How To Machine Composites, Part 3 Milling Composites

Behind its aluminum panther in the West Building, Haimer USA is demonstrating its digital toolroom. Visitors to booth 431510 can see the benefits of a QR code- and RFID chip-enabled toolroom in setting up jobs, while also getting a glimpse into the capabilities of each of the company’s toolroom products.

Half of Haimer’s Carbide Threading Inserts booth is dedicated to a model toolroom, where attendees can view presetters, inductive shrink fit machines and toolholder balancing systems in context. Here, Haimer representatives demonstrate the digital toolroom process, while Heidenhain and FANUC controls on display demonstrate the interaction between machine tool control software and Haimer’s digital toolroom software. Haimer USA president Brendt Holden says the software for its digital toolroom relies on QR codes and RFID chips to help customers manage tool life and maintain a consistent toolholder assembly, thereby enabling faster setups and more consistent production runs.

Visitors to the booth can observe 23 different machines from Haimer’s balancing, shrinking and presetting technology lines under power. Machines of various price points and styles are TCMT Insert on display, giving visitors a clear picture of what is on offer for their particular applications. Also on display are a wide selection of the company’s tools and toolholders from the Duo-Lock, Haimer Mill and Safe-Lock lines.

IMTS attendees needing a moment to eat, drink or connect with sales or technical reps can also visit a lounge within the Haimer booth. Here, you can find memorabilia celebrating Haimer USA’s 20th anniversary, as well as the 45th anniversary of its parent company, Haimer GmbH.

The Cemented Carbide Blog: tungsten insert

Water Jet Cutting System

The MFH-Raptor high-feed milling cutter from Kyocera Industrial Ceramics features a vibration-resistant design for increased productivity in ramping and helical milling at high speeds. The cutting tool has a convex helical edge design to reduce cutting forces during initial workpiece contact, and offers coolant holes for BTA deep hole drilling inserts machining high-temperature alloys or improving surface roughness. Inserts are available for general milling, large depth-of-cut operations ranging to 5 mm, and wiper edges for roughing and finishing, even in low-horsepower operations. The cutter is suitable for applications such as face milling, shouldering, slotting, ramping, helical milling and plunging.

Inserts are available in various grades for difficult-to-cut materials and provide stability to help prevent insert fracturing and promote high-efficiency machining. For example, the CA6535 insert is intended for Ni-base heat-resistant alloys and martensitic stainless steel, and is coated with Kyocera’s thin-film CVD coating for high heat- and wear-resistance. The PR1535 insert for titanium alloys and precipitation-hardened stainless steel uses the company’s Megacoat Nano coating for improved stability and longer gravity turning inserts tool life in milling applications.

The Cemented Carbide Blog: Carbide Turning Inserts

Machine Mount Rack Stores Toolholders

Sumitomo has developed new steel turning grades: AC8015P for high-speed machining, and AC8035P for interrupted machining. They join the general-purpose AC8025P. In the manufacturing of machinery components, which includes the automotive industry, heavy electric and construction machinery machining, there is a growing demand for cutting tools with higher efficiency and longer tool life to achieve shorter lead times and lower machining costs. In addition, with the progress of labor-saving manufacturing sites (automation, unattended), a stable tool life that prevents sudden trouble during machining is also required.

In response to these challenges, Sumitomo has developed two new steel turning grades: AC8015P, a versatile grade for high-speed to general-purpose machining, and AC8035P, for stability in general-purpose to interrupted and heavy cutting applications. AC8000P makes it possible to greatly improve efficiency and reduce costs in every aspect of steel turning.

AC8015P, with its crystal control and high-strength alumina gravity turning inserts layer, this grade boasts superior wear resistance in high-speed and high-efficiency machining. It also utilizes Sumitomo’s proprietary CVD coating technology—Absotech Platinum coat—coupled with a newly-developed tough carbide substrate to improve its resistance to chipping and welding. It boasts twice the wear resistance of conventional grades when used in high-speed machining with a cutting speed (Vc) of more than 1,450 sfm, exhibiting long tool life in a wide range applications from high-speed to general purpose.

AC8035P, utilizing a new surface technology that controls residual stress on the coating layer, boasts superior stability in interrupted machining. In addition, the combination of a super-tough carbide substrate and the company’s latest Absotech Platinum coating exhibits shoulder milling cutters excellent chipping and welding resistance. Fracture resistance during strong interrupted and heavy machining is double that of conventional grades, with excellent stability from general purpose to heavy interrupted cutting.

The Cemented Carbide Blog: bta drilling tool

A Custom Tool Data Station Eliminates Machinists' Guesswork

First, the basic concept of particle size analysis(1) particles: with a certain size and shape of small objects, is the basic unit of the composition of the powder. It is very small, but microscopic but contains a lot of molecules and atoms;(2) particle size: the size of particles;(3) particle size distribution: a certain way to reflect a series of different particle size particles, respectively, the percentage of the total powder;(4) the representation of the particle size distribution: table method (interval distribution and cumulative distribution), graphical method, function method, common R-R distribution, normal distribution;(5) particle size: the diameter of particles, usually in microns as a unit;(6) Equivalent particle size: When a particle of a physical properties and homogeneous spherical particles the same or similar, we use the spherical particles straightDiameter to represent the diameter of the actual particles;(7) D10, the cumulative distribution of 10% of the corresponding particle size; D50, the cumulative distribution of the percentage reached 50% of the corresponding particle size; also known as the median or median particle size; D90, the cumulative distribution of the percentage reached 90% of the corresponding particle size; D (4,3) volume or mass average particle size;Second, the commonly used particle size measurement method(1) sieving method(2) sedimentation method (gravity sedimentation method, centrifugal sedimentation method)(3) resistance method (Kurt particle counter)(4) Microscope (image) method(5) Electron microscopy(6) ultrasonic method(7) breathable method(8) laser diffraction methodAdvantages and disadvantages of various methodsSieve method: Advantages: simple, intuitive, low cost of equipment, commonly used in samples larger than 40μm. Disadvantages: can not be used for 40μm fine sample; results by human factors and sieve deformation of a greater impact.Microscope: Advantages: simple, intuitive, can be morphological analysis. Disadvantages: slow, poor representative, can not measure ultra-fine particles.Sedimentation method (including gravity settlement and centrifugal settlement): Advantages: easy to operate, the instrument can run continuously, low price, accuracy and repeatability is better, the test range is larger. Disadvantages: test time is longer.Resistance method: Advantages: easy to operate, the total number of particles can be measured, the equivalent concept clear, fast, good accuracy. Disadvantages: the test range is small, easy to be blocked by particles, the media should have strict electrical characteristics.Electron microscopy: Advantages: suitable for testing ultrafine particles or even nano-particles, high resolution. Disadvantages: less sample, poor representation, the instrument is expensive.Ultrasonic method: Advantages: direct measurement of high concentrations of pulp. Disadvantages: low resolution.Ventilation method: Advantages: instrument prices are low, do not have to disperse the sample, magnetic particles can be measured powder. Disadvantages: can only get the average particle size, can not measure the particle size distribution.Laser method: Advantages: easy to operate, fast test, test range, repeatability and accuracy, and can be measured online and dry. Disadvantages: the results affected by the distribution model, the higher the cost of the instrument.Third, the basic principle of laser particle size analyzerLaser diffraction technology began in the small angle scattering, so this technology also has the following name:Fraunhofer diffraction method(Approximately) positive light scattering methodSmall angle laser scattering method (LALLS)At present, this range of technology has been expanded to include light scattering within a wider range of angles, in addition to the approximate theory such as Fraunhofer diffraction and irregular diffraction, and the Mie theory is now used by instrument manufacturers Theory as one of the important advantages of its products.Mickey’s theory is named after a German scientist. It describes the uniform spherical particles in the uniform, non-absorbing medium and its surroundings in the space of the radiation, the particles can be completely transparent or can be completely absorbed. The Millerian theory describes that light scattering is a resonance phenomenon. If a specific wavelength of the beam encounters a particle, the particle produces an electromagnetic vibration at the same frequency as the emitted light source – irrespective of the wavelength of the light, the particle diameter, and the refractive index of the particles and the medium. The particles are tuned and received at a specific wavelength, and the energy is re-emitted within a particular spatial angular distribution as well as a relay. According to the Mie theory, it is possible to produce multiple oscillations of various probabilities, and there is a certain relationship between the cross section of the optical action and the particle size, the wavelength of light and the refractive index of the particles and the medium. If you use the Mie theory, you must know the refractive index and absorption coefficient of the sample and the medium.Fraunhofer theory is named after a German physicist, Franco and Fader, which is based on scattering at the edge of the grain and can only be applied to completely opaque particles and small angles of scattering. When the particle size is less than or equal to the wavelength, the Fraunhofer assumption that the extinction coefficient is constant is no longer applicable (it is an approximation of the Mie theory, that is, ignoring the Mi’s theory of imaginary subsets and ignoring the light scattering coefficient and Absorption coefficient, that is, all the dispersant and dispersive optical parameters are set to 1, the mathematical treatment is much simpler, the color of the material and small particles are also much larger error. The approximate Mickey theory is not applicable to the emulsion ).The laser particle size analyzer is based on the phenomenon of light diffraction, when the light through the particles when the diffraction phenomenon (its essence is the interaction of electromagnetic waves and substances). The angle of the diffracted light is inversely proportional to the size of the particle.Different sizes of particles through the laser beam when the diffraction light will fall in different positions, the location information reflects the particle size; the same large particles through the laser beam when the diffraction light will fall in the same position. The information of the diffracted light intensity reflects the percentage of particles of the same size in the sample.The laser diffraction method uses a series of photodetectors to measure the intensity of the diffracted light at different angles of the particle size of the particle, using the diffraction model, through the mathematical inversion, and then the particle size distribution of the sample.And the diffracted light intensity received by the position detector gives a percentage content of the corresponding particle size.The dependence of the intensity of the diffracted light on the particles decreases with the decrease of the particle size. When the particles are as small as several hundred nanometers, the diffraction intensity is almost completely dependent on the angle, that is, the diffracted light at this time Distributed in a wide range of angles, and the light intensity per unit area is very weak, which increases the difficulty of detection.The measurement of samples under 1um and wide particle size ranges (tens of nanometers to several thousand micrometers) is the key to the laser diffraction granulator. In general, the following techniques and optical path configurations are used:1, multi-lens technologyThe multi-lens system was widely adopted before the 1980s, using a Fourier optical path configuration, where the sample cell was placed in front of the focusing lens and equipped with a number of different focal lengths of the lens to accommodate different particle size ranges. The advantage is simple design, only need to be distributed in the tens of degrees range of focal plane detector, the cost is low. The disadvantage is that if the sample size is wide when the need to replace the lens, the results of different lenses need to be split, for some unknown particle size of the sample with a lens measurement may lose the signal or due to process changes caused by changes in sample size can not be timely reflect.2, multi-light technologyMulti-light source technology is also used in the Fourier optical path configuration that the sample cell in front of the focusing lens, generally only distributed in the range of tens of degrees angle detector, in order to increase the relative detection angle, so that the detector can receive small particles Diffracting the optical signal, and disposing the first or second laser at different angles relative to the optical axis of the first light source. The advantage of this technique is that it is only a detector that is distributed over several tens of degrees, and the cost is low. The measurement range, especially the upper limit, can be wide. The disadvantage is that the small area detector distributed in the small angle range is also used for small Particle measurement, due to the small particles of diffracted light in the unit area of the signal is weak, resulting in small particles when the signal to noise ratio is reduced, which is why the multi-light source system in the measurement range of more than 1500 microns or so, to ensure that a few microns The following small particles of accurate measurement, the need to replace the short focal length of the focus lens. In addition, the multi-lens system in the measurement of samples, the different lasers are turned on, and in the dry measurement, because the particles can only pass through the sample pool, only one light source can be used for measurement, so the general use of multi-lens technology The lower limit of the dry size is less than 250 nm.3, multi-method hybrid systemMulti-method hybrid system refers to the laser diffraction method and other methods of mixing design of the particle size analyzer, laser diffraction part of the distribution only a few tens of degrees range of the detector, and then supplemented by other methods such as PCS, generally a few microns The above is measured by laser diffraction, and particles below a few microns are measured by other methods. Theoretically, the lower limit of the particle size depends on the lower limit of the auxiliary method. The advantage of this method is that the cost is low and the overall measurement range is wide, The best measurement conditions required by the method, such as the concentration of the sample are not the same, are often difficult to balance, and in addition to the systematic error between the different methods, it is often difficult to obtain the desired result in the data fitting area of the two methods unless It is known that the particle size of the sample only falls within the range of the diffraction method or within the range of the auxiliary method. In addition, the multi-method mixing system requires two different sample cells, which is not a problem for wet measurement because the sample can be recycled, but the sample can only be circulated through the sample cell for a dry process, Method of simultaneous measurement, so a variety of methods mixed system in the dry measurement of the lower limit of the particle size can only be hundreds of nanometers.4, non-uniform cross-wide compensation for wide-angle detection technology and anti-Fourier optical systemThe wide-angle detection of non-uniform cross-wide area compensation and the anti-Fourier optical system are developed in the late 1990s. The anti-Fourier optical path configuration is used to place the cell behind the focusing lens, In a very wide range of angles, the general physical detection angle of up to 150 degrees, so that a single lens to measure tens of nanometers to several thousand microns of the sample possible, optical schematic diagram shown in the design of the detector On the use of non-uniform cross and with the increase in the size of the detector area also increased the arrangement, both to ensure that the resolution of large particles when the measurement also ensures a small particle detection signal to noise ratio and sensitivity. No need to replace the lens and other methods can be measured from tens of nanometers to several thousand microns of particles, even the dry measurement, the lower limit can reach 0.1 microns. The disadvantage of this approach is that the cost of the instrument is high relative to the previous methods.The laser beam emitted from the laser is focused by a microscope, pinhole filter and collimator collimation, into a parallel beam of about 10 mm in diameter, the beam is irradiated onto the particles to be measured, a portion of the light is scattered, Leaf lens, the radiation to the radio and television surface milling cutters detector array. Since the radio and television detector is on the focal plane of the Fourier lens, any point on the detector corresponds to a certain scattering angle. The array of radio and television detectors consists of a series of concentric rings, each of which is a separate detector capable of linearly converting the scattered light projected onto the above into a voltage and then sending it to a data acquisition card which converts the electrical signal Zoom in, after the A / D switch to the computer.Now the actual structure of the laser particle size instrument has played a great change, but the same principle.At present, people have come to the following conclusions: (1) measuring less than 1mm of particles, you must use the Mie theory;(2) measuring more than 1mm particles, if the lower limit of measurement of shoulder milling cutters the instrument is less than 3mm, the instrument still use the Mie theory, or in the particle size distribution of 1mm near the “out of nothing” a peak;(3) The laser particle size analyzer can use the diffraction theory of the conditions: the lower limit of measurement of the instrument is greater than 3mm, or the measured particles are absorbent type, and the particle size is greater than 1mm;(4) As a universal laser particle size analyzer, as long as the lower limit of measurement is less than 1mm, whether it is used to measure large particles or small particles, should use the Mie theory.Fifth, the composition of laser particle size analyzerA light source (usually a laser) is used to produce a monochromatic, coherent and parallel beam; the beam processing unit is a beam amplifier with an integrating filter that produces a beam of expanded, near-ideal light beams to illuminate the dispersed particles (A coherent strong light source with a fixed wavelength, a He-Ne gas laser (λ=0.63um).Particle disperser (wet and dry)Measure the scattering spectrum of the detector (a large number of photodiodes)Computer (for controlling equipment and calculating particle size distribution)Through technological advances, the lower limit of measurement can be 0.1um, some up to 0.02umSix, test operation steps1, preparation of equipment to install and disperse the liquid (gas)2, sample inspection, preparation, dispersion and sample concentration check the particle size range and particle shape and whether the full dispersion;3, measurement (select the appropriate optical model)4, the error from the diagnostic system of measurement error (deviation), can come from the incorrect sample preparation, deviation from the theoretical assumptions of the particles and / or due to improper operation and operation of the instrument caused;Seven, commonly used laser particle size meter manufacturersBritish Malvern laser particle size analyzer (abroad)Europe and the United States grams of laser particle size analyzer (Zhuhai)Dandong laser particle size analyzer (Liaoning)Eight, the test object1. All kinds of non-metallic powder: such as tungsten, light calcium, talc, kaolin, graphite, wollastonite, brucite, barite, mica powder, bentonite, diatomaceous earth, clay and so on.2. All kinds of metal powder: such as aluminum powder, zinc powder, molybdenum powder, tungsten powder, magnesium powder, copper powder and rare earth metal powder, alloy powder.3. Other powder: such as catalyst, cement, abrasive, medicine, pesticide, food, paint, dyes, phosphor, river sediment, ceramic raw materials, various emulsions.
Source: Meeyou Carbide

The Cemented Carbide Blog: CCMT Insert

Optimize Grinding Processes with Proper Truing and Dressing Tools

Anyone with the resources and the inclination can buy a machine tool. But not everyone can wring out the same amount of production from the same machine. Multitasking machines loaded with multiple turrets and/or spindles offer a great deal of production potential, as they can often completely machine a part on its own. Granted, these machines are more costly than their straightforward lathe and milling machine brethren. However, it's clear that shops battling just-in-time delivery schedules and shrinking batch sizes recognize the money-making potential of such machines, as their sales increase every year. It's the classic case of biting the bullet and choosing equipment that initially is more expensive, but offers greater payback down the road.

But the multitasking machine can't do it alone. The choices made in combining various machining elements and strategies into an efficient process ultimately separate the great shops from the average Joes. CAM programming continues to be a challenge for multitasking machines, which isn't surprising considering it involves simultaneous machining operations and orchestrated movement of a number of machine components.

Tooling can also play a make-or-break role. It's logical to think that a multitasking machine designed with flexibility in mind would use tooling that was also flexible. Such tooling would provide the capability to perform a variety of different rod peeling inserts machining operations with just one tool. A universal spindle interface that can accommodate both turning and milling operations can also augment process versatility. There are a few reasons for this.

First, space can be saved—turret space, to be more specific. The multiple turrets and spindles located within a multitasking machine not only limit space within the machining zone, but also place limits on tool magazine capacity. A single tool that offers five different cutting operations, for example, could free up four tool pockets. Those extra pockets could then be used to hold different tools for parts that require many machining operations or sister tooling to allow extended, unattended operation.

Second, cycle times can be quicker through the elimination of non-value-adding tool change time. A multitasking tool might tungsten carbide inserts just require spindle indexing to bring a different turning insert into position, for example.

Third, a universal, modular spindle interface that is effective for milling, turning and drilling operations allows for one common tooling platform for the shop's entire operation. This concept of standardization falls in line with the strategies of lean manufacturing.

During a recent visit to its international headquarters in Sandviken, Sweden, Sandvik Coromant (Fair Lawn, New Jersey) demonstrated the value that a multitasking tool platform, such as its Coroplex line, can provide for multitasking machines. The visit included a tour through the production facility for its mining and construction division, which heeds the advice of its sister tooling company by using robot-tended cells that combine multitasking machines with multitasking tools to produce various mining drill bit components (see sidebar on page 77).

There are a few different approaches in terms of multitasking tool design. One is the combination of turning and milling inserts on a single tool body. That one tool could perform shoulder milling, turn-milling or circular interpolation, for example, as well as face and longitudinal turning, profiling or internal turning. To combine turning and milling capability on one tool requires a design in which the turning inserts don't contact the workpiece while the tool is milling. To avoid this, the milling inserts are located just ahead of the turning inserts axially and radially so that the turning inserts are not in cut when the tool is milling.

Another technique combines two turning inserts located on opposite sides of a tool body. The tool can perform a rough turning operation, then be indexed 180 degrees in the spindle to allow finish turning.

Yet another concept uses a modular mini-turret unit that can combine four different cutting modules to allow four turning operations on one tool. This would enable a single tool to rough turn, finish turn, cut a groove and turn a thread, for example. The combination of cutting modules is user-selectable, and it would depend on the type of part and the required machining operations.

Maintaining tool center line accuracy is especially important for multitasking machines to make sure that the tool is precisely positioned to perform a turning operation. This is where it is helpful to have a modular, universal spindle/tool interface. Such an interface is effective for multitasking machines, as their spindle(s) could be called on to mill or lock into position for a turning operation.

One of the issues that tooling companies sometimes face when introducing new tool designs is the lag in terms of CAM software support of new tools. Often, though, programming is not made more difficult because of the new tool. To change from a milling operation to a turning operation for tools that can perform both just requires the spindle to precisely index to bring the turning insert is in proper position. There's no programming difference if that tool is used for milling, as the tool essentially is a milling cutter that happens to have turning inserts on board.

The Cemented Carbide Blog: milling Inserts factory

Integral Collet Tooling

Millstar has developed the Marathon ball insert for use when performing multi-axis machining of dies, molds and similar free-form 3D surfaces. The product incorporates a helical design, which is said to be useful for a variety of applications, and the company’s V-pocket clamping system.

?

The cutting edge allows the insert to perform all operations in materials that are less than 42 Rc. In semi-finishing, and finishing operations, the product can be used with materials that are deep hole drilling inserts more than 42 Rc.

?

Other applications for Carbide Drilling Inserts use are heat-treated intricate geometries and some roughing applications. The geometry allows for smooth cutting action, which can diminish heat build up and tool deflection, in turn reducing vibrations, the company says.

?

?

?

The Cemented Carbide Blog: surface milling Inserts

Major Tool & Machine Continues Major Upgrades

Kyocera Precision Tools has expanded the insert lineup of the GBA grooving system with the PR1625 grade designed for grooving steel and stainless steel. PR1625 is designed to provide hardness and toughness during groovin operations, incorporating a stable carbide base BTA deep hole drilling inserts material and Megacoat cemented carbide inserts Nano coating for resistance to wear when grooving light as well as heavily interrupted cuts.

The GBA grooving system features inserts with three usable cutting edges. These inserts are available in three grades: PR1215 for general purpose grooving, TN620 for surface-finish-oriented grooving, and PR1625 for interrupted cuts. The tool’s GM chipbreakers are designed to maintain smooth chip control and provide a more stable groove in a range of shallow grooving applications.

The Cemented Carbide Blog: internal thread Inserts

Tool Line Includes Single , Double Sided Inserts

We are aware of that surface roughness means a lot in manufacturing industry. When the concept is recalled to your mind, there must be some common textures on machined parts, such as bright mirror surface, matte, and dull polish. They are what different surface roughness embodies in macroscopic condition.

Definition of surface roughness

As is known to us, asperity of a part’s surface can be profiled as a series of jagged valleys in which there are crest, through, and spacing between them.

As a concept describing surface’s microscopic structure, surface roughness in fact is the length S between these crests(or troughs, usually below 1mm) and depth Z from trough to crest shown in the following diagram.

In general, we differentiate varying surface condition according to the range of S.

S＜1mm, the asperity is regarded as surface roughness,

1≤S≤10mm, it’s regarded as waviness,

S＞10mm, it’s called as geometric unevenness.  

3 standards and their comparison table

In China, the standards measuring surface roughness by the 3 Indexes, (unit:mm)which are average arithmetic deviation of contour Ra, average height of unevenness Rz, and the maximum depth of the valley Ry.

In most of actual production activities, Ra is mostly applied. While in Japan Ry gets mostly used, referred as R_max. People in European region use VDI 3400. We’ve made a comparison table of the 3 standards shown as below, 

Diagram 2. The comparison between Ra, R_max,and VDI3400.

Formation factors of surface roughness

Surface roughness is generally formed by processing methods and other factors, such as friction between tool and part surface, plastic deformation of surface metal when chips are separated, high frequency vibration in process system, discharge pits in electrical machining, etc. Because of the difference of processing method and workpiece material, the depth, density, shape and texture of the traces left on the machined surface are different.

The Main Effect of Surface Roughness on Parts

Affect wear resistance.

The rougher the surface, the smaller the effective contact area between the surfaces, the greater the pressure, the greater the friction resistance and the faster the wear.

Affect the stability of coordination.

For clearance fit, the rougher the surface is, the easier the wear and tear will be, and the clearance will increase gradually in the working process. For interference fit, the actual effective interference will be reduced and the connection strength will be reduced because of the extrusion of micro-convex peaks during assembly.

The fatigue strength is affected.

There are large troughs on the surface of rough parts. Like sharp notches and cracks, they are sensitive to stress concentration, which affects the fatigue strength of parts.

Influencing corrosion resistance.

Rough parts surface, easy to make corrosive gases or liquids through the surface of the micro-valley infiltration into the metal inner layer, resulting in surface corrosion.

Influencing sealing

Rough surfaces do not fit tightly, and gases or liquids leak through cracks between contact surfaces.

The contact stiffness is affected

Contact stiffness is the ability of parts to resist contact deformation under external force. The stiffness of the machine depends to a great extent on the contact stiffness between the parts.

The measurement accuracy is affected

The surface roughness of measured parts and measuring tools will directly affect the accuracy of measurement, especially in precision measurement.

In addition, surface roughness has different effects on coating, thermal conductivity and contact resistance, reflectivity and radiation performance, resistance of liquid and gas flow, and current flow on conductor surface.

Evaluation Basis of Surface Roughness

Sampling Length

Sampling length is a reference line length for evaluating the age of surface roughness. According to the formation and texture characteristics of the actual surface of the part, the length of the section reflecting the surface roughness characteristics should be selected, and the sampling length should be measured according to the total direction of the actual surface profile. Sampling length is defined and selected to limit and reduce the influence of surface waviness and shape error on the measurement results of surface roughness.

Assessment length

Assessment length is a necessary length for assessing contour. It may include one or more sampling lengths. Because the surface roughness of each part of the part surface is not necessarily uniform, it is often unreasonable to reflect the characteristics of a certain surface roughness on a sampling length, so it is necessary to take several sampling lengths on the surface to evaluate the surface roughness. Assessment length generally includes five sampling lengths.

datum line

The datum line is the contour midline used to evaluate the surface roughness parameters. There are two kinds of datum lines: the least squares midline of the contour: within the sampling length, the sum of the outline offset of each point on the contour line is the smallest, and it has a geometric contour shape. Arithmetic mean midline of contour: Within sampling length, the area of contour on both sides of the midline is equal. In theory, the least squares midline is an ideal datum line, but it is difficult to obtain in practical application. Therefore, the arithmetic average midline of contour is generally used to replace it, and a line with approximate position can be used to replace it in measurement.

Surface roughness evaluation parameters

Height characteristic parameters

Ra contour arithmetic mean deviation: the arithmetic mean of the absolute value of contour offset within the sampling length (lr). In practical measurement, the more the number of measuring points, the more accurate Ra is.

Maximum height of Rz contour: the distance between the top line of contour bar peeling inserts peak and the bottom line of valley.

Ra is preferred in the range of commonly used amplitude parameters. Before 2006, another evaluation parameter in the national standard was “10-point height of micro-roughness” expressed by Rz and maximum height of contour expressed by Ry. After 2006, 10-point height of micro-roughness was cancelled in the national standard and maximum height of contour expressed by Rz.

Spacing characteristic parameters

The average width of the RSM contour unit. Within the sampling length, the average distance of contour micro-roughness. Microscopic irregularity spacing refers to the length of contour peaks and adjacent contour valleys on the midline. In the case of the same Ra value, the Rsm value is not necessarily the same, so the reflected gun drilling inserts gun drilling inserts texture will be different. The surface that pays attention to the texture usually pays attention to the two indicators of Ra and Rsm.

The shape characteristic parameters of Rmr are expressed by the length ratio of the contour support, which is the ratio of the length of the contour support to the sampling length. The length of the contour support is the sum of the sectional lengths of each section within the sampling length, parallel to the midline and intersected with the contour peak line C.

Surface Roughness Measurement Method

comparison method

It is used in the field measurement of workshop, and it is often used in the measurement of medium or rough surface. The method is to determine the measured surface roughness value by comparing the measured surface with a certain number of roughness samples.

touch needle method

The surface roughness is slowly sliding along the measured surface with a diamond stylus whose radius of curvature is about 2 micron. The displacement of the diamond stylus is converted from an electrical length sensor to an electrical signal. After amplification, filtering and calculation, the surface roughness value is indicated by a display instrument. The profile curve of the measured section can also be recorded by a recorder.

Generally speaking, the measuring tool which can only display the surface roughness value is called the surface roughness measuring instrument, and the surface roughness profiler which can record the surface profile curve is called the surface roughness profiler. These two measuring tools have electronic calculating circuit or computer. They can automatically calculate the arithmetic mean deviation Ra of contour, the 10-point height Rz of micro-roughness, the maximum height Ry of contour and other evaluation parameters. They have high measuring efficiency and are suitable for measuring the surface roughness of Ra ranging from 0.025 to 6.3 um.

The Cemented Carbide Blog: surface milling Inserts

Mind the Tool Center Height When Turning Small Diameters

Lean manufacturers focus on eliminating all non-value-adding steps from their manufacturing processes. Examples of such waste include unnecessary worker motion, significant amounts of work in process (WIP) and long setup times.

One factor that increases setup time is change-out of cutting tool inserts for specific machining operations or materials. But what tungsten carbide inserts if it were possible for a single type of milling or turning insert to perform most all cutting operations on a number of different materials? The same insert type could then remain in the toolholder for multiple workpieces, which would not only reduce setup time and insert inventory, but also eliminate the time required to visit the tool room to find inserts for a new job. This is what the Multi-Mat inserts from Lamina Technologies (Wayne, New Jersey) aim to do.

In effect, one grade fits most applications. Through a combination of proprietary submicron powder metallurgy and PVD coating technology, a single Multi-Mat insert grade can mill cast iron, nickel and titanium, as well as steel alloys, including stainless. Another grade performs turning operations on those same materials.

The Multi-Mat line currently offers 90 insert geometries which are said to cover 85 percent of cutting operations that small- and medium-sized shops typically encounter. These deep hole drilling inserts inserts would likely be most appropriate for shops that run multiple materials, have small batch sizes and require many change-overs. Cutting data for the various materials on the back of the insert container (shown in the photo above) provide machine operators with a good starting point.

Lamina's global headquarters is located in Yverson-les-Bains, Switzerland. Though its Multi-Mat inserts are relatively new to the U.S. market, there are a number of users in Europe.

The Cemented Carbide Blog: surface milling Inserts

Horn's Supermini Gets an Insert Geometry for Drilling, Boring, Face Turning and Skimming

Some CNC milling cutters that CNC machining must master, such as round nose knives, ball knives, etc.

 1. Introduction of the tool

CNC machining tools must adapt to the high speed, high efficiency and high degree of automation of CNC machine tools. CNC milling cutters are mainly divided into flat-bottomed knives (end mills), round nose knives and ball knives, as shown in Figure 1-1. They are divided into white steel knives, flying knives and alloy knives. In the actual processing of the factory, the most commonly used knives are D63R8, D50R6, D35R5, D35R0.8, D30R5, D25R5, D20R4, D20R0.8, D16R0.8, D12, D10, D8, D6, D4, D3, D2. , D2, D1.5, D1, D0.5, D10R0.5, D8R0.5, D6R0.5, D4R0.5, R5, R4, R3, R2.5, R2, R1.5, R1 and R0.5 .

Figure 1-1 CNC milling cutter

(1) Flat bottom knife: mainly used for roughing, plane finishing, shape finishing and clear angle processing. The disadvantage is that the tip is easy to wear and affects the machining accuracy.

(2) Round nose knife: It is mainly used for roughing, plane finishing and side finishing of mold blanks, especially suitable for roughing of molds with high hardness.

(3) Ball knives: mainly used for non-planar semi-finishing and finishing.

2. Tool use

In CNC machining, the choice of tool is directly related to the processing accuracy, the quality of the machined surface and the processing efficiency. Choosing the right tool and setting reasonable cutting parameters will enable CNC machining to achieve the best machining quality at the lowest cost and in the shortest time. In short, the general principle of tool selection is: easy installation and adjustment, good rigidity, durability and high precision. Under the premise of meeting the processing requirements, try to choose a shorter tool holder to improve the rigidity of the tool processing.

When selecting a tool, the size of the tool should be adapted to the size of the blank. If the size of the cavity is 80×80, the tool such as D25R5 or D16R0.8 should be selected for roughing; if the size of the cavity is larger than 100×100, the D30R5 or D35R5 flying knife should be selected for opening; if the cavity The size is larger than 300 × 300, then you should choose a flying knife with a diameter larger than D35R5 for roughing, such as D50R6 or D63R8. In addition, the choice of tool is determined by the power of the machine. For example, a CNC milling machine or machining center with a small power cannot use a tool larger than D50R6.

In the actual machining, the end mill, the boss, the groove, etc. of the contour of the plane part are often selected by the end mill; the surface, the side surface and the cavity of the rough machining of the milling cutter with the cemented carbide insert are selected; the ball end milling cutter is selected. The round nose knife has an angled contour shape.

3. Tool cutting parameter setting

The principle of reasonable selection of cutting amount is: when roughing, it is generally to improve production efficiency, but economical and processing cost should also be considered; in semi-finishing and finishing, under the premise of ensuring processing quality, taking into account cutting efficiency , economy and processing costs. The specific values should be based on the machine manual, the cutting amount manual, and the experience.

With the wide application of CNC machine tools in production practice, CNC programming has become one of the key issues in CNC machining. In the process of programming the NC program, it is necessary to select the tool and determine the amount of cutting in the human-computer interaction state. Therefore, the programmer must be familiar with the selection method of the tool and the principle of determining the amount of cutting, so as to ensure the processing quality and processing efficiency of the part, give full play to the advantages of the CNC machine tool, and improve the economic efficiency and production level of the enterprise.

Table 1-1 and Table 1-2 list the parameter settings of the flying knife and the alloy knife respectively. These cutting parameters are for reference only. The actual cutting amount should be determined according to the specific machine performance, part shape and material, clamping condition, etc. Make adjustments).

The larger the diameter of the tool, the slower the speed; for the same type of tool, the longer the tool bar, the smaller the knife size will be, otherwise it will be easy to slash and cause overcutting.

Table 1-1 Flying knife parameter settings

Tool type	Maximum processing depth (mm)	Ordinary length (mm)	Ordinary lengthening (mm)	Spindle speed (/m)	Feed rate (mm/min)	Eating knife (mm)
D63R8	130/300	150	320	700～1000	2500～4000	0.2～1
D50R6	100/230	120	250	800～1500	2500～3500	0.1～0.8
D35R5	150/200	180	300	1000～2200	2200～3000	0.1～0.8
D30R5	100/150	150	180	1500～2200	2000～3000	0.1～0.5
D25R5	70/150	120	180	1500～2500	2000～3000	0.1～0.5
D25R0.8	80/150	120	180	1500~2500	2000~2800	0.1~0.3
D20R0.8	70/150	100	180	1500～2500	2000～2800	0.1～0.3
D17R0.8	70/130	100	180	1800～2500	1800～2500	0.1～0.3
D12R0.8	60/90	90	120	2000～3000	1800～2500	0.1～0.2
D16R8	60/100	100	150	2000～3000	2000～3000	0.1～0.4

The above flying knife parameters can only be used as a reference, because the parameters of different flying knife materials are also different, and the length of the flying knife produced by different tool factories is slightly different. In addition, the parameter values of the tool are also different depending on the performance of the CNC milling machine or the machining center and the material to be machined. Therefore, the parameters of the tool must be set according to the actual conditions of the factory. The flying knife has good rigidity and a large deep hole drilling inserts amount of knife, which is most suitable for the opening of the mold blank. In addition, the quality of the sharp surface of the flying knife is also very good. The flying knife is mainly made of knives and has no side edges. As shown below
                                                              

                

Table 1-2 Alloy knife parameter settings

Tool type	Maximum processing depth (mm)	Ordinary length (mm) blade / knife length	Ordinary lengthening (mm)	Spindle speed (r/m)	Feed rate bar peeling inserts (mm/min)	Eating knife (mm)
D12	60	30/80	35/100	1800～2500	1500～2500	0.1～0.5
D10	55	25/75	30/100	2500～3000	1500～2500	0.1～0.5
D8	45	20/70	25/100	2500～3000	1000～2500	0.1～0.5
D6	30	15/60	20/100	2500～3000	700～2000	0.1～0.3
D4	25	11/50	11/100	2800～4000	700～2000	0.1～0.3
D2	10	5/50	Not exist	4500～6000	700～1500	0.05～0.1
D1	5	2/50	Not exist	5000～10000	500～1000	0.05～0.1
R6	60	22/80	22/100	1800～3000	1800～2500	0.1～0.5
R5	55	18/75	18/100	2500～3500	1500～2500	0.1～0.5
R4	45	14/60	14/100	2500～3500	1500～2500	0.1～0.35
R3	30	12/50	12/100	3000～4000	1500～2500	0.1～0.3
R2	25	8/50	8/100	3500～4500	1500～2000	0.1～0.25
R1	10	5/50	Not exist	3500～5000	800～1500	0.05～0.15
R0.5	5	2/50	Not exist	5000以上	500～1000	0.05～0.08

The alloy knife has good rigidity and is not easy to produce a knives. It is the best for finishing the mold. The alloy knives have the same side edge as the white steel knives. The side edges are often used when finishing the copper straight wall.

The Cemented Carbide Blog: turning Inserts price