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Technical Blog excerpt courtesy of Techniks USA It is critical to properly assemble the collet and collet nut to avoid damage to the collet and make the most accurate and rigid assembly possible. The extraction groove of the collet must be properly seated to the extraction ring of the collet nut.
If the collet extraction groove is not properly seated to the collet nut extraction ring, the collet will appear seated below the face of the nut. This typically occurs when the collet is placed in the collet pocket of the tool holder and then the nut is threaded on the tool holder. In a correct assembly, the collet will seat at the face of the collet nut. The image below shows a correct assembly on the left and an incorrect assembly on the right.  DO NOT tighten the collet nut if the collet appears seated below the face of the nut as this will create galling on the 30° face of the collet. Galling appear as grooves or lines in the lead face of the collet. Recognize Galling on Your ER ColletGalling on the lead face of the collet can result in reduced clamping pressure on the cutting tool shank that may lead to the cutting tool slipping while cutting, or even tool breakage.
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By John Zaya, Product Specialist, BIG DAISHOWA—Americas  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. 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. 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:
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. Warning on holders that cannot support adjusting screwsIt 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. compiled & edited by Bernard Martin  RMS and Ra are based on different methods of calculating the roughness. Both are done with a profilometer, but the profilometer calculates the roughness differently for Ra and RMS. Ra is the arithmetic average of surface heights measured across a surface. Simply average the height across the microscopic peaks and valleys. Ra and RMS are both representations of surface roughness, but each is calculated differently. Ra is calculated as the Roughness Average of a surfaces measured microscopic peaks and valleys. RMS is calculated as the Root Mean Square of a surfaces measured microscopic peaks and valleys. Each value uses the same individual height measurements of the surfaces peaks and valleys, but uses the measurements in a different formula. A single large peak or flaw within the microscopic surface texture will effect (raise) the RMS value more than the Ra value, which is why Ra is more commonly used today as a measurement.
RMS: What is Root Mean Squared?Ra roughness average is the main height as calculated over the entire measured length or area. It is quoted in micrometers or micro-inches. For 2 dimensional computation: Ra = 1/n * SUM(ABS[Zi-Zmean] from i = 1 to n RMS is a Root Mean Squared calculation. That means you:
The Root Mean Square (RMS) average is precisely that: the square root of the average height deviations from the mean line/surface squared. RMS = SQRT[ 1/n* SUM(Zi-Zmean)^2 ] from i=1 to n  Technical Blog excerpt courtesy of Techniks USA  Techniks offers the broadest selection of ER collets including standard, steelsealed, coolant, rigid & floating tap, and DNA - Dead Nuts Accurate, collets. It is important to understand how collets work, what impacts their performance, how to maintain collets for long service life, and how to recognize when to replace them. Collets are a high-precision wear component of a tool holding system and require maintenance to ensure accuracy. First, it’s important to remember that collets are the softest component in a collet-based tool-holding system assembly and are designed to wear out. Here is an overview of the wear pattern of a collet-based tool-holding system. The machine spindle is harder than the tool holder/collet chuck that fits into the spindle, so any wear between these two components will mostly occur to the collet chuck. That’s good. It protects the spindle from expensive maintenance. Collets are softer than both the collet chuck body and the cutting tool, so any wear forces between these items will mostly occur to the collet. Since collets are generally the least expensive component in a collet chuck tool holding system, it is preferred that the collets wear out before the other components. Worn-out collets will not achieve the same level of accuracy and rigidity that newer collets can provide. The result is more chatter when cutting workpieces, less accuracy, and shorter cutting tool life. When to Replace ColletsCollets are designed to wear out as they lose accuracy and rigidity with use. High side-load forces during milling operations cause cutting tool deflection as illustrated below.  Over time, these side-load forces will bell-mouth the collet at its face.  As the collet experiences bell-mouthing, the cutting tool is allowed to deflect more and more during milling operations. Unfortunately, the collet may still indicate good accuracy on a presetter where there are no side-load forces. However, once the tool is put into service and begins experiencing side-load forces, the cutting tool is allowed more room to deflect, resulting in increased chatter and reduced tool life. It is recommended to change collets out every 4-6 months, depending on usage, to ensure the most rigid and accurate collet chuck assembly. A good rule of thumb is to replace collets every 4-6 months to maximize the performance of your tooling. Again, collets are designed to wear out and are generally the least expensive component in the system. It is much less expensive to replace the collets as opposed to prematurely wearing out cutting tools. The following tips will help you in maintaining collets:
Signs that Your Collet Should be Replaced
If you see signs of fretting on the collet, it is advised to replace the collet. You should also ensure that collet nuts are tightened to the correct torque specifications during setup.
CLICK HERE to see all of our more in-depth articles on FRETTING to learn more.  The L:D ratio of a tool assembly is calculated by using the length of the bar (or body) of a tool assembly and the diameter of the tool, not the workpiece bore diameter and depth.
To expand on this concept, we see in the first configuration below the Ø16mm bar is sticking out 160mm which is a 10:1 although the bore is only a 2.5:1. In some applications this extra reach is needed to get around a fixture or a feature of the part. However, in those cases where it is not needed, decreasing the overhang by 55mm means the new L:D of 105:16 is 6.5:1. This alone would represent approximately 10x increase in cutting speed by increasing from 20mm/min vs. 200mm/min. The use of modular reductions has also been found to be a good strategy to improve tool performance. Comparing the lower two assemblies below, the middle assembly uses the same connection size for the length of the tool, ignoring the larger access diameter, and results in a 6.4:1 ratio. When a shank with a larger connection size is used along with a modular reduction, the ratio is halved, and provides a 350% productivity improvement (14mm/min to 50mm/min). In all cases, reducing the L:D ratio provides an improvement in speed which then provides longer tool life, better surface finish and size control of the bore. by Frank Twomey | OSG USA By switching to the AE-TL-N, Ross Industries has reduced about 75 percent of cycle time on the upper chambers and is now on average achieving a 150 percent cycle time reduction on other aluminum parts.  AE-TL-N DLC Coated Carbide End Mill Drives Greater Efficiency in Aluminum Part Processing Founded in 1968, Ross Industries, Inc. is a specialist in food processing and packaging solutions. Some of its key products include meat tenderizers, antimicrobial intervention systems, chilling and freezing equipment, formers and presses, slicers, macerators, tray sealing equipment, and more. All Ross systems are designed to help processors streamline food manufacturing and packaging functions to improve quality, productivity, and food safety while minimizing waste. With more than 50 years of industry expertise, Ross Industries has built an international reputation as one of the world’s finest food processing and packaging system providers. Employing approximately 100 staff, Ross Industries’ manufacturing plant is located in the city of Midland, Virginia, USA, with an estimate production area of 80,000-square-feet.  Founded in 1968, Ross Industries, Inc. is a specialist in food processing and packaging solutions. Employing approximately 100 staff, Ross Industries’ manufacturing plant is located in the city of Midland, Virginia, USA, with an estimate production area of 80,000-square-feet. Recently, Ross Industries was tasked with reducing cycle times on all of its aluminum parts. OSG Territory Sales Manager Frank Twomey has been in touch with Ross Industries through a distributor for about two years ago. In need to optimize productivity, OSG was given with an opportunity to test cut the upper chamber 6061 aluminum alloy part used in Ross Industries’ tray sealers for food packaging.  A CAD model of the front & back of the upper chamber, a part used in Ross Industries' tray sealers for food packaging Ross Industries has been producing these aluminum upper chambers for more than 25 years. Approximately 80 chambers are made annually along with thousands of other aluminum parts. The upper chambers are machined using a Doosan HM 1000 horizontal machining center with CAT-50 spindle taper.  The upper chambers are machined using a Doosan HM 1000 horizontal machining center with CAT-50 spindle taper Ross Industries was originally using a competitor 1.5-inch diameter indexable shoulder cutter for the application. The competitor tool was used at a speed of 6,000 rpm (2,358 sfm, 717.8 m/min), a feed rate of 120 ipm (3,048 mm/min), 0.005 ipt (0.127 mm/t), 0.3-inch (7.62 mm) radial depth of cut, 0.375-inch (9.525 mm) axial depth of cut, and at a metal removal rate of 13.5 inch3/min (221.2 cm3/min).  The upper chambers are made of 6061 aluminum alloy Upon a detail evaluation of the application, Twomey recommended OSG’s 3-flute 1-inch diameter AE-TL-N DLC coated square end mill (EDP# 86301809). The AE-TL-N DLC coated carbide end mill is extremely effective for non-ferrous materials such as aluminum alloys that require welding resistance and lubricity. With excellent cutting sharpness, it is able to suppress burrs to achieve superb surface finish. The AE-TL-N features a unique flute form to enable trouble-free chip evacuation and a large core design for high rigidity to prevent chattering. Its center cutting edge configuration enables the tool to be used for plunging. Furthermore, with the addition of OSG’s DLC-SUPER HARD coating, long tool life can be achieved. This end mill series is available in square, sharp corner edge and radius types to accommodate a wide range of applications.  The AE-TL-N DLC coated carbide end mill was tested at a speed of 5,125 rpm (1,343 sfm, 408.7 m/min), a feed rate of 231 ipm (5,867 mm/min), 0.015 ipt (0.382 mm/t), 0.14-inch (3.556 mm) radial depth of cut, 1.62-inch (41.148 mm) axial depth of cut, and at a metal removal rate of 52.39 inch3/min (858.5 cm3/min). Cycle time on the upper chambers went from 34.5 hours to nine hours. By switching to the AE-TL-N, Ross Industries has reduced about 75 percent of cycle time on the upper chambers and is now on average achieving a 150 percent cycle time reduction on other aluminum parts.  Switching to the AE-TL-N DLC coated carbide end mill, cycle time on the upper chambers went from 34.5 hours to nine hours. “This end mill creates chips so fast that our machines chip conveyors couldn’t keep up,” said Ross Industries Machine Shop Manager Greg Williams. “We had to speed up the conveyors.” Taken in consideration of factors such as tool change time, machine cost, labor, etc., it is estimated that an annual cost savings of $183,000 can be gained. In addition to the upper chamber part, Ross Industries has also converted all of its aluminum end mills to OSG’s AE-TL-N series in various sizes.  From left, Ross Industries Machine Shop Manager Greg Williams and OSG USA Territory Sales Manager Frank Twomey pose for a photograph with a completed upper chamber. “With the performance and consistent tool life of the AE-TL-N we are able to run these tools lights out,” said Williams. “In some cases, it is able to achieve as much as four times the metal removal rate versus the competitor tool.”
For more information on OSG’s AE-TL-N DLC coated end mill for non-ferrous materials and Ross Industries Technical Blog excerpt courtesy of Techniks USA Collets come in many different types and sizes. Here is an overview of three of the more popular types of collets, along with the pros and cons of each system. ER Collets ER collets have between a 0.020” and 0.040” holding range The ER collet system has become very popular due to the flexibility of the system to hold a variety of cutting tool shank types including drills, end mills, and taps. Also, ER collets provide several solutions for increasingly popular coolant-through cutting tools. Most standard ER collets have between a 0.020” and 0.040” holding range, making them a good choice when needing to hold odd-sized cutting tool shanks. This holding range also means fewer ER collets are required to hold a range of cutting tool shank diameters as opposed to other collet systems like TG. The popularity of the ER collet system has led to several variations to hold a wide assortment of cutting tool shanks. Some ER collets have been modified with squares at the bottom to hold taps. Others have been modified to provide quick-change capabilities or compensation, also called “float”, for rigid tapping cycles as shown in the images below. Specialized ER ColletsOther modifications include special slotting designs that seal around the cutting tool shank and force coolant through channels in coolant-through tooling, as well as modifications to include coolant ports in the collet that direct coolant to the cutting area. TG Collets TG collets have about the same accuracy as DA collets, but because there are more slots, and therefore more faces clamping on the cutting tool shank, they tend to deliver greater holding power. TG can be a good solution for larger shank diameter cutting tools, but they generally limit how far down into a pocket you can reach due to interference with the collet nut, as TG collet nuts tend to be quite large. TG collets are not as popular as ER collets for several reasons. Most notably, the larger diameter collet nuts can require the use of extended end mills to avoid interference from the collet nut when milling pockets. Also, since TG collets have a very small collapse range, they are intended for use with one size cutting tool shank. ER collets, by contrast, offer a large collapse range that can be helpful when clamping odd-shank diameter tools. On the flip side, TG collets tend to have a bit more holding power than ER collets due to the collet base having a 4° taper as opposed to the 8° taper found in ER collets. This can make TG collets a good choice when machining with longer-length cutting tools. Double-Angle (DA) Collets Please stop using DA collets in CNC Machining Double-Angle (DA) collets have been around for a long time and continue to be used in the market. There are, however, many issues associated with DA collets of which users should be aware.
Let's just clear the air and say it: Don't use them. If you have them in your shop, replace them with ER Collets and ER Collet Chucks as soon as possible and you will recoup the cost of the new holders and collets in your tool life probably within a month or two. One of the primary issues with DA collets is that they essentially clamp on the cutting tool shank with only two opposing faces in the I.D. bore. DA collets have four slots in the front of the collet and four slots in the back of the collet creating four clamping faces. However, when DA collets are tightened towards the lower end of their collapse range, two of the faces tend to be pushed out of the way so only two of the faces are clamping on the cutting tool shank. This may cause some runout at the nose when the tool is inspected in a presetter. Additionally, when the tool begins cutting and side forces are applied to the cutting tool, the cutting tool tends to deflect into the area where the faces are not clamping on the tool shank. This results in excessive chatter that dramatically reduces tool life and results in rough surface finishes. You will be hard-pressed to find a quality end mill holder manufacturer endorsing the performance of their tooling in DA collets.  Jergens has introduced its new Washdown Tool, which provides 360° of spray using coolant flow to wash away chips from exposed surfaces. The in-between-processes tool is programmed inline after a predetermined number of machining cycles. The Washdown Tool provides thorough chip removal from the many exposed surfaces inside the machining area. In turn, this saves time for operators by reducing the time spent cleaning chips from a machine interior, workpiece or workholding setup. The unit uses multiple spray nozzles on its circumference, providing a steady and pressurized stream. Each nozzle can be plugged or opened to create customized spray patterns. Added spindle rotation is said to ensure that coolant reaches virtually everywhere inside the machine. Residing in the tool changer, the Jergens Washdown Tool is deployed periodically at scheduled intervals. This automation shortens cleaning time and supports long machining cycles, even lights out manufacturing periods when no operator is present. Jergens Machine Washdown Tool is a cleaning tool attachment for machine spindles and fits 16mm Weldon holders. The user selects which outlets to open, which controls the pressure and direction of the jets. Moving and rotating the spindle under a constant flow of coolant achieves an excellent and systematic cleaning of the machine interior. Through the optional installation of a pressure gauge, the status of the pump, filter, and entire supply line can be checked. Product Specifications:
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Technical Support BlogAt Next Generation Tool we often run into many of the same technical questions from different customers. This section should answer many of your most common questions.
We set up this special blog for the most commonly asked questions and machinist data tables for your easy reference. If you've got a question that's not answered here, then just send us a quick note via email or reach one of us on our CONTACTS page here on the website AuthorshipOur technical section is written by several different people. Sometimes, it's from our team here at Next Generation Tooling & at other times it's by one of the innovative manufacturer's we represent in California and Nevada. Archives
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