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Question #: 14491

Question: What is the best way to determine speeds and feeds for machine and bit longevity?

Current Solution

The speeds and feeds are generally based on the amount of flutes that are being used per pass and how hot the end mill is getting when milling.  You want to use as much of the flutes as possible on single cuts.  Make the deepest cuts you can to increase the life of the tool.  For instance, if a tool that is 1 inch in cut length and the depth per pass is 1/4", then only that 1/4" is being used for the cutting.  The 1/4" tip of that tool will wear faster.  
Make sure the feedrate is as fast as possible without a cost to the edge finish.  This will keep the end mill cool since there will be minimal friction as you are always cutting into fresh cooler material.  
Use the end mill manufacturer's chip load for the tool to determine the starting feed rate.

Feedrate (IPM - Inches/Min) = Spindle RPM x # of Flutes x Chip Load
See each end mill for the chip load value.

If your machine cannot achieve these feed rates, reduce the spindle RPM using this formula:
Speed (RPM) = Feed Rate (IPM) / (# of Flutes x Chip Load)

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Other Possible Solutions to this Question

  • I'm building my own machine using your motors and drivers. What is the best dip switch settings for the 3.0 amp drivers powering the 425 oz motors

    The settings that you will use for your 3.0 amp driver to properly power and turn your 425 oz-in stepper motor will cheifly depend on your application and the mechanical parts you are using on your machine. In all circumstances, the amp setting for the stepper motor (according to the datasheet) should be 2.8 amps. Use the closest setting on the driver without going over.

    Here is a good rule of thumb for the microstepping which will correspond to the resolution, but wil also affect torque. You always want to try to achieve the best torque and resolution for the axis you are moving but go with the lowest microstepping possible. In cases where there is mechanical advantage, like a lead screw scenario, where for each motor revolution, the axis move a very small amount, you will want a very low microstep value. This is because the mechanical configuration will provide most of the finer resolution and you will not need the microstepping to assist in this. Increase the microstepping only in conditions where the axis is not moving smooth enough, or where there is a mechanical disadvantage. A mechanical disadvantage would be where the stepper motor is causing a great amount of movement in the axis and the resolutions suffers from this condition. Increase the microstep value up to your desired resolution, but don't go over since the torque of the motor will decrease.

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    I'm building my own machine using your motors and drivers. What is the best dip switch settings for the 3.0 amp drivers powering the 425 oz motors

  • What is the best way to calibrate my machine?

    In Mach3, go to the Settings Tab, and select "Set Steps Per Unit". It will ask you how far to move the machine. Before you do this, make a mark on the table exactly where the end mill is resting. You can do this by lowering the end mill until it touches the material, then spinning it by hand to cut a small dimple in the material. Then, raise the end mill to clear the material, and assign a distance to move the machine. Once the machine moves and stops, measure the exact distance that it actually traveled with a tape measure, and enter this value into the dialog box that asks how far it moved. Mach3 will automatically adjust your steps per unit for that axis to be more accurate. Do this for all axes often to ensure you are cutting accurately. The longer distances you use calibrate, and the more precise you are with your measurements, the better.

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    What is the best way to calibrate my machine?

  • WHAT IS THE FORMULA TO DETERMINE STEPS PER INCH OR RESOLUTION FOR EACH AXIS?

    The formula and calculation is a starting point to get into the area of steps per inch. You will then need to use the mach3 calibration utility to get the exact steps per inch.

    Formula:
    step per inch = (motor steps * microstepping) / (travel at one turn of the motor in inches)
    if microstepping is set at 16 (1/16 on the driver) then and you are using a sprocket and chain with a pitch of .25 inches and 12 teeth on the drive sprocket
    = (200 * 16) / (12 * .25)
    = 3200 / 3
    = 1066.666 steps per inch

    For lead screw that has a travel of .5 inches at one turn like the 5 start 1/2 inch lead screw and using 4 microsteps per step (1/4):
    = (200 * 4) / (.5)
    = 800 / .5
    = 1600 steps per inch

    Remember to use the mach3 calibration wizard and double check the driver microstep setting.

    Additional Information:

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    WHAT IS THE FORMULA TO DETERMINE STEPS PER INCH OR RESOLUTION FOR EACH AXIS?

  • What is the recommended unit or brand of CPU cooling system for the 2.2 kw spindle on the Fabricator Pro machine

    There really isn't any specific brand. We purchase the components in a disparate fashion from China. I will product a video today that shows all of the components that we use and also offer the components on the website.

    From the upcoming video, you will be able to identify the parts is you feel you want to search for these components yourself.

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    What is the recommended unit or brand of CPU cooling system for the 2.2 kw spindle on the Fabricator Pro machine

  • I need a machine to cut guitar bodies. The bodies are 12" x 16" and 1.5" thick. What would work best?

    I would recommend using the blackToe CNC machine kit. The overall travel dimensions are 24" x 48" x 6". This will provide a bit of space on the sides as wiggle room if your guitar bodies are at the extremes of the 12". Also, if you are manufacturing may of these, the larger routing area, the more guitar bodies you will be able to cut at one time.

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    I need a machine to cut guitar bodies. The bodies are 12" x 16" and 1.5" thick. What would work best?

  • WHAT IS THE LEAD TIME FOR REDFROG PICK AND PLACE MACHINE?

    You can expect a two week lead time for the redFrog pick and place machine.

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    WHAT IS THE LEAD TIME FOR REDFROG PICK AND PLACE MACHINE?

  • What is your shipping costs for the greenLean CNC machine to Perth Western Australia

    You can determine if the country is serviceable by:
    - selecting the items you want to purchase on the website
    - go to the cart (shopping cart top left of any webpage)
    - log in, or register
    - Enter the address and click on calculate shipping.

    The webpage will return the direct rates and whether your area is serviced or not. Feel free to enter any address as long as you are able to receive the package from that address.

    The shipping times are determined by the service you select in the shopping cart. If a machine is purchased, we generally have a one week lead time unless otherwise stated in the description of the machine's product page.

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    What is your shipping costs for the greenLean CNC machine to Perth Western Australia

  • What is the difference between a NEMA 23 and NEMA 24 motor? can I use either one on a machine?

    The frame size difference of the NEMA 23 and 24 is very slight and, depending on the motor mount both will most likely fit. The bigger difference between these stepping motors is the torque. Make sure that the motor that you purchase has the appropriate torque for the axis that it will move.

    Is is safe to go with the higher torque? Or if the torque is too high for what i need is that bad?

    You can use a motor with higher torque. Just make sure to select the correct driver for that motor.

    Additional Information:
    The frame size has nothing to do with torque. Nema 23 means a 2.3" frame. Nema 24 means a 2.4" frame. That's all. Either could have more or less torque depending on speed and power.

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    What is the difference between a NEMA 23 and NEMA 24 motor? can I use either one on a machine?

  • What is the difference between a NEMA 23 and NEMA 24 motor? can I use either one on a machine?

    The frame size difference of the NEMA 23 and 24 is very slight and, depending on the motor mount both will most likely fit. The bigger difference between these stepping motors is the torque. Make sure that the motor that you purchase has the appropriate torque for the axis that it will move.

    Is is safe to go with the higher torque? Or if the torque is too high for what i need is that bad?

    You can use a motor with higher torque. Just make sure to select the correct driver for that motor.

    Additional Information:
    The frame size has nothing to do with torque. Nema 23 means a 2.3" frame. Nema 24 means a 2.4" frame. That's all. Either could have more or less torque depending on speed and power.

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    What is the difference between a NEMA 23 and NEMA 24 motor? can I use either one on a machine?

  • DO NEED TO SQUARE UP THE MACHINE AND IF SO YOU HAVE INSTRUCTIONS OR VIDEO FOR THIS?

    The eyebolts are used in the squaring of the machine. I would use a standard carpenters square and first run the end mill along the edge of the square to first make it parallel with the long axis. Then run the end mill along the other edge with the short axis and adjust the eye bolts and chain according to the angle that the machine is out of square.

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    DO NEED TO SQUARE UP THE MACHINE AND IF SO YOU HAVE INSTRUCTIONS OR VIDEO FOR THIS?

  • New here, what is the best 3 axis kit for a Sherline 5400? Higher torque and quietness is my goal. Thanks

    The required motors are the 425 oz-in stepping motors, would be the required motors to run the machine efficiently.

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    New here, what is the best 3 axis kit for a Sherline 5400? Higher torque and quietness is my goal. Thanks

  • What are some good ways to control the vertical laser from a Linux machine?

    There really isn't any good way to use Linux when using a traditional Laser Controller. If LaserCAD worked under the Linux OS, then that would work.

    Would you like to know an alternative to use Linux using maybe LinuxCNC? There are ways to do it, but you will find yourself deep in g-code and out of the box wiring configurations, most likely.

    Alternatively, you can create a dual boot scenario and put Window on the other part of the hard drive. This way, you would be able to run LaserCAD.

    You can also "attempt" to use LaserCAD in the wine environment, but I have a feeling that will probably not work.

    Additional Information:
    We're a small family-owned electronics and hardware manufacturer, using LinuxCNC already for milling. Dual-boot into Windows isn't a sensible option -- it would greatly reduce the utility of the machine. I have more information about our use case in https://buildyourcnc.com/FAQ/13985.

    Additional Information:
    Ok, fair enough. Then let's get into the details on how you can use LinuxCNC to operate a Laser machine.

    Do you have an idea what controller you will be using? Parallel?

    Additional Information:
    My first inclination was to use LinuCNC with the parallel interface board. Of that's the answer, then we might want to just add to the LinuxCNC discussion that's starting to firm up at https://buildyourcnc.com/FAQ/13985 rather than duplicate the information here.

    I'm open to other alternatives and am happy to hack; we make PCBs and cable harnesses as a business, so that's not a limitation either. One answer might be to use one of the open source controllers that are starting to show up.

    Additional Information:
    My turn for phone typos. ;-) I meant to say "If that's the answer, then..."

    Additional Information:
    I've started a forum topic about this at http://www.buildyourtools.com/phpBB3/viewtopic.php?f=9&t=8412&start=0

    Additional Information:
    Good idea. Thanks.

    When a direct solution is realized on buildyourtools, I will post it here.

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    What are some good ways to control the vertical laser from a Linux machine?

  • What precision do the CNC machine have, for instance the 12’’ x 36’’ x 3’’?

    Our machine that matches those dimensions, the blueChick, uses roller chain for both X and Y axes, and a 1/2" 5 start 10 TPI lead screw for the Z axis. The precision is generally related to repeatability and we have not does extensive measurement of these tolerances. The resolution is set at better than 1000 steps per inch.

    Here is the link for the blueChick:
    https://www.buildyourcnc.com/blueChickVersion42CNCMachineKit.aspx

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    What precision do the CNC machine have, for instance the 12’’ x 36’’ x 3’’?

  • For cutting with the BlackTooth, what is the best type of clear plastic/acrylic to use, and can you recommend a source?

    The blackTooth will cut acrylic very easily. The type of acrylic (cast or extruded) is not important since the acrylic itself has 100% absorption with CO2 lasers. Any plastic retailer, even the home improvements stores will have sheets of acrylic.

    Avoid using plastics that will off-gas toxic and corrosive fumes. One example is PVC which is Polyvinyl Chloride. The burning of that material will exhaust chloride into the air and combine with the hydrogen in the air causing a chemical reaction yielding hydrochloric acid which is corrosive and highly toxic to humans.

    Always read the MSDS (Material Safety Data Sheet) for any material that you intend to burn with the CO2 laser.

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    For cutting with the BlackTooth, what is the best type of clear plastic/acrylic to use, and can you recommend a source?

  • What tolerance can I expect from your largest cnc machine and the laser cutter? Also, what depth can I get on the z axis?

    The largest CNC machine we make at this time (12/04/2015) is the GreenBull 6'x12' model. This model has 2 options for Z-axis travel.

    The short-z option has a total Z travel of 5.75 inches. From that you would subtract the length of the end mill used and the thickness of the spoil board to determine the maximum material thickness. (Example: If the end mill extends 1.25" from the collet and the spoil board is .75", then the material could be up to 5.75 - 1.25 - 0.75 = 3.75 inches in thickness). This is good for most sheet-type materials.

    The long-z option, used mainly for large 3D carvings, requires a custom frame and allows for up to 36" of travel.

    The tolerance of our machines, like any machine, depends on several variables. The major variables include the manufacturing tolerance, the type of machine control used, the precision of assembly, the thoroughness of maintenance, and the initial and ongoing calibration of the machine. Because we sell kits only most of these variables are outside our control. Therefore, we are hesitant to guarantee a certain level of tolerance for an end user. However, in our experience, tolerances of .001" are readily achievable with our machines.

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    What tolerance can I expect from your largest cnc machine and the laser cutter? Also, what depth can I get on the z axis?

  • WHAT LEAD TIME CAN EXPECT FOR BLACKTOE SO PICK UP THE MACHINE?

    You can expect a one week lead time for our machines.

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    WHAT LEAD TIME CAN EXPECT FOR BLACKTOE SO PICK UP THE MACHINE?

  • what do you mean by Kits , are they complete machines ready for use or prototypes to be followed?

    Our kits include all of the parts needed to put a whole working machine together. However, understand that the kits are quite advanced and require a good level of mechanical competence to be completed correctly. We offer assembled machines for those that can't assemble these machines due to their complexity and need for fastening the overall components in a way that there is good smooth and tight motion, minimizing backlash to the fullest.

    We do have a few kits that you need to supply the table which include the greenBull 4x,5x and 6x, and the blackFoot. The tables would be far to large and heavy to ship. Our greenBull Kit is our best selling machine. All of the other machines are all inclusive.

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    what do you mean by Kits , are they complete machines ready for use or prototypes to be followed?

  • Which controller(DSP or FPGA or other) is best for CNC machine for G code interpreter operations?

    It's probably better to use an FPGA or a microcontroller that is clocked (provided by a crystal oscillator) fast enough to simultaneously output pulse trains for the number of axes you intent to drive on the CNC and to provide for other processor operations, like spindle control, processing inputs from the machine and other outputs you may have (mist, coolant, etc.).

    Additional Information:
    Hi,
    Thanks for the information.
    Some CNC controllers having both FPGA & DSP. Is there any advantages? What is the role of DSP in this case?

    regards,
    Naveen

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    Which controller(DSP or FPGA or other) is best for CNC machine for G code interpreter operations?

  • I am using Windows 10 and my Shopbot PRT 4g uses Shopbot's proprietary software https://www.shopbottools.com/support/control-software. How can I determine if the 4th axis you offer will be compatible with my machine?

    Generally, you’ll need to check what control software will need to be used with the CNC router. Our machines use industry standard electronics and control software that is nonproprietary so you can use just about any software out there with our machines.

    Specifically, what software are you planning on using?

    Additional Information:
    dear Sir,
    I'm searching for the best one,I think that I have to learn more about that in order to be able to make the right decision.

    Additional Information:
    If you are using a computer running Microsoft Windows, then I would recommend using Mach3 or Mach4. If you prefer Linux, then LinuxCNC is the best control software in my opinion.

    Click the link to respond:
    I am using Windows 10 and my Shopbot PRT 4g uses Shopbot's proprietary software https://www.shopbottools.com/support/control-software. How can I determine if the 4th axis you offer will be compatible with my machine?