Although EDM (electrical discharge machining) is among the most recent metal processing methods, its earliest application began in the mid-1940s when it was used to remove broken taps and sheared-off bolts from valuable aluminum castings. Rapidly pulsing high-voltage electrical discharges (sparks) were passed across the gap between the electrode and the grounded workpiece, removing taps and bolts from the castings by erosion. Hardened taps were removed without force or extreme heat, leaving the castings unaffected.

On the heels of this simple drilling operation, the second element of EDM processing developed: ram EDM or sinker discharge machining. Essentially identical to EDM drilling, ram EDM added a complex form to the end of the “drill�?electrode, allowing a finished and precise cavity shape to be “machined�?in one action. A third EDM type soon followed. Wire-cut EDM uses a straight wire electrode to cut a vertical or angled slot, as the wire is slowly fed through the cut to maintain a new electrode at all times.

EDM in 2023

Manufacturers typically choose electrical discharge machining (EDM) when conventional machining methods cannot provide a solution. The EDM process uses thermal energy to burn away material from a workpiece to create the desired shape. Although it is not the most commonly-used CNC machining process, engineers turn to EDM whenever hard materials and complex shapes are not conducive to traditional machining.

EDM does not require or employ mechanical force for material removal. Instead, it uses a rapid sequence of electrical current discharges between electrode materials submerged in a dielectric fluid. The electrodes (one being the workpiece) are separated by a spark gap generating extreme electrothermal heat in the spark gap zone. The heat vaporizes portions of the workpiece surface, a process called spark erosion.

Let’s look at the EDM process in detail to discover its two main types, where it’s used, and what benefits it offers:

What are the Two Main Types of EDM Machines?

The two main types of EDM machines are Ram EDM and Wire EDM.

How Does Ram EDM Work?

Ram goes by several names, including conventional EDM, die-sinking EDM, sinker EDM, spark-eroding EDM, and cavity-type EDM. But no matter what you call the process, it works like this: An electrical potential difference is created between the electrode and workpiece, electrically conductive materials, and submerged in a dielectric fluid such as deionized water.

In the Ram method, a graphite electrode (cutting tool) is machined into the mirror image of the desired shape and “sunk�?into the workpiece on the end of a vertical ram. A sinker EDM machine uses electric spark erosion to remove the metal, creating the angles and contours of the part or cavity. The dielectric fluid acts as an insulator until the process reaches a sufficiently high voltage.

The dielectric oil also works like a coolant, removing heat from the piece to prevent excessive thermal expansion. As the oil cycles through a filter, it removes the metal particles and continues through a chiller that keeps the oil below its flash point.

Ram EDM electrode tools, like graphite or copper, must display high melting and vaporization temperatures or high thermal conductivity. The tool materials must also show the ease of fabrication and wear resistance. Cost is another consideration when choosing the material for a tool electrode.

The following are essential factors determining the suitability of a material as an electrode tool in EDM machining:

• Higher metal removal rate
• Lower tool wear
• High degree of electrical efficiency

Although any conductive material can be an electrode material, taking into account the factors and properties for better application in EDM, graphite has been the most popular tool material. It exhibits a relatively low wear rate with a higher degree of electrical efficiency and is inexpensive and easy to fabricate.

How Does Wire EDM Work?

Wire EDM machining is similar to ram EDM, but the electrode is an electrically charged thin wire that cuts the metal part into various shapes. Machining a workpiece using this process also involves submerging it into a dielectric fluid and moving the wire through it to produce sparks as it passes an electric current.

Wire burning produces small chips and high accuracy by melting or vaporizing the material—even hardened steel—instead of cutting it. This so-called wire erosion process slices through metal to create parts deemed unsuitable for conventional machining techniques, and it works well as long as the workpiece has conductivity.

Like ram EDM, wire-cut EDM is another example of non-contact spark machining, during which the wire does not touch the metal. When the wire and the workpiece close, a hot electric charge jumps the gap and melts tiny pieces of the metal.

The wire is continuously fed from a spool and held between upper and lower diamond guides. Since the automatic feeder constantly unspools new wire for use in the machining, as the old wire becomes dull, new wire is there to take its place, so the wire used in this process does not necessarily need to have strong resistance properties.

The guides move in the X-Y plane, but sometimes the upper guide can also move independently, allowing for transitioning shapes, such as circular on the bottom and square at the top. The wire electrode can be programmed to cut complex geometries with excellent surface finishes while holding tight tolerances.

What is Small Hole Drilling EDM?

Although not used as often as wire and ram EDM, hole drill EDM machining is designed to drill small, deep holes with diameters as small as 0.065 mm and depths up to 1m (or 250 times the hole diameter). The electrode and the workpiece are connected to a power supply. After sufficient charge builds up on the electrode to create a high-temperature spark, the electrode vaporizes and erodes the workpiece in a localized area.

The electrode is hollow, allowing dielectric fluid to pass through it, and along with the rotation of the electrode, stabilizes the EDM process and helps remove the workpiece debris. The spark erodes the material as the electrode is rotated and moved down until the hole is complete.

What are the Applications of EDM Machining?

Because they are high-precision machine tools, wire EDM machines are top-rated in the automotive, medical, and aerospace industries. However, they help make prototypes or for full production runs and are often employed in the manufacturing industry for metal components and tools. The EDM process is favored for applications requiring low levels of residual stress.

Here are the three leading industries of EDM machining:

Automotive Industry

The automotive industry requires a manufacturing process for parts with complex shapes using hard materials. Because of this, they favor using wire EDM machines because the process does not rely on mechanical forces that lead to tool wear, and the wire electrode does not need to be stronger than the workpiece. The process works well for making holes and cavities for parts like bumpers, dashboards, and car doors.

Medical Industry

EDM machines produce accurate parts in all medical fields, including optometry and dentistry. They are used to manufacture medical equipment parts and components and medical and dental implants and syringe components without affecting their structural integrity.

Aerospace Industry

Wire EDM produces close-tolerance parts for aerospace part manufacturers. This process benefits parts unable to withstand the high temperature and stress associated with traditional cutting tools. For example, many of these components—engines, turbine blades, and landing gear parts—require accuracy and an excellent surface finish.

Applications Specific to Ram EDM

Ram EDM can create complex cavities, making it particularly useful for fabricating molds, dies, and other types of tooling made from hard materials such as tungsten, carbide, and tool steel. It also works better than conventional machining processes for creating sharp inside corners and deep ribs.

Common ram EDM applications include:

• Dies
• Plastic injection molds
• Deep and thin ribs
• Blind cavities
• Rapid tooling
• Sharp inside corners
• Blind keyways
• Internal splines
• Threads

Is EDM a CNC machine?

An EDM machine is one of several CNC machines like CNC mills, lathes, and routers. Programming a wire EDM, for instance, is much like a two-dimensional milling machine, and the program can start away from the workpiece or in the middle inside a pre-drilled hole. Wire EDMs require an NC G-code program for the geometry, as found in milling (G90, G91, G00, G01, G02, G03).

The differences are in the M-code commands. Wire EDMs have many specialty M-codes specific to wire EDM operations. The most effective method for wire EDM programming is a dedicated software module designed for wire EDM operations. This specialty software provides time-saving processing tools that will not be found in software designed for milling.

What Materials Can Be Machined by EDM?

Any conductive material, including stainless steel, titanium, tungsten, carbide, aluminum, brass, alloys, and superalloys, can be cut using the EDM machining method. Because of its accuracy and capabilities on hardened steel, EDM, specifically the wire-cut technique, has become a popular cutting method in all industries.

What are the Benefits of EDM Machining?

One primary advantage of the EDM process is that the tool electrode (wire or graphite) never touches the workpiece, meaning that it never stresses the part. For example, medical device manufacturers can use EDM to add slots, grooves, and eyelets in machined parts while applying minimal stress.

Another plus of EDM is its high-quality surface finish. The EDM process creates smooth surfaces without burrs while holding tight tolerances. For instance, wire EDM can build very thin eyelets and through-slots in medical devices, which cannot be machined using conventional machining centers.

Other advantages of the EDM method include:

• Manufacturers can use EDM successfully on heat-treated or any hard materials
• An excellent surface finish, up to 0.2 microns, can be achieved
• Because the tool and work do not have contact, mechanical stresses are not developed
• Complex shapes can be reproduced
• Highly accurate
• Economical
• Machining time is not significantly more than the traditional machining process.
• The tool life is extended because of proper lubrication and cooling
• Hard surfaces that are also resistant to erosion can be developed easily on the dies
• EDM works on any material that is electrically conductive

What are the Limits (Disadvantages) of EDM?

The EDM process removes material with electrical charges, which means it’s limited to electronically conductive workpieces and will not work on composite or dielectric materials. Wire EDM cutting may create an oxide layer on the surface of specific metals, so it must be cleaned to maintain optimal quality.

Electric discharge machining is challenged by parts and components that can only be held firmly without compromising the shape. For example, tubular-shaped parts risk being deformed while secured for EDM cutting, causing quality issues.

Other disadvantages of EDM machining include:

• Slower machining times
• Excessive electrode tool wear
• Reproduction of sharp corners might not always be possible
• Metallurgical properties of the material could change from the high heat
• Deep-hole electrodes often need redressing
• Experienced EDM operators are hard to find
• EDM machines consume high amounts of power

In Summary

A quick comparison of sinker EDM and wire EDM reveals their differences:

Sinker EDM uses a graphite electrode tool with a shape machined on the end that is “sunk�?into the workpiece. The movement of this method is mainly along the Z-axis. The dielectric liquid in which the operation occurs is typically hydrocarbon oil. The process is predominately used in mold making.

On the other hand, wire EDM has thin brass wire as its electrode to cut into the workpiece from the side. The movement in this method is along the X and Y axes, and its dielectric liquid is usually deionized water. Wire EDM has numerous applications, with punches, tooling, and dies being high on the list.

As with other CNC machine tools, EDM machines are becoming more intelligent, resulting in devices requiring little or no attention. Most of these changes focus on making the equipment easier to operate or run without an operator.

As things stand now, EDM machining offers various benefits such as high accuracy, good surface finish, and the capability to machine hardened material. However, EDM machining has a few disadvantages, such as slower machining times, that must be addressed when applying EDM machining.

Source: cncmasters.com

Choosing a milling process

Choosing the right milling tool, using rolling cutting in face milling, and using a milling cutter for hole machining when conditions are right, manufacturers can significantly increase production capacity and increase processing efficiency without investing in new equipment, which saves a lot of time and cost.

Milling cutter main angle:

The main declination angle is the angle between the cutting edge and the cutting plane. The main declination angle has a great influence on the radial cutting force and cutting depth. The magnitude of the radial cutting force directly affects the cutting power and the vibration resistance of the tool. The smaller the main declination angle of the milling cutter, the smaller the radial cutting force and the better the vibration resistance, but the cutting depth also decreases.

When milling the plane with square shoulders, select a 90° lead angle. This kind of tool has good versatility and is used in a single piece and small-batch processing. Because the radial cutting force of this type of tool is equal to the cutting force, the feed resistance is large and it is easy to vibrate, so the machine tool is required to have greater power and sufficient rigidity.

When machining a flat surface with a square shoulder, a milling cutter with an 88° main angle can also be used. Compared with the 90° main declination milling cutter, its cutting performance has been improved. Face milling with 90° square shoulder milling cutters is also very common. In some cases, this choice makes sense. The shape of the milled work piece is irregular, or the surface of the casting will cause the depth of cut to change. A square shoulder milling cutter may be the best choice. But in other cases, the standard 45° face milling cutter may benefit more.

When the cutting angle of the milling cutter is less than 90°, the thickness of the axial chip will be smaller than the feed rate of the milling cutter due to the thinning of the chip. The cutting angle of the milling cutter will have a great influence on the applicable feed per tooth.

In face milling, a face milling cutter with an angle of 45° will make the chips thinner. As the cutting angle decreases, the chip thickness will be less than the feed per tooth, which in turn can increase the feed rate to 1.4 times the original. The radial cutting force of the 45° main declination milling cutter is greatly reduced, which is approximately equal to the axial cutting force. The cutting load is distributed on the longer cutting edge. It has good vibration resistance and is suitable for the overhang of the spindle of the boring and milling mac hine. Longer processing occasions. When machining flat surfaces with this type of tool, the blade breakage rate is low and the durability is high; when machining cast iron parts, the edges of the work piece are not prone to chipping.

Selection of milling cutter size:

The diameter of the standard index able face milling cutter is Φ16～�?30mm. The diameter of the milling cutter should be selected according to the milling width and depth. Generally, the larger the depth and width before milling, the larger the diameter of the milling cutter. During rough milling, the diameter of the milling cutter of the milling machine is smaller; when finishing milling, the diameter of the milling cutter is larger, as far as possible to accommodate the entire processing width of the work piece and to reduce the traces of tool connection between two adjacent feeds.

When face milling large parts, they use milling cutters with smaller diameters, which leaves much room for improving productivity. In an ideal situation, a milling cutter should have 70% of the cutting edges involved in cutting. When milling holes with a milling cutter, the tool size becomes particularly important. Compared with the hole diameter, the diameter of the milling cutter is too small, then a core may be formed in the center of the hole during processing. When the core falls, it may damage the work-piece or tool. If the diameter of the milling cutter is too large, it will damage the tool itself and the work piece, because the milling cutter is not cutting in the center and may collide at the bottom of the tool.

Selection of milling method:

Another way to improve the milling process is to optimize the milling strategy of the face milling cutter. When programming surface milling, the user must first consider the way the tool cuts into the work piece. Usually, the milling cutter simply cuts directly into the work piece. This cutting method is usually accompanied by a large impact noise because when the insert is withdrawn, the milling cutter produces the thickest chips. Because the blade forms a large impact on the work piece material, it often causes vibration and produces tensile stress that will shorten the life of the tool.

A better way to feed is to use the rolling cutting method, that is, without reducing the feed rate and cutting speed, the milling cutter rolls into the work piece. This means that the milling cutter must rotate clockwise to ensure that it is processed in a milling manner. The chips formed in this way are from thick to thin, which can reduce vibration and tensile stress on the tool, and transfer more cutting heat to the chips. By changing the way, the milling cutter cuts into the work piece each time, the tool life can be extended by 1-2 times. To achieve this in-feed method, the programming radius of the tool path should be 1/2 of the diameter of the milling cutter, and increase the offset distance from the tool to the work piece.

Although the rolling cutting method is mainly used to improve the way the tool cuts into the work piece, the same machining principle can also be applied to other stages of milling. For large-area plane milling, the commonly used programming method is to let the tool pass through the entire length of the work piece one after another and complete the next cut in the opposite direction. To maintain a constant radial tool intake and eliminate vibrations, the use of a combination of helical lower knife and rolling milling work piece corners usually results in better results.

Mechanics are familiar with the cutting noise caused by vibration. It usually occurs when the tool cuts into the work piece, or when the tool makes a sharp 90° turn while eating. Roll milling of work piece corners can eliminate this noise and extend tool life. In general, the corner radius of the work piece should be 75%-100% of the diameter of the milling cutter, which can shorten the arc length of the milling cutter and reduce vibration, and allow the use of higher feed rates.

To prolong the life of the tool, in the face milling process, the tool should be avoided as far as possible from the hole or interrupted part of the work piece (if possible). When the face milling cutter passes through the middle of a hole in the work piece, the cutter is milled along one side of the hole and the reverse milling is performed on the other side of the hole, which will cause a great impact on the insert. This can be avoided by bypassing holes and pockets when programming the tool path.

Use down milling or up milling:

More and more manufacturers use milling cutters to machine holes in helical or circular interpolation. Although the processing speed of this method is slightly slower than that of drilling, it is more advantageous for many processes. When drilling holes on irregular surfaces, it may be difficult for the drill bit to drill into the work piece along the center line, causing the drill bit to drift on the work piece surface. Besides, the drill bit requires about 10 horsepower for each 25mm hole diameter, which means that when drilling on a small power tool, the optimal power value may not be achieved. Also, some parts need to process many holes of different sizes. If the tool magazine’s tool magazine capacity is limited, the use of milling holes can avoid a frequent shutdown of the machine tool due to tool replacement.

When milling holes with a milling cutter, the tool size becomes particularly important. If the diameter of the milling cutter is too small relative to the hole diameter, a core may be formed in the center of the hole during machining. When the core falls, it may damage the work piece or tool. If the diameter of the milling cutter is too large, it will damage the tool itself and the work piece, because the milling cutter is not cutting in the center and may collide at the bottom of the tool.

To prolong the life of the tool, in face milling, the tool should be avoided as far as possible from the hole or interrupted part on the work piece. When the face milling cutter passes through the middle of a hole in the work piece, the cutter is milled along one side of the hole and the reverse milling is performed on the other side of the hole, which will cause a great impact on the insert. This can be avoided by bypassing holes and pockets when programming the tool path.

By selecting the appropriate milling cutter angle, size and feed method, the tool can cut into the work piece material with minimum vibration and tensile stress, and know under which circumstances milling holes is more effective than drilling, and manufacturers can be highly efficient, Low-cost processing of work piece blanks into exquisite parts.

Source: market-prospects.com

As the title implies adjusting screws, also known as back-up screws, stop screws and preset screws, are not just a simple set screw. They are a screw with a purpose–three actually. The first is to provide a fixed stop for a cutting tool to rest against during tool changes. This allows an operator to save time as they do not have to pull out a ruler, setting jig, etc. to reassemble the cutter into a holder. A secondary purpose of the adjusting screw is to assist the tool holder in keeping the cutter from being pushed up into the holder if the cutting loads increase to the point where the tool may slip up into the holder. The third is to offer sealing for coolant-through tools.

1. Expected repeatability of cutting tool length

When an old cutter is swapped out and a new one put in its place, the repeatability of this process will vary based on a few parameters such as cleanliness and the OEM cutting tool overall length tolerances. Cleaning the clamping bore or collet of a holder provides better runout repeatability which should be old news to everyone, but if old coolant and contaminants are not removed, they would get jammed between the end face of the shank and the adjusting screw, affecting the length setting.

Cutting tool overall length tolerances may also vary from one OEM to another. We have seen them range from ±.3mm to ±.5mm (±.012�?to ±.019�?. Others may be tighter or looser. Most modern machining centers come with tool length offset measurement systems which will provide the final precise gage length of a tool assembly. With the rough position provided by the adjusting screw, the machine operator can continue working and does not need to worry about tool clearances and stick outs.

2. Forms of adjusting screws

The clamping mechanism of the holder also affects the length repeatability. Both hydraulic chucks and milling chucks are radial clamping systems, whereas a tapered collet is drawn down into a taper by a threaded nut. This draw down causes the cutter to be drawn down as well. For this we have two types of adjusting screws: HMA/HDA solid type and NBA rubberized type. The solid type is a one-piece steel construction part, whereas the rubberized type has a rubber padded conical pocket that absorbs the axial travel of the cutter shank as the collet is clamped.

3. Option for adjustable reduction sleeves for MEGA DS/HMC

Milling chucks also have a second type of adjustment screw option that can be built into the back end of a reduction sleeve. As cutting tool diameters get smaller, the length of the shank also gets shorter. As such, the end face of the shank may not reach the HMA adjusting screw when installed it the body of the holder. The AC Type Collet adjuster screws into the back end of the reduction sleeve where the shank the tool can easily be reached.

4. Warning on holders that cannot support adjusting screws

It is always recommended to consult the tool holder catalog or technical documentation to ensure that a holder can support an adjusting screw. Some holders are very short or have very deep internal features that may not allow for the use of any adjusting screw. In those cases, a depth setting ring or collar on the shank of the cutting tool may be an acceptable alternative.

Caution should be used on shrink-fit holders. Thermal expansion/contraction occurs in all three axes, so as the body of a shrink-fit holder cools down it will draw the cutter down jamming onto the adjusting screw. This could lead to damage to the screw, the holder or the cutter.

Theo John Zaya – bigdaishowa.com

We have certainly discussed anvil micrometers on the Higher Precision blog. But what about the slightly more obscure v-anvil micrometer? Well, it is time for the v-anvil micrometer to get a bit of the spotlight. This specialty tool provides precision in measurements when other tools just will not suffice. But we will get into that in a bit. First we would like to introduce you to the general design of the v-anvil micrometer so you can understand what we are referring to throughout.

THE DESIGN OF V-ANVIL MICROMETER

The v-anvil micrometer is similar in overall structure to the standard micrometer. The main parts include the ratchet, knurled gripe, thimble, sleeve, lock nut, c frame, spindle, and anvil. The difference that sets the v-anvil apart is the shape of the anvil itself, which is shaped like the letter “V�?laying on its side. The v of the v-anvil itself comes with more widely distanced or close together tips, and the point where the two lines of the “V�?connect can be touching and fused or may have a small gap between them. Finally, the end of the spindle may be flat across or be conical in structure with varying degrees of a point at the tip. All of these minor adjustments in design provide greater levels of precision based upon what it is you are using the v-anvil micrometer to measure. V-anvil micrometers also come with a ratchet stop in order to apply a more constant force and can be made with a centerline groove that provides further specialization of measurement. Finally, v-anvil micrometers come in both digital and Vernier styles. Benefits of using a digital v-anvil micrometer include having a precise zero-setting, data hold for ongoing measurements, a 2-point preset for more efficient use, a function lock to lock the position in place, clearer data output, and conversion capabilities between inches and millimeters.

USES FOR THE V-ANVIL MICROMETER

The v-anvil micrometer has two common uses. These include measuring the outside diameter of cutting tools that are built with an odd number of flutes and checking a part for roundness. We will describe both of these applications in more detail.

MEASURING THE OUTSIDE DIAMETER OF CUTTING TOOLS

When taking a measurement of outside diameter from a cutting tool with an odd number of flutes, it is difficult to use a standard micrometer or caliper given the uneven placement of the part surfaces used for measurement. This is where the v-anvil micrometer is particularly useful. Given the placement of the v-shaped sides of the anvil, a cutting tool with an odd number of flutes can be measured easily. Simply lay the cutting tool on its side perpendicular to the v-anvil micrometer anvil, align the lanes of the flutes up with the anvil surface and spin the ratchet to adjust the spindle into place. The v-anvil micrometer is ideal when measuring cutting tools such as taps, reamers, and end mills. Additionally, v-anvil micrometers are useful for measuring the pitch diameter of a tap that has a small diameter. This can be accomplished by the single-wire method. One important factor to keep in mind when measuring tools with odd numbers of flutes is that the number of flutes will determine the specific design of v-anvil micrometer that is required. For example, when inspecting a tool with 5 flutes you will need a different v-anvil micrometer than when inspecting a tool with 3 flutes.

CHECKING FOR ROUNDNESS

Another use for the v-anvil micrometer is to check for roundness of a part, also known as checking for out-of-roundness. The way in which this is done is to first take several measurements at different locations around the outside of the part cylinder or shaft. Then, you subtract the smallest diameter from the largest diameter. Finally, you divide the resulting number by two. The outcome represents the amount of out-of-roundness that the part exhibits. Checking for roundness is made easier by the v-anvil micrometer because of the location the sides of the v-shaped anvil are well-positioned to place a part horizontally and have contact points be around the edge.

BENEFITS OF THE V-ANVIL MICROMETER

The v-anvil micrometer increases measurement precision when collecting data on diameter because of the way in which the measurement is collected. Each diameter measurement is taken with contact made at three points (each side of the anvil “V�?and the spindle). Having three points of contact is in contrast to the normal two points of contact available when using a standard micrometer or caliper. In fact, when working with cutting tools that have an odd number of flutes, the v-anvil micrometer remains the only device capable of taking a highly precise measurement.

TECHNICAL DATA FOR V-ANVIL MICROMETERS

Having some basic technical data regarding the design of v-anvil micrometers is helpful for those hoping to understand the details of application. V-anvil micrometers are available with or without a centerline groove. Having a centerline groove can be helpful when taking the measurement of pitch diameters on taps that have three or five flutes. The zero reading of the v-anvil micrometer always starts from the point where the two sides of the “V�?meet. Often, the v-anvil micrometer will come pre-equipped with a cylindrical zero set check. On analog models, graduation is 0.01mm, .001mm, or .0001mm and flatness of the spindle and anvil is 0.6µm[.000024”] /1.3µm[.00005”]. On digital models, flatness of the spindle and anvil is 0.3µm[.000012”] /1µm[.00004] and the battery life can be expected to last 1-2 years with normal usage. The resolution of the digital models is typically 0.001mm or .00005�?0.001mm. Functionally, a digital v-anvil micrometer has a zero-setting, data hold, function lock, data output, 2-point pre-set, and conversion capabilities.

CONCLUSION

V-anvil micrometers are just the tools you need for very specific precision measurement tasks. When working with an odd number of flutes on a cutting tool or checking for out-of-roundness, these tools will provide the measurements you require with ease. While they may not be as versatile as the standard micrometer or caliper, v-anvil micrometers are a requirement for any metrologist tool set.

Source: higherprecision.com

The Mitutoyo Profile Projector-Plus is a new series of profile projectors that utilize LED lighting and provides reliable measurements in manufacturing site environments. The Profile Projector-Plus provides stable dimension and angle measurements in harsher environments conventional models can’t handle, such as manufacturing and processing lines.

Key features:

• LED illumination: Implementing LED vs. halogen lighting eliminates the need for a main-unit cooling fan, limiting entry of oil, mist, dust, etc. into the measuring instrument. LEDs are also more durable, greatly reducing lamp burnout and power consumption.
• Stepless illumination adjustment: Stepless illumination control is more efficient and allows light levels to be set precisely to suit surface textures and color or a workpiece.
• Built-in digital XY counter: Displays XY axes and angle readings in large characters on the front of the machine for easier readability and eliminates the need for an auxiliary DRO.
• Improved durability: The absence of a cooling fan (via LED illumination) reduces adhesion of oil and dust to the internal mirror and light source to maintain a higher optical performance. The LED bulb lasts much longer than halogens, meaning less maintenance and reduced down time.

Find more information and details in the full PJ-Plus New Product Information Letter.

Source: mitutoyo.com

There are three particularly sensitive areas of the tool holder assembly that can experience process-affecting wear and tear and cause a cycle to change. By identifying and addressing issues early in these areas, you can prevent small tool holding imperfections from turning into bigger problems.

You’ve got a brand new setup working on the floor. You’ve invested in new holders and cutters. The job’s been expertly engineered and programmed. Everything is going smoothly. Then, suddenly, something starts changing and nobody knows exactly why. All the fundamentals are the same: material, machine, tooling, temperature, etc.

There’s a good chance the issue is with a tool holder system, one of its small, hard-to-reach, often-overlooked nooks or crannies. While I understand it can be time-consuming to clean and maintain holders, doing so is critical to long-term process control. If you treat holders and accessories right, both in and out of assembly, not only will their performance improve, but overall costs will be reduced by avoiding costly spindle repairs and tool breakage. Proper use and maintenance is especially important for three particular areas of the assembly that can experience process-affecting wear and tear: pull studs, collets/nuts and the tool holder taper. Let’s examine these so you can identify and address issues early to prevent small tool holding imperfections from turning into bigger problems.

Pull Studs

I’ve visited shops of all shapes and sizes for more than 15 years and I’m still amazed by how often I see buckets of pull studs sitting around. Though small commodities, as the single component that keeps a holder in the spindle �?weathering up to 7,500 lb of load in 50-taper arrangements �?pull studs are critical to protecting both your people and machinery. If you’ve ever experienced a break, you know how scary and dangerous it can be. What’s more, if that tool comes out it’s going to damage the spindle, resulting in necessary repairs that can easily exceed $50,000.

As with any metal-on-metal contact, one is the wear part. In a tool holder setting, the backside of the pull stud assumes this role. Depending on the collet type, repetitive ATC (automatic tool change) can cause dents that lead to stress risers and potentially breakage. A testament to how important this is to consistent performance is that we’ve actually changed all of our smaller-taper knobs to a high-purity tool steel. Regardless of the type of pull stud you’re using, we recommend inspecting them every time you change the cutting tool, both for wear and to make sure they aren’t loosening. Get the bad ones out immediately or you’ll begin to see effects throughout the interface and the workpiece. Pull studs generally last about three years, so finding a way to track them, whether you use studs manufactured with date coding or develop a system of your own, is very helpful.

Finally, in addition to helping to maintain a consistent form longer, installing pull studs correctly ensures the taper won’t bulge at the end and disrupt spindle contact. Use a removable thread locker and a torque wrench, but definitely not a cheater bar or hammer. Torque recommendations are:

• 30-taper: 18-22 ft-lb
• 40-taper: 55-65 ft-lb
• 50-taper: 100-120 ft-lb

Collets/Nuts

When it comes to a traditional setup like solid clamping nuts with an ER style collet, it’s all about friction. Collets and nuts are wear products too. The repeated twisting and sliding of the nut on the collet during clamping adds up. Likewise, since the nut’s threads are what’s actually pulling, the coating of the thread that helps maintain the proper relationship between the two can deteriorate. What’s the big deal, you ask? The nut and collet connection directly impacts runout and gripping force �?becoming other potential culprits of those unexpected, hard-to-explain changes in a cycle’s performance. In testing, we found that after 500 clampings with a solid ER nut, runout accuracy changes by about 35 percent �?that 12xD drill you’re using is now off center. We also found after 500 clampings that gripping force can decrease up to 50 percent, increasing the chances of tool breakage. And the price of carbide is only going up.

The best way to prevent these issues is pretty simple: keep them clean. I recommend an ultrasonic tank with a precision part cleaner. A small bench-top tank is great for removing swarf, particles, coolant residue and oil. Immediately after cleaning, dip them in rust-preventative oil �?the longer the planned storage period, the heavier the oil. Since you must only ever work with a clean, dry collet, give them one more cleaning before returning them into cycle. This cleaning method is not, however, recommended for bearing nuts since cleaning fluid can get caught in the bearings and cause premature failure. Then again, their design in and of itself addresses most of these common to ER styles.

The Taper

The longer I wear a shoe the more it reshapes to adapt to my foot. Spindles and holders aren’t much different. The problem for machinists is that holders rarely stay paired with the same spindle. As such, trauma on a holder or spindle �?dings, scratches, gouges, etc. �?can magnify quickly. One bad holder can spread its problems like an illness. I’ve said it twice, I’ll say it again, if you’re seeing disruptions like these on your holders, get them out of the rotation. For the sake of this discussion, I’ll address the most common type of taper wear �?fretting �?the thin, rust-looking build-up that appears over time. Interestingly, it’s not actually oxidation due to exposure; rather, it’s caused by micro vibrations that push oil off the contact points resulting in metal-to-metal rub. Need another reason to get bad holders out of play?

Well here it is: if there’s fretting on the taper, you can bet it’s on the spindle. The good news is that we know this is almost always caused by pushing the tools too hard for the machine, fixturing or workpiece. If you see fretting, I advise reevaluating your processes and dialing back to the proper specifications for each part of the process. As with collets and nuts, proper and thorough cleaning, with taper and spindle cleaners, also helps prevent fretting and other damage from starting in the first place. That said, an easy way to nip this in the bud is with a dual-contact interface that will all but eliminate the root cause of fretting: micro vibrations.

Of course, every part of the tool holding assembly wears in one way or another, which speaks further to the importance of proper maintenance and use, but these three areas are especially sensitive. So when a cycle mysteriously changes, don’t overlook these three parts of the holder assembly. Better yet, instead of waiting for the “we aren’t sure what’s going on�?stage, take care of your holders.

Source: bigkaiser.com

Cermets are titanium carbide-based (TIC, TiCN) hard metals, meaning a compound of ceramic particles in a metallic binder. Compared to tungsten carbide, cermet has better wear resistance and less tendency to build up cutting edges.

Cermets, with titanium compound as the main component, have low affinity with iron, providing a glossy machined surface on ferrous metals. Cermets have also been attracting attention in recent years for using only a small amount of tungsten, which is a scarce resource.

Our newly developed cermet substrate T2500Z with excellent thermal conductivity, improves thermal crack and notch wear resistance. Thanks to our Brilliant Coat® technology, T2500Z achieves excellent wear and adhesion resistance, providing stable and excellent machined surface quality in various work materials such as bearing steel, carbon steel and alloy steel.

Brilliant Coat® has excellent lubricity and significantly reduces reactions with ferrous metals. This greatly reduces the formation of built-up edges and thus significantly reduces the risk of fractures. Additionally, the wear resistance has been improved by over 1.5 times as compared to conventional products. T2500Z not only provides beautiful finished surfaces but also a longer tool life in the finishing process.

What is a Collet?

A collet is a form of chuck, but it is not identical. While a chuck is tightened around an object, a collet utilizes clamping pressure by forming a collar around the object being held, holding it securely in place. This clamping force is typing applied through a tapered design that uses a sleeve and inner cylindrical surface. While there are varying designs, all collet types operate by being pressed over the element to be held, resulting in both accurate alignment and static friction. While the collet is not suitable for every tool and operation, it does allow for self-centering, resistance against loosening, fast-chucking and steady clamping pressure.

Collet Types for Woodworking and Metalworking

As with any tool or chuck, there are a variety of collets, making them versatile clamping devices. However, in general, different collet types are used in two specific fields of construction and manufacturing.

Woodworking

It should come as no surprise that a collet is useful in woodworking, as it is a tool found in drill presses and other machinery. However, the collet is most often used in routers to hold the cutting bits in place. The collet is secured to the tool using a hexagonal collet nut, allowing it to be tightened or loosened to the motor arbor.

Metalworking

While woodworking may only have a few varieties of collets, metalworking uses many types with varying holding capacities. Granted, the standard metalworking collet is used for holding round bar or tools, but there are also hexagonal, square and other shaped collets for specific tasks and tools. In addition to the different shapes and styles, there are also e-collets and step collets. E-collets or soft collets are typically machined for a specific job while step collets are designed to hold larger pieces.

ER Collets

While there are several types of collets, ER collets are the gold standard when it comes to clamping systems. Developed by Rego-Fix and patented in 1973, the ER collet is manufactured and used worldwide as one of the most trusted clamping systems. The er collet chuck derived its name by combining the already established E-collet with the first letter of the development brand �?Rego-Fix. These collets come in a standard series ER-8 through ER-50 with each series number referring to the receptacles tapered diameter size in millimeters.

While the revamped design allowed for broader clamping usages and convenience, the geometry and spring design make the ER collet useful only for cylindrical parts, meaning that square and hexagonal pieces still require specialty collets, like the 5C. However, despite the drawbacks of the cylindrical design, this collet system is still widely accepted as the most versatile collet chuck system.

Source: //www.tmsmith.com/2019/02/19/collet-types-and-sizes/

A coordinate measuring machine, also known as a CMM, is a piece of equipment that measures the geometries of physical objects. CMMs using a probing system to detect discreet points on the surfaces of objects.

The very first CMM made its appearance in the early 60s. Originally developed by Ferranti Company in Scotland in the 50s, this 2-axis CMM used a 3D tracing device with a simple digital readout that displayed XYZ positions. Ferranti used its CMM to measure precision components for their military products. Three-axis models were developed in the later 60s.

CMMs are most often used to test a part or assemble to determine whether or not it respects the original design intent. CMMs are integrated within quality assurance or quality control workflows to check the dimensions of manufactured components to prevent or resolve quality issues.

The advantages of using CMMs over manual inspections or checks performed with conventional metrology instruments, such as micrometers and height gauges, are: accuracy, speed and the reduction of human error.

There are several different types of CMMs. Typically, CMMs are categorized based on their structures. Each structure has its pros and cons. Let’s take a look at different CMM types in more detail.

What are the different CMM types?

Bridge CMM

Bridge CMMs feature a probing system that moves along three axes: X, Y and Z; these axes are orthogonal to each other in a Cartesian coordinate system. Each axis has a sensor that monitors the probe’s position (in micrometres) as it moves along an object and detects points on the object’s surface. These points form what is called a point cloud, which “illustrates�?the surface area users are interested in inspecting. Bridge CMMs can be divided into two CMM sub-types: moveable-table and moveable-bridge CMMs.

The pros of bridge CMMs

• One of the most accurate types of CMMs
• Ideal to measure machined parts with high tolerances
• Perfect for small- to medium-sized components
• Enabled for multi-sensor measurements, such as probing and scanning

The cons of bridge CMMs

• Can be expensive
• Have a fixed measurement volume
• Lack of portability; you need to bring the part to the system or use machinery to move them around
• Sensitive to vibrations and must be used in a metrology lab
• Require rigid setups for each inspected part
• Complex to operate and needs skilled workers to program the device

Gantry CMM

Gantry CMMs are somewhat like bridge CMMs; however, they are usually much larger. Because they are designed to eliminate the need to lift a part onto a table and offer similar accuracy levels as bridge CMMs, Gantry CMMs are regularly used for very heavy or large parts. Gantry CMMs must be mounted on a solid foundation, directly on the floor.

The pros of gantry CMMs

• Highly accurate
• Large measurement volume, which facilitates inspections of large/heavy parts
• Easier to load and unload components than a bridge CMM

The cons of gantry CMMs

• Can be expensive
• Have a fixed measurement volume
• Lack of portability; you need to bring the part to the system or carry out significant assembly/disassembly to move the CMM
• Takes up a lot of floor space
• Sensitive to vibrations and must be used in a metrology lab
• Require rigid setups for each inspected part
• Complex to operate and needs skilled workers to program the device

Cantilever CMM

A cantilever CMM differs from a bridge CMMS as the measuring head is only attached to one side of a rigid base. Cantilever CMMs provide open access to inspection technicians on all three sides for ease of operation

The pros of cantilever CMMs

• Highly accurate
• Suitable for smaller parts
• Access to three sides makes it easier to manually or automatically load and unload components

The cons of cantilever CMMs

• Can be expensive
• Have a fixed measurement volume
• Lack of portability; you need to bring the part to the system
• Sensitive to vibrations and must be used in a metrology lab
• Require rigid setups for each inspected part
• Complex to operate and needs skilled workers to program the device

Horizontal Arm CMM

Horizontal arm CMMs, as their name implies, have horizontally mounted probes as opposed to vertically mounted probes like other CMMs. They are designed to measure long and thin objects that could not be inspected with vertical CMMs, like sheet metal. Horizontal arm CMMs are also often used to inspect geometries that are difficult to reach. There are two types of horizontal arm CMMs: plate-mounted and runway-mounted.

The pros of horizontal arm CMMs

• Long measurement volume (long and thin parts)
• Good for parts requiring low tolerances
• Does not require a significant foundation system
• Quick and easy installation
• Smaller footprint
• Requires less ceiling height than other types of CMMs
• Cost-effective

The cons of horizontal arm CMMs

• Less accurate than other CMMs
• Have a fixed measurement volume
• Lack of portability; you need to bring the part to the system
• Sensitive to vibrations and must be used in a metrology lab
• Require rigid setups for each inspected part
• Complex to operate and needs skilled workers to program the device

Portable measuring arm CMM

Portable measuring arm CMMs are coordinate measuring machines that can take measurements of parts right on shop floors, allowing for quick results and real-time analysis. As opposed to inspectors bringing components to a lab to be measured, technicians use an articulated arm, with either a six- or seven-axis system, to measure components wherever required; this is particularly useful to analyze parts while still integrated into their fixtures or assemblies. Portable measurement arms.

The pros of measuring arm CMMs

• Portable and lightweight: you can bring the CMM to the part
• Extendable measurement volume (leapfrog)
• Enabled for multi-sensor measurements, such as probing and scanning
• Relatively inexpensive
• Easy to operate (no programming)

The cons of measuring arm CMMs

• Less accurate than other types of CMMs
• Sensitive to environmental vibrations
• Requires rigid setups

Optical CMM

Optical CMMs are portable non-contact devices. These CMMs use an arm-free system with optical triangulation methods to scan and acquire 3D measurements of objects. Thanks to sophisticated image processing technology, optical CMMs are ultra-fast and guarantee metrology-grade accuracy. Optical CMM scanners are particularly conducive Industry 4.0 manufacturing.

While optical CMMs have a slightly lower level of accuracy, they are nevertheless accurate for a wide range of applications. In fact, optical CMMs are used in conjunction with traditional CMMs in order to free up production bottlenecks. Therefore, parts that require the critical level of accuracy are inspected with a conventional CMM. All other components can be assessed using a more cost-effective optical CMM, which provides satisfactory accuracy—but also portability, flexibility and speed.

The pros of optical CMMs

• Portable and lightweight: you can bring the CMM to the part
• Extendable measurement volume (leapfrog)
• Enabled for multi-sensor measurements, such as probing and scanning
• Very fast acquisition times
• Relatively inexpensive
• Easy to operate (no programming)
• No rigid setups required

The cons of optical CMMs

• Somewhat less accurate than conventional CMMs, depending upon the application

Why are we talking about CMM speed all the time?

Today’s manufacturers are under more pressure to increase throughput, offer just-in-time delivery schedules, and accelerate their time to market—all while significantly reducing costs to a minimum. When bottlenecks at the CMM occur, inspection procedures extend cycle times and ultimately increase non-value-added quality costs. CMM speed and efficiency is therefore critical.

As previously mentioned, gridlocks at the CMM are often caused by the sheer volume of work that has to be carried out by a limited number of qualified metrologists. CMM programming times also significantly lengthen inspections as the CMM has to be configured for each type of component or sub-assembly to be assessed.

Conventional CMMs that are equipped with CMM probes are slow and not suitable for efficiently measuring complex shapes. Other CMMs, which have CMM sensors, tend to speed up inspection processes; however, they still need to be operated by experts.

Manufacturers are therefore increasingly looking for inspection technologies, like innovative optical CMMs, that can keep up with the breakneck pace required in demanding production environments and stringent quality assurance and quality control standards.

Source: //www.creaform3d.com/blog/what-is-cmm-and-their-types/

What Is a Micrometer?

A micrometer is a measuring instrument that can make extraordinarily precise measurements. Most micrometers are designed to measure within one one-thousandth of an inch! That’s a close fit. Exact measurements like this are necessary when even the smallest of space between objects can cause problems or difficulties.

There are several types of micrometers that are designed to measure different types of objects or spaces. Most micrometers are available in sets to accommodate measurements of varying size.

Outside Micrometer: This type of micrometer is designed for measuring the outside of objects—the outside diameter (OD). They look and move much like a C-clamp, which opens and closes by turning an internal screw. In a micrometer, the object you wish to measure is clamped between the anvil (the stationary end of the clamp) and the spindle (the moving part of the clamp). Once the object is secured in the clamp, you use the numbering system on the thimble (the handle portion) to find your measurement.

Inside Micrometer: While the outside micrometer is used for measuring the outer diameter of an object, the inside micrometer is used to measure the inside, or inside diameter (ID). These look more like a pen, but with a thimble in the middle that turns. As the thimble turns, the micrometer expands like a curtain rod would. This then extends until each end of the tool is touching the inside of the pipe. When this happens, you use the numbering system on the thimble to find your measurement.

Depth Micrometers: While inside and outside micrometers are both used to measure the diameter of an object or hole, a depth micrometer is for measuring the depth of a hole, recess or slot. Depth micrometers have a base that aligns with the top of the recess that needs to be measured. The thimble is on a shaft that sticks up from the base. As the thimble turns, a measurement rod comes down from the shaft. You continue to turn until the rod hits the bottom surface of the hole being measured. When this happens you use the numbering system on the thimble to find your measurement.

When Would I Use a Micrometer?

You would use a micrometer when a very precise measurement is needed. There are several different designs, depending on what needs to be measured. This could be the size of a pipe, tool or object from the outside. This could be the inside width of a pipe, bearing or another hollow object. Or this could be the depth of a hole or recess.

These are the tools you will reach for when accuracy is the most important factor. This is frequently true for machines with moving parts. Parts that move in and out of each other, like a piston, for example, need to remain in a steady, straight line. If these parts have even the smallest bit of sway, they can begin to fail. This is also true in other applications, such as the use of bearings. Other applications that require the most exact measurement are pipe fittings—especially if the pipe will be moving gases with very small and light molecules, like helium. Micrometers are also the preferred tool when measuring the thickness of items like sheet metals.

How Do I Read a Micrometer?

It is important to check if the micrometer is English or metric before using it for measurements. Make sure you are using a tool that has the same unit of measure as whatever you are already working with.

Once the micrometer is rotated into the proper measurement, the measurement can be taken. This requires adding together numbers found on the spindle and thimble which will give you the accurate measure. How to find the numbers you want will vary depending on the type and design of the micrometer. Instructions on how to read your micrometer will come from the manufacturer with your tool.

Getting It Right

Micrometers are a necessary tool when a precise measurement is required. They come in many designs and styles to fit the needs of whatever object it is you need measured. Since micrometers only have a limited measurement span, they frequently come in packages of varying sizes to accommodate your needs.

Source: //www.grainger.com/know-how/equipment-information/kh-how-to-read-a-micrometer

Lake Mary, Fla, March, 5, 2020 �?FARO® Technologies, Inc. (NASDAQ: FARO) �?FARO, a global leader in 3D measurement and imaging solutions, announces today the latest iteration of its CAM2® 2020 Software. The release includes a variety of performance and user interface improvements, new features and a new subscription licensing option. Users can now achieve greater control over their full manufacturing process at a lower up-front cost in this latest iteration of the metrology software platform.

The new subscription model empowers users to benefit from CAM2 with a lower initial investment. It offers scalability through a flexible licensing model and ensures users always have access to the latest and most up to date version of CAM2.

“FARO CAM2 is a powerful, intuitive and application-focused 3D measurement platform designed to help users efficiently fulfil their quality assurance and inspection tasks. We’re pleased to offer a software experience developed directly from our customers�?feedback, based on the metrology needs they encounter every day,�?said Michael Carris, Vice President of Product Marketing. “What’s more, this release strengthens the relationship between quality assurance and production operations with new capabilities that ensure even greater process control.�?/p>

FARO CAM2 2020 is helping users get the most from their manufacturing processes, with an intuitive, streamlined and application-focused platform. Through a continuous improvement process, user feedback and requirements are continually collected, integrated and deployed. FARO CAM2 2020 is the culmination of these efforts, which lead to a variety of new features, including an enhanced measurement experience and an updated statistical process control tool that assists users in identifying production data trends that may indicate when a process is moving out of a specified parameter. Being able to predict this kind of error reduces wasted time, scrap and rework, and helps keep production capacity at full strength. As part of an established lineup of smart features, this release represents a fully realized solution for the everyday production tasks of the customer.

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About FARO

FARO Technologies develops and markets computer-aided measurement and imaging devices and software enabling our customers to easily and accurately connect the physical world to the virtual world. FARO solutions include 3D manufacturing, construction BIM, 3D design, public safety forensics and photonics industries. More information is available at //www.faro.com.

Source: //www.faro.com/en/News-Library/2020/New-subscription-model-offered-with-faro-cam2-software