Sharpening cutters for wood: manual work, using grinding wheels and a grinding machine. Sharpening and manufacturing of hobs

In the modern variety of services on the market building materials, it is easy to find help in sharpening cutters.

But don't rush this work you can do it yourself. This is typical not only for work on sharpening cutters, but also for other types of work.

The standard milling machine has two chucks of different configurations. One of them for three spade cutters, and the second for two and four spade cutters. err in this case difficult, because if the number of cutter feathers is not set correctly, it will not be possible to insert the cutter into the chuck.

Having decided on the choice of cartridge, you can proceed to the direct stages of sharpening cutters:

• sharpening on a ribbon;
• edge sharpening.

Ribbon sharpening

One of the appropriate cup sockets must be used. From standard set collets we select the corresponding collet in size (8 mm, 10 mm, 12 mm).

We put the collet into the chuck and fix it with a clamping nut. This procedure is done without any effort, the clamping nut rotates freely and does not need to be tightened.

1. In the nest of the glass, we set the length of the tape to be sharpened. As a rule, this distance is adjusted by unscrewing the screws located in the cup socket. By moving the bottom of the socket up or down, select the length, and then fix the screws back.
2. We install the cutter in the chuck through the upper hole, while setting the diameter of the cutter and the sharpening angle on the adjusting screw in advance. We fix the prepared cartridge in a glass, while correctly setting the lines of the cutter in relation to the element to be sharpened. That is, with its grooves, the cutter should cling to the pin.
3. Then we turn on the machine and with the feed regulator we bring the cutter to the grinding wheel until the sound of contact begins and we sharpen the cutter's ribbon from all sides. Removal of metal from the cutter being sharpened can be reduced and increased using the regulators installed on the machine. This adjustment is necessary when changing the diameter of the cutter and correcting existing irregularities on the machined cutter.

Edge cutter sharpening

To sharpen the cutter on the end, you must use the second socket for the cartridge located on the machine.

In this case, you need to do the steps described earlier to set the diameter and length.

1. Depending on the hardness of the metal being processed, the settings on the socket are set. The harder the metal, the more the socket ring turns towards the “+” sign.
2. Next, turn on the machine, insert the prepared cartridge with the cutter into the socket and process the part until the characteristic noise stops. Each groove of the cutter is machined.
3. In the additional socket of the machine, the cutter is sharpened from the end, for which the above steps are performed.
4. The last operation is the processing of the back wall of the cutter, which is carried out by inserting the chuck with the cutter into the corresponding socket of the machine.
5. Thus, the cutter was sharpened in compliance with all the required geometric features separately and in relation to each other. Sharpening is uniform on all sides.

Do-it-yourself cutter sharpening

This procedure can be performed by yourself and use improvised means.

Such an opportunity will save money, and in case of repeated use, it will save valuable time.

1. First, we clean the cutter from soot, for which we use a special liquid, similar to those used to clean car engines. It is necessary to fill the cutter and wait about three minutes, then clean the cutter from all sides with a brush.
2. Next, we take a diamond bar and begin to sharpen the cutter along the leading edge (the movement of the cutter channel along the diamond bar).
3. The bar is wetted with ordinary water. After sharpening, wipe the cutter with a cloth.

The quality of manual sharpening differs significantly from sharpening using a special machine, but the manual version saves time.

2016-11-04

Sharpening cutters - hard work requiring special training and equipment. The geometry of the cutting edges has a curvilinear structure - this is what main feature process. The grinding wheel must follow exactly the contour of the cutter's sharp teeth in order to maintain its shaped profile.

• The backed teeth are sharpened along the front surface.
• Sharply protruding teeth are processed along the back wall.
• Slitting and cutting cutters are sharpened on the front and back sides.

How to sharpen cutters?

Can be sharpened manually or with grinder for cutters.

Rice. one .

The machine provides synchronization different types movement and fixation of the cutter. For example, to sharpen end mill, it is necessary to combine translational and rotational movements, while maintaining a uniform clamping force of the tool to the grinding wheel. Great importance has a rotation speed, abrasive grain size, its material.

• Electrocorundum abrasive wheels are suitable for sharpening milling cutters for metal and wood (the material of manufacture is high-speed or tool steel of the “Standard” class).
• Elborovy (CBN) circles sharpen cutters from high-speed steel of increased productivity.
• Diamond (PCD) and silicon carbide wheels are used to sharpen the teeth of carbide cutters.

It is important to take into account that strong heating reduces the hardness of abrasives and leads to a partial loss of cutting properties. Below is a table of thermal stability of the main materials used for the production of abrasive wheels.

Rice. 2.

To cool the grinding tool during operation, water alone will not be enough - the machine will rust. Masters advise adding soap to water and soda ash, nitrite, sodium silicate, etc. - electrolytes create a protective film on the surface of the grinding wheel.

There are over 20 grinding wheel configurations for sharpening milling tools. The rear planes of the incisors are ground with disk-shaped or cup-shaped circles, the front ones - with flat or disk-shaped ones.

Rice. 2.1

Automated sharpening modes

It is impossible to sharpen carbide tools in "hard" modes of operation of the machine - chipping of the edge of the teeth is possible.

The average circumferential speed of a grinding wheel for processing hard alloys should not exceed 10 - 18 m / s. This means that for a circle d 125 mm, 2700 rpm is the maximum rate of engine rotation. For softer materials, it is enough not to cross the threshold of 1500 rpm.

Milling cutter sharpening technology on the machine

The cutter is fixed in its original position, then the machine is turned on and the tool is slowly brought to the grinding wheel (until it sparkles). There comes the moment of setting the thickness of the removed metal layer, usually not higher than 50 microns and not less than 25 microns.

Sharpening is done on each tooth separately. The needle of the machine must constantly be in contact with the surface of the cutter, start sharpening by placing the needle in the tail groove of the tooth. The loan turns on the machine and, gradually retracting the spindle with the cutter, perform the procedure.

The skill of a professional lies in maintaining a uniform sharpening course on all cutting edges. The same movements will need to be repeated several times for each tooth.

Different types of cutters require different movements.

How to sharpen a cutter by hand?

A shaped end mill for sticky materials (wood) can be sharpened by hand without resorting to expensive equipment. You will need:

• work table and plank in steel or hardwood;
• diamond bar;
• abrasive wheel;
• solvent;
• water with soap or alkali;
• sandpaper.

Rice. 3 .

The diamond bar is fixed on the edge of the table, moistened with soapy water. The cutter must be freed from the bearing (if any), cleaned from the remnants of wood resin. The size of the front angle of sharpening varies in the range:

• 10 - 20 ⁰ for wood cutters;
• - 5 - 0⁰ for tools for metals (mainly for steels).

The range of the sharpening angle of the back surface is wide and not limited by the indicators.

Sharpening is done with smooth movements on a diamond bar.

It is necessary to try to make the same number of movements of the cutter along the bar with the same pressing force. As the cutting edges sharpen, the graininess of the abrasive decreases, the final stage of processing can be done with sandpaper.

The result of sharpening is evaluated visually using a magnifying glass or kerosene. The teeth should not contain even small notches and cracks. To detect microcracks, the surface of the cutting edge is moistened with kerosene - kerosene will show through more in the area of ​​the crack. Notches and micro-cleavages are determined by eye or through a magnifying glass.

If you succeed with proper quality, and you know how to carefully use the tool, then the need for sharpening comes much later than in cases with low-grade products. Big choice high-quality cutters (about 20 types) are always available in the Rinkom store. It is convenient to choose and order tools of the widest profile on the Internet, today it is not dangerous and modern.

Cutter sharpening operations maintain the technical and physical characteristics of the parts, thereby extending their working life. There are many approaches to the implementation of such activities, the choice among which is determined by the nature of the operation and the design of the element. The intensity of cutter wear largely depends on its design, based on which the master selects maintenance modes.

For example, the selection of a method for regrinding high-speed parts is guided by the wear of the front surface. On the other hand, sharpening cutters on the back surface is more suitable for shaped elements. Therefore, it is important to take into account as many operational factors as possible, which will allow you to make the right choice of processing technology.

Types of cutters

Such elements are widely used in the processing of parts on copying, molding and tenoning, milling and other machines. As a rule, this is woodworking equipment, although there are also parts for working with metal blanks. Cutters differ in size, shape and purpose.

In general, two categories of elements are distinguished - end and mounted. The former are distinguished by the presence of a shank, which is fixed in a special niche of the spindle. Products of the second group have a central hole, which allows them to be mounted on the working spindle and securely fixed. Accordingly, such sharpening of cutters differs more high level quality, not to mention the ease of handling parts for the operator. Attached elements can be composite, solid and prefabricated.

A feature of this group is the possibility of forming cutting tool from several milling parts. It is also worth noting the category of end mills, which can be prefabricated and solid. The elements are also divided according to the quality of the backed processing. So, sharpening of cutters with relief surfaces is carried out along the front edge in order to maintain the basic angular indicators.

Mill maintenance

Despite the use of high-strength alloys in the manufacture of cutters, long time operation leads to erasure, as well as deformation of the faces. Over time, worn elements are disposed of, but before the expiration of the working life, the master can restore the characteristics of the part using measures Maintenance. It is important to bear in mind that sharpening cutters allows not only to endow them with the same geometry, providing quality work. This procedure also increases the life of the element, reducing tool consumption. But this does not mean that any cutter can be restored in this way.

Technologists do not recommend bringing the tool to a state of complete wear. Manufacturers of cutters indicate in the markings technical and operational values ​​that are limiting for a particular element, and after overcoming them, the cutting edges cannot be restored.

sharpening process

To perform sharpening, special milling machines, equipped with spindles with an average speed of up to 24,000 rpm. Before starting work on them, the master balances the cutters. It can be done in two ways - dynamic and static. In the first case, the procedure is performed on special machine, which provides not only balancing the force, but also the moment acting on the cutter during rotation. This technique is especially relevant for cases when the cutter is sharpened for metal.

Machine tools for balancing according to the static method involve only balancing the force acting on the cutter. The element is fixed in the frame, after which it is balanced through a device consisting of two horizontal guide knives. Directly sharpening is carried out on special high-precision equipment.

Machines are produced in different configurations, involving both manual and automatic control. Common to all units of this type is the presence of a working surface on the guides. This design solution makes it possible to achieve high accuracy in moving the element, as a rule, with an error of 0.005 mm.

equipment requirements

To ensure high-quality sharpening of cutters, you should not only use the equipment suitable for this task, but also properly prepare it. First of all, the equipment spindles must have sufficient vibration resistance, rotate freely and have minimal runout. Further, the feed mechanism must work stably in all directions provided for by the design without delays and with minimal gaps. The elevation angle settings are of great importance - this parameter should also contain high accuracy. For example, sharpening a worm cutter, which is performed on automatic machines, involves setting both a certain angle of elevation and a helical groove pitch. If they are used grinding wheels, then it is important to ensure a secure fit of the replaceable washers and spindles, due to which the working element is precisely fitted.

End Mill Machining

The processing of end elements is most often done manually on universal grinding equipment. Typically, this technique is used to update the performance of a helical tooth tool. In many ways, sharpening end mills is similar to updating cylindrical cutters with a cup wheel. This applies to operations that require the end mill to be centered. seat. Also, similar sharpening is performed on semi-automatic models. In this case, end mills with a diameter of 14 to 50 mm can be serviced. In this case, the processing is suitable for both the back and the front surface.

End mill sharpening

Milling cutters made of as well as some elements equipped with carbide plates are sharpened in assembled form. Main rear surface end mill is sharpened by a grinding cup wheel. Before performing the same operation on the plane of the secondary rear side, the element is first installed so that its cutting edge is in horizontal position. After that, the axis of the cutter rotates horizontally and at the same time tilts in a vertical plane. In contrast to the scheme, according to which end mills are sharpened, in this case, the position of the workpiece is changed several times. Work with the front surface of the tooth can be carried out by the end part of the grinding disc wheel or by the disk wheel from the peripheral side.

Working with disc cutters

On the rear main surface, the processing of disk elements is carried out by a cup circle. The auxiliary rear surface is made by analogy with end mills, that is, by turning the cutting edges horizontally. At the same time, the features of processing the end teeth of such a tool are noted. In this case sharpening disc cutters is performed along the front surface so that the processed teeth are directed upwards. The cutter itself at this moment should occupy a vertical position. The angle of inclination of the element axis along the vertical must correspond to the position of the main cutting edge.

Features of sharpening cutters for wood

End fittings are sharpened without special devices, usually with a thin diamond bar. This element either lies on the edge of the desktop, or, if the cutter has a deep recess, it is fixed additional tool. The cutter is inserted along a fixed bar. During processing, the bar is periodically wetted with water. When the procedure is completed, the master thoroughly washes and dries the product. As the front surfaces are ground down, the edge becomes sharper, but the diameter of the tool will decrease. If the cutter has a guide bearing, it must be removed first and then the operation can be continued. The fact is that sharpening a cutter on a tree along with a ruined bearing can lead to damage to the element. It is also necessary to clean the tool from the remnants of wood resins with a special solvent.

Features of sharpening cutters for metal

Such elements are less common and at the same time require less effort in the preparation process. Processing is done using grinding wheels suitable grit. In this case, the materials can be different, in particular, the use of parts made of ordinary or white electrocorundum is also common. If you plan to sharpen end mills for metal, made from tool steel, then it is recommended to choose electrocorundum discs. For products with higher characteristics, it is desirable to use CBN wheels. The most productive and efficient sharpening parts are made of silicon carbide. They are used to service cutters made of hard alloys. Before work, the abrasive is cooled, as high temperature loads during the operation can adversely affect the structure of the circle.

Processing of relief milling cutters

Relief elements are used in cases where it is required to increase the stability of the cutting part and reduce surface roughness. The teeth of a relief cutter are processed along the front surface in such a way that after regrinding in a radial section, the profile of the functional edge retains its original parameters until the part is fully exploited. Sharpening of such cutters is also carried out in compliance with a strictly established rake angle. In the case of processing sharp-edged elements, it is necessary to maintain a constant pointing angle.

Finishing cutters

In essence, this is an operation designed to correct the result obtained during the main sharpening process. As a rule, finishing is performed in order to ensure optimal roughness or in cases where it is necessary to correct the sharpening angle of the cutter with working edges. The techniques of abrasive and diamond finishing are quite common. In the first case, the use of fine-grained silicon carbide wheels is assumed, and in the second case, diamond discs on a bakelite bond are supposed to be used. Both techniques make it possible to handle, among other things, carbide tools.

Sharpening quality control

During the verification process, the master evaluates the geometric parameters of the cutting surfaces for compliance technical requirements. In particular, the runout of the cutter is determined, as well as the degree of roughness of the finished or sharpened planes. Auxiliary devices can be used in the control of parameters directly at the workplace. For example, if the end mill was sharpened on wood material, then the specialist can measure the angles along the working edges. For this, a goniometer is used, in which the scale is presented in the form of an arc. Special ones are also used to evaluate other parameters, again, most of them are focused on checking the geometric data of the cutter.

Conclusion

The need for machining cutting tools persists even in the age of high technology. The only change in this regard has been with the milling equipment control systems. Appeared automatic devices, allowing to optimize the process of handling blanks. However, milling cutters, bits and other processing metal elements are still performed using abrasives. Of course, there are alternative technologies that allow you to restore the geometry of parts, but so far there is no need to talk about their wide distribution. This applies to laser technologies, hydrodynamic machines, as well as installations that have a thermal effect. At this stage of their development, for economic reasons, many enterprises still prefer traditional methods sharpening.

Enough is being produced today a large number of cutters of various sizes. They can be classified according to functional and constructive qualities.

Sharpening of end mills is carried out using special devices for such tools. In some cases, sharpening can be done manually.

The cutters have a relatively large length and uneven teeth for cutting. In the process of sharpening, you will need to take care of the movement of the base of the circle along the edge. In this case, it will be necessary to sharpen the shaped cutters that have a backed corner. You should know that sharpening is quite difficult. To preserve the profile of the structure and facilitate the sharpening process, the backed teeth will need to be sharpened exclusively along the front base. Sharp teeth, which have a flat or curved shape, must be sharpened exclusively along the back base. Slotting and parting cutters can be sharpened on the front and back bases of the teeth.

Tooth geometry

The geometry of the teeth of the cutter: a - sharpened tooth, b - backed tooth.

To sharpen correctly, you need to know the geometry of the teeth of the cutter. According to the design of the teeth, cutters with backed and sharp teeth are distinguished. At last part the rear base, which is adjacent to the cutting edge, is a plane. Teeth with sharp ends in most cases are sharpened along the back base, but they can also be sharpened along the front base of the tooth.

The backed teeth, which come with end mills, have a back base made in the Archimedes spiral. It is quite difficult to process a shaped base technologically, therefore it is possible to sharpen cutters with backed teeth only along the front base.

Regardless of the number of teeth in the cutter, each of them can be considered as a separate tooth, which is characterized by typical parameters for a tooth - the angles of the front and back, the size of the grinding area, and the angle of the teeth.

The sharpening platform is an element of the back base of the tooth, which is subjected to grinding during sharpening along the back base. On this basis, the maximum wear of the teeth will occur. Its size affects the magnitude of the friction force between the tool and the workpiece, so the base must be maintained in a specific range.

The scheme of sharpening prefabricated cutters on a universal grinding machine.

The basic rake angle is the angle between the tangent to the front base and the base of the axis. It can be measured in a plane that will pass through a given point perpendicular to the main cutting edge.

The main back angle is the angle between the tangent to the back base at given point the main edge for cutting and the tangent to the plane of rotation of this point. This angle helps to reduce friction between the tool and the workpiece.

With the help of the auxiliary rear angle, it is possible to characterize a large gap between the milled base and the body of the clove. It is necessary to sharpen the tool along an additional angle with a specific amount of damage to the tool and an increase in the area for sharpening. The purpose of this action is to reduce friction between the tooth and the workpiece to be milled. You should be aware that not all tools of this type have this angle.

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How to sharpen end mills for woodworking?

The shape of the teeth can be straight or helical. The inclination of the tool teeth can be described as the angle between the developed edge of the helical type and the axial part of the tool.

The values ​​of the tooth angles will depend on the type of tool, the grade of alloy and steel from which it is made, as well as the type of material that the tool is intended to mill.

When milling viscous materials, the main rake angle should be selected in the range of 15-20° or more. For instruments from solid metals for steel milling, the angle will be 0° or -5°. The rear angle varies over a wide range.

Items you will need:

1. Diamond beam.
2. Table.
3. Water or soapy solution.
4. Solvent.
5. abrasive paper.
6. Hardwood plank or steel strip.
7. abrasive circle.

It is possible to sharpen shaped end mills without special devices for sharpening, along the front base, with a diamond bar of small thickness. The beam must be installed on the extreme part of the table. If the tool has a large recess, then the tool must be fixed along the table.

Heat resistance table various materials, °C.

When sharpening, the timber will need to be moistened with clean water or a solution with soap. After sharpening, the tool will need to be washed and dried.

In the process of sharpening the front base, the edge will become sharper, but the diameter of the tool will decrease slightly.

If a bearing is installed on the tool, then the first step is to dismantle it, and then sharpen it. Trying to save time in this case may end up with a damaged bearing and a broken cutter.

Be sure to clean the cutter from excess resin from trees. For this, it is best to use a solvent.

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In the process of sharpening tools, it will be necessary to use bars of different grain sizes. The grit will depend on the thickness of the removed layer of material and the desired cleanliness of the base. Before sharpening, you will need to make sure that the timber has the right shape.

Figure 1. Grinding wheel shapes.

If the teeth of the cutter are made of a relatively soft material, instead of a bar, abrasive paper can be used, which is glued to a flat base. As a base, you can use a plank of hardwood or a steel strip.

End mills for milling wood are sharpened on a special device with a low speed of rotation of the circle. In this case, you will need to use a suitable abrasive wheel.

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Sharpening wheels

Sharpening of modular cutters can be done with circles of white or ordinary electrocorundum, diamond and others. For example, using electrocorundum wheels, you can qualitatively sharpen milling cutters for working with metal and wood, which are made of tool or other standard steel. Elborovymi circles have the ability to sharpen high-performance steel structures. Silicon carbide and diamond wheels are used for sharpening hard metal cutters.

By increasing the temperature, the hardness of such a device decreases. A temperature of 1000°C can reduce the hardness by almost 2 times. At a temperature of 1300 ° C, this indicator will decrease by about 6 times.

Figure 2. Sharpening of the end mill: a - the main cutting edge, b - the auxiliary cutting edge, c - installation diagram of the cutter for sharpening the teeth of the auxiliary cutting edge.

The use of water to reduce the temperature in most cases leads to rust on the workpieces and corners of the machine. To eliminate corrosion, soap and some electrolytes must be added to the water, which can form films for protection. When grinding, a solution with soap or soda is almost always used. If fine grinding is performed, then a low-concentration emulsion should be used.

In order to increase the quality of grinding with an abrasive wheel and reduce significant damage, it is recommended to select the maximum grit that can provide the necessary cleanliness class of the base of the used cutter.

The circumferential speed of the wheel during sharpening of hard metal teeth should be approximately 15-18 m/s. For example, in the process of using a circle with a diameter of 12.5 cm, the engine speed should be approximately 1600-2700 rpm. If it is necessary to sharpen more brittle materials, the operations must be performed at a lower speed. In the process of using tools made of hard metals, the use of a hard mode leads to the appearance high voltage and cracks, and in some cases damage to cutting edges. Wheel wear in this case will increase.

Wheel shape for sharpening the rear corner of the teeth on the base cylindrical shape should be cup or plate. To sharpen the front corner, you need to use a disc-shaped or flat-shaped circle.

The existing forms of grinding wheels can be seen in (Fig. 1).

Such an operation as sharpening a wood cutter is not so simple. This process requires certain knowledge and skills.

Buying cutters for wood in Kiev and other cities is not a big problem now. But sooner or later the highest quality of them will become dull, and then it will have to be sharpened. How to do it right?

Wood cutter: basic sharpening rules

The teeth of the product can be completely different. The slope of these elements can be different and is characterized by the main part of the edge. The parameters for determining suitable teeth depend on the tool, as well as on the features of the product you have chosen.

The process of sharpening the cutter can do without special expensive equipment, since diamond bars of small thickness can be used. In this case, you need to use plain water or a liquid with a soapy solution. When the sharpening process comes to an end, it is worth washing and drying the tool.

First, the cutter must be dismantled. The main thing is that you do not forget to clean it from resins and wood. A conventional solvent can cope with these tasks.

To effectively solve these problems, you must make a choice in favor of quality materials. If you do not do this, then the work will not bring the desired result.

• you need to use bars with different grit levels. This setting depends on the material you are about to remove;
• An important role is played by the purity of the base, determined by you initially. Before you start the sharpening process, you should make sure that the timber will be the shape you need;
• symmetry is preserved only if you try to create a configuration similar to the movement of the cutters during the process of sharpening the product;
• if the material of the teeth is rather soft, then replace the beam with abrasive paper, which will provide a perfectly even base;
• end products are sharpened on the device that is intended for this. The wheel does not rotate too fast, so you will have to buy an abrasive product.

Of course, the process of sharpening the cutter takes a lot of time. However, this resource will pay off over time, because you will do your job with maximum effect.

These are the main points that relate to this area of ​​\u200b\u200bactivity. You must take into account all the nuances in order to achieve the maximum result, because all other rules will not provide you with the same effect.

Fast cleaning and sharpening of cutters for wood. Or how to sharpen an end mill with your own hands: