CARBIDE INSERT QUOTATION,INDEXABLE CARBIDE INSERTS,CARBIDE INSERTS

It should be no surprise. Trends in the manufacturing industry drive trends in metalcutting insert development. Changes in workpiece materials, manufacturing processes and even government regulations catalyze parallel advances in metalcutting tooling technology.

As manufacturers continually seek and apply new manufacturing materials that are lighter and stronger—and therefore more fuel efficient—it Thread Cutting Insert follows that cutting tool makers must develop tools that can machine the new materials at the highest possible levels of productivity.

By finetuning combinations of tool material compositions, coatings, and geometries, toolmakers enable users to make more parts faster and at reduced manufacturing costs. The development process is continuous and interactive.

A good example of material-driven tooling development is the growing selection of tools for machining aluminum. In the quest for fuel efficiency, the use of aluminum in vehicle manufacturing is constantly increasing. While in 1980 aluminum made up approximately 3 percent (representing 34 kg/75 lbs) of a typical midsize car, that proportion had risen to about 5 percent by 1990. Forecasts for cars of the future indicate that aluminum usage will rise to between 10 percent and 20 percent of the total vehicle weight, with engine blocks, cylinder heads, and housings being major contributors to consumption.

Although uncoated carbides and polycrystalline diamond tools presently dominate the turning, milling and drilling of aluminum/silicon alloys, the increasing aluminum usage has hastened the development of thinfilm diamondcoated carbide cutting tools (Figure 1, at left). Diamondcoated tools offer wear resistance comparable to polycrystalline diamond materials, while also providing multiple insert edges and the ability to support complex chipcontrol geometries. The dual advantages of high wear resistance and geometric flexibility make diamondcoated tools excellent candidates to replace uncoated carbides as well as expensive PCD cutting tools. Diamond coating is being extended to more difficult tool geometries including drills and end mills. And, for hypoeutectic aluminum as well as magnesium alloys, titanium diboride (TiB2) coatings applied by the physical vapor deposition (PVD) process offer productivity advantages (Figure 2, below).

Gray cast iron, another mainstay of vehicular manufacturing, frequently is being replaced by stronger, tougher nodular cast irons in components such as housings, crankshafts and camshafts (Figure 3). However, the strength and toughness that make nodular irons desirable workpiece materials also make them difficult to machine. Tools to machine these irons must resist abrasive wear and endure interruptions in the cut, as well as be capable of productive cutting speeds and feed rates.

Nodular irons typically would be machined with carbide inserts featuring chemicalvapordeposition (CVD) coatings. CVD coatings have been commercially available for about 30 years, and the fact that more than half of the inserts sold are CVDcoated testifies to the effectiveness of these coatings. However, the high temperatures (about 1,000°C) involved in the CVD process create an embrittlement called “eta phase” at the coating/substrate interface. Depending on its extent, the embrittlement can affect performance in operations involving interruptions of cut and inconsistency of workpiece microstructure such as found in some nodular irons. Recently developed mediumtemperatureCVD (MTCVD) coatings have shown a reduced tendency to formation of eta phase. MTCVDcoated tools offer increased resistance to thermal shock and edge chipping compared to conventional CVDcoated tools. The result is greater tool life as well as increased toughness compared to hightemperature CVD coatings.

Physical-vapor-deposition (PVD) coatings also offer advantages over CVD coatings in certain operations and/or workpiece materials. Commercialized in the mid1980s, the PVD coating process involves relatively low deposition temperatures (approximately 500°C), and permits coating of sharp insert edges. (CVDcoated insert edges are usually honed before coating to minimize the effect of eta phase.) Sharp, strong insert edges are essential in operations such as milling, drilling, threading and cutoff, and for effective cutting of longchipping materials such as lowcarbon steels (Figure 4, at below). In fact, a wide range of “problem” materials—such as titanium, nickelbased alloys, and nonferrous materials—can be productively machined with PVD coated tools. From a workpiece structure point of view, sharp edges reduce cutting forces, so PVD coated tools can offer a true advantage when machining thinwalled components.

The first PVD coatings were titanium nitride (TiN), but more recently developed PVD technologies include titanium carbonitride (TiCN) and titanium aluminum nitride (TiAlN), which offer higher hardness, increased toughness, and improved wear resistance. TiAlN tools in particular, through their higher chemical stability, offer increased resistance to chemical wear and thereby increased capability for higher speeds.

Recent developments in PVD coatings include “soft” coatings such as molybdenum disulfide (MoS2) for dry drilling applications. Combination soft/hard coatings, such as MoS2 over a PVD TiN or TiAlN, also show great potential, as the hard (TiN or TiAlN) coating provides wear resistance while the softer, more lubricious outer layer expedites chip flow.

Government mandates also can affect cutting tool development. In some countries, increasingly strict environmental regulations governing the disposal of cutting fluids are resulting in increased use of dry machining. While dry machining is not appropriate for every process and workpiece material, in some cases careful selection of cutting tool material can enable a user to minimize or avoid the use of coolant. A cutting tool with a thick alumina coating can allow increased feed rates in the machining of steel, reducing contact time of the insert with the workpiece and minimizing exposure of the tool to high cutting temperatures, and thereby enabling productive dry machining (Figure 5, below). In addition, advanced coatings such as PVD TiAlN can provide good performance in dry machining or in minimal coolant systems. As mentioned previously, lubricious PVD MoS2 coatings can also facilitate dry drilling and tapping. A focus on dry machining will spark further effort to develop cutting tools with high resistance to thermal load.

Cermet cutting tools (also effective in dry machining applications) are one facet of the cutting tool industry’s response to nearnetshape manufacturing trends. These trends entail efforts to lower manufacturing costs by casting and forging components to near their final (net) shape, thereby reducing the number of machining operations necessary to complete a part. Fewer heavy roughing operations are required, and the need for tools engineered for semifinishing to finishing duty expands. Development of cermet tools is one way tool manufacturers are addressing this need. Cermets, comprised mostly of titanium carbonitride (TiCN) with a nickelcobalt binder, are hard and chemically stable, leading to high wear resistance. Cermets work best in materials that produce a ductile chip, such as steels and ductile irons. Their increased speed capability enables them to machine carbon, stainless steels and ductile irons at high speeds while producing excellent surface finishes.

Recently developed cermets combine excellent resistance to deformation and chemical wear with a degree of toughness that enables them to be used in semifinishing as well as finishing operations. PVD coatings further enhance the performance of cermets on a wide variety of workpiece materials.

Both environmental/governmental factors (disposal of coolant/swarf) and economic concerns (the high cost of grinding) are accelerating the replacement of grinding by machining in the processing of hardened workpieces. The cutting tool industry is constantly developing and evaluating tools engineered to provide maximum productivity in hard-machining operations. These tools include superhard materials such as polycrystalline cubic boron nitrides, as well as ceramic tools.

Coatings, which reduce frictional heat and promote longer tool life, are among the new concepts being utilized in tools for hard turning (Figure 6, at left).

In field tests, coated superhards have outlasted other PCBN tools by 20 to 100 percent. Coatings have also proven effective on ceramic tools engineered for hard turning. In situations where the hardened workpiece doesn’t have roughness or other interruptions, coated ceramics offer more cutting edges and lower cost, and can be a costeffective alternative to PCBN tools in hard turning.

Development efforts in ceramic tool technology are enabling these hightech tools to move into new areas of application. While recently developed silicon nitride tools offer improved fracture resistance compared to their predecessors, their relatively low resistance to chemical wear has limited their use in the machining of nodular cast irons (Figure 7, below). However, wearresistant CVD alumina coatings have expanded the application range of siliconnitridebased tools to include these difficult tomachine irons.

Regarding alumina (A1203based) ceramics, the addition of silicon carbide whiskers offers increased productivity in the machining of Inconel and similar highstrength, hightemperature alloys in the aerospace industry. Singlecrystal whiskers deflect cracks in the alumina matrix and thereby improve fracture toughness of the tool.

Perhaps the common thread through all manufacturing is the drive for increased productivity and reliability. As metalcutting operations become increasingly finetuned, the relationship between cutting tool micro (cutting edge preparation) and macro (rake face topography) geometry is becoming more and more important. Chip control, tool life, workpiece finish and accuracy can be greatly improved by applying the proper combination of micro and macro geometries in conjunction with the proper substrate and coating. Control of the chip, dissipation or deflection of heat via restricted contact topographies, and reduced cutting forces as a result of positive rake surfaces all lead to the improved performance of today’s modern molded cutting insert geometries. Advances in tool manufacturing technology are making possible more precise matching of macro geometries and hones to specific machining applications.

True breakthroughs in cutting tool technology occur, but they are rare. Machining Carbide Inserts Most tool development comes from development, refinement and innovative combinations of existing tool materials. The direction for this development begins with the analysis of the characteristics of the materials being machined, includes the demands of specific operations, and involves ongoing communication between toolmaker and end user. MMS

About the author: David B. Arnold is the vice president and chief technical officer for Kennametal Inc.

Seco Tools offers Jetstream Tooling, a line of high performance gravity turning inserts tools designed to deliver coolant directly at the insert cutting edge for better chip control and long tool life. The high cutting speed and feed rates are said to be maintained across coolant pressures ranging from 70 to 5,000 psi for materials including titanium alloys, nickel-chromium, aluminum and steel alloys, and stainless steel.

Coolant is applied through the tooling nozzle at high pressure, close to the cutting edge, cooling the work area and producing smaller, hard, brittle chips. The high-pressure jet then breaks and lifts the chips away from the cutting area without damaging components or tooling, the company says. Additionally, there is less contact length of the chip on the rake fence, which helps prevent crater wear and improve surface finish.

The coolant inducer for this ISO range of the toolholders is designed to gun drilling inserts gun drilling inserts pivot, allowing access to index the carbide insert while the tool is still in position. The tooling product range can be applied in combination with the company’s various inserts.

1.laser weldingLaser welding: laser radiation to be processed surface, the surface heat through the heat conduction to the internal diffusion, by controlling the laser pulse width, energy, peak power and repetition frequency and other laser parameters, so that the workpiece melting, the formation of a specific pool.Laser welding can be used to achieve continuous or pulsed laser beam, the principle of laser welding can be divided into heat conduction welding and laser deep welding. Power density of less than 10 ~ 10 W / cm for the heat conduction welding, this time the depth of penetration, welding speed is slow; power density greater than 10 ~ 10W / cm, the metal surface under the heat of the concave into a “hole” to form a deep welding, Welding speed, depth ratio of large features.Laser welding technology is widely transported in the automotive, ship, aircraft, high-speed rail and other high-precision manufacturing areas, to people’s quality of life has brought a significant upgrade, it is to lead the home appliance industry into the Seiko era.Especially in the Volkswagen to create 42 meters seamless welding technology, greatly improving the overall body and stability, the appliance leading enterprises Haier Group launched a grand laser welding technology used in the production of washing machines, advanced laser technology can be The people’s lives have brought great changes.2.laser composite weldingLaser composite welding is a combination of laser beam welding and MIG welding technology to obtain the best welding effect, fast and weld bypass capability, is the most advanced welding methods.The advantages of laser composite welding are: fast, small thermal deformation, small heat affected area, and to ensure that the weld metal structure and mechanical properties.Laser composite welding in addition to automotive sheet structure welding, but also for many other applications. Such as the application of this technology to the production of concrete pumps and mobile crane girders, which require high strength steels to be processed, and conventional techniques tend to result in increased costs due to the need for other ancillary processes such as preheating. Furthermore, the tube process inserts technology can also be applied to the manufacture of rail vehicles and conventional steel structures (such as bridges, fuel tanks, etc.).3.friction stir weldingFriction stir welding is the use of friction heat and plastic deformation heat as a welding heat source. The friction stir welding process is carried out by means of a cylinder or other shape (such as a threaded cylinder) into the joint of the workpiece, through the high-speed rotation of the welding head to make it with the welding workpiece material friction, so that the connection The material temperature is softened.Stirring Friction Welding In the welding process, the workpiece must be rigidly fixed on the back pad, the welding head is rotated at high speed, and the joint of the workpiece along the workpiece moves relative to the workpiece.The protruding section of Carbide Milling Inserts the welding head extends into the interior of the material for friction and stirring. The shoulder of the welding head is rubbed against the surface of the workpiece and used to prevent the overflow of the plastic state material, and it can also remove the surface oxide film.Stirring the friction at the end of the weld leaving a keyhole at the end. Usually the keyhole can be cut off, you can also use other welding methods sealed to live.Friction stir welding can achieve dissimilar material welding, such as metal, ceramics, plastics and so on. Friction stir welding welding high quality, easy to produce defects, easy to achieve mechanization, automation, quality and low cost efficiency.4. electron beam weldingElectron beam welding is the use of accelerated and focused electron beam bombardment in a vacuum or non-vacuum welding of the heat generated by the welding method.Electron beam welding is widely used in many industries such as aerospace, atomic energy, national defense and military, automobile and electrical and electrical instrumentation because of its advantages such as no welding rod, easy oxidation, good process reproducibility and small thermal deformation.Electron beam welding working principleElectrons from the electron gun in the emitter (cathode) to escape, under the action of accelerating voltage, the electron is accelerated to the speed of light 0.3 to 0.7 times, with a certain kinetic energy. And then by the electron gun in the role of electrostatic lens and electromagnetic lens, convergence success rate of high density of electron beam flow. This electron beam impinges on the surface of the workpiece, and the kinetic energy of electrons changes into heat to melt and evaporate the metal quickly. In the high-pressure metal vapor, the workpiece surface is quickly “drill” out of a small hole, also known as “keyhole”, with the relative movement of the electron beam and the workpiece, liquid metal flows around the hole along the hole, And cooled to form a weld.Main features of electron beam weldingElectron beam penetrating ability, high power density, weld aspect ratio, up to 50: 1, can achieve a large thickness of a material forming, the maximum welding thickness of 300mm. Welding accessibility, welding speed, generally more than 1m / min, heat affected zone is small, welding deformation is small, high precision welding structure. Electron beam energy can be adjusted, the thickness of the metal can be welded from thin to 0.05mm to thick to 300mm, do not open the groove, a welding forming, which is other welding methods can not be achieved. The range of materials that can be used for electron beam welding is large, especially for reactive metal, refractory metals and high quality workpiece welding.5.Ultrasonic metal weldingUltrasonic metal welding is the use of ultrasonic frequency of mechanical vibration energy, connected to the same kind of metal or a special method of dissimilar metals. Metal in the ultrasonic welding, neither to the workpiece to send current, nor to the workpiece to the high temperature heat source, but under the static pressure, the frame vibration energy into the work of the friction work, deformation energy and limited temperature rise. The metallurgical bonding between the joints is a solid state welding where the base material does not melt.It effectively overcome the resistance welding generated by the splash and oxidation and other phenomena, ultrasonic metal welding machine can copper, silver, aluminum, nickel and other non-ferrous metal filament or sheet material for single-point welding, multi-point welding and short Shaped welding. Can be widely used in SCR wire, fuse chip, electrical leads, lithium battery pole pieces, the ear of the welding.Ultrasonic metal welding using high-frequency vibration wave to be welded to the metal surface, in the case of pressure, so that the two metal surfaces friction between the formation of molecular layer between the fusion.Ultrasonic metal welding is characterized by fast, energy saving, high fusion strength, good conductivity, no spark, close to cold processing; the disadvantage is that the welding metal parts can not be too thick (generally less than or equal to 5mm), the solder bit can not be too large, need Pressurized.6. flash butt weldingThe principle of flash butt welding is to use the welding machine to make both ends of the metal contact, through the low voltage of the high current, until the metal is heated to a certain temperature softening, the axial pressure upset forthe formation of butt welding joints.Two weldments are not touched by the two clamp electrode clamped and connected to the power supply, move the movable fixture, the two pieces of the end of the light contact that is heated, the contact point due to heating the formation of liquid metal blasting, jet sparks flash, Continuous moving movable fixture, continuous flash, welding pieces at both ends of the heating, to a certain temperature, the extrusion of the workpiece side, cut off the welding power, firmly welded together. The use of resistance heating welding joints to make the contact point flash, melting the weld end of the metal, the rapid application of the top force to complete the welding.Reinforcing steel flash butt welding is the installation of two bars into a docking form, the use of welding current through the two steel contact point generated by the heat resistance, the contact point of metal melting, resulting in a strong splash, the formation of flash, accompanied by irritating odor, the release of trace Molecules, the rapid application of the forging force to complete a welding method.
Source: Meeyou Carbide

Emuge’s SpeedSynchro toolholding Carbide Drilling Inserts solution features an integrated transmission of 1:4.412 for optimizing gun drilling inserts gun drilling inserts thread production on CNC machines with synchronous spindles. The integrated transmission is combined with the product’s minimum-length compensation to efficiently work with high cutting speeds and a relatively low synchronous machine tool speed, compensating for synchronization errors during the threading process.  

According to the company, the product achieves exact thread depths because it does not reverse the direction of rotation. The toolholder supports a maximum spindle speed of 2,000 rpm and a maximum tapping speed of 8,824 rpm. The cutting range is from M1 - M8 and an ER16 toolholder size is offered. Internal coolant capability is provided.

Surface finish, or texture, can be viewed from two very different perspectives. From the machinist's point of view, texture is a result of the manufacturing process. By altering the process, the texture can be changed. From the part designer's point of view, surface finish is a condition that affects the functionality of the part to which it applies. By changing the surface finish specification, the part's functionality can be altered—and hopefully, improved.

Bridging the gap between these two perspectives is the manufacturing engineer, who must determine how the machinist is to produce the surface finish specified by the design engineer. The methods one chooses to measure surface finish, therefore, depend upon perspective, and upon what one hopes to achieve.

Turning, milling, grinding and all other machining processes impose characteristic irregularities on a part's surface. Additional factors such as cutting tool selection, machine tool condition, speeds, feeds, vibration and other environmental influences further influence these irregularities.

Texture consists of the peaks and valleys that make up a surface and their direction on the surface. On analysis, texture can be broken down into three components: roughness, waviness, and form.

Roughness is essentially synonymous with tool marks. Every pass of a cutting tool leaves a groove of some width and depth. In the case of grinding, the individual abrasive granules on the wheel constitute millions of tiny cutting tools, each of which leaves a mark on the surface.

Waviness is the result of small fluctuations in the distance between the cutting tool and the workpiece during machining. These changes are caused by cutting tool instability and by vibration, several sources of which affect the stability of every machine tool. Some of these sources are external and sporadic—for example, a passing forklift, and the operation of other machines on the shop floor. Other vibration sources are internal, such as worn spindle bearings, power motor vibration, and so on.

Assuming that the part is nominally straight and/or flat, errors of form are due to a lack of straightness or flatness in the machine tool's ways. This is a highly repeatable type of irregularity, as the machine will always follow the same out-of-straight path.

All three surface finish components exist simultaneously, superimposed over one another. In many cases it is desirable to examine each condition independently. We approach this problem by making the assumption—a correct one, in most cases—that roughness has a shorter wavelength than waviness, which in turn has a shorter wavelength than does form.

Gages separate surface finish components using discrete units of length, called cutoffs. The length of the cutoff selected and implemented by various electrical filtering techniques permits the measurement of roughness by itself, waviness by itself, or "total profile," which combines roughness, waviness and form.

For parts produced by modern machine tools at typical speeds and feeds, roughness may be defined, for example, as any irregularity with a wavelength shorter than 0.030 inch; waviness as between 0.030 inch and 0.300 inch, and form errors as having wavelengths greater than 0.300 inch. These figures are quite flexible, and standards exist for roughness measurements with wavelengths from below 0.003 inch and up to 1 inch.

Surface finish tends to be a stable condition; it should not change from part to part, unless process conditions change. Manufacturing engineers, in fact, can generally predict the surface finish that a process will generate, given a known material, machine tool, cutting tool, coolant, speed, feed rate, and depth of cut. For this reason, surface finish measurements have historically been used primarily as a means of monitoring the stability of manufacturing processes. By taking an occasional measurement, a machinist can establish that the entire process is running as it should.

If the measurement changes, it is a signal that some element of the process has changed significantly—perhaps the cutting tool has reached its wear limits, the coolant needs changing, or a new source of vibration has arisen. By examining roughness, waviness, or total profile separately, machinists can narrow the search for sources of error, and take effective action to reduce or eliminate them.

Parameters are the quantitative methods used to describe and compare surface characteristics. These are defined by the algorithms that are used to turn raw measurement data into a numerical value. Although more than 100 parameters exist, machinists have traditionally relied upon just one or two parameters.

Currently, Ra, or average roughness, is the parameter most widely specified and measured. The algorithm for Ra calculates the average height of the entire surface, within the sampling length, from the mean line. It serves as an effective means of monitoring process stability, which explains why it is the predominant parameter in use today (see Figure 1).

Of more than a dozen roughness parameters specified by ASME in Standard B46.1-1995, two others that are widely used on the shop floor are Rmax and Rz. Rmax measures the vertical distance from the highest peak to the lowest valley within five sampling lengths, and selects the largest of the five values. It is, therefore, very sensitive to anomalies such as scratches and burrs on the part's surface, and specifically useful for inspecting for these conditions. But because a single scratch or burr is often not the result of a symptomatic problem in the manufacturing process, this parameter is not so useful for monitoring process stability. On the other hand, Ra, as an averaging function, is fairly insensitive to occasional anomalies, and is therefore not useful to detect the presence of these features.

Rz is widely used in Germany and elsewhere in Europe, in preference to Ra. Like Rmax, Rz is based on the evaluation of five sampling lengths. But instead of selecting the largest peak-to-valley distance of the five, it averages the five values.

Thus, even within the single component of roughness, the specification of surface finish goes far beyond the notion of a simple smooth/rough continuum. Through parameters, surfaces can be defined and described in great detail, and engineers have made correlations between parameters and part performance under various conditions.

In some applications, a single scratch may render a part unacceptable from a design-engineering point of view, regardless of how fine its average roughness value. These slot milling cutters same considerations apply to the multiple parameters for waviness and total profile.

When a design engineer specifies a surface finish parameter and value, therefore, he must do so with an understanding of how they will affect the part's performance. Selecting the ideal parameter(s) for a given application is somewhat complicated by the great number of parameters in existence, but most of these have limited applications. The majority of applications can be successfully specified using a few well-known parameters.

Smoother, of course, is not always better. There are obvious economic benefits to machining parts as quickly as possible, and to minimizing the amount of secondary work performed. Additionally, there are applications in which a certain degree of roughness enhances functionality, and specifications may specify minimum as well as maximum roughness values. bar peeling inserts Having some definite roughness to the surface, for example, often enhances adhesion of paint or other coatings.

Some parts that perform multiple functions require complex surfaces to perform optimally. Engine cylinder walls, for example, must be smooth enough to provide a good sealing surface for the piston rings, to promote compression and prevent blow-by. At the same time, they must have "pockets" of sufficient size, number, and distribution, to hold lubricating oil. The Rk family of parameters was developed to describe such complex, multifunctional surfaces. This is an example of the parameters that were developed as design, rather than inspection, tools.

Once a surface has been defined and specified, the manufacturing engineer must determine how to produce it reliably and cost-effectively. In the case of surfaces specified only by the Ra parameter, this is usually quite easy, because the actual shape of the surface can vary considerably and still meet a given Ra value. Finer Ra values can be achieved by many alternate approaches, including slowing the speeds or feeds, making shallower cuts, or following the primary cutting process with a secondary process such as fine-grinding, honing, lapping, and so on. If Ra is the only parameter specified, the manufacturing engineer can choose whichever approach he determines is the most economical and efficient.

But where Ra is strictly a quantitative parameter, the Rk parameters are both quantitative and qualitative, in that they define the shape of the surface. The manufacturing engineer is faced with a more complex task. In the case of the cylinder wall described above, the desired surface requires two-step processing, at minimum. The first step, which may be boring, grinding, or rough honing, produces a relatively rough surface, with many prominent peaks and valleys. The second step, plateau honing, knocks the tops off the peaks, but does not extend to the bottoms of the valleys, leaving a mainly smooth surface with a number of oil pockets (see Figure 2).

After the part has been designed and manufactured, it must, of course, be inspected. For surfaces specified only by a roughness parameter, this is a simple matter. Pocket-sized, battery-powered gages that offer a small number of roughness parameters are available at low cost (below $2,000), are extremely easy to use, and can be very flexible in application. (See setup boxes.)

More complex parameters require full-featured instruments that are run by computers, and these devices may cost over $10,000. Some of these surface analysis systems are hardened for shopfloor use, and recent advances in software have made even complex measurements relatively easy to perform.

Existing standards are written around the use of instruments that measure part texture by moving a stylus in a straight line across the surface, and by monitoring the vertical movement of the stylus. Generally, the less expensive stylus-type gages that measure only roughness use the surface of the part itself as a reference. These are called skidded gages. In contrast, the full-featured instruments incorporate a precision internal reference surface, which enables them to measure waviness and total profile in addition to roughness. These are called skidless gages.

Traditional stylus-type inspection is not feasible in all instances, however. Gold-plated surfaces, for example, may be scratched by the stylus. Some high-speed or continuous manufacturing processes require faster throughput than stylus instruments allow. And some design applications require analysis of the surface over an area rather than in a straight line. For such applications, instruments using optical and other non-contact methods, or special area-measuring stylus methods, are available. These are generally quite expensive, however, and standards regulating their performance are still under development, so their use is generally restricted to applications in which traditional stylus methods are impractical.

Inexpensive, compact "roughness" gages, however, often retain their traditional utility, even where more complex parameters are specified. A shop may maintain one skidless gage for manufacturing engineering and quality assurance purposes, while making several of the more economical skidded gages readily available to machinists. Once the process is established and confirmed on the skidless gage, machinists use the skidded gages to measure parts for Ra or another roughness parameter, strictly as a means of ensuring process stability. This often represents a practical approach to meeting surface finish specifications.