Can someone send me some guide or something i need to read before start projecting it?
I need informations about stepping motor electronics and mechanical guidance.
I will use arduino PRO mini.
What stepper driver is better?
L298N Module Dual H Bridge Stepper Motor Driver(2A single bridge)
Pololu A4988(1A)
What type of motor(speed and force) is better? How much i will need of them? (1 per axis, 2 per axis)
NEMA17 1.8A
NEMA23 2.0A
What type of power supply is better?
It need to have regulated current?
if it have +/- 12v connectors and not 12v and gnd, how i should connect them?
I need a control board or something in addition to arduino?
What program i should use to convert my CAD drawings to arduino commands? Can this program also set speed movements and power supply current to cutter?
How can it be precise in moviments(mm steps)?
Can i recycling RAMPS 1.4 board to avoid to build a printed circuit board?
Can it be edited to use with a 2 axis cnc?
What are it's limits with power supply?
Can someone send me some guide or something i need to read before start projecting it?
I need informations about stepping motor electronics and mechanical guidance.
I will use arduino PRO mini.
Don't decide on the Arduino at this stage in case you need more functionality
What stepper driver is better?
L298N Module Dual H Bridge Stepper Motor Driver(2A single bridge)
Pololu A4988(1A)
Don't under any circumstances consider an L298.
You need to choose the motor before you select a suitable stepper driver because it must be able to handle the motor current
What type of motor(speed and force) is better? How much i will need of them? (1 per axis, 2 per axis)
NEMA17 1.8A
NEMA23 2.0A
NEMA17 etc just defines the physical size of the front face of the motor. It says nothing about torque. You need to decide what torque is required for your project and then find a suitable motor. And then select a suitable stepper driver.
What type of power supply is better?
It need to have regulated current?
if it have +/- 12v connectors and not 12v and gnd, how i should connect them?
Stepper motors perform better with higher voltages. The A4988 can work with 30v I think. Some stepper drivers can work with 50v or more. The voltage rating of motors is irrelevant as long as you use a stepper driver that can limit the current to the maximum for the motor
I need a control board or something in addition to arduino?
Yes - the A4988 or something equivalent that is suitable for your motors
What program i should use to convert my CAD drawings to arduino commands? Can this program also set speed movements and power supply current to cutter?
I can't answer that
How can it be precise in moviments(mm steps)?
I don't know if this refers to the CAD drawings or the mechanics of your machine.
Can i recycling RAMPS 1.4 board to avoid to build a printed circuit board?
Can it be edited to use with a 2 axis cnc?
What are it's limits with power supply?
I don't know enough about it.
8 ) How much Endstop i'll need?
2 per axis?
That probably depends on your machine and software. In theory one per axis is enough to allow the software to set the Zero position for the stepper motors.
[9) Where i can find mechanics informations?
There are several CNC forums and Google knows a lot.
We need to know a lot more about what this is for. All CNC means is "computer numerical control".
You only say X and Y. Are you positioning a pointer on a map? Moving a Laser to cut things? A blade to cut vinyl and paper? A water jet or plasma cutter?
polymorph:
We need to know a lot more about what this is for. All CNC means is "computer numerical control".
You only say X and Y. Are you positioning a pointer on a map? Moving a Laser to cut things? A blade to cut vinyl and paper? A water jet or plasma cutter?
A laser cutter.
What program i should use to convert my CAD drawings to arduino commands? Can this program also set speed movements and power supply current to cutter?
That's the most important thing i need to know about this project, becouse if i can't convert from a cad it's so inconvenient to create complex drawings.
I just realized I could have given a better answer to Question 5.
I don't know what software you should use (because I am no sufficiently familiar with CAD) but the usual process is to convert drawings to GCode and then convert the GCode to commands for the stepper motors. There are lots of programs that convert CAD to GCode. You will probably get advice on CNC Forums or on the RepRap forum.
You can't choose motors till you know the torque and speed you need,
so you start with the mechanical side of things, and your designed rapid speed
and resolution, max cutting forces, etc.
You may then have to determine the drive motor torque by measurement, only then
can you begin to think about sizing the motors, and then motor drivers and PSUs...
What kind of machine though? A milling machine and a 3D printer have massively
different mechanical requirements...
figure out the machine you want to build, or the work you want to do.
a metal cutting machine will probably start at 48 volts and go up to 70 with 5 to 7 amp steppers.
the drawing process is to design your work in a CAD program or a drawing program and then run that through a post processor.
when you draw in CAD, each line is laid out in sequence that you drew them. the corrections in the middle and at the end become fragments that are no attached to your part, but to you look fine.
the post processor will convert your work into a tool path that is more fluid and will allow for cutter diameter and roughing passes and finish passes.
the final passing of the file to the axes needs to be very high speed
you will find all this and more on the CNC forums.
Can you tell me advice on motors? A better motor should have higher Rated Current, 2 phase, what can you tell me on Phase inductance, Phase resistance and Rate voltage?
Can i use a drive to drive exactly 2 motors in sincro?
Yaro:
Can you tell me advice on motors? A better motor should have higher Rated Current, 2 phase, what can you tell me on Phase inductance, Phase resistance and Rate voltage?
Can i use a drive to drive exactly 2 motors in sincro?
You need to choose a motor with suitable torque for your application. Bipolar motors are the easiest to work with.
When you have found motors with suitable torque you will get the best high speed performance from low voltage / high current motors. But remember that the voltage is just a nominal figure that is irrelevant when the driver can control the current.
Also note that stepper drivers for high current motors will be more expensive.
Each motor must have its own stepper driver board even if they are to work in step with each other.
You could drive a pair of motors with the same step signals if they are to operate exactly in step. If you want to make one motor do 100 steps in the same time that the other takes 56 steps then that must be managed by your software.
Robin2:
You could drive a pair of motors with the same step signals if they are to operate exactly in step. If you want to make one motor do 100 steps in the same time that the other takes 56 steps then that must be managed by your software.
...R
if they are to operate exactly in step, all the time as if they are one motor.
if one motor missed a step, it will be forever out of step until you do something to get them back in step.
Robin2:
If you want to make one motor do 100 steps in the same time that the other takes 56 steps then that must be managed by your software.
...R
for clarification,
you MUST have two motors and TWO drivers. it is not possible to have two motors on one driver and run them separately.
Yaro:
Can you tell me advice on motors? A better motor should have higher Rated Current, 2 phase, what can you tell me on Phase inductance, Phase resistance and Rate voltage?
Can i use a drive to drive exactly 2 motors in sincro?
I want to have a vehicle go across the country, can you tell me what oil to use and what is the best valve timing ?
later on, I will tell you if it is a jet plane, a motorcycle, a freight train or a truck.
your question does not apply to this stage of your project.
what do you want the CNC machine to do ? a laser cutter is a non-contact device that runs near 1,000 inches per minute on an axis and much start and stop the entire weight of the axis at any time.
a foam cutting hot wire CNC is non-contact and moves slowly and only needs to move itself.
a metal cutting milling machine requires high power at slow speed
a wood router needs to move faster.
a printer or scanner only needs to move some plastic parts around.
you need to pick the power requirements first.
but, if you just want to learn, then get the A4988 driver board and a stepper that will meet the specs for the driver. make your device and then work out the software. the software will be the same no matter the size of the motor. and the investment of parts is minimal. think of it as the cost of learning.
dave-in-nj:
for clarification,
you MUST have two motors and TWO drivers. it is not possible to have two motors on one driver and run them separately.
I did mention that in Reply #9
...R
Yes, you did. however, I have been dealing with people who try and try to figure out how to drive multiple motors with one driver with any logic possible.
I wanted to close that door, hard.
.
You could drive a pair of motors with the same step signals if they are to operate exactly in step.
this could have someone try to turn that into something it is not. Regardless of the fact that you said both before and after this sentence, that you need individual drivers.
Yaro:
5) What program i should use to convert my CAD drawings to arduino commands? Can this program also set speed movements and power supply current to cutter?
use your CAD or drawing program.
this will create a file with all the points or coordeinates.
to turn this into g-code, you can use a post processor. there are many post processors available.
google your CAD or drawing package and 'post processor' then read about what is available and what things cost.
especially about the cost. some have an annual license of $10,000 USD per seat per year.
some are very low cost.
but they will allow you to add features like cutting the center of a part before cutting the outside. or tool cutting diameter.
How can it be precise in moviments(mm steps)?
consider that a 200 step per revolution stepper with a 8x micro-stepping driver will offer 1,600 steps per revolution.
then you have a pulley that is 20cm dia, connected to a belt. one revolution of the pulley is pi() x 20 cm / 1600
or, consider that the same pulley is connected to a screw that has 10 threads per cm. so, 1600 x 10 = steps per cm
now calculate the speed of the step output and you can calculate how long it will take to move those 1600 steps. one axis will move very fast and have fewer steps per mm. the other axis will move very slow but have multiple steps per mm.
a very small motor would be needed to generate high force if using a screw. a very large motor is needed to accelerate and stop a heavy gantry on a belt drive.
if you cannot move the axis as fast as the device requires, then the machine will not work properly.
dave-in-nj:
a foam cutting hot wire CNC is non-contact and moves slowly and only needs to move itself.
a metal cutting milling machine requires high power at slow speed
a wood router needs to move faster.
All the above need to do rapids, so they all want fast movement - the most annoying
aspect of a misdesigned CNC machine is glacially slow rapids. The clue is in the name.
dave-in-nj:
a foam cutting hot wire CNC is non-contact and moves slowly and only needs to move itself.
a metal cutting milling machine requires high power at slow speed
a wood router needs to move faster.
All the above need to do rapids, so they all want fast movement - the most annoying
aspect of a misdesigned CNC machine is glacially slow rapids. The clue is in the name.
rapids is a relational. typically double normal axis speed or maximum cutting speed.
a CNC milling machine rapid could be 20 ipm, a laser cutter that does 5,000 imp cutting speeds does not really need rapids in the same sense.
the distance has a lot to do with it. no need for 5,000 ipm rapids on a 12 inch wide machine. and having 20 ipm on a 16 foot table would be insane !
I ask for motors becouse the price do a big leap from a 1.8A motor to a 2.5A motor, same for drivers. So i want to dimensionate the project to have minimum expenses. A method i tought is to connect 2 motors to a same axis(like 3d printers do to Y axis) to have more torque power. But to do this and have some advantage they need to operate exactly at the same time and the speed of arduino processor can allow it i think.
I have another question, ebay sellers and other sellers don't provide torque motor, but only detent and holding torque, so i can buy motor based only to voltage, phase and current.
A stepper driver like A4988 have a 1 A output per coil, so if i find a motor that have nominal current of 1.8A i can presume that is 0.9A per coil?
Yaro:
I ask for motors becouse the price do a big leap from a 1.8A motor to a 2.5A motor, same for drivers. So i want to dimensionate the project to have minimum expenses. A method i tought is to connect 2 motors to a same axis(like 3d printers do to Y axis) to have more torque power. But to do this and have some advantage they need to operate exactly at the same time and the speed of arduino processor can allow it i think.
there are some people who use two motors and two drivers on the same axis with the same signal. on a long machine, it allows a motor on each end. although it is not recommended, it can and does work. you can think of it as one motor and one driver and it only needs one signal. the problem is that if one motor misses steps, the machine needs to be re-set. you can do that with a home switch on each end AND some way to set the axis. if you turn the power off and set physical end stops, you can just push the axis so that each side is at the end stop. then turn the power back on. an alternative is to have both drivers controlled separately and then use on to set the home switch for alignment. it is very difficult to set both to be exact. that is why many people do not like to use this method.
Yaro:
I have another question, ebay sellers and other sellers don't provide torque motor, but only detent and holding torque, so i can buy motor based only to voltage, phase and current.
A stepper driver like A4988 have a 1 A output per coil, so if i find a motor that have nominal current of 1.8A i can presume that is 0.9A per coil?
the motor torque is calculated based on voltage and amps. no one can know how you will use it.
the torques needed for your project can only be calculated until you apply the motors. if your axis weighs more, you need more power. if it weighs less, you can use less power.
the motor rating of 1.8A should be 1.8A per coil. you can power that with the A4988 and it will deliver power for what you provide. since watts is amps times volts, the higher voltage your provide the more power you are giving to the motor.
if you need high power, you will pay a high price. the chips get larger and cost more. also, as you get a better driver, you get more features and better performance. I like the Gecko drivers, typically about $150 USD for each driver, can handle 70 volts and 7 amps. they are 10x microstepping. These will power the largest usable steppers available. if you need more power, you should not be using steppers.