Manufacturer: Sunmill, production: Taiwan
General information about JHV-710 CNC vertical machining center
Linear guides (standard equipment):
The spindle uses special high-precision bearings that allow it to withstand parameters of 8000 rpm (BT-40) and optionally 10000 and 12000.
The guides of the three axes are connected by a ball screw pair through a coupling with a servomotor. This allows you to achieve the highest precision in your work. Bearings of the highest class C3 allow you to achieve thermal stability during operation.
To maintain a constant temperature inside the control element, a heat exchanger is installed on the machine. This provides exceptional protection for control and electrical components on the machine.
Allows you to avoid spindle destruction due to thermal loads, and also allows you to maintain high accuracy and speed of the spindle.
Technical Specifications of JHV-710 CNC Vertical Machining Center
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Options, descriptions
Each SUNMILL machine undergoes tests:
BALL BAR TEST
Using the ball bar test, roundness, deviation from geometry and reverse stroke(drive mismatch).
Laser check
Additional options:
4- and 5-axis machining (optional):
On milling machine With CNC it is possible to install a 4th/5th axis, and accordingly create a 4/5-axis machining center. Can be installed vertically on the machining center table Rotary table(4th axis) and rotary-tilt axis (5th axis). When installing the 4th or 5th axis, it is recommended to use the FANUC 18iMB control system.
Coolant supply through the spindle:
Supplying coolant through the spindle using a special tool allows for better heat removal when machining blind holes and avoids overheating of the tool and workpiece. Supplied complete with filtration system.
High-speed spindle, allowing to withstand parameters: 10000, 12000, 15000 rpm.
Tool magazine for 20 or 24 positions.
Complete set of this machine.
- CNC system Fanuc 0i-MD controller.
- Fourth axis interface.
- Spindle BT40 10,000 rpm
- Engine power 5.5 / 7.5 kW
- Spindle drive
- Spindle cone blowing system
- Automatic lubrication system
- Carousel tool magazine ATC 16-tools, BT40
- Complete cutting area enclosure
- Machine lighting
- Toolkit and Documentation Set
- Oil cooled spindle
- Screw Conveyor for Chip Removal
Equipment for an additional fee:
| Tool store drum type ATC 24-tools, BT40 * | 5,600 USD |
| Coolant supply through the spindle 20 bar * | 7,600 USD |
| Chip removal belt conveyor + tank * | 3,800 USD |
| Increasing machine power to 7.5 / 11 kW | 1,000 USD |
| 4th axis, rotary table, 200 mm faceplate | 16,800 USD |
| 5th axis, rotary table, faceplate 175 mm | 36,000 USD |
| Renishaw TS27R Tool Setting Probe | 4,000 USD |
| Renishaw NC4 proximity sensor | 13,000 USD |
| Renishaw OMP60 Touch Torque Sensor | 17,000 USD |
| Carousel type tool magazine 20 tools VT40 | 800 USD |
| Increasing spindle speed up to 12,000 rpm (belt drive) | 2,700 USD |
| Increasing spindle speed to 15,000, 24,000, 30,000, 36,000 rpm | On request |
Metalworking production can only be considered effective when the number of unpleasant surprises that appear during the manufacturing process of parts is minimized.
Efficient production cannot afford to increase the cycle time for manufacturing a part, or to obtain correctable or irreparable defects. Most often this occurs due to improper clamping of the workpiece, improper use of the tool, heating of the workpiece during processing, etc. In addition, you need to pay attention to the reasons associated with the failure of machine spindles.
In production, especially those involved in the manufacture of parts high precision, when ordering equipment, care should be taken to install the most suitable spindles. During operation of the machine, it is important that the spindle does not overheat, so that there are no collisions with workpieces and machine tools and coolant and metal shavings did not leak through the seals and damage the spindle components.
WHEN HEATED, SOLIDS EXPAND
Not only the workpieces, but also the spindle itself can expand from the heat generated during the processing process. This usually occurs during high-speed processing and processing that requires high power over a long period of time. If the expansion of the spindle is large enough, it can extend relative to its normal position, and this, in turn, leads to the dimensions of the part being outside the tolerance range.
With linear expansion, the timing wheel can move relative to the machine sensors so much that the machine does not know the exact position of the spindle, and therefore the tool. As a result, it is quite likely that the machine will stop; this is especially unpleasant when it is operating in an automatic cycle. Other possible problem- loss of connection between the position of the tool and the position of the manipulator’s hand for changing the tool. The manipulator arm works in unison with the spindle rod to secure the tool. If their movements are not coordinated, the manipulator may crash into the tool, and the manipulator, tool, and also the spindle may be damaged.
The linear expansion of a spindle can be controlled by several methods. The first method is to supply cooling to it. The working fluid is a mixture of water and glycol. It passes through a cooling jacket and its temperature is maintained by a cooling station. The second method is to design the spindle in such a way that when heated, it expands backwards rather than forwards. Therefore, the dimensional accuracy of the part will not be affected.
COOLANT MUST BE IN THE WORK AREA
The spindle can also be damaged by cutting fluid that penetrates the seals and reaches the bearings. Coolant penetration into the spindle is one of the main causes of spindle failure. In this case, the spindle has two main enemies - high pressure coolant systems and coolant systems with a large number of nozzles. The nozzles must be precisely adjusted to ensure that the minimum amount of coolant enters the machine spindle. In any case, coolant will enter the spindle, so additional screens, mechanical or labyrinth seals may be needed. These seals should not interfere automatic change tool. Another way to help keep coolant out of the spindle is to use a spindle air purge system. It turns on when changing a tool, increasing or decreasing the spindle speed. When changing the spindle speed air currents and the heat generated from it causes the coolant mist to penetrate into the spindle. The air cleaning system removes coolant and thereby protects the spindle from damage. The use of an air purge system is not necessary for all machining applications, but it will be cheaper to install it as an option and save on spindle repairs. When grinding, the air cleaning system also protects the spindle from fine metal dust.
HOW TO AVOID COLLISIONS
Spindle breakage as a result of a collision is a fairly common occurrence. Collisions occur due to various reasons. For example, an operator may accidentally enter an incorrect value, forgetting to put a separator, and press a button. Even if he immediately realizes the error, there may not be enough time to stop the machine. One way to solve this kind of problem is to use software for processing simulation. The graphical interface allows you to follow the entire process step by step and see points of possible collision with the workpiece, fixture or the machine itself.
Often it is necessary to carry out processing quite close to the machine tooling. For example, when milling or drilling - close to a vice. As a result, rigidity increases, and, consequently, manufacturing accuracy. Vibrations are dealt with in the same way. The proximity of the tool to the machine tooling during modeling can result in a collision in reality. In this case, after modeling, programmers must warn operators about possible collision locations, and then the latter will be ready to pass through dangerous areas while debugging the program at minimum speed.
To spindle negative impact can cause vibrations that occur when the machine-fixture-tool-workpiece system is insufficiently rigid. Some applications may require anti-vibration tools and fixtures that provide high rigidity to the tool mount.
For good chip removal when drilling, coolant must be supplied through the tool. If the machine is not equipped with a coolant supply system through the spindle, it is recommended to
For good chip removal when drilling, coolant must be supplied through the tool. If the machine is not equipped with a through-spindle coolant system, it is recommended to supply coolant through special rotating adapters. When the hole depth is less than 1xD, the use of external cooling and reduced modes is allowed. The diagram shows the coolant consumption for various types drills and materials. Coolant type 6-8% emulsion is recommended. When drilling of stainless steel and high-strength steels, use a 10% emulsion. When using IDM drill heads, use 7-15% emulsion based on mineral and vegetable oils for drilling stainless steel and high temperature alloys. Drilling without coolant It is possible to drill cast iron without coolant with the supply of oil mist through the drill channels. Symptoms of drill head wear Diameter change 0 > D nominal + 0.15mm D nominal (1) New head (2) Worn head Vibration and noise increase greatly flow Coolant flow (l/min) Minimum coolant pressure (bar) Drill diameter D (mm) Drill diameter D (mm) For special drills larger than 8xD recommended high pressure Coolant 15 70 bar.
02.11.2012
New directions in coolant technology for metalworking
1. Oil instead of emulsion
In the early 90s. proposals for replacing coolant emulsions with pure oils were considered from the point of view of analyzing the total cost of the process. The main objection was the high cost of water-free working fluids (5-17% of the total cost of the process) compared to cutting fluids for water based.
Currently, replacing coolant emulsions with pure oils is a possible solution to many problems. When using pure oils, the advantage is not only in price, but also in improving the quality of metalworking, as well as ensuring safety in the workplace. In terms of safety, pure oils are less harmful when exposed to exposed areas of human skin than emulsions. They do not contain biocides or fungicides. Waterless coolants have a longer service life (from 6 weeks for individual machines to 2-3 years in centralized circulation systems). Using pure oils has less Negative influence on ecology. Pure oils provide higher quality metalworking at almost all stages of the process (more than 90%).
Replacing emulsions with oils provides better lubricity of coolant, improves surface quality during grinding (finishing) and significantly increases equipment service life. Price analysis showed that during the production of a gearbox, the cost of almost all stages is halved.
When using waterless coolants, the service life of CBN (cubic boron nitride) equipment for roughing and broaching holes increases by 10-20 times. In addition, when processing cast iron and mild steels no additional corrosion protection is required. The same applies to equipment, even if it is damaged protective layer paints.
The only disadvantage of waterless cutting fluids is the release of a large amount of heat during metalworking. Heat dissipation can be reduced by a factor of four, which is especially important for operations such as drilling hard, high-carbon materials. In this case, the viscosity of the oils used should be as low as possible. However, this leads to a decrease in operational safety (oil mist, etc.), and volatility depends exponentially on the decrease in viscosity. In addition, the flash point is reduced. This problem can be solved by using non-traditional (synthetic) oil bases that combine a high flash point with low volatility and viscosity.
The first oils to meet these requirements were blends of hydrocracked oils and esters, which appeared in the late 1980s. XX century, and pure essential oils that entered the market in the early 90s.
The most interesting are ester-based oils. They have very low volatility. These oils are products of different chemical structures, obtained from both animal and vegetable fats. In addition to low volatility, essential oils are characterized by good tribological properties. Even without additives, they provide reduced friction and wear due to their polarity. In addition, they are characterized by a high viscosity-temperature index, explosion and fire safety, high biostability and can be used not only as coolants, but also as lubricating oils. In practice it is better to use a mixture essential oils and hydrocracking oils, since the tribological characteristics remain high and their price is significantly lower.
1.1. Family of multifunctional coolants
A decisive step in optimizing the cost of lubricants in metalworking processes has been the use of pure oils. When calculating the total cost of coolant, the influence of the cost of lubricants used in metalworking was underestimated. Studies in Europe and the USA have shown that hydraulic fluids and coolant are mixed three to ten times per year.
In Fig. 1 shows this data graphically over a 10-year period in the European automotive industry.
In the case of using water-based coolant, the penetration of significant quantities of oil into the coolant leads to a serious change in the quality of the emulsion, which deteriorates the quality of metalworking, causes corrosion and leads to an increase in cost. When using pure oils, contamination of the coolant by lubricants is imperceptible and becomes a problem only when machining accuracy begins to decrease and equipment wear increases.
Trends in the use of pure oils as metalworking coolants open up a number of cost reduction opportunities. An analysis conducted by German machine builders showed that on average, seven different types of lubricants are used in each type of metalworking machine. This in turn raises issues of leakage, compatibility and cost of all lubricants used. Incorrect selection and use of lubricants can lead to equipment failure, which will likely result in production shutdown. One of possible solutions This problem is the use of multifunctional products that satisfy a wide range of requirements and can replace lubricants for various purposes. An obstacle to the use of universal fluids is the requirements of the standard ISO to hydraulic fluids VG 32 and 46, since modern hydraulic equipment is developed taking into account the viscosity values given in these standards. On the other hand, metalworking requires low-viscosity cutting fluids to reduce losses and improve heat dissipation during high-speed cutting of metal. These contradictions in viscosity requirements at different uses lubricants are allowed to use additives, which reduces the overall cost.
Advantages:
. the inevitable losses of hydraulic and running-in oils do not deteriorate the coolant;
. consistency of quality, which eliminates complex analyses;
. the use of cutting fluids as lubricating oils reduces the overall cost;
. Improving reliability, process results and equipment durability significantly reduces the overall cost of production;
. versatility of application.
Rational use of universal liquids is preferable for the consumer. An example of this is engine building. The same oil can be used during the initial processing of the cylinder block and during honing. This technology is very effective.
1.2. Washing lines
Water-based cleaning solutions must be eliminated from these cleaning operation lines to avoid the formation of unwanted mixtures with hydrophilic oils. Solid contaminants are removed from oils by ultrafiltration, and detergents(energy costs for water purification and pumping, analysis of waste water quality) can be eliminated, which will lead to a reduction in the overall cost of production.
1.3. Removing oil from scrap metal and equipment
The correct selection of additives allows oils extracted from metal waste and equipment to be brought back into the process. The volume of recirculate is up to 50% of losses.
1.4. Prospects for universal fluids - " Unifluid»
The future belongs to low-viscosity oil, which will be used both as a hydraulic fluid and as a metalworking coolant. Universal liquid " Unifluid» developed and tested in German research project sponsored by the ministry Agriculture. This fluid has a viscosity of 10 mm 2 /s at a temperature of 40 ° C and shows excellent results in automotive engine manufacturing plants in metalworking processes, for lubrication and in power lines, including hydraulic systems.
2. Minimizing the amount of lubricants
Changes in legislation and increasing requirements for protection environment also apply to the production of coolant. Given international competition, the metalworking industry is taking all possible measures to reduce production costs. An analysis of the automotive industry published in the 90s showed that the main cost problems are caused by the use of working fluids, with the cost of coolants playing an important role in this case. The real cost is determined by the cost of the systems themselves, the cost of labor and the cost of maintaining liquids in working condition, the cost of purification of both liquids and water, as well as disposal (Fig. 2).
All this leads to great attention being paid to the possible reduction in lubricant use. A significant reduction in the amount of coolant used, as a result of the use of new technologies, makes it possible to reduce production costs. However, this requires that coolant functions such as heat removal, friction reduction, and removal of solid contaminants be solved using other technological processes.
2.1. Analysis of coolant requirements for various processes metalworking
If coolant is not used, then, naturally, the equipment overheats during operation, which can lead to structural changes and tempering of the metal, changes in size and even equipment breakdown. The use of coolant, firstly, allows heat to be removed, and secondly, it reduces friction during metal processing. However, if the equipment is made of carbon alloys, then the use of coolant can, on the contrary, lead to its breakdown and, accordingly, reduce its service life. Yet, as a rule, the use of coolants (especially due to their ability to reduce friction) leads to increased equipment life. In the case of grinding and honing, the use of coolant is extremely important. The cooling system plays a huge role in these processes, as the normal temperature of the equipment is maintained, which is very important in metalworking. When removing chips, approximately 80% of the heat is released, and the coolant performs a double function here, cooling both the cutter and the chips, preventing possible overheating. In addition, some of the fine chips go away along with the coolant.
In Fig. Figure 3 shows the coolant requirements for various metalworking processes.
Dry (without the use of coolant) metal processing is possible during processes such as crushing, and very rarely during turning and drilling. But you should pay attention to the fact that dry processing with a geometrically inaccurate end cutting tool is impossible, since in this case heat removal and liquid spray have a decisive impact on the quality of the product and the service life of the equipment. Dry processing for crushing cast iron and steel is currently used using special equipment. However, chip removal must be done either by simple cleaning or by compressed air, and as a result new problems arise: increased noise, additional cost compressed air, as well as the need for thorough cleaning from dust. In addition, dust containing cobalt or chromium-nickel is toxic, which also affects production costs; The increased fire and explosion hazard during dry processing of aluminum and magnesium cannot be ignored.
2.2. Low coolant systems
By definition, the minimum amount of lubricant is considered to be an amount not exceeding 50 ml/h.
In Fig. 4 is given circuit diagram systems with a minimum amount of lubricant.
Using a dosing device, a small amount of coolant (maximum 50 ml/h) is supplied in the form of fine sprays to the metalworking site. Of all the types of dosing devices existing on the market, only two types are successfully used in metalworking. Most wide application find systems operating under pressure. Systems are used where oil and compressed air are mixed in a container, and the aerosol is supplied with a hose directly to the metalworking site. There are also systems where oil and compressed air, without mixing, are supplied under pressure to the nozzle. The volume of liquid supplied by the piston per stroke and the frequency of operation of the piston are very different. The amount of compressed air supplied is determined separately. The advantage of using a dosing pump is that it is possible to use computer programs, controlling the entire work process.
Since very small quantities of lubricant are used, the lubricant must be supplied directly to the work site with extreme care. There are two coolant supply options that are quite different: internal and external. When liquid is supplied externally, the mixture is sprayed by nozzles onto the surface of the cutting tool. This process is relatively inexpensive, easy to perform and does not require much labor. However, with external coolant supply, the ratio of tool length to hole diameter should be no more than 3. In addition, when changing the cutting tool, it is easy to make a positional error. With internal coolant supply, the aerosol is fed through a channel inside the cutting tool. The length to diameter ratio must be greater than 3, and positional errors are excluded. In addition, chips are easily removed through the same internal channels. The minimum tool diameter is 4 mm, due to the presence of a coolant supply channel. This process is more expensive since the coolant is supplied through the machine spindle. Low coolant systems have one common feature: liquid enters work area in the form of small droplets (aerosol). In this case, the main problems are toxicity and maintaining workplace hygiene standards at the proper level. Modern developments of aerosol coolant supply systems make it possible to prevent flooding of the workplace, reduce losses due to splashing, thereby improving air quality in the workplace. A large number of systems of small coolant supply leads to the fact that although it is possible to select the required droplet size, many indicators, such as concentration, particle size, etc., have not been sufficiently studied.
2.3. Coolant for low flow systems
Along with mineral oils and water-based cutting fluids, oils based on esters and fatty alcohols are used today. Since low-coolant systems use flow-through lubrication oils sprayed into the work area in the form of aerosols and oil mist, occupational health and safety (OHS) issues become a priority. In this regard, it is preferable to use lubricants based on esters and fatty alcohols with low-toxic additives. Natural fats and oils have a big drawback - low oxidation stability. When using lubricants based on esters and fatty acids no precipitation forms in the working area due to their high antioxidant stability. In table 1 shows data on lubricants based on esters and fatty alcohols.
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For systems with low coolant supply it has great importance correct selection of lubricant. To reduce emissions, the lubricant used must be low-toxic and dermatologically safe, while possessing high lubricity and thermal stability. Lubricants based on synthetic esters and fatty alcohols are characterized by low volatility, high temperature outbreaks, low toxicity and have proven themselves in practical application. The main indicators when selecting low-emission lubricants are flash point ( DIN EN ISO 2592) and Noack evaporation losses ( DIN 51 581Т01). t VSP should be no lower than 150 °C, and losses due to evaporation at a temperature of 250 °C should not exceed 65%. Viscosity at 40 °C> 10 mm 2 /s.
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At equal viscosities, fatty alcohol-based lubricants have a lower flash point than ester-based lubricants. Their evaporation rate is higher, so the cooling effect is lower. Lubricating properties are also relatively low compared to ester-based lubricants. Fatty alcohols can be used where lubricity is not a primary requirement. For example, when processing gray cast iron. Carbon (graphite), which is part of cast iron, itself provides a lubricating effect. They can also be used when cutting cast iron, steel and aluminum, since the working area remains dry as a result of rapid evaporation. However, too high evaporation is undesirable due to air pollution in the working area with oil mist (should not exceed 10 mg/m3). Ester-based lubricants are advisable to use when good lubrication is required and high chip waste is observed, for example when threading, drilling and turning. The advantage of ester-based lubricants is their high boiling and flash points with low viscosity. As a result, volatility is lower. At the same time, a corrosion-preventing film remains on the surface of the part. In addition, ester-based lubricants are easily biodegradable and have a class 1 water pollution rating.
In table 2 provides examples of the use of lubricants based on synthetic esters and fatty alcohols.
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The main aspects considered when developing coolant for low flow systems are given below. The main thing that you should pay attention to when developing cutting fluids is their low volatility, non-toxicity, low impact on human skin, combined with a high flash point. The results of new research on the selection of optimal cutting fluids are shown below.
2.4. Study of factors influencing the formation of coolant oil mist for low-flow systems
When a system with a low coolant supply is used in the metalworking process, aerosol formation occurs when liquid is supplied to the working area, and a high aerosol concentration is observed when using external system splashing. In this case, the aerosol is an oil mist (particle size from 1 to 5 microns), which has a harmful effect on the human lungs. Factors contributing to the formation of oil mist were studied (Fig. 5).
Of particular interest is the effect of lubricant viscosity, namely the decrease in oil mist concentration (oil mist index) with increasing coolant viscosity. Research has been conducted on the effect of anti-fog additives in order to reduce its harmful effects on human lungs.
It was necessary to find out how the pressure applied in the coolant system affected the amount of oil mist generated. In order to evaluate the generated oil mist, a device based on the Tyndall cone effect was used - a Tyndallometer (Fig. 6).
To assess oil mist, a tyndallometer is placed at some distance from the nozzle. Next, the obtained data is processed on a computer. Below are the evaluation results in the form of graphs. From these graphs it can be seen that the formation of oil mist increases with increasing spray pressure, especially when using low-viscosity fluids. Increasing the spray pressure by a factor of two causes a corresponding increase in the volume of the generated fog also by a factor of two. However, if the splash pressure is low and the starting characteristics of the equipment are low, then the period during which the amount of coolant reaches the required standards to ensure normal operation increases. At the same time, the oil mist index increases significantly as the coolant viscosity decreases. On the other hand, the starting characteristics of splashing equipment are higher when using low-viscosity fluid than when using high-viscosity cutting fluids.
This problem is solved by adding anti-fog additives to the coolant, which reduces the amount of fog generated for liquids with different viscosities (Fig. 7).
The use of such additives makes it possible to reduce the formation of fog by more than 80%, without compromising the starting characteristics of the system, nor the stability of the coolant, nor the characteristics of the oil mist itself. Studies have shown that fog formation can be significantly reduced by making the right choice splash pressure and viscosity of the coolant used. The introduction of appropriate anti-fog additives also leads to positive results.
2.5. Optimization of low coolant systems for drilling equipment
Tests were carried out on materials used in systems with low coolant supply (deep drilling (length/diameter ratio more than 3) with external coolant supply), on drilling equipment DMG(Table 3)
In a workpiece made of high-alloy steel (X90MoSg18) with high tensile strength (from 1000 N/mm 2), it is required to drill blind hole. High Carbon Steel Drill S.E.- a rod with a cutting edge with high resistance to bending, coated PVD-TIN. Coolants were selected in order to obtain optimal conditions process taking into account external supply. The influence of the viscosity of the ether (coolant base) and the composition of special additives on the service life of the drill was studied. The test bench allows you to measure the magnitude of cutting forces in the z-axis direction (in depth) using a Kistler measuring platform. Spindle performance was measured throughout the entire drilling time. Two methods adopted to measure single drilling loads allowed the loads to be determined throughout the test. In Fig. 8 shows the properties of two esters, each with the same additives.
Roman Maslov.
Based on materials from foreign publications.
Most often, the cutting fluid is supplied to the processing zone by a free-falling jet. Coolant drains from the nozzles various designs under a pressure of 0.03-0.1 MPa (that is, under the influence of gravity).
In addition to the irrigation method, there are the following types of liquid supply:
- pressure jet;
- a jet of air-liquid mixture in a spray state;
- through channels in the body of the cutting tool.
Pressure jet feeding is widely used in deep drilling operations. The jet pressure usually varies between 0.1-2.5 MPa, but can reach 10 MPa.
The pressure jet can be supplied both to the processing zone (from the rear edge of the tool) and through channels in the body of the tool. When supplied to the processing zone, the speed of the pressure jet reaches 40-60 m/s. In order to reduce splashing, it is recommended to branch the coolant flow: direct part of the flow as a thin pressure jet, and part as a free flow.
When supplying coolant with a high-pressure jet, the following disadvantages are observed:
- the difficulty of ensuring the desired direction of the coolant jet on cutting edge tool;
- the need to thoroughly clean the coolant to avoid nozzle clogging;
- mandatory equipment of the machine with special pumping station;
- strong splashing of liquid.
Coolant supply in a spray state is carried out by mixing the liquid with air and directing it to the cutting zone. This supply of coolant is more effective than cooling with a non-sprayed jet, since the physical and chemical activity of aerosol coolant is higher. In addition, the spray method features extremely low coolant consumption.
Spray cooling is used when watering with liquid is impossible or ineffective, when it is necessary to improve working conditions, in order to reduce temperature deformations of parts during processing.
Coolant in the form of aerosols is used on aggregate machines, automatic lines and CNC machines, including multi-operational ones.
Feeding through channels in the body of the tool is very effective, but is possible for a limited range of tools. This technology has become widespread when processing deep holes with spiral, gun and annular drills, taps, and broaches. To supply coolant to rotating tools with internal channels, special cartridges and oil receivers are used.
Deep holes are drilled with forced external or internal chip removal and coolant supply.
The greatest difficulties arise when choosing a coolant supply technology for machining deep holes with small-sized tools without internal channels. In these cases, it is advisable to supply several jets of liquid into the cutting zone evenly along a cone, the axis of which coincides with the axis of the cutting tool, and the apex is located in the gap between the guide bushing and the workpiece.
When machining deep holes, supplying coolant using the pulse (impact) method is also promising. Thus, when supplying coolant with a frequency of 10-13 Hz, the productivity of processing, crushing and removal of chips is 2-2.5 times higher than when supplying coolant with a continuous pressure jet.
In some drilling operations, when countersinking and reaming holes less than two diameters deep, as well as small-diameter holes, coolant is supplied through ring attachments.
