The wafering/sectioning blade itself is only a small factor in your sectioning operation. A successful wafering or sectioning operation is both an art and a science. Requires proper use and understanding of selecting the right diamond wafering or sectioning for your material or application. Find everything you need to make a sectioning export.

For you to get the most out of your wafering or sectioning blade, we strongly urge you to read and follow these instructions and suggestions. Doing so will help you save money and time. These suggestions and recommendations have come from years of experience in the research, development, and manufacturing of wafering and sectioning blades. As well as years of personal experience and observations of clients like you. The wafering/sectioning blade itself is only a small factor in your sectioning operation. A successful wafering or sectioning operation is both an art and a science. Requires proper use and understanding of selecting the right diamond wafering or sectioning for your material or application. Maintaining and using proper 

Selecting the right wafering or sectioning blade parameters often involves a trial-and-error process. Many, of which can be avoided through experience and understanding of how to use these parameters for your specific application. What works for one application may not work for another. While there is no real substitute for experience, even new wafering and sectioning saw operators can quickly become proficient by learning and applying some basic principles of wafering and sectioning. Many parts of this guide have been published, presented in several industry magazines, or presented at conventions. 

Safety

Always wear proper safety equipment: safety footwear, snug-fitting clothing, safety goggles, hearing and head protection, and proper respiratory equipment. Always use the blade guards provided on machines. Do not remove these safety devices. They are for your protection.

Before Using

Make sure that the arrow on the wheel points in the same direction as the shaft rotation. The best performance and life will result. Before performing any cutting operations, let the tool run for a few seconds without loading. If the blade wobbles, vibrations, or unusual noises occur, stop the tool immediately. Inspect the blade for damage or incorrect mounting.

Dressing is the process of sharpening and exposing diamond particles in the bond matrix for the diamond particles to freely penetrate the material, minimize loads, and provide good cut quality. Another reason for dressing blades is to clean a loaded blade from debris that is filling the pores between the abrasive particles. Cutting into the dressing plate creates mechanical and thermal stress and thus produces a clean surface being cut. Wafering or sectioning blades that are poorly dressed will tend to push the material, creating high loads, high cutting temperatures, and poor cut quality. This can also cause blade breakage. Resin bond wafering and sectioning blades have a soft binder and, in most cases, will require minimum dressing, if any at all. Resin bond wafering and sectioning blades are typically dressed in the material being cut. This is why they are frequently called “self-dressing blades." Nickel bond and metal bond blades have a much harder binder, and a much more aggressive dressing is needed to achieve the above-mentioned goals. Nickel bond wafering and sectioning blades require dressing. The diamonds need to be well-protruded and exposed to easily penetrate the material.

RECOMMENDED DRESSING PROCESS

Dressing procedures are established by the end user based on experience and the application concerned. There is not one common method that applies to all applications.

The dressing stick used to dress the blade should have the same or similar diamond grit or mesh size as the wafering blade being dressed. Many sectioning saws are equipped with an automatic dressing chuck that allows the user, at the push of a button, to slowly forward the dressing stock into the rotating blade as it is sectioning a sample. This ensures the blade is continuously dressed as it cuts through the sample. This process is highly recommended, especially for cutting soft and gummy samples or materials such as plastic-mounted resins that typically tend to smear or gum up the blade. For best results, we recommend that the dressing stock used matches the dimensions of the sample as closely as possible. When sectioning extremely hard and working throughout the process,

For dense materials such as silicon nitride, it is a good idea to implement a secondary dressing process. Dressing the blade before starting to cut the sample. Doing so will re-sharpen the diamond particles, so they are working at their maximum level of efficiency from the very beginning. This can be accomplished by making five cuts through the dressing stick so that the dressing stick covers the diamond section. Make sure the coolant is turned on and working during this process.

When and how often should I dress my diamond-wafering blade?

There are no specific recommendations or guidelines on when or how often the wafering blade should be dressed. The sectioning saw operator should use their best judgment in determining when and how to dress the blade being used. A good rule of thumb to remember is that when you notice the cutting rate or speed is significantly slower than when the blade was first used, it is a good sign the blade you are using needs to be dressed. Eventually, all diamond wafering blades will need to be dressed, regardless of the material being cut. The amount of dressing a blade will require will depend on the material's hardness, density, porosity, diameter, shape, and geometry. Dressing will re-sharpen and re-expose the diamond crystals and particles in the blade bond matrix, as well as unload the blade from material debris covering the diamond section surface. When cutting very soft and gummy materials such as plastics and some epoxy-filled composites, the blade will have to be dressed more frequently than when cutting ceramics and other ultra-hard and brittle materials.

At the same time, when cutting large-diameter materials, the wafering blade is taken almost to its maximum cutting capacity. For example, when cutting 1” (25.4mm) of material with a 5” wafering blade, the blade should be dressed continuously during its operation. Doing so will help prevent the “build-up” edge on the blade and keep the blade from binding up.

Continuously dressing sintered (metal bond) and resin bond wafering blades will not in any way reduce the life of the blade. Dressing will most likely increase the life of the blade, avoid possible blade damage or wreckage, and optimize your sectioning operation.

COOLING

Coolant should always be used to cool and lubricate the blade. Coolant supply position and pressure are critical to minimizing chipping and maintaining consistent and acceptable cut quality. The most frequent source of diamond wafer blade damage and material deformation is coolant not effectively reaching the cutting zone.

  • Coolant serves many functions in wafering and sectioning operations, including:
  • Cools the blade, diamond section, and material being cut.
  • Provides lubrication to minimize friction between blade and material.
  • It washes out and removes powder residue and swarf from the cutting process.

It has been found that a generous flow of coolant increases diamond blade efficiency, improves surface finish, and reduces heat buildup and material cracks and deformation associated with overheating. Coolant must be applied in the proper place, or it will not cool the blade or material being worked on properly. Coolant should always be directed so that the full flow is at the point of contact between the blade and material, facing the same direction as the rotation of the blade. The amount of coolant used should increase with the hardness of the material being cut. If you see sparks, there is insufficient coolant reaching the cutting zone, or it is simply ineffective. 

Determine the type of coolant you are planning to use. The most frequently used coolants for sectioning operations are water-solvent-based coolants and mineral oils. Mineral oil is typically used for sectioning hard metals, where water-soluble coolant is preferred over the remaining family of materials.

Plain water evaporates at 212 F. Often, the temperature in your cutting zone reaches as much as 500 degrees F. Often, water evaporates before it has a chance of effectively cooling the wafering blade and sample being sectioned. Resulting in shorter blade life, material damage, or microcracks associated with overheating. 

Water-soluble coolant will greatly benefit your sectioning operation, reducing sample/material thermal stress, edge damage, and internal cracking and ensuring the long-term integrity of the material being sectioned. Water-soluble coolant acts both as a coolant and a lubricant. The lubrication provided by the coolant reduces the friction between the wafering blade and the material or sample. The coolant prevents the sample from sticking to the blade and will improve cut quality and minimize material deformation.

Plain water is not recommended for sectioning operations. However, If you must use water as a coolant, check with the blade manufacturer to see what type of water is recommended for your blade. City water with 90 psi, or running water, is usually used for cutting. For some applications, you may want to use an additive with your coolant. If you decide to go this route, you will need a circulating system and the right ratio between your additive and coolant.

Coolant SUPPLY TO CUTTING ZONE

However, when cutting ultra-hard and brittle materials, the coolant flow direction and position will play a major role in determining blade life and performance.

A dual-nozzle configuration is best suited to supply an adequate amount of coolant at the point of contact between the blade and material. This type of coolant delivery configuration provides many advantages over other coolant supply methods for cutting zones. Coolant should be pointed at the blade point of contact and the leading edge of the blade. The dual-nozzle system provides two separate streams of coolant into the cutting zone at the cutting edge of the blade. Each stream will cool one side of the blade. The nozzles should be as close as possible to the point where the blade enters the material or sample. Coolant flow should blast with high velocity into the kerf to improve removing debris. wide kerfs Premature blade water is a result of an improper coolant amount or flow applied at the cutting zone. By correctly positioning the coolant stream in front of the blade, the coolant will flow on top of the material. In addition, coolant will be drawn into the kef.

When cutting softer material or samples, the direction of cutting is not of ultimate importance. However, when cutting hard and brittle materials that are hard to section, this is quite different. The blade should enter the material “cutting down." As the blade penetrates the surface of the material, chips removed by diamond particles become smaller the deeper the blade penetrates. This cutting direction is optimal to provide the best-cut quality and minimize material deformation.

Coolant maintenance and optimization

Coolant is one of the most overlooked variables in the sectioning process. Effective and proper use of coolant and recalculating the coolant system will pay off in terms of improved surface finish quality, increased blade life, and more consistent cutting results. Coolant does more than just cool the blade and material; its other more important roles include lubrication and flushing away swarf particles. For the most effective use of coolant, the quality of water being used, coolant concentration, and maintenance of the coolant tank make a difference. Different geographic areas have different water harnesses. Water containing less than six grains of dissolved minerals per gallon is considered soft water; water containing more than seventeen grains per gallon is considered hard. The best coolant water to use in a coolant system is chemically pure water, which is free of all dissolved solids. Chemically pure water and reverse osmosis. Reverse osmosis is the method most recommended by coolant manufacturers; however, it is not always available. Deionized water offers much improvement over available city water.

Water in the tank can evaporate, and the remaining water can become harder. Hard water affects coolant capabilities in many ways, including decreased capability for the rust inhibitor, increased foaming, the formation of sticky residue, and increased bacteria counts. Coolant concentration should be controlled and maintained to ensure that the coolant is being used at optimum efficiency. Too little coolant in the tank will lead to corrosion and rancidity, while too high a concentration can also cause foaming. Maintenance of the recirculating tank is also critical to coolant performance. Cleaning the tank is a dirty job, but if done often enough and thoroughly, it can increase the performance of your sectioning saw. Keeping the coolant tank clean will ensure that you are getting the most from your coolant, keeping corrosion and bacterial growth at bay while providing the necessary coolant, lubrication, and protection for your blades and materials.

RECIRCULATING COOLANT SYSTEMS

Recirculating systems in the past have been used very infrequently in most laboratory environments. Today, the increasing variety of work and materials sectioned by materials research and sample preparation labs is an overlooked aspect and requirement for many applications.

Recalculating coolant systems requires filtering to remove the swarf particles created during the cutting process. These coolant systems typically use either a cartridge, centrifugal, or cascade. Which process to use will depend on your application. An excessive amount of swarf particles mixed in the coolant will slow heat transfer and may cause surface damage to the material being cut. The cooling system must be constantly controlled and monitored to ensure process consistency.

Coolant temperature will also affect blade life and cut quality. Typically, coolant temperatures of 50 degrees F (10 degrees Celsius) will provide the best results. White coolant temperatures above 80 degrees F (27 C) should be avoided. Refrigeration of the coolant system can be used with most coolant systems and will provide the best results.

SAMPLE CLEANING

Sectioned samples should be cleaned with sap, water, or alcohol after sectioning. An ultrasonic bath is an excellent tool for speeding up this process and removing entrapped debris or fluids. To speed up this process, you can also place the samples in an oven for several minutes. This will relieve the material sample of any remaining fluid from its pores.

SAMPLE, MATERIAL CLAMPING, AND FIXTURING

Properly securing the material in place is one of the first and most important steps in the sectioning process. The function of the chuck or hollowing fixture is to keep the sample or material firmly in place, preventing it from moving. Various sample chucks and holding fixtures are available for a large variety of sectioning saws to accommodate all types of material shapes and geometries. It's very important to use the right mounting media for your specific sample. Which chuck to use for your application will depend on the beginning sample or material dimensions, desired cut depth, and material properties (hardness, brittleness, shape, and geometry). Some challenges of sample chuck mounting and fixing include occasional chipping at the bottom of the cut. The problem is the back side of the material does not have firm support at the cutting area, therefore creating a higher chipping rate when the blade exits the cut.

Holding the sample or material firmly in place

The sample should not move while being sectioned. Movement of the sample can damage the material or blade. As well as any possibility of obtaining a planar section. At the same time, the sample must not be over-tightened. Doing so may damage the chuck or sample. Some of the more brittle materials, such as glass and refractory materials, can fracture if overtightened in the chuck. Where the harder and denser materials, such as silicon carbide, may cause dents in the chuck if excessive force is applied. Dents or nicks in the chuck will affect samples sectioned in the same chuck, causing damage and possible cracks.

Chuck Padding

Padding can help prevent damage to the material or sample held inside the chuck and the chuck itself. Padding serves many functions, including: protecting material or chuck; protecting the sample chuck; avoiding sample shifting when pressure is applied; and buffering damaged or nicked areas of the chuck.

CHUCK POSITIONING/ALIGNMENT

The sample chuck should be securely attached to the load arm. For most applications, this is done on the right-hand side of the load arm. Longer samples can be mounted on the left-hand side of the load arm to provide extra clearance and minimize the possibility of the sample coming into contact with the saw hood. Improper mounting of the chuck or sample can cause damage to both the sample or material and the wafering blade.

The position of the sample and its angle, when it comes into contact with the cutting blade, can play an important role in determining cut quality and material deformation. As well as affect the time it takes to cut or section. For best results, position or align the sample so that the smallest section or angle comes into contact with the blade first. Doing so will ensure the sample or material is cut faster than if the widest dimension of the material or sample comes into contact with the blade.

This is especially critical for materials and samples with different compositions and properties. For example, coated specimens should be positioned so that the coated side is cut first. It helps avoid excessive damage to the coating, which has different material properties than the remaining material.

Samples and materials should be aligned with the blade in such a way that the sample chuck does not toughen the blade support flanges. During your sectioning operation, if you find the sample chuck is toughening blade flanges, the chuck should be attached to a different position on the saw load arm. Depending on the design and configuration of your saw, this may not always be feasible. Another alternative to resolving this issue is to reposition the sample in the chuck to the point where there is proper clearance between the chuck and blade flange.

EPOXY SAMPLE MOUNTING

Very small and difficult-to-clamp or fixture samples can be filled with epoxy to allow for easier holding and clamping while being sectioned.

BLADE MOUNTING

Flanges

Proper blade mounting on a flange set in acceptable condition is key to any successful wafering or sectioning operation. Flanges are designed to add additional support and stability to both sides of the blade. Flanges prevent the wafering blade from warping, blade wreckage, slanting cuts, damage to material or sample, and much more. The flange diameter to use would be based on the blade diameter and thickness used and the material diameter and dimensions (the desired exposure ratio). Flange diameter affects the directional stability of the diamond wafering blade. As a general rule of thumb, the largest possible flange diameter should always be used. Flanges must provide sufficient clarity for the sample so the cut may be completed without any interruption. For thinner and smaller-diameter wafering blades, the recommended flange size is ¾ of the outside diameter of the wafering blade.

Often extending right up to the diamond section. For larger and thicker blades, the recommended flange diameter is approximately 1/3 the diameter of the blade. Flanges must be free of rust and dirt. Your blade should turn perfectly true after the flange nut is tightened. Carriage alignment must be accurate for deeper cuts to prevent blade bending.

Any small scratch or nick on the flange edge can cause improper blade mounting. This can lead to slanted cuts, blade wobbling and wider cuts, more chipping, or even possible blade breakage.

OPTIMIZING SECTIONING PARAMETERS

When it comes to optimizing your sectioning operation, two of the most important variables besides the wafering blade itself are spindle speed and load/feed rate. These two parameters will typically take precedence over all others.

SPINDLE SPEED / RPMS

Optimal speeds and RPMs will vary depending on the OD (outside diameter) of the blade, application, material to be cut, and equipment used. Using optimal RPMs for your application will help increase blade life and reduce blade wreckage. Different materials have different requirements for cutting speed. Material hardness, density, and spindle speed will affect both spindle speed and, therefore, cut quality.

Low spindle RPMs will cause the blade to wear faster to maintain better cut quality. This causes a softer wafering or sectioning action, where each diamond particle grinds out a larger portion of the material. Higher spindle RPMs will do the opposite. Each diamond particle will grind away a small portion of the material, creating a harder cutting action. A good rule of thumb to remember is that for soft, abrasive materials, RPM should increase. For hard, dense materials, RPM should decrease.

LOAD/FEED RATE

The load amount and feed rate should be determined by your desired cut quality, material hardness, density, geometry, and thickness. The load to be applied to the sample should be a function of your desired cut quality and speed. Typically, most loads for sectioning saws used today are between 10 and 1,000 grams.

Since the goal of the majority of metallographic, material research, sample preparation, and failure analysis operations is to introduce the most minimal amount of sample or material deformation and preserve true material microstructure,. The load arm should feed the sample or material slowly into the blade so the blade does not lead off. Excessive pressure can cause the wafering blade to bend, warp, and cause part of the diamond section to fracture. Excessive pressure can also cause unwanted material burning, smearing, cracks, and deformation.

The best practice to follow would be to start by applying light to medium pressure. Gradually feed the load arm into the rotating blade until it begins to cut at its speed. If you can see dark “burn” marks around the diamond section, the cutting speed you are using is too fast or you are applying too much pressure. The load or feed rate should never be so great that the blade slows down. For this reason, great care and caution should be taken when increasing the amount of load or weight applied to the sample. When cutting completely through a sample or material and the cut is near completion, reduce the load or pressure on your blade considerably. Doing so will reduce the chipping of the sample or material as you exit the cut. 

Suggested Guidelines for Sectioning Specific Materials 0.25" (6.4mm) diameter rod. Using a SMART CUT 4002 sectioning saw.