CNC router

[ZlatePWR]

First, hi to everyone and sory about my English. I strart a project of CNC router i need i little opinion i make plans for the router of my own but i dont know if it works becouse on the x axis the lead screw it will be only on one side. Do u think that this will work?

[massajamesb]

you will need to either put all the force in the middle with your screw, or make a drive setup that will drive one screw on each side. Otherwise, your machine will want to go crooked when you move back and forth.

[ZlatePWR]

Firs thanks for the reply. Like first i'm limited with step motors, i cant find it in my contry, second on is the belt i can't find i too so i can't put two leadscrews. And how to put all the force in the middle wit the screw? Sorry for my questions i'm good in electronics but not so good in mechanikal stuff.

[massajamesb]

Well, mount the motor in the center of the table, underneath the cutting area or above the cutter, so you have equal force on both sides.
Can you not ship in from the USA?

[ZlatePWR]

well i made first parts fro aluminium i the shape of U but the weight was 33.07 lbs (15kg) without any load and the steppers war not so powerful to move nicle the y axis, so i made a new design like in the pdf document where there is not ability to setup the motor in the center, while surfing on internet i find a working simular design. And i can't ship from USA i live in Macedonia. And realy thanks for the replay.

[massajamesb]

So pulleys, belts, etc are not available there? sorry, don't know much about that area.
can you get roller chain? run one motor in the middle, with a sprocket on it. Have chain looped around the sprocket, going to a leadscrew on each side.
Make sense? you could do the same thing with belts.
Can you ship from the U.K.? I know this stuff is available in the UK

[ZlatePWR]

rooler chain, that is good idea and is avalible here. but it vill be precise ?

[afh]

Well, I does not know, but chain does actually stretch,so you have to adjust it regulary.

You can use 2 leadscrew and use 2 stepmotors coupled in parallell to drive each side of X-axis?

Belt, leadscrew or ballscrew - all of them has disadvances and advances.
Me? I'm gonna use ballscrews and belt because they are more effective, but as of now, my first prototype CNC-machine, I am cheap as possible, so I am using M8 leadscrews with Nema16 (something like that!). I doubt that I'll get high precision, but I need to understand the principle and get it working together with software,electronics and mechanic.

Just give it time and be careful with planning. I have done the same, and I am still at my prototype, but it has been fun to look at pictures posted here and read technical stuff to be inspired and I have learned a lot.
Use this as a opportunity to be better in "mechanikal stuff"!

What will you use CNC to?
What is your budget?
What is your requirment of precison/accuraty?
What cutting size and height does you want to have?
What spindle do you want to use? It is strong enought? It is too heavy?
What driver do you want to use?
Does it fit your motors? Does it fit your software?
Does you need lubrication of the cutting material?
What about the security issues, make it safe for ME to use it? (E-Stop)
Is the stepmotor strong enought? Can it turn the ballscrew/belt with the load of Y/Z-axis? How do I know?

You have to ask yourself the questions and answer them yourself.

You does not need servomotors, steppers is strong enought, but it is easy to upgrade (but it cost

[ZlatePWR]

hi Afh and thanks for your reply

Like first i will use my CNC for eengraving and making parts from aluminium
My budget thats a dificult question
Well every one need precision
M cuting size will be 700mm to 500mm and height is 120mm
Iwill use a small router powerful to cut aluminium, and not to heavy (500g)
I'm using self made L297-298 PMiMO drivers up to 2.1A with choper board
My motors are size nema57 127oz-in 2A
Well i dont know about lubrication i will know in my first cut
Have a E-stop and probobli will be safe (made some optical sensors so i will mount them for more security)
Well the steper by calculations is double power than requerd so i will see in my first test is that true
I made today 3 trapezoid leadscrews TR12-3 (M12)

[afh]

Lubrication is not always necessary, and it IS messy, but it increases the tool-life and cutting speed. That is something I likes, so I'll require it for my own machine.

Funny, I have planned that my CNC will have around 750mm x 500mm x 150mm cutting area.

High accuraty is difficult to get; as it need attention to all details.
The linear rails, does have small height difference, the leadscrew have small differences in the pitch. add that up, and you'll get your total accuraty.
I want to have between 0.02-0.05mm accuraty. I does not know now if it is unrealistic goal, but I'll see!

My first prototype shall not have E-stop (AAGH!), as it is only for testing.

optosensors is a good idea, I have thinked at the same thing, but how did you coupled it up? I have some difficulty understanding them, so I'll need to check it out more. Can you bother yourself to tell me more about your optocouplers? *AHEM*

[ZlatePWR]

like firs afh for what do u want do use opto sensor (on which sections) so if u like i can design u circuit for you needs

[afh]

Sorry for my late reply.
I have thought to have six optocouplers. Each coupled to each side of X/Z/Y-axis.
Well, each of these has 3 leads. I suppose that I need to learn more of the principle, so you'll have to excuse me of my incompetance.

Now I have only three optocouplers, but it is easy to buy more later.

If you can bother yourself to tell me how to couple two optocouplers together,
to make this working and the powersignal will be zero when something appears between the optocouplers, I'll be very grateful.

(I haven't read/learned more since the last post)

BTW, I forgot to write more about lubrication:
You can squirt lubrication manually, with a spraybox at the cutting area.
I shall do that in the beginning.

damn, it is so much details to take care of, that I am really enjoying this progress!