° cutting edge angle, formed by a tooth height of 5.6-7.6 mm, and with a set of teeth to the left. to the right. straight.
Band-saw. multi-cutter machine tool for sawing wood with an endless (closed) flexible steel band with teeth. The belt is driven by pulleys on which it is put on. Corresponding band saw geometry allows ripping cuts.
The band saw consists of a steel band saw blade with teeth one at the edges in the amount of at least three.
The geometric parameters of the saw are strictly balanced and optimally correspond to the type of wood being cut, engine power and are determined by:
The band saw tooth profile has been developed and verified experimentally over the years and is an intelligently capacious product that has been tested on millions of cubic meters of wood and is 4 ° / 32 °; 7 ° / 34 °; 7 ° / 39 °; 9 ° / 29 °; 10 ° / 30 °; 13 ° / 29 ° with a tooth pitch of 22, 225 mm.
The essence of the utility model is illustrated by drawings. FIG. 1. shows a diagram of a band saw, where C. tooth pitch, A. tooth height, E. front angle of the tooth (angle of engagement), P. back angle of the tooth.
FIG. 2. shows the diagrams of a band saw with tooth profiles (sharpening angles) 4 ° / 32 °; 7 ° / 34 °; 7 ° / 39 °; 9 ° / 29 °; 10 ° / 30 °; 13 ° / 29 °.
The band saw (Fig. 1) contains a blade (1) with teeth (2) made with sharpening angles of the front angle of 4 °, or 7 °, or 9 °, or 10 °, or 13 ° (3), rear angle of 32 °. or 34 °, or 39 °, or 29 °, or 30 °, or 29 ° (4) (Fig. 2), with a set of teeth according to the scheme to the left. to the right. straight, with a cutting edge angle of 90, the tooth pitch is 22, 225 mm, and the tooth height is 5.6-7.6 mm.
The rake or hook angle (forward tilt of the tooth) allows the teeth to sink themselves into the wood. The teeth must grip enough wood for the saw to sink itself into the wood. The value of the hook angle is selected in such a way as to reduce the feed force. If the rake angle is too large compared to the feed rate, it will rattle the saw and make a rough, poor cut (washboard). If the angle of engagement is too small, you will have to force the saw into the wood, which reduces the cutting speed, and as a result, in most cases, reduces productivity. Too large or too small a rake angle will increase the load on the blade, especially in the sinuses, resulting in cracks and premature saw rupture. The rake angle is determined by the hardness of the wood. The angle of the tooth engagement should be selected based on the type of wood you are sawing. Softwoods require large sharpening angles (10 °.13 °). Hard, frozen or knotty wood requires smaller tooth angles (4 °.10 °). 10 ° tooth engagement is a good, versatile profile recommended for most sawing applications.
The back angle of the tooth is formed from the front angle and determines the overall geometry of the tooth.
The height of the tooth must be large enough to allow the cavity to carry all sawdust out of the cut. Saws are supplied with different tooth heights depending on the tooth profile. Saws designed for cutting softwood have taller teeth. Saws for cutting exceptionally hard wood or frozen logs have shorter teeth. Band saw tooth height is 5.6-7.6 mm.
Tooth pitch. the distance between each tooth from one apex to the other. The sawtooth pitch is 22.225 mm and should always be the same. Tooth pitch calculation is based on the linear speed of the saw, with the option of using less power.
Tooth divorce. the distance by which the tooth is bent beyond the plane of the saw blade, and is performed according to the scheme to the left. to the right. straight, suitable for sawing different types of wood. Tooth cleavage is an important factor in the saw’s ability to cut and is necessary for the blade (from the bosom to the back) to move smoothly in the cut. The setting of the sawtooth setting, depending on the hardness of the cut wood, is set at 0.46-0.76 mm. The setting can be considered optimal when there is a mixture of 65-70% sawdust and 35-30% air between the saw blade and the tree it is sawing. An outward manifestation of the fact that the saw is set correctly is that approximately 80-85% of sawdust is thrown out of the cut).
Tooth profiles in band saws for sawing wood in the claimed utility model are made in six versions and are intended for:
Profile 13/29. specially designed for cutting soft, restructured rocks. This profile allows you to increase the cutting speed.
Profile 10/30. universal profile, designed for sawing both soft, medium-hard and hard wood.
Profile 9/29. designed for cutting hard and frozen wood with high density.
Profile 7/39. designed for sawing very hard woods on machines with a motor less than 15 kW.
Profile 7/34. designed for sawing very hard woods on machines with a motor of more than 15 kW.
Profile 4/32. designed for cutting super-hard and frozen wood species, recommended for industrial machines in winter.
Table 1 shows the indicators of band saw tooth formation.
|Front corner||Back corner||Tooth pitch||Tooth profile||Cutting edge angle||Tooth height||Divorce scheme|
|4 °||32 °||22,225 mm||4/32||90 °||6,3 mm||To the left. to the right. straight|
|7 °||34 °||7/34||6,3 mm|
|7 °||39 °||7/39||6,3 mm|
|9 °||29 °||9/29||5.6 mm|
|10 °||30 °||10/30||6,3 mm|
|13 °||29 °||13/29||7.6 mm|
The sharpening of the tooth profile is carried out on a BMS500 or BMS250 sharpening machine, and setting on a BMT100 or BMT200 or BMT250 or BMT300 adjustable machine, manufactured by Wood-Mizer.
When sharpening with Wood-Mizer grinding equipment using the corresponding profiled grinding wheels, the tooth profile, its derivative tooth height and tooth pitch remain unchanged.
Thus, the claimed utility model provides a technical result, using less power, the use of a band saw of the appropriate profile allows you to cut any wood species with different hardness and density in different climatic conditions, while maintaining the high quality of the material obtained.
Band saw, including a band saw with teeth made with sharpening angles of the front angle of 10 ° and the back angle of 30 °, with a set of teeth according to the scheme, with a tooth cutting edge angle of 90 °, characterized in that the saw is additionally made with sharpening angles of the front corner 4 °, or 7 °, or 9 °, or 13 °, back angle 32 °, or 34 °, or 39 °, or 29 °, defining the tooth profiles 4 ° / 32 °; 7 ° / 34 °; 7 ° / 39 °; 9 ° / 29 °; 10 ° / 30 °; 13 ° / 29 °, while the tooth pitch is 22, 225 mm, the tooth height is 5.6-7.6 mm, and the teeth are set according to the left-right-straight pattern.
How to choose a band saw for wood?
In this article, we will tell you in detail how to choose a band saw for a band sawmill, what types of saws are there and how they work.
Almost all sawmakers and businessmen who have a band sawmill face the task of how to choose a band saw. Which saw will cut for a long time, which will cut exactly which saw you can sharpen less often, these and other questions arise from our clients. And so, everything in order.
All band saws for sawing wood can be divided into two categories
- Carbon saws. made of high quality carbon steel C75 and its analogues
- Alloyed saws. made of alloy steel D6A or its analogs with increased wear resistance and resistance to alternating loads.
Also, all saws for sawing logs or saws for band saws are supplied in several versions:
- Saw with a serrated tooth, profiled. Band saw with uniform hardness, that is, the body and the tooth have the same hardness ≈ 40–45 HRC, these saws, like all the others, are welded into a ring, but before work they need to be sharpened and diluted on special machines. Plus these saws in cost, this is the cheapest option. The disadvantage is the low resistance of the tooth until the next sharpening and the need to prepare the saw for work. The advantages are the low cost of the saw and the ability to cut wood with a variety of inclusions such as nails, stones, splinters. It is used on sawmills, the daily productivity of which does not exceed the cutting of 2-4 m of sawlogs. The work is carried out at minimum feeds. 6-10 m / min.
- Saw with a sharpened and set tooth. this saw has the same hardness of the tooth as the body of the saw, the only difference from the first group is that it is already sharpened and divorced, you can immediately start work and, accordingly, it is more expensive.
- The saw is ready to work with a hardened tooth. has a set, sharpened and hardened tooth tip (a black tooth). Hardening increases the hardness of the sawtooth to a hardness of 60-65HRC, which increases its wear resistance. The durability of such a saw is usually 2 times higher than a saw without a hardened tooth.
The tooth is hardened in several versions
- With weak tooth retention. when the upper part of the tooth tip is hardened
- Medium hold
- Strong tooth fixation
The stronger the fixation of the tooth by hardening, the better the saw holds the divorce and works more steadily in the cut, but also a tooth with strong fixation easily breaks when trying to re-dilute it.
Bimetal Band Saw Blades
These saws consist of two materials: a body made of D6A steel with a hardness of ≈ 40–45 HRC and a laser welded to the end of a tooth of ≈ 1.5 mm with a fast cut with a hardness of ≈ 65 HRC. The fast cutter can be of various brands, mainly M-2, M-42, “Matrix”, which provide slightly different wear resistance of the cutting edge of the tooth. The belt undergoes a special treatment that normalizes (leveling) the steel structure along its entire length.
The work on these saws is divided into two stages:
Work with maximum productivity at feed rates of 15–20 m / min, with high-quality sawing. The number of sawn logs between sharpenings is 2–5 m 3. The number of sharpenings is 7–10 times. The work is carried out at high feed rates. 15-20 m / min.
2. Thanks to normalization, the saw body becomes so homogeneous that it acquires additional unique properties. The resource of the cutting edge increases by 20–25%, that is, between sharpening the saw can cut already 1–1.5 m 3 of the sawlogs. The number of possible sharpenings is 45-50. The work is carried out at medium feeds. 8-12 m / min.
Manufacturers: BAHCO (SANDFLEX), Simonds, Morze, ARNTZ, LENOX.
Note. Normalization is a complex multi-stage technological process. The resulting saw becomes almost uniform along its entire length, that is, a minimum number of stress concentrators remains in it. In ordinary saws, there are often many such concentrators. Under alternating loads, microcracks appear in these places after a certain time, which grow into cracks, and the saw breaks. The normalization process, with proper saw preparation and a tuned sawmill, increases the saw life by 2-3 times.
Band saw for cutting frozen wood
The utility model relates to the sawmill and woodworking industries, in particular to the preparation of band saws for sawing frozen wood. A band saw for cutting frozen wood, includes a blade with teeth made with sharpening of the front and rear edges of the teeth and setting the teeth according to the scheme with the setting value per side by the same amount, while the teeth are made with the setting according to the scheme: right-left. This setting eliminates the presence of a straight cleaning tooth, and increases the number of cutting teeth, while increasing the efficiency of the saw.
The utility model relates to the sawmill and woodworking industries, in particular to the preparation of band saws for sawing frozen wood.
From the prior art, a crown of a clean-cutting saw is known, including teeth arranged in groups, each of which contains cutting and undercutting teeth with a 10-30 ° rake angle sharpening and a setting of undercutting teeth on the side of 0.2-0.5 mm. When sawing wood, the moisture content of which is higher than 30%, it is allowed to set the cutting teeth, but with a smaller amount of divorce in comparison with the undercutting teeth. (RU, p. 2053868, В27В 33/08. This saw is intended only for fine cutting of wood.
As a prototype, a band saw was adopted for sawing frozen wood with a front angle sharpening of 8-10 °, with a tooth pitch of 19 mm, with a wiring size of 0.40-0.48 mm and a wiring diagram: right-left-straight. The straight tooth acts as a cleaning tooth and removes sawdust from the cutting zone. (Www / wmstan.ru/ articles / 1/1 rekomendatsili-lentochnyh-pil / Recommendations for the use of band saws when used on sawmills.)
A significant drawback of this saw is the wiring diagram: right-left-straight.This wiring diagram assumes the presence of a cleaning straight tooth for removing sawdust, which, as practice has shown, is not necessary, since when sawing frozen wood, little sawdust is formed and takes them out into the gap between the set teeth. In addition, the presence of a cleaning tooth reduces the number of cutting teeth, which affects the efficiency of the work, namely. reduces the efficiency of the saw.
The technical result of the claimed technical solution is to increase the efficiency of the saw by increasing the number of cutting teeth of the saw. The technical result is achieved by the fact that the band saw for sawing frozen wood includes a blade with teeth made with sharpening of the front and rear edges of the teeth and setting the teeth according to the scheme with the amount of setting per side by the same amount, while the teeth are made with the setting according to the scheme: right-left.
The implementation of the claimed saw for sawing frozen wood with a set of teeth, made according to the scheme: right-left, excludes the presence of a direct cleaning tooth, which is not necessary when cutting frozen wood, since when sawing frozen wood, little sawdust is formed. The absence of a cleaning tooth leads to an increase in the number of cutting teeth in the saw, which contributes to an increase in the efficiency of the saw.
Band saw for cutting frozen wood, includes a blade with teeth made with sharpening angles of the front edge of 10 °, rear edge of 30 ° and setting the teeth according to the scheme: right-left, with the amount of setting on the side. 0.38-0.50 mm. The saw is used with a width of 32-40 mm with a tooth pitch of 22 mm. Sharpening of teeth is carried out on grinding machines manufactured by Woodmaser and Westron. Moscow, and the wiring on the adjustable machine of the Baltic company IRM.
When sawing frozen wood with a set of teeth according to the scheme: right-left? sawdust, and few of them are formed, are carried out in the gap between the set teeth. This saw allows you to work at temperatures from 15 ° and below. The lower the temperature, the greater the setting value, which prevents sawdust from sticking, and as a result, a decrease in the load on the saw. Using this saw when cutting frozen wood can increase productivity by 40-50%.
Band saw for cutting frozen wood, including a blade with teeth made with sharpening angles of the front and rear edges of the teeth, respectively, 10 ° and 30 ° and a set of teeth according to the right-left scheme with a set value per side of 0.38-0.50 mm.
Bandsaw complexes. Quality cut technology
The arrival of bandsaws in the woodworking industry was a breakthrough in quality. The technology based on band sawing made it possible to reduce the proportion of waste, obtain lumber with increased strength properties, and optimize the process of cutting the workpiece. Having passed the way from the model workshop, “band sawmills” are now increasingly taking the lead in modern sawmills.
The prototype of the band saw unit in primary cutting machines was actually a small machine used for sawing curved furniture pieces. The operator manually fed the bar along the table to the “running” narrow belt in the form of a ring, dressed on two pulleys (Fig. 1). The teeth were carved into the belt so that they could easily saw the wood along the specified path. Perhaps this invention remained only in the service of fine craftsmen, if not for the trends that have become priority in the field of primary timber processing.
The development of a fundamentally new approach to this problem, which became known as the radial sawing method, and led the developers to the creation of band saw complexes (Fig. 4). Cutting from the peripheral regions of the log section (Fig.6b) required that the workpiece be turned over several times during the rip sawing process. All dimensions. thickness, lumber arrangement were calculated in the process of cutting optimization based on the principle of maximum selection of high-quality boards. Only such a blank, with the same high mechanical properties over the entire end area, is suitable for further splicing and obtaining a high-strength bar for load-bearing building structures. Another essential point is the use of a special type of tool. a band saw, which minimizes the proportion of chips. Suffice it to say that the transition to this type of processing raises the percentage of finished product output to 65-72%!
Band saws are often referred to as band saws, after the name given to traditional primary sawing equipment. The band saw is mounted on two steel pulleys with a special convex profile (fig. 1). The tensioning mechanism creates the force necessary for stable operation of the saw unit, which prevents slipping or slipping of the band. In powerful machines with a tool width of 100-200 mm, this value reaches several tons! The protrusion of the teeth over the edge of the pulley is adjusted using the tilt device to an angle α (Fig. 1), not exceeding 1-3 degrees.
Another advantage of the band compared to the gang saw is the high and stable cutting speed. It communicates from a rotating drive pulley. To exclude the oscillation of the tool, in addition to its tension, a special damper pos. 6 (Fig. 4), brought by the operator to the cutting zone as close as possible. Thus, the resulting sawn timber has very good surface roughness indicators, corresponding to the export GOST.
The existing model range can be conditionally divided into two broad groups. with vertical (Fig. 2) and horizontal (Fig. 3) arrangement of the tool. The horizontal layout is most often found in small-sized complexes consisting of a slipway, on which a workpiece that is stationary during cutting and a saw unit moving along it is fixed. The characteristics of such systems are offered in tab. one.
A combination of indicators such as a relatively low cost from 150,000 rubles. and mobility have made these light series models very popular where other requirements are not high. It should be added that for greater maneuverability, machines of this class are produced on a chassis in the form of a trailer and can have autonomous drives such as internal combustion engines running on liquid fuel.
But for mass production of lumber, with processing volumes of 50 m 3 per shift, powerful units with a vertical orientation of the band saw are preferable. A block diagram of one of them is shown in Fig. 4. The saw unit is stationary and mounted on a special foundation.
The log is installed on the carriage pos. 1 moving along the rails. Fixation takes place with paired clamps pos. 4 so that the force connection does not touch the surface of the carriage. This subsequently minimizes wear on the guide bars. In this position, the workpiece can move in the transverse direction together with the racks pos. 2 and longitudinal. with a carriage pos. 1. Requirement of technology. the rotation of the log occurs by extending the special chain rotators pos. 5 until the required position is reached.
The whole complex is controlled by one operator using a combined control panel. Its place, depending on the modification, can be located both on the carriage and next to the machine. Since machines of this class have high productivity, most of the functions in them are mechanized. In particular, the movement of the saw damper occurs on command, with the inclusion of an electric or hydraulic drive.
After the saw, pos. 8, it is tensioned by the upper pulley pos. 7. As in the previous case, both mechanical and hydraulic tensioners are found in various models. The unit is started up by the drive pulley pos. 9. It is necessary to note a number of features of such nodes.
- Saw widths vary from 100 to 250 mm.
- Pulley diameter 1000-1400 mm
- The drive power is also significant. from 22 to 55 kW
- The presence of a protective cover, a pulley cleaner from surface contamination, a saw damper pos. 6 with controlled vertical position.
- The presence of a device for drip lubrication of the tape, which prevents the adhesion of wood resin and facilitates the cutting process.
The most important indicator of the operation of the complex. the straight cut of the workpiece has, in addition to the already known components, one more. the straightness of the movement of the carriage pos. 1. And here the guarantor is the precise installation of the guide rails, as well as the massiveness and rigidity of the structure, which compensates for all shock and load loads. Modern models have a moving part mass of 3500-5000 kg. To accelerate them up to standard speeds (and on the reverse, “idle” run, they can reach more than 100 m / min.), Powerful, high-torque drives are required, eliminating jamming during the working stroke of the carriage and, accordingly, the workpiece. In this capacity, hydraulic motors with a power of 5 kW or more with the possibility of smooth speed control by the hydraulic system throttle have proven themselves well.
Number of racks pos. 2 when choosing a model depends on the length of the workpiece (tab. 2) and determines the cutting geometry.
The technology of high-quality cutting of the workpiece necessarily involves the formation and use of the base edge. This is done at the first transition. When a whole log has just been placed on the carriage. The transverse movement of the racks pos. 2, the required protrusion of the workpiece beyond the cutting plane is achieved, and the working stroke begins. At the end point, the sawn slab is separated from the log and thrown off the machine.
Then the workpiece is rotated by 180 °. At the same time, special stops are extended pos. 3, with which the resulting reference surface is in contact. The log is again fixed with clamps pos. 4, the movement cycles of the legs and carriage are repeated.
The band saw complex is built into the technological line, as a rule, according to the typical scheme shown in Fig. 5. Logs are fed along the transverse conveyor through a log feeder or a piece-by-piece log feed device. Here, you can fully assess the ability of the carriage to compensate for the loads from rolling half-ton blanks even from a height of 100-200 mm.
Next, a cyclical cutting of a log is performed with alternate discharge of either a slab, or a board, or a bar onto the receiving conveyor. The task of the transportation system is in operational recognition and the corresponding direction of this or that semi-finished product. If the function of the band saw is to obtain a half-bar with subsequent sawing on a multi-saw machine (maximum productivity), then, if necessary, without additional efforts, the head machine can completely take over the production of sawn timber (maximum share of finished products).
The performance of a band saw is evaluated by means of cyclograms. For a rough estimate, we can assume that the average feed rate is 20-30 m / min., The return stroke is 2 times faster. The speed of transverse movement can be neglected, since it is 0.1-0.5 m / s. Significant loss of time occurs at the stage of the first positioning of the log, assessing the quality of the workpiece and planning the cutting plan. Inevitably, malfunctions in the sorting system of the shop, if any, affect the work of the site. If we turn again to the question of the layout of the machine, then the vertical arrangement of the wide saw, firstly, excludes its clamping by the workpiece, and secondly, due to the larger area, intense heat transfer is observed, which prevents the tape from overheating. All this contributes to increased tool life, tool life and, as a result, reduced equipment downtime.
Satisfactory is the indicator for the industrial class of machine tools at the level of 50−70 m 3 of processed raw materials per shift (8 hours). Only in this case, the cost of the complex, starting from 50 thousand. i.e. (on average), comparable to the profit received during 9-12 months of work.
In recent years, in Russia, band saw machines, like no other equipment, have become the subject of replication by dozens of domestic manufacturers. The misconception about simplicity of design, multiplied by a zero marketing forecast, has led to the fact that almost all exhibitions related to woodworking are literally full of “do-it-yourself” ribbons. A natural question arises: are the difficulties of mastering other classes of sawmill equipment so insurmountable??
At the same time, foreign factories are offering new solutions. These include Italian independent gripper systems, hydrostatic positioning drives, replacing traditional screw pairs. As a result, the speed and accuracy of the workpiece is increased by an order of magnitude. In the same vein, a competitive struggle is unfolding to reduce the time for main and auxiliary operations due to the active introduction of automation and telemechanics. Aggregated modules, including up to 4 sawing units and a continuous log supply system, are already successfully operating as part of sawmills with a processing volume of up to 200,000 m 3 of raw materials per year. The uniqueness of the situation is that, despite all these achievements, there will always be supporters of both band and alternative sawing methods, which means that the rivalry of innovative ideas will never stop.
Note: The classic technology of sawing logs. round logs with a diameter of 150 to 1000 mm and a length of 4 to 6 m. is the so-called double-row cutting. In the first row, the log is passed through the sawmill, where the frame saws cut off two slabs, leaving a two-edged bar. This semi-finished product goes to the smaller second row sawmill. Here a half-bar (“carriage”) is sawn into a board with the same tool. Due to the peculiarities of the work, the flow rate does not exceed 5-7 m / min, and the share of waste is 40-45%. But the main limitation of this method is the inhomogeneity of the board in the cross section, obtained by the so-called tangential sawing (Fig. 6a). This is especially evident in lumber extracted from the core of the log, where strength is minimal in its central part. As a consequence, the deformation of the board during subsequent drying. The use of such products is possible only in construction and only in those places where the requirements for the strength of parts are minimal. That is why this type of lumber is also called abbreviated “construction board”.
Reference: A band saw is made from a blank. a steel band with teeth cut on one side. Special steel is used, elastic and susceptible to alternating bending loads, well weldable and wear resistant. Its thickness in the prepared state ranges from 1 to 2 mm. Whereas frame or circular saws make a cut with a width of 4 mm. This difference has allowed band saws to be rightfully considered the most economical tool. The preparation of the saw consists in cutting it off, welding the joint so that the shape of the ring is formed. Subsequently, the welded seam is cleaned, the tool is rolled and sharpened. There are two main ways to form the cutting edges of the teeth. forming-setting or hardfacing of carbide tips. In both cases, the finishing operation will be the sharpening of the front and rear working surfaces of the tooth (for soldered teeth, the formation of side faces is also necessary). The saw’s durability is relatively low. from 2 to 4 hours of intensive work until the next sharpening. Nevertheless, with the correct organization of the technological cycle, this indicator is fully justified by the overall economic effect of such production.
Important note: the automatic control system of the log sawing complex is configured in such a way that the zero transverse coordinate coincides with the base surface of the retractable stops pos. 3. This greatly facilitates the positioning task. It should also be noted that manufacturers of such complexes offer a choice of control systems. from the simplest mechanical to digital, with CNC. The latter are capable of storing typical cutting plans in memory, determining the optimal modes and managing the complex as a whole. But regardless of the type chosen, each of them is equipped with a transverse displacement transducer in absolute and relative coordinate grids, which gives the operator the minimum necessary initial parameters for setting up the machine at the next transition.
Non-compliance with thickness: problem in the saw
“Let’s say it’s a straight line. says Janos, while sketching a sawmill. On the one hand, we have a log, on the other. band saw. Depending on the type of equipment, we either push the log to the saw, or the saw to the log. If these two forces meet in the same plane, then, in principle, we cannot cut the defective lumber “.
Each sawmill has its own capacity. It depends on the engine that is installed on it, on the design of the sawmill, on the band saw that works on it. When the machine is just started, a kind of vibration appears, which is a side force and pushes the saw in different directions. The amount and magnitude of these side forces depends on the design of the machine and the manufacturer of the equipment. Even the runout of the “wheels” of the band saw, depending on how well balanced it is in the statically dynamic direction, affects the ejection of the saw. The vibration generated during this process, again, can lead to the appearance of cracks in the saws.
“There is a band saw that needs to be perfectly symmetrical on both sides. explains Janos, again drawing a diagram for better perception of the information. This is due to the fact that when the saw meets the log, and the tooth is asymmetrical, it will not push either in one direction or the other. Consider the main factors that can distort the file in one direction or another. When the band saw enters the wood, spraying creates sawdust that can either be carried away or collect on the surface of the board. If the saw blade itself is not perfectly flat along the plane, then when we start cutting, the saw goes forward and its rear part begins to distort in the direction where it is uneven, and the upper part. in the opposite direction due to sawdust, which cannot be removed normally. This effect is the side force that will push the file to the side “.
To prevent this, good band saws are made so that the surface is flat to the nearest 0.02 mm.
Features of sawing wood using band saws
Productivity is determined not only by how fast the saw moves in the wood, but also the time it takes to feed the round timber to the frame, the time it takes to clean the sawn board. If the frame operator does not want to closely monitor the device, you can check when these parameters were not met and what shortage this entailed.
When Janos Urban, the owner of the A-LAP company, started working with band saws, he was 35 years old. At that time, he did not know anything about them. However, a lot of time has passed since then and now they have become the meaning of his life.
With such a small historical excursion, the fascinating seminar “Advantages of A-LAP band saws”, organized by this company, began. However, despite the name, they talked mostly not about the advantages of the company, but about what generally breaks saws and really bad spraying. is it their fault?
The seminar was conducted by Janos Urban himself, who explained each issue in detail with the help of diagrams, and was assisted with translation by Robert Chereshnya, financial manager of the company.
Having some experience with band saws, Mr. Janos is confident that at every woodworking company that specializes in sawing wood with band saws, there are two main problems in the process. First. a problem with an equal cut, that is, the saw creates a “wave” and does not provide the required thickness of material to be cut. Second. this is when the saws have cracks and tears. If there are no such problems, then you can only strive to increase productivity.
Despite his rich experience, only recently Mr. Urban managed to formulate the process of sawing wood in one sentence: namely sawing. this is nothing more than a meeting of two opposite forces, and if they are located in the same plane, then problems with m of a given thickness should not arise. However, if such a problem still exists, then what causes it?
Saw without marriage!
At the end of the seminar, representatives of the company demonstrated a device of their own production, which allows the operator of a band sawmill to work at maximum speed in the conditions that he has, without spraying defects and low-quality products.
This device has a micrometer and green, yellow and red bulbs. When the green light comes on, the saw is tilted to the side by 0.1 mm. Even if the yellow light comes on, it means that the spraying is occurring with an error within 1 mm.
According to the developers, the device allows to improve the quality of products, as it helps to avoid scrap and increase productivity, as the frame maker sees at which maximum speed he can cut without scrap. Today, the device is being improved and in the future it will provide information on how long the saw is in the tree for 8 hours, that is, how much time it actually saws, and how much time the frame maker spends on preparatory operations.
Saws (blade) for band sawmills
Band saw table
To make it easier for you to make a choice, below is a table of sizes of horizontal saw bands for sawmills of different types and manufacturers. Bimetallic band saws. these are the most practical and durable saws that require the least maintenance and fine sharpening, at the moment such saws are the most modern type of carbide-tipped saws made of M42 steel, the so-called quick cut.
|Sawmill name and model||Saw length, mm|
|Altai 700, Altai 700A||3570|
|Taiga T1, Taiga T1B||3608|
|Vanguard LP-60 Farmer||3960|
|Wood-Mizer LT15, Wood-Mizer LT20B, Wood-Mizer LT20, Wood-Mizer LT40||4005|
|Taiga T2, Taiga T2B, Taiga T2M, Altai 900, Altai 1000||4026|
|Altai 900 Prof, Altai 900A Prof||4270|
|Taiga T3, Taiga T3B||4290|
|Avangard LP-60, Avangard LP-60A||4850|
|Avangard LP-80, Avangard LP-80A, Avangard LP-80 S.E.N.||5550|
We know about band saws. ALL!
Band saws. it is the most cost effective way to cut wood. Wood band saw is widely used for sawing round wood into planks and squared beams, because it is the most economical way of sawing wood, high precision and minimum waste. With all the characteristics, band saws require proper maintenance, namely sharpening and setting the teeth. Sharpening a band saw requires experience and sharpening skill. We supply sharpening and adjustable machines all over Russia, they will facilitate the work of the sharpener and will allow to nullify all the mistakes made during sharpening and wiring. The sharpening machine for band saws can be with a narrow and profile sharpening wheel. The wiring is done with an adjustable machine using a divorce sensor. pressure gauge.
Three types of band saws for wood: bimetal saws. band saw hardened tooth, band saws profiled tooth for sawmills and band-dividing machines, the price is different.
SPECIFIC FEATURES OF BAND SAWING MACHINES FOR ROUND FOREST CUTTING
Baranov A.V., process engineer,
Belarusian State Technological University
The first band saws appeared in the late 19th and early 20th centuries. These were hand-operated narrow band saws designed for the needs of farms. Currently, this type of machine is almost the most common for sawing round timber in small and medium-sized enterprises in the woodworking industry. In this article, we will consider the capabilities of modern sawmill equipment and the features of its use.
Sawing process on band saws
A band saw is a multi-cutter tool that looks like an endless thin band with teeth along the working edge. Moving linearly and progressively, it separates the wood, and its feed movement is in most cases uniform, and the trajectories of the teeth in the cut are parallel to the straight lines of the mowing line.
Narrow and wide band saw blades
At the household level, these machines are usually divided into narrow-band (with a saw blade width of 30–40 mm) and wide-band (saw blade width exceeding 100 mm). Machine tools of these types differ in both productivity and size and specifics of working with saw blades. For example, let’s compare the technical characteristics of a narrow-band machine made by the company “Taiga” of the Russian Federation (Table 1) and a wide-band machine Mebor Slovenia (Table 2).
Analysis of these tables shows that the main advantage of wide-belt machines is their high productivity. It is achieved, first of all, by increasing the width of the saw blade and the associated height of the tooth, which should not exceed 20% of the width of the band. Going beyond this limitation leads to a decrease in the strength characteristics of the web. With an increase in the height of the tooth, while maintaining the step size, the amount of sawdust removed from the cut increases, which means that the speed and productivity of sawing increases.
On a narrow blade, in order to avoid jamming the saw during operation, a so-called divorce is performed. On the one hand, this has a positive effect on its work, and on the other hand, it imposes restrictions on the cutting speed, since each of the three saw teeth takes out only 33% of the sawdust from the cut. At the same time, in wide-band saws, due to the higher tooth height, it is possible to flatten or solder the carbide tip.
Above. the work of the teeth of a narrow band saw; below. the work of the teeth of a wide band saw
But despite all the advantages, wide band saws have their own specific features.
The specifics of the work of wide-band sawing machines
One of the main design features of a wide-belt machine is the convex profile of the saw pulleys and their mutual rotation relative to each other. Consider the conditions that ensure reliable fixation of the tensioned saw on the pulleys and compensate for the thermal elongation of its leading edge.
The cost of a wide band saw is many times higher than a narrow band saw, respectively, its choice and preparation methods require special attention and special knowledge.
First, you need to pay attention to the quality of the steel from which the saw is made. In our market there are tool steels of the German company ThyssenKrupp AG, the Swedish company Sandvik and the Austrian concern BÖHLER UDDEHOLM.
Secondly, when choosing a saw, it is necessary to pay attention to the thickness of the blade (S), which is related to the diameter of the saw pulleys as follows:
If the thickness of the tape exceeds the value determined by the ratio, cracks form on the blade in the places of rounding of the tooth hollows.
Thirdly, a mandatory rule is a strictly limited operating time of a band saw, which cannot exceed 2–2.5 hours for saws with a blade width of 100–120 mm. over, the restoration of working capacity requires a break in the operation of the saw for at least 12 hours. Saws are usually numbered with a permanent marker. to keep track of working time, resource and maintenance.
On wide band saws, crimped and stellated teeth are generally used. A crimped tooth is made by plastic deformation of the upper front of the tooth to the desired shape and width, followed by sharpening. Stellited teeth are obtained as a result of soldering, welding or surfacing on the cutting part of the tooth of plates made of hard alloys, followed by sharpening of both the mowing line of the teeth and the side edges. The wear resistance of stellite is 3–5 times higher than that of a conventional crimped tooth. The only significant inconvenience of stellated teeth can be considered a complex manufacturing technology that requires special equipment.
The shape and parameters of the saw teeth are determined by the cutting conditions, that is, the type of wood, its moisture content, condition, design and class of the band saw.
Angles and other dimensional values formed when sharpening a tooth are shown in the figure.
α is the clearance angle measured from the mowing line,
drawn through the tips of the teeth;
β is the angle of the tip of the tooth;
γ. rake angle, measured with respect to
well perpendicular from the mowing line, check
data through the tips of the teeth;
h is the height of the tooth;
b. width of the saw blade.
The value of the angle γ has a great influence on the lateral stability of the tooth. Its parameters, both for crimped and stellated teeth, are selected in the range of 20-30 °, depending on the species and moisture content of the wood. So, small angles, 20-25 °, are used for working with hard, dry rocks, and angles from 25 ° to 30 °. for soft and wet.
Rolling is of great importance in preparing band saw blades for work. This is longitudinal rolling of the blade with roller rollers with the application of force to certain zones of the saw (see article in No. 2, 2012 “Rolling wide band saws. Practical advice for beginners”. ed.)
The frequency of the tracks and the pressure of the rollers are selected so that the entire blade lies in the shape of a pulley, similar to a flat belt stretched on it.
Rolling is also necessary to give the saw blade the required stress state, which is then maintained throughout the entire operation. A new blade must be rolled on pulleys for at least 30 minutes in an idle state, and a previously operated blade must be rolled in at least 5 minutes before starting sawing to stabilize internal stresses.
After rolling and during operation, the band saw blade must remain level, free from kinks and twists. The maximum deviation from a straight line can be 0.05 mm (± 0.025 mm). Measurement is performed with a standard measuring ruler on the plane of the rolling workbench along the entire blade, in all directions, not excluding the saw teeth, as this is the only reliable way to detect bent teeth.
A loose saw blade is an unacceptable defect. In the general case, it is subject to correction. straightening. There are three main types of defects. abyss (bulging), slack (stretching), tie (compression).
How to mill lumber with a band saw
Rolling a wide saw band How to check the flatness of the saw blade
However, it must be remembered that everything we do with a saw band to fix a defect is not really a fix. Any our impact on the metal changes its structure, that is, creates a new defect, as a result of which the saw blade acquires the required shape and condition. The correctness of the defect identification and the minimum impact on the metal of the saw are the determining factors of the quality of work, affecting the resource of the tool and the reduction of maintenance work. Therefore, the skill and qualifications of the saw blade are of great importance.
Of course, in one article it is impossible to describe all the subtleties and nuances of working with this type of equipment, but we still hope that the information provided will serve the readers well and help in solving everyday work tasks.
Metabo bas 261 precision
The band saw for wood gives excellent cutting quality, has three steel rollers, ensuring reliable operation. Equipped with a cast iron bed with a tilting rotary table, which allows for tilting sawing. Provides low noise and vibration levels during operation, which increases comfort. The belt is changed quickly and without additional tools. For convenience and increasing the accuracy of work, there is an LED flashlight that illuminates the cutting area. A vacuum cleaner can be attached to the machine to clean the table from chips.
Density, size and pitch of teeth
The setting is the alternate bending of the teeth in different directions: the first to the left, the second to the right, the third in the center. The more the saw teeth are tilted, the less heat the machine and saw band get. Correct dilution prolongs the life of the equipment, produces a clean cut and reduces vibration. If the teeth are not set enough, the sawdust will stick to the surface of the board. If the saw is set too far apart, there will be tooth marks on the board.
A blade with a certain tooth pitch is selected for each wood:
- 19 mm. requires increased engine power and low feed, easily handles frozen wood.
- 22 mm. common saw blade.
- 25.4 mm. found on 5 cm wide saw blades, used in high speed work.
The higher the height of the tooth, the easier it is to handle hard or frozen wood, as well as logs. Small teeth are chosen for thin board and shape cutting.
With a low density of teeth, the load on the part decreases, with a high density, it increases.
After each start, it is necessary to re-sharpen the saw band. In this case, you need to ensure that the step remains the same.
Enkor Corvette 31M 90311
The Russian band saw, thanks to its small size and weight of 17 kilograms, takes up little space and is easy to move. The work table is made of aluminum, has an additional extension for cutting long workpieces and tilts up to 45 degrees. This saw is designed to cut wood quickly.
Technical parameters and design features
The band saw consists of:
- C-shaped cast or welded bed.
- Upper and lower pulley.
- Toothed blades.
- Electric motor.
- Brake mechanism.
- Guide ruler.
Machines with horizontal saw installation are considered the most powerful, they are able to cut not only frozen wood, but also hard tree species. The best band saws for wood are used in sawmills.
The Japanese band saw is equipped with a 2.5 meter long cord, which allows you not to look for a place for it next to the outlet. For convenience, there is a branch pipe for connecting a vacuum cleaner, which reduces the cleaning time. It is not cheap because of the high build quality and materials, which means it will last several years without breakdowns. A powerful motor is installed, protected from overheating and overload. A special feature of this saw is the figured cutting of wood. The work table tilts to any side up to 45 degrees. There is a spot illumination of the working area. If something goes wrong in the work, the machine can be stopped by pressing one button.
Jet jwbs 9x
The inexpensive bandsaw has won a place in the ranking due to its excellent woodworking result. Its disadvantage is low power, but it does not interfere with the work. Thanks to the belt drive, the machine generates a minimum of vibration. Workpiece thickness. 2 cm. The band saw is easily controlled and adjusted before each job. Equipped with a wing screw for quick adjustment of the band tension. The working area is illuminated by a lamp for comfortable work in a dimly lit room. A graduated scale is available for cutting the workpiece at the desired angle.
Proma PP-250 25601250
The small band saw is designed for sawing plastic and wood products. Has a swivel stop for easy cutting at an angle. Equipped with an economical electric motor that does not require regular maintenance. The body has a branch pipe to which you can connect a hose from the vacuum cleaner. A blunt band saw can be easily changed without the need for additional tools.