I plan to build CNC machine. I have already found 3 unipolar stepper motor from old printer.
Type of CNC will be like http://reprap.org/wiki/WolfStrap-English#WolfStrap-Fran.C3.A7ais
For electronic part I have two options:
L298 driver (3psc=12.48$) + Arduino Mega (14$) from aliexpress.com In addition I don’t any information about any other complete solutions for arduino. Could you please advice if you know or have experience in this subject?
3 Axis TB6560 3.5A 16 Segments CNC stepper motor driver from (40$) http://www.aliexpress.com/item/3-Axis-Stepper-Driver-Controller-stepping-motor-Driver-Board-TB6560-UC045/327355240.html
Please help me, and give me some advice which option is better, based on your experience? I liked the first option, because it is based on arduino.
I would rather use the second option. To drive it you would really want a parallel port rather than a usb to parallel cable. 3.5A should drive some decent steppers.
Supply voltage I have just checked supply voltage for second option. Supply voltage is 12-36v. My steppers voltage is 3.2v 1.5A (0.75A phase). So it means second option is not applicable, doesn’t it?
push a good deal more voltage to their steppers than they are rated for. I believe I have read 5 to 10 times the stated voltage. As long as you don’t feed your steppers more current than they can handle everything should be good. Higher voltage lets the steppers run faster.
Repraps and CNC mills should be built differently.
A CNC mill is built to hold position while it is cutting. This means for it to be accurate it has to be sturdy. By hobby standards, sturdy means it will have a fair bit of mass and not move terribly quickly.
A reprap is built to position itself quickly with very little resistance to its movement. It has to be sturdy and stable like the mill, but, the head should have as little mass as possible.
We have a member that tried to make a printer out of a mill. He actually ended up with a broken mill and no printer. This all boils down to, if you want a mill build a mill and use it as such. If you want a printer, build a printer. If you want a repstrap, say as much and realize what you are getting yourself in to.
Thank you birdmun! What about if I will use CNC only for wood or plastic with thikness max 3mm. Stepper will work slowly. In this case I can use light weight spindle and some time I can change spindle to extruder. How you thing it can be done in this way? In my CNC i plane to use screw.
I have a great deal of personal experience on this one, and I second what TinHead said, a mill is not a printer and a printer is not a mill.
Here’s my 2 cents (about CNC’s in general)… In my mind, there is no reason to build a “hobby” machine at all. It is nearly impossible to build a machine stiff enough using MDF and (God forbid) drawer glides. In the end, you will have a machine that will indeed move in 3 directions, but won’t cut much more than styrofoam. So in the end, you have spent maybe $500 on a machine that you can not use for really anything.
Instead, I would put that $500 into building (or buying) a proper machine. As a point of reference, my machine is built of 2"x3"x 3/8" steel box tube. There is not a piece of metal on the machine that is less than 1/4" thick. It weighs about 700 lbs. and eats aluminum alive… That said, I still wish it was twice as heavy and stiff. --As a matter of fact, I built this machine twice, having underbuilt the first version quite a bit. I personally believe that one really can’t make a proper machine from anything but metal.
Again, there is really no “middle ground” in my mind. You are building a printer, or you are building a CNC toy or model, or you are building an actual machine you can actually use. Again, only going a few hundred dollars into this thing will not get you much --One really has to be looking at $2000+ to get into something you can acutally use.
Thank you all for your time and for sharing experiences! Now my plan is to create a 3D-printer. It was just the kind of information that was needed to me. For electronics I chose Reprap Shield with Driver A4988 and with ready extruder.
This information is very useful to those people who need specific instructions to build something from scratch. Employees who work in different industries need to follow specialized courses to learn how to use the machines with which they work and also how to maintain them in proper conditions. For instance, these beveling machines, often used in metal manufacturing, must be used correctly, if not, they will damage fast. Therefore, only experienced and professional workers must use them.
