is this an ok driver Newb question

[evilr1]

Thanks guys but will this be an okay driver for the motors

Kollmorgen SMC-100

for milling aluminuim and brass small pieces and how do i measure or estimate what size motors i need with different machine builds thanks in advance

[KOC62]

You don't provide enough information to make an educated guess.

One would use a motor size that would meet the requirement of the machine doing the work. The machine (which is unknown to me) requires a certain torque, RPM and hosrsepower to do the work. This requirement guides your motor selection. The motor selected will guide the driver required - and so forth....

[evilr1]

thanks for the reply am just new to forums and i will try my best to know how to question and answer thanks for your patience. . .


I gathered bits and pieces of other designs for a home build if by using a strong frame as i seem to understood by the informations here and using bigger lead screw and linear guides as an example here

on the x axis two linear guides on bottom each side 35diameter on top of that another 35 diameter ballscrew nut rod and on top another rail of 35diameter
so like bottom rail guide middle lead screw with the nut and another rail guard on top so will be 3 rods on each side to run the x axis with a motor on each side do i need to go bigger for more stability or is that to much i am just trying to get the concept of doing metal objects


to solve this flexing issue i keep hearing unless i got it all wrong so if i increase my frame and rails and use a water cooled spindle would my DIY be strong enough like that to mill aluminium and copper, we are not talking mass production but couple of mod job a day with my work, if i am missing anything or i just got the whole things wrong a helping hand, before i start this build next week thanks in advcance. . .

my size would be 650x650 most parts would be motorbike parts computer mods, the copper is for computer water cooling small blocks

[KOC62]

I can sympathize with your challenges. I haven't built my CNC yet but have started the mdf type. I used the "joe2006" design as a guide for motor and lead screw selection, and its overall cutting area - footprint. Its for wood, and perhaps plastic, cutting mainly.

Your design is intended for metal and thus will have different issues to resolve. Metal cutting also use tighter tolerances than cutting wood. Hence your need for more mass and rigidity.
You may want to look into the approximate cutting forces involved with the materials you plan to cut, and the depth of cut along with its feed rate. This would allow you to ball-park the spindle horsepower size, torque and RPM required. Your current part selection seem reasonable to me. Another suggestion is to find a similar size and cutting materials machine on the CNCZONE for ideas and comparisons. There are more advanced builders than I on this forum.

Engineering is fraught with compromises especially when using whatever parts you find. Under these circumstances we can't expect to make our first machine the best and last machine due to our lack of engineering knowledge. So, take the challenge, work slow and methodically. Yet treat this journey as a learning experience for your future designs. Setbacks are lessons for positive improvements. With this forum you will succeed!

[James Newton]

There is some good information about how to estimate the size of the motors and driver you need at techref.massmind.org/techref/io/steppers.htm#Estimating

[evilr1]

thanks for that and advice much appreciated am not trying to get my 1st machine to be perfect 1st go as u said no engineer here just wanted to see is that the concept like there is this german company step cnc such a simple square design and they bloody cutting anything they like so if it is the frame and ballscrw being more stronger not a twig figure, just wanted to know if i was heading in the right direction or grasping the idea slowly, thank i will do that so will this be your second or 1st machine. and i have seen built small machines out of a teflon hard plastic am not sure what it called but whjat skate board legs are made of and it very small milling metal easy so its making me have a lot of question in the factor of is it really cheap with mdf or not

[KOC62]

I'm on my first CNC machine. My intent was to use as much of local materials as possible and learn from that - just as you appear to do. For example, I'm using a hardware store threaded rod which most users here don't recommend. Hence my machine is for learning "why not?". I understand their objections. Secondly, I come from an electronic background, not mechanical, and I have no real project requiring a CNC machine, but love to tinker with electronic stuff. Hence my uncertainty as to what size I should build. After some years of lurking, I decided on something like a joe2006 using whatever parts I could find in our hardware stores. I did buy 4 Keling 425 oz-in stepping motors and the Gecko G540 driver. My 50VDC power supply is canabalized from a 200watt stereo amplifier. I then discovered that the G540 is a 10u stepper, which may not get me the best speed for my threaded rod as lead screw because computer software has an upper limit to pulse repetition output. But I'm going with it to learn. Maybe in the future I'll build another improved version - if needed. I'm using roller skate bearings for my linear motion.
I built a small electronic circuit, as a manual speed controller, to drive one axis of the G540 to run one motor. I wanted to know how fast my stepper could turn under no load. I got over 4600RPM - no load. The G540 can handle over 250,000 pulses per second (>7500RPM). Next is to attach it to one of my X-axis "truck" and see how fast the motor will go under some load, using my threaded rod. So it's incremental learning for me. No rush on my part.

[evilr1]

i get what u mean exactly, am more computer mechanical as auto and spray painting to me construction is not a strong point, and for bloody a play a geko and those motors is little more to it but one thing confuse me with the board tb4? i see u dont need driver with some people why is that and somehow u might know as elec is your point i got a $16 5 axis controller dont know why but was told will do the job nicley if you have an email u can pm me and will send you the board and the a controller that i got to see what u think, and just then it came to my head i need it to do some custom work so why am i getting sillly parts again, but another thought was those boards and drivers pull the same job so there is me going confused again, but am going to crank up the sizes of these ballscrew and frame and linear and me just guessing i maybe can pull a decent DIY but only the experts and the guys here with expreince can give a yes or no to this idea, but PM please to see what u think of these