[ Register ]

### Question #: 14241

Question: So after I install the stepper motors, how does the system know what’s the start position ? I’m modifying a lathe.

Current Solution

If you are using a control program, like Mach3, then you will move (jog) the axis to the location that you want to set as your start position and "zero" that axis. Make sure that the axis moves in the positive direction where you would expect. If this is not the case, you will need to reverse that axis according to the instruction with your control program.

Respond:

### Other Possible Solutions to this Question

• How to determine lead screw length needed. My Thomson 1 1:4 rails are 60 inches long roughly for the router I’m building. I know I have to have it long enough to couple up with the stepper motor of course but does it matter if it’s a little long on the other end

It generally does not matter if it is longer at the other end as long as the lead screw provides the desired travel for that axis. The lead screw will only need to be long enough for the travel, plus any structure and lead-nut positioning.

For example:
- The motor that will turn the lead screw will need to be mounted at some position (generally at one end of the axis). In many cases, this positioning will be mounted where some of the lead screw will not be used (the lead nut will not be able to moved close to the coupling of the lead screw to the motor shaft). Add some of the length of the lead screw to be inserted into the coupling.

- If the lead screw will contain bearings at either end of the travel, that portion of the mechanical assembly will need to be considered in the lead screw length.

- The lead-nut will need to be mounted in a position on a structural member of the part that is to move. The distance from the part of the structure that will extend closest to the motor will have some distance to the position of the lead nut. This distance will need to be added to the lead screw length.

Add these discrepancies to the length of the lead screw and the travel length and you will have the final length.

• How far does the X axis of the blackfoot travel per turn of the stepper motor ?

The amount traveled per turn in our blackFoot, will be dependent on the steps per inch settings that you will implement to your drivers and within the software (mach3 (ex)) motor tunning: steps per inch/ 1422.22, 1/4 on your driver will give you a different distance if used as 1/2 or 1/8 etc.

Here is a in depth tutorial on how to find the correct steps per inch for a specifications: (

)

How far does the X axis of the blackfoot travel per turn of the stepper motor ?

• Is there a manual or some documentation of how a binary value in the printer port translates to position on each motor?

The parallel (printer cable) port is uses the computer as its main source of pulse trains to operate the motor driver directly. Parallel ports are a direct connection from the processor commonly referred to as GPIO pins (General Purpose I/O pins) and provides a convenient and powerful way to interface with the computer. The parallel breakout board is included in those kits only to condition those signals for use with the drivers.

The USB serves at the actual controller, sending the pulse trains, but the computer sends simple human readable instructions to the USB controller to tell the controller how to send pulses.

The non-technical differences that may serve as the most important information to you is that the parallel configurations allow for a wider variety of industry standard software that can be used to control the cnc machine. The USB that we offer requires the operator to use a software called Planet-CNC software which is a very well made and feature full cnc control software.

• My cnc router started doing strange things today after about 20 minutes into a fairly simple project. I noticed the red lights were flashing in my 4 Stepping Motor Drivers (24-70. Does anyone know where I should look to solve my problem?

Can you describe strange a bit further? Also which specific drivers are you using? CW230 or 3.0A driver? or the 6.0A driver or CW8060?

• What kind of computer comes with the blacktooth and do i need to install windows after purchase?

For the integrated computer for the blackTooth, the hard drive doe not need to be formatted, but will require an OS (operating system) to be installed. Ubuntu Linux can be installed with the CNC integrated software from Linuxcnc.org. Windows can also be installed.

What kind of computer comes with the blacktooth and do i need to install windows after purchase?

• Whereb can I find directions on how to install the Mach3 USB board with Mach 4 software? I do not have a parallell port.

You can find instructions for the Mach3 USB here:
https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach3-USB-Board

You will probably need to use the Mach3 USB board with Mach3. We have not tested the Mach3 usb card with Mach4.

• I need the calculation to determine the stepper motor torque to find the load that it can withstand in horizontal position using a lead screw at 1/2" diameter with 13 TPI.

There are two main questions that we can answer with respect to motor torque and the mechanical advantage of lead screws, 1) What torque motor do you need to lift a particular weight, or 2) What maximum weight will my motor torque be able to lift.

This formula uses Newtons (N) as it's final unit. Use this with the included radius (R) to determine the torque. Newtons can easily be converted to lbs or ounces using online conversions.

Effort = Sf + (Load/(2 x pi x (R/p) x Se))

where:
p = pitch of the screw
Se = screw efficiency = Standard lead screw will be between 20% (.2) and 40% (.4)
Sf = static force. This is the force that is needed to start the movement. The number may be eliminated, but it is good to use a number in the 5 N to 20 N range.
Load = the expected load that the effort will need to carry (i.e., the router and the included axis assembly that the motor will need to lift)

This formula is based on the "law of the machine"

The final effort amount with its unit of newtons and R will be the torque. For example, if the effort comes to 100 N (newtons) and the R is .5 inches, then you can assume that the effort is 50 N-in since it would take twice the effort to turn form the one inch mark from the center of the shaft.

Example:

Load = 90 N (20.2 lbs)
R = 1 inch since that is the length from the center of the shaft that the motor is rated
p = 1 inch / 13 = .08 inches

Effort = 5 N + (90 N / (2 x 3.14 x (1 / .08) x .2))
Effort = 5 N + (90 N / (6.28 x 12.5 x .2))
Effort = 5 N + (90 N / (15.7))
Effort = 5 N + (5.73 N)
Effort = 10.7 N = 2.4 lbs = 38.4 oz-in

I am putting the oz-in on the end because the formula considers the distance from the center of the shaft to be one inch.

Therefore, a 425 oz-in motor would be able to lift a 20.2 lb Router with its accompanying assembly. If the assembly and router is heavier, plug in the numbers and determine the effort required.

With a bit of algebra, the formula can be rewritten to find the load:

Load = (Effort - Sf) x (2 x pi x (R/p) x Se)

Another formula that does not consider friction at all:

Effort = (Load x p) / (2 x pi x R)

Lets see if we get similar results:

Effort = (20 lb x .08 inches) / (2 x 3.14 x 1)
Effort = 1.6 / 6.28 = .255 lbs = 4.08 oz-in

The results from both formulas appear to be very small because a 13 TPI screw will have enormous mechanical advantage.

It is evident that the first formula that does consider friction that we are loosely estimating is far more conservative than the second formula. Either way, even the most conservative formula shows that the 425 oz-in motor will handle very large weights. If you are using a lead screw with only two turns per inch, .5 inch pitch, you can determine the requirements with the first formula.

Example for a 10 TPI 5 start (2 turns per inch) lead screw:

Load = 90 N (20.2 lbs)
R = 1 inch since that is the length from the center of the shaft that the motor is rated
p = 1 inch / 2 = .5 inches

Effort = 5 N + (90 N / (2 x 3.14 x (1 / .5) x .2))
Effort = 5 N + (90 N / (6.28 x 2 x .2))
Effort = 5 N + (90 N / (2.512))
Effort = 5 N + (35.83 N)
Effort = 40.828 N = 9.18 lbs = 146.88 oz-in

Customer Response:
thank you so much

how do i calculate torque of stepper motor if lead screw coupled to motor shaft and load applied by lead screw on plate is 100 kg by vertically

Pls

1m 16mmdiameter ball screws calculations

• Does the USB controller come with driver installation instructions so we could create our own user interface to communicate with the motor?

You can use a Pickit 2 programming to load firmware onto the usb driver. The USB use a Microchip pic microcontroller. If you can manage writing a program for the Pic microcontroller and have a Pickit 2 firmware uploader (programmer), you should have no problem.

• What side of the x and y axis do you mount the stepper motor to? If it does not matter what side, do I have to change something in mach3?

It is usually best to mount the motor in a way so it is spinning clockwise to avoid confusion.

ok, but lets say the motors turn clockwise. if you mount it to ether side of the y axis it will pull to that side so what are the correct positions of the stepper motors. is it the left side or the right side of the y axis and also is it the front or back of the x axis?

cw250 with mach3 controller

• I installed the USB CNC Planet and got out of your USB controler \$ 75 .Viska have linked to a video 'Party - 2.. X - running and y and z-axis does not work, it moves step motors and controller positions X -axis works, and Y and Z does not work.

Recommend first test to check a non-working axis, is to connect the current working axis(ex X-axis) to either the y/z axis to test the actual board and wiring in other axis setup. If tests failed and working (x-axis setup) does not working in the new axis location, go the Planet-CNC/File/Settings/Axes and check if your current non-working axis setup requires a inverted pulse. Check box and test again.
Next test if first fails, is to check continuity in your wires. A simple multimeter(ohm's) will work, just connect the positive and negative ends to one side of the same wire and if reading comes to 0.000, wire has continuity and if reads 0.L then there is a break in the wire and should be replaced.

• Are the stepper motors on x and y axis suppose to be hot after running for approximately 30 min. I can touch them but they are hot.

If your motors are hot to the touch, this is normal. Current is being drawn by the motor coils as the motor moves and as the motor stays at a position. If the motor is not using the current in the coils to move (holding it's position), the energy will be translated as heat (rather than motion, sound or light). Even while moving, some of the energy will be lost as heat. Remember that energy cannot be created nor destroyed.

• I am building a machine that requires 2 steppers to drive the Y axis, can you make me a redleaf system using the 651oz steppers that will work for me?

Yes, we can make a redLeaf system that has all 6A drivers for use with the 651 oz-in motors. We can also wire the electronics in a way that two of the drivers will use the pins of the same axis so that axis will drive two drivers and motors.

• stepper motor runs smooth then rough for a moment then smooth, etc. Does this at all steps, and connected motors.

This sounds like it could be a loose wire, or poor connection with the motor wires. Make sure all wires that are to be connected to each other are soldered and use a lineman's splice when putting the wires together. Also, make sure that the wires going into the driver is securely fastened.

If this is an issue where the motors have run well for a long time then just started to show this performance issue, then make sure that there are no wire ties or other binding method that is chaffing the wires. This would make the motors run oddly at certain travel positions where the chafing has caused a short with the wires.

If this is an issue where you don't have the motor plugged in at all and are just trying to turn it by hand and this phenomenon is occuring, then make sure all of the wires are not touching each other. When wires are touching each other and you are trying to spin the shaft by hand, the motor will feed current back into the motor making it difficult to turn.

• Hi I live in South Africa and want to know if i can buy a wiring and component diagram for the readleaf plug and play computer system?

The best wiring diagram that can be used for the redLeaf and redSprout CNC computer system would be found on instruction #1 (datasheet for the breakout board) on this page: https://www.buildyourcnc.com/item/electronicsAndMotors-parallel-breakout-relay

• Hi I live in South Africa and want to know if i can buy a wiring and component diagram for the readleaf plug and play computer system?

The best wiring diagram that can be used for the redLeaf and redSprout CNC computer system would be found on instruction #1 (datasheet for the breakout board) on this page: https://www.buildyourcnc.com/item/electronicsAndMotors-parallel-breakout-relay

• The instructions for installing the USB board say there should be a blue LED light up when computer is connected. I get a flashing red LED that goes solid when I start

This is correct if it is the Mach3 USB controller. You will also get a rapid flashing led if you jog the machine (assuming the machine is not in reset mode or e-stop mode).

• Installing THC to my limit ports on the breakout board. Once wired how do I get Mach 3 to reconize the port?

Getting continuity from the x--/x++ might not mean it is a faulty board, unless they are bridged, so both get a pulse rather than one. But to check if you might have a opposite connection for those input:
Planet-cnc/file/settings/input/invert inputs/input 1/input 2.

In input port section in config. Scroll down and you will see THC On, Up and Down. Enter your input pin numbers there.

• I'm trying to build my CNC router 3m*1.3m, but i'm not sure what is the type of stepper motor i should pay, all my CNC body is Al. I need to bay 4 Stepper motors, 4 drivers, spindle, inverter, and i don't know what is the type of controller ?

The size of the stepper motor is measured in holding torque, generally oz/in. You will determine the torque loads of your axes when selecting steppers. Once you know which stepper you need, the drivers and controller board are simple to pair with them.

• Hi please could you tell me how to work out the size required for the stepper motors ? which kit to get thanks

The size of motors required for your machine build will depend on many characteristics of the machine.

If the machine uses a gantry (rather than moving the table bed) and the weight of the gantry (specifically with inertia),

The mechanics used with the axes, lead screw, roller chain, timing belt or rack and pinion. Generally you will need less torque if using lead screw due to the mechanical advantage, but friction is important to consider.

If you are building a 4'x8' or larger machine, it would be best to use: https://buildyourcnc.com/item/electronicsAndMotors-3axis-heavy-gantry-elcombo

Otherwise: this electronics: https://buildyourcnc.com/item/electronicsAndMotors-3axis-425-elcombo should be fine for most configurations.

If you feel that you need extra torque on the z-axis (the z-axis will use a very heavy spindle, for instance), use this electronics: https://buildyourcnc.com/item/electronicsAndMotors-3axis-651-elcombo