Need advice for control software for mill conversion


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    Default Need advice for control software for mill conversion

    I have an order on a Precision Matthews mill and need advice on how to wire up the conversion of the mill to CNC, using the PM ballscrew kit. My goal is to mill aluminum and mild steel.

    By way of experience, I currently have an Avid CNC Router Parts with their turn-key electronics running Mach4. I put together the mechanics (8020 and motion system), but have bought the electronics already assembled in their industrial box. Have quite a bit of experience with using the router on plywood and sheet aluminum (which in reality only means I broke many bits). Then have upgraded to plasma motion (THC) myself. Also have experience with Fusion 360 and PlasmaCam.

    What is the most streamlined way to run the mill on the same computer? What electronics boards and motor drives and motors to get? Am leaning towards NEMA 23 steppers unless advised otherwise. Am considering a Centroid Acorn but is there a reliable way to use Mach4 which I already have and like? Thank you kindly for any advice.

    Similar Threads:
    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    OK, I ordered the Centroid Acorn.

    Is there a substantial advantage in going with servos over steppers? I read up on it, and it seems as if steppers would do, but then again, I might miss something.

    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi,
    I've been using Mach4 on my mini-mill for six years and will use it on my new build mill as well.
    If you already have Mach4 and like it then just get another controller like an Ethernet SmoothStepper and have at it!

    My new build mill will have 750W Delta servos, a real step up in power and speed over the 5-phase Vexta steppers of my mini-mill.
    Servos are a huge step up in power and speed compared to steppers. Steppers very promptly stall if they get overloaded whereas servos just
    'dig in' as they have three to fourfold (of rated) overload torque.

    The downside is that servos are still way more expensive. Its very tempting to get cheap Chinese made servos, and to be fair to them they are
    good value for money but the set-up and tuning documentation is crap, avoid like the plague. You need to spend some extra to get either Delta or DMM
    servos, both good quality at fair prices with good tuning/setup documentation and PC based setup software.

    Many people have used steppers on machines like yours with good results if used within their limitations. Servos are a step up....but only if you are
    prepared to get good servos, you'll kick yourself if you get cheap Chinese servos and then really struggle to set them up and tune them. Tuning servos
    is way WAY more involved than steppers.

    Craig



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    Default Re: Need advice for control software for mill conversion

    Thank you for your reply.

    I have looked at Delta servos, what model do you intend to use? I saw this model as a possible candidate. Am considering Clearpath servos, that I expect are equally well supported, but have looked at 400 W models. Do you think 400W will do for a mill, or should I start with 750W? I generally favor “buy once cry once” but am trying to calibrate so I don’t overbuy, and am quite ignorant about the needs of a mill.

    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi,

    I have looked at Delta servos, what model do you intend to use?
    I have bought B2 series servos, they have a 160,000 count per rev incremental encoder. They are effectively Deltas entry level model. You pay more for A2,A3 and the latest B3
    series but is doubtful to me that I would get any great benefit over and above the B2 series which are truly impressive themselves. The A2 series (and possibly the A3 and B3 series)
    has a dual feedback loop. Thus the principle feedback from the motor is still the rotary encoder, normal for any AC servo, but the drive can accept a second encoder input, say a linear scale
    attached direct to the axis and the position control loop incorporates both encoders. Very impressive, and only about $50 more than a B2 series. This is an example of 'load sensing
    position control' which all the top-flight servo manufacturers use in various guises. Clearpath dosen't even come close to that level of sophistication.

    Clearpath servos are good quality and well supported but are expensive for their power output. For the same or less money than you would pay for a 400W Clearpath you can get
    a 750W Delta or DMM. Additionally in order to make Clearpaths as appealing to first time servo buyer as possible they have vey limited IO and control modes whereas Delta
    and DMM have vastly more IO and mixed control modes.

    The sizing of a servo, or stepper come to that, is all about inertia. Contrary to popular belief the dominating component in the inertia equation is the rotating components, particularly the ballscrew.

    I am using 32mm diameter C5 double nut ballscrews of 5mm pitch. The ballscrews represent 85% of the inertia with the servo armature contributing another 10% with the axis bed (at 115kg) contributes
    only 5%.

    If you tell me what size, pitch and length ballscrews you are using I can tell you what size servos you will need, and surprisingly is less affected..... much less affected by axis mass than you might believe.

    Craig



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    Default Re: Need advice for control software for mill conversion

    Hi,
    by the way, when I bought my servos I found that I could have 750W servos for another $38 over 400W servos, so naturally I got the more powerful ones.
    The 750W B2 series servos cost me at the time (approx ten months ago) $460USD excluding shipping and I got one braked 750W B2 servo which cost $600USD
    excluding shipping.

    I believe that you could get the same thing today even cheaper, maybe $375 and $525 respectively.

    Servos are still quite a step up from stepper price wise.....but they are real eye openers!!!!

    Craig



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    Default Need advice for control software for mill conversion

    Quote Originally Posted by joeavaerage View Post
    Hi,
    I have bought B2 series servos, they have a 160,000 count per rev incremental encoder. They are effectively Deltas entry level model. You pay more for A2,A3 and the latest B3 series but is doubtful to me that I would get any great benefit over and above the B2 series which are truly impressive themselves. The A2 series (and possibly the A3 and B3 series)
    has a dual feedback loop. Thus the principle feedback from the motor is still the rotary encoder, normal for any AC servo, but the drive can accept a second encoder input, say a linear scale attached direct to the axis and the position control loop incorporates both encoders. Very impressive, and only about $50 more than a B2 series. This is an example of 'load sensing position control' which all the top-flight servo manufacturers use in various guises. Clearpath dosen't even come close to that level of sophistication.

    Clearpath servos are good quality and well supported but are expensive for their power output. For the same or less money than you would pay for a 400W Clearpath you can get a 750W Delta or DMM. Additionally in order to make Clearpaths as appealing to first time servo buyer as possible they have vey limited IO and control modes whereas Delta and DMM have vastly more IO and mixed control modes.

    The sizing of a servo, or stepper come to that, is all about inertia. Contrary to popular belief the dominating component in the inertia equation is the rotating components, particularly the ballscrew.

    I am using 32mm diameter C5 double nut ballscrews of 5mm pitch. The ballscrews represent 85% of the inertia with the servo armature contributing another 10% with the axis bed (at 115kg) contributes only 5%.
    Thanks Craig, that is very helpful advice and helps me clarify my path. First, I decided to continue with Mach4 and will buy a second ESS (one is already installed for my CNC router. This way I can hopefully use the configuration for homing and limit switches and auto-zero from Avid CNC RouterParts. That will also save some money from returning the Acorn + software.

    Second, I’d like go with servos and not steppers. It was very easy to find documentation on the Delta ASD-B2 series, which I think is the optimal choice for me, but I am having a very difficult time finding vendors. Where did you get yours? I saw some on eBay with "shipping from China" but I want to buy from a US vendor.

    Quote Originally Posted by joeavaerage View Post
    If you tell me what size, pitch and length ballscrews you are using I can tell you what size servos you will need, and surprisingly is less affected..... much less affected by axis mass than you might believe.
    I do not know the size, pitch or length of the ball screws, as I have not yet received them, but from the documentation on the Precision Matthews size and the use of 7001 series ball bearing, I guess 1/2". From the description of the PM-728VT mill, the length of the x is probably about 19", y is maybe 10"; don't know the pitch.

    The PM site also mentions that the attachments on x and y are for NEMA 23 and for z is NEMA 34. Does this change the choice of servo motor? Will 400W servos adapt?
    Need advice for control software for mill conversion-pm-728-cnc-ball-screw-kit-jpg

    Attached Thumbnails Attached Thumbnails Need advice for control software for mill conversion-pm-728-cnc-ball-screw-kit-jpg  
    Last edited by koenbro; 12-02-2020 at 03:07 PM.
    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi,
    I bought from:

    https://www.fasttobuy.com/

    They have/had a good range at best or near to best prices. They are in China but I had no problems with them. Note that they have their own brand of servo, ToAuto, which to be fair to
    them are quite good and great value, but the documentation is crap and no set-up software, don't go there! They really push them, I guess they make good money from them, but don't be fooled
    they are not Delta's.

    They charged me $80USD shipping for each of the three servo kits, but that was 3 day DHL....superb. I tracked them from China to my doorstep in New Zealand in 2 days 14 hours. That was
    prior to COVID of course....

    They must also have a reasonably close arrangement with Delta because they did not have the braked servo I wanted so they got it in direct from Delta within 24hours.
    They have emailed me since claiming that Delta have offered them even better discounts on the basis of sales volumes and wish to encourage me to buy a whole bunch more
    by passing some of that discount on.

    I suspect that from your picture the ballscrews are 20mm or maybe 16mm. Really do need to find out, the rotational inertia of a ballscrew varies as the fourth power of radius
    and so the inertia equation is very sensitve to ballscrew diameter. Do a little more research and try to find diameter, length and pitch. We can guess at length and pitch without introducing
    a large error but not so with ballscrew diameter.

    The PM site also mentions that the attachments on x and y are for NEMA 23 and for z is NEMA 34. Does this change the choice of servo motor? Will 400W servos adapt?
    400W Delta B2 series servos are NEMA 23 size and 750W Delta B2 series is NEMA 34 size. Two 400W servos for X and Y, and a 750W for Z sounds pretty good to me. These servos will
    'eat' any stepper ever made!!!

    Craig



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    Default Re: Need advice for control software for mill conversion

    I am going to wait to receive the CNC upgrade kit and will check back with dimensions. In the meantime I am continuing to read up on the various options.

    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi koenbro,

    I am an Applications Engineer at Teknic and came across this post.

    I wanted to offer my assistance and advice when sizing/selecting a servo motor for your CNC machine.

    When selecting the best servo solution for your application across different lines, there are a number of points which must be considered. One such consideration (which was mentioned in this thread) is the price vs. performance of different servo systems. Although this is a largely subjective topic, you should be sure to consider the total system cost of each servo system when comparing different options. Often times there are "hidden costs" among different solutions that are not always apparent at face value.

    To make an accurate cost comparison, it's necessary to include the cost of the required encoder cable and motor cable for non-integrated solutions. These parts are not needed for ClearPath, but would be additional costs for other options, which can add up substantially. Additionally, these added items will reduce the system reliability and create more possible points of failure.

    If you do choose ClearPath, we have a number of resources that can help narrow down your different options. For example, if you know your torque and speed requirements, you can use our motor selection tool to help select the proper ClearPath motor:
    https://www.teknic.com/products/clea...lection-guide/

    If you don't know your torque and speed requirements, feel free to submit a contact request online and an Applications Engineer will reach out to you directly to help pick the optimal servo solution. They would just need to know details about the machine mechanics, load weights, inertias, and motion requirements:
    https://www.teknic.com/contact/

    I hope you find this information helpful in your decision; and good luck with your project! Again feel free to reach out to us directly with any specific questions related to servo options or motor sizing.

    Best regards,
    -Ian R., Teknic Servo Systems Engineer



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    Default Re: Need advice for control software for mill conversion

    Quote Originally Posted by Teknic_Servo View Post
    Hi koenbro,

    I am an Applications Engineer at Teknic and came across this post. [...]

    If you don't know your torque and speed requirements, feel free to submit a contact request online and an Applications Engineer will reach out to you directly to help pick the optimal servo solution. They would just need to know details about the machine mechanics, load weights, inertias, and motion requirements:
    https://www.teknic.com/contact/

    I hope you find this information helpful in your decision; and good luck with your project! Again feel free to reach out to us directly with any specific questions related to servo options or motor sizing.

    Best regards,
    -Ian R., Teknic Servo Systems Engineer
    Thank you very much Ian for reaching out to me. This is exactly the kind of communication that I am looking for. I have just filled out a request for help via the contact link you posted. I am looking forward to their reply so I can place the order.

    Basically I intend to mill 6061 or similar aluminum and mild steel, with, say, a 1/2 HSS mill. I do not know my torque requirements, but I can estimate feed rates, say for steel:

    SFM ~ 90-100
    Cutter Dia 1/2" with 4 flutes
    RPM will be around 700

    Chipload of ~0.002" per tooth
    Feedrate will be around 6 ipm.
    I hope I didn't mess up the calculation, I am new at this. Also, I don't think rapids matter much for a mill of my size (Table Size 7” x 28?; vertical travel 16") in a non-production environment.

    As for the ballscrews, I emailed PM to ask, and they wrote back with the following specs:

    • Double Nut, Precision Rolled Ball Screws for X, Y, and Z Axis, 5mm Pitch
    • Cast Iron X and Y Axis Mounting Brackets sized for NEMA 23 Motors
    • Cast Iron Z Axis Mounting Brackets sized for NEMA 34 Motors
    • Couplers for motor to ball screw connection (X and Y Couplers are for 8mm motor shaft, Z coupler fits 14mm motor shaft. Ball screw ends are all 10mm)
    • (6) 7001VV Angular Contact Bearings


    When connecting the servo to the Acorn do I need this board ?
    Finally, does Teknic offer NEMA 34 motors WITH BRAKES for the z axis?

    Once again thank you for any advice.

    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi,

    To make an accurate cost comparison, it's necessary to include the cost of the required encoder cable and motor cable for non-integrated solutions.
    The prices I quoted for Delta servo kits includes the drive-to servo and the encoder-to-drive cables and even the plug and shells for an IO cable, no extra hardware required.

    Craig



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    Default Re: Need advice for control software for mill conversion

    Quote Originally Posted by joeavaerage View Post
    Hi,
    The prices I quoted for Delta servo kits includes the drive-to servo and the encoder-to-drive cables and even the plug and shells for an IO cable, no extra hardware required.

    Craig
    Very much appreciate your advice Craig. Nothing against Delta, I have one of their VFDs in my control box for the Avid spindle; great documentation, flawless performance. Unfortunately I was unable to find Delta representation in the US, beyond the factory website, and buying from China is out of the question. I am glad you had a good experience, but I am not willing to chance that when there are domestic options one phone call away.

    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi,
    then consider DMM, a Canadian brand and well regarded for after sales support.

    With Clearpath you are on track to spend an extra 50% for the same or less power, vastly restricted IO and control modes, and a piss-poor encoder
    to boot.

    Craig



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    Default Re: Need advice for control software for mill conversion

    Hi Craig, I have contacted DMM on their website contact form, and called several times and left vm -- never heard back, so thus far am pretty unimpressed by them.

    When you say above that ClearPath has "vastly restricted IO and control modes, and a piss-poor encoder to boot" what does that mean for the end user?

    I surely don't want to sink $2k into a bad option, and I take your advice very seriously. But as an end-user what does the poor encoder really mean? Will it not run my mill? Also, I am not that interested in a million options for IO and control modes -- if and when I get it up and running, a simple control mode is actually preferred. Although my Delta VFD and Warp ESS on my existing CNC router have the proverbial million options, I have not messed with any of them in the year that I've so far run the system.

    Finally, you seem strongly opinionated against Teknic, both here and on other forums. I frankly don't care one way or another, but would you share why the strong criticism? Any relevant negative personal experience? You can DM if you wish. Thanks man.

    Avid CNCRP Pro 4824, Warp ESS, Nema 23 steppers
    Hypertherm Powermax 45XP with TMC3in1 THC and 2.2kW spindle w/ Delta VFD


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    Default Re: Need advice for control software for mill conversion

    Hi,
    I have nothing against Clearpath other than the price.

    On another thread a gut is going to buy three 350W Clearppath servos, and they will work well for him. For the same money, excluding shipping, he could have 750W Delta servo kits.
    Double the power for the same money.........which do you prefer?

    Delta have eight programmable digital outputs that can be assigned to fault conditions for instance, two analogue outputs which can be assigned to various analogue variables like
    speed and current say, and six programmable digital inputs.

    Clearpaths have two digital inputs, step and direction, one digital output called HLFB, no analogue outputs at all, no encoder output channel at all.

    Delta have analogue input speed and torque modes plus usual step/direction position modes and a whole bunch of mixed modes where the control of the servo
    can be switched from say analogue speed mode to step/direction position mode on assertion of one of the digital inputs. Clearpath has step/direction position
    mode only.

    The entry level Delta servo, the B2 series has an encoder of 160,000 cpr, and the A2 series is 1,280,000 cpr whereas the Clearpaths have either 800cpr or 6400 cpr,
    even 6400 cpr is less than el-cheapo Chinese made servos, they have 10,000 cpr encoders.

    I have no bad or otherwise personal experience with Clearpath but I refuse to pay $450USD (plus shipping) for a 350W servo with piss poor encoder and IO
    when I can have a 750W Delta with 160,000 cpr encoder and industry standard IO and control for $450USD (plus shipping).

    Craig



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Need advice for control software for mill conversion

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Need advice for control software for mill conversion