Hobby CNC

Hello all,
I am new around here and could really use some help. I would really like to build a CNC for my own personal use. Mainly for hard plastics and soft metals for any given project that I may be doing at some time.
I don't have a ton of CNC experience, but I have enough to start some trouble. I used to run a Makino F5 using NX software to write programs for Hard Milling and also a basic Haas TM-1 with low grade BobCad-Cam software for roughing and doing "not-so-precision" work on mold frames and cavities. I currently am running Charmilles RF55 and a Charmilles RF50 sinker EDM machines and don't get many opportunities to run mills anymore. I have had minimal training with all of these machines and have learned most of what I know through reading manuals and researching the Internet.

......ON TO THE POINT.....

I have acquired a 3-axis Micro-Vu from my previous employer. It has ball screws, linear rails, scales, and a VERY rigid frame with a 320mm x 320mm table with about 150mm height clearance. I would love to fit this with some stepper motors and required components to make this a small CNC mill.
This is where you all come in... I have looked around and cannot find a definitive answer on what exactly it would take to get this frame up and running. Such as motors, controllers, power supply and what not. I would like to find a user friendly 3-D software as well to design and write tool paths with.
So, out of curiosity, where would you guys begin with this?
I would like this to be a quality build, so I don't mind spending some money on good products, however I don't want to break the bank. I would just like to hear your feedback and thoughts on this idea.

All comments, questions and criticism are Very much appreciated.
Thanks!

So that's an old CMM? And that thing that looks like a spindle isn't one? It seems like it should be fairly easy to convert to a mill, but you need to figure out a spindle that works with the sort of materials you want to cut. If the hardest material you wanted to cut was aluminum, then it's pretty simple; there are plenty of high-speed all-in-one spindles that would do. But if you need to slow it down to cut harder metals, then it gets more complicated. Maybe someone out there knows of a spindle kit you can buy, otherwise you might have to rig it up with a splined shaft and pulleys. Reusing the linear scales will be another complication; most of the systems we hobbyists use rely on optical encoders fixed to the back shafts of the steppers. But the rest of the project should be fairly straightforward. See if you can find a good T-slotted table to mount onto that frame, and look for stepper motors with low inductance.

Thanks for the input AWERBY. I have stripped all of the electronics off and am down to just the 3-axis frame. I did plan for a t-slot table and was thinking about using a new set of scales, but I'll look more into the optical encoders before I make any purchases. I was considering a 2.2 kW spindle, but I've noticed that the running speed is commonly 12,000 to 24,000 RPM. I would mostly be cutting softer metals (brass, aluminum) and some plastics, so I feel like that should suffice. However I would like to be able to cut steel if the opportunity presented itself. Please pardon my newby questions, but when you say Inductance, is this referring to the the torque (i.e. N.m) of the motor? I guess I've just never seen the word inductance in any of the product specs when looking at motor kits.
Thanks again for the input!

Disregard my last statement... I've just been overlooking the inductance. oops

I am a CNC worker but new here. Actually, I am interested to gain ma knowledge about its advanced features in it and how it works. It is my passion that is why I am here.

Hi,
most of the Windows OS based CNC software solutions, Mach3 or Mach4, UCCNC or Planet CNC are not feedback capable and so linear scales cannot be used as feedback.
It is a function of the way Windows works. The vast majority of hobby machines that use these software solutions are open loop, and most commonly stepper driven. A well designed
and spec'ed open loop stepper system will be every bit as good as a closed loop system and very much cheaper and less complex. That would be my recomendation.

If you absolutely insist on closed loop then there are a few alternatives:
You could use a motion controller like Galil which could close the position loop on the linear scales but is an expensive solution.
You could use 'load sensing servos' like Delta A2's, but again is a costly excerise.
You could use LinuxCNC. LinuxCNC is run on a realtime capable PC and can therefore close the loop. You have to be familiar with Linux. LinuxCNC favours people
with good C and C++ coding skills.

Craig

Hi Clef - You will need to make mounts to fit steppers where the handwheels are. You will need to measure the lead of the screws so someone can calculate the size motors you will need (I'm sure N23 will do). Then you will need either discrete devices:

break out board - motor drivers to suit motors. Then power sources to suit motors/drivers, say $200AUD

Then software to create CAD eg fusion 360 for hobbyists (free) or commercial options rhino, solidworks, alibre pick from 1000's of cad systems (free to infinite $$$)
Then CAM to create G code eg again fusion for hobbyists (free) or pick from 1000's of cam systems (free to infinite $$$)
Then a machine operating system like UCCNC or Mach4 or similiar Say $300AUD including a motion controller

I suggest you look for a one box stepper driver system saves a lot of work. Eg buildbotics or https://www.spark-concepts.com/cnc-xpro-v5/,

or buy this - https://www.oyostepper.com/goods-478...or-Driver.html

Then there's hybrid steppers, servos and all manner of advanced options to learn about. Welcome to the CNC zone. :) Regards Peter

Hi,
can you post some more pics of the linear rails and the ballscews? Knowing the sizes, grades and even the manufacturers would be helpful. The basic machine looks to be very good quality
and if that is indeed the case it would make sense to try to match the quality if doing a CNC conversion. That would in turn give you a ballpark figure for the sort of hardware and electronics
you would want which determines what the cost would be. That's a very useful number to have BEFORE you start building it........it may mean you have to get a divorce before you start...(joking).

Craig

Hi,
Craig, Peter, you two have given me a ton of advise moving forward with this project... In fact I had started another thread in the "CNC DO-IT-YOURSELF" section of the forum... Here is the link to a newer thread with all of the helpful information you guys have given me. https://www.cnczone.com/forums/cnc-d...are-posts.html
The ball screws that I decided to go with are C5 ground SFA 2010 (X,Y) and SFA2005 (Z).
The frame came with IKO brand linear bearings CRW6-450 for X,Y and CRW3-275 for the Z.
I don't currently have any plans to change these unless they don't hold up once I have the machine up and running.
I have purchased most everything that I need to start this build. So, the money is spent and my girl hasn't left me YET.

Now I'm just down to making some mods on the frame to make the Z a little more robust. And building some small components such as motor mounts, limit sensor mounts and a stand for everything to sit happily on. I'm still far from a finished build, but I am MUCH closer than I was last fall , thanks to you guys!!

As I continue with this build, I'll be updating in the D.I.Y. thread.

Thanks to you both for such great information and helping a laymen like me get started!

-Caleb