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MGBeaver
01-18-2012, 07:05 PM
I have almost zero knowledge about CNC machines so please forgive me if I don't understand something. Me and my boss are trying to figure out if and how we can convert his Enco mill into a CNC mill. The model is 100-1427. It was made in 1958. We understand the basic idea of using stepper motors and controller to control the X, Y, and Z axes. we need to find out what motors and parts would be best for this conversion and what the overall cost of the conversion would be.

We are also trying to decide if it would be more cost effective to buy a used CNC Mill for around $5K.

If anyone can give any advice or point us in the right direction we would be grateful.

Thanks,
-Matt

Sparky_NY
01-18-2012, 07:38 PM
Expect about $2000 to convert the mill you have, ballscrews being the largest cost. A commercial built cnc will outperform it in every way and may have a toolchanger as well. I have been both ways and would vote for a used commercial cnc machine without reservation. Of course the condition of that used machine has to be checked out.

MGBeaver
01-19-2012, 06:47 PM
So your saying the befits of a commercial CNC out way the cost of the conversion?

What would I need to look for in the condition of the machine?

I've noticed in the machines we can afford that the controllers don't seem to have a way of importing commands. So I'm guessing if you have a CAD draft you would need to input the commands manually. Is there any software that can look at a CAD file and calculate the commands needed by a CNC machine?

Thanks,
-Matt

Sparky_NY
01-22-2012, 08:20 AM
Even the older commercial cnc machines had a way to import files for machining. The most common way was a RS232 serial port on the machines controller, your drawing program outputs the code to the machine via a serial cable.

As for condition of a machine, there is a lot of things to look for, most no different than what you would look for in a manual machine. Way condition, spindle noises etc. It then becomes a matter of making sure the electronics works, best way is if the machine is still connected and can be demonstrated. Even if the electronics are not functional, the machine can still be retrofitted to new electronics. Next best approach is finding someone that knows what to look for to assist.

macona
01-31-2012, 03:29 AM
So your saying the befits of a commercial CNC out way the cost of the conversion?

What would I need to look for in the condition of the machine?

I've noticed in the machines we can afford that the controllers don't seem to have a way of importing commands. So I'm guessing if you have a CAD draft you would need to input the commands manually. Is there any software that can look at a CAD file and calculate the commands needed by a CNC machine?

Thanks,
-Matt

Don't take this the wrong way, but you don't know anything about CNC, do you?

You just can't take a drawing and enter it into a computer. You need cam software that allows you to create tool paths. These tool paths are turned into g-code which the machine runs. Old machines will have a couple different ways of getting data to them. Floppies or serial. Old, old machines have paper tape and you don't want to mess with anything that old.

Machines like old bridgeport Boss's will have a serial port and you "drip feed" the commands from the pc.

It is a waste of time and money to turn a manual machine into a cnc and it destroys the value of the manual machine. Spend the money on a working machine and sell the manual machine if need be.

MGBeaver
02-08-2012, 04:58 PM
Thanks Manona. I did some more research and found that out. I suspected as much already.

You say it's a waste of time and money to convert a machine. What are the advantages exactly? I'm guessing the commercial machine will be more accurate, but by how much? I know that it will be a pain to do the conversion and that we would loose manual control, but wouldn't it be possible to make a controller for the pc that would allow you to use manual control? My idea is building joystick type controller that has 3 wheels to control the axes and running it through a program that converts the signal to G-code.

We are also looking at what programs we can use. I'm up in the air about using Solidworks or Autocad plus a CAM program.

Sorry about all the stupid questions, but I'm trying to get a good idea of our options.

MGBeaver
02-08-2012, 06:11 PM
I think I posted this thread in the wrong forum. If a mod could move it to the right one I'd be grateful.

Thanks,
-Matt

George Bulliss
02-08-2012, 07:50 PM
I think I posted this thread in the wrong forum. If a mod could move it to the right one I'd be grateful.

Thanks,
-Matt

It's moved.

macona
02-08-2012, 08:32 PM
Thanks Manona. I did some more research and found that out. I suspected as much already.

You say it's a waste of time and money to convert a machine. What are the advantages exactly? I'm guessing the commercial machine will be more accurate, but by how much? I know that it will be a pain to do the conversion and that we would loose manual control, but wouldn't it be possible to make a controller for the pc that would allow you to use manual control? My idea is building joystick type controller that has 3 wheels to control the axes and running it through a program that converts the signal to G-code.

We are also looking at what programs we can use. I'm up in the air about using Solidworks or Autocad plus a CAM program.

Sorry about all the stupid questions, but I'm trying to get a good idea of our options.

First there is the time spent to do the retrofit. This means replacing the X and Y acme screws with ball screws and building motor mounts. Then there is the Z axis which you can do one of two way, motorize the knee or the quill. So you have to come up with a way to do that. Then you still have to do motors and controls.

After all this your converted machine will be worth less than it was before.

With an old machine with a dead control you, in general, just replace the motors and controls and are off and going.

Dont kid yourself about the manual control. Once you get used to using the control you will never go back to using manual control. You can enter commands via the MDI.

Joysticks suck for cnc machines. It just does not work well. Best thing is buttons and a MPG hand wheel. There are plugins for Mach3 that will allow you to use one, but they are not fun. There is a plug in that creates g-code from jogs as well.

I don't have a manual mill and don't miss not having one. A manual lathe is a different critter. That I have to have.

Software is going to depend on how much you have to spend. Solidworks is about $5k and so is Autocad. You might look at something cheaper like Cut2D or Cut3D.

Jim Shaper
02-08-2012, 08:57 PM
I still use my manual mill all the time and it's right next to my cnc.

MGBeaver
02-09-2012, 02:39 PM
Thanks George.

Now that's an idea I hadn't considered yet; taking a com CNC with broken controls or steppers and retrofitting new parts. Is there a simple controller that just has serial input from a pc? Something like this that was used on a retrofit: http://www.kelinginc.net/c10.pdf

I can see the need to keep a manual machine around, my boss is a bit of an oldtimer and I'm not sure he'd be happy with only digital input. Plus..there is a bit of a "feel" to manual machining. I can't easily explain it.

I'm a student, so I can get Solidworks and Autocad cheap.

macona
02-09-2012, 04:36 PM
That board is only for interfacing your drives to a pc's parallel port or other parallel port pinned motion control. And there is no real beast like you are talking about.

Basically, it is going to take getting a machine to know what your next step is. Depending on what ran the machine will determine what you need to do whether you get a machine that has steppers like a early boss or a later machine that has servos. Either way you will end up needing to replace either motors, drives, or both.

The manual feel thing is one excuse among many that machinists come up with as an excuse not to go cnc. There is basic science behind the cutters and if you do the math and follow the basic recommendations of the cutter's manufacturer you will be making chips and not guessing. With math you will have the proper chip load, surface speed, and everything else that will maximize your tool life.

Using a student edition in a situation like this will violate the licensing terms. CAD is only one part of the software equation. CAM is the other side.

MGBeaver
02-10-2012, 03:12 PM
Ok, then we'll have to know what we're working with. From everything said I've pretty much counted out doing the conversion. That leaves either buying a broken machine and fixing it or just buying a used machine. Is there and machines that I should avoid that have hard to find parts or other issues?

At this point I still see a use for the manual, but given time and experience with a CNC I may change my mind. My boss on the other hand will probably continue to prefer the manual. But only experience will tell.

I didn't know that, thanks. I'll look into the other software then.

macona
02-10-2012, 09:15 PM
Anything with a real control, that is not mach or emc, is worth looking at. There are a lot of local companies that still work on older machines. Its going to just depend on what is available locally.