CNC Router vs 3D Printer

[magnets]

The 4' x 8' was a shopbot, although I don't know the model number off the top of my head. They don't sell it any more but the replacement was this.

http://www.shopbottools.com/mProducts/prSalpha.htm

I know that when we bought it, the list price was under 15k, and somehow we managed to get it for less. We also went for the spindle instead of the router because we cut aluminum a lot. It's used in all the tech classes in our school, including the electric vehicle class, where it makes the body panels for the cars.

It's the best purchase our team has ever made, and we're really happy with the results. By the end of build season, we have freshmen who have never heard of CNC before who have learned how to operate the thing by themselves.

[techhelpbb]

Originally Posted by magnets

The 4' x 8' was a shopbot

I've used plenty of ShopBots they are great machines to have.
Just my two cents.

[IanW]

Everyone has brought up good points, so I'll try to address some of the major ones.

Originally Posted by Ian Curtis

What is the problem with using school equipment for your own projects? I would think most schools would be ecstatic to have students doing cool stuff with their machinery.

I'm actually not sure what the policy is at my school (OSU). I will look into it, but I would feel guilty if a personal project got in the way of senior design or class projects.

Originally Posted by Akash Rastogi

What kind of projects do you expect to be working on while you finish up school?

For the projects I currently have in mind, I think a 3D printer may actually be more useful. The few I have been considering would not experience heavy loads that require aluminum plate or anything of that nature. It would certainly be cool, but not necessary.

As I mentioned, I had some exposure to 3D printed parts in FRC, was pleased with the results, and was intrigued by the possibilities. It isn't based on hearing some online hype. Again, using it for FRC is not the primary purpose, merely an added benefit. I came here to draw upon the community's general treasure trove of knowledge.
I should have made it clearer, but I was in part asking whether the parts produced from a low to mid-range consumer printer would be at all comparable to the high end consumer printer (uPrint SE) that I have experience with.

For those suggesting to get a router, did you look at the system I spec'd out in the excel document attached to the OP? Assuming I was able to solve the issue of where to keep it, would you suggest any other parts or improvements? Or even a different system entirely?

[techhelpbb]

Originally Posted by IanW

For those suggesting to get a router, did you look at the system I spec'd out in the excel document attached to the OP? Assuming I was able to solve the issue of where to keep it, would you suggest any other parts or improvements? Or even a different system entirely?

Frankly I suggest the 3D printer if that's what you want.
Just be prepared it will be obsolete before you blink.

However I have the following concerns about your spreadsheet:

1. What does the first choice use for the stepper controller / driver?
The Gecko is an excellent product I would recommend it.
It is already in the second choice you present.

2. Do the electronics kits include the power supplies?
If not budget for that as well.

Both of these kits (the first I have actually assembled before for someone) are ACME screw kits.
They have power loss in the screws and no provision to gear them (direct shaft coupled).
Their rapids are listed unloaded. In short you won't move anywhere near that fast while doing any operation.
These are more targeted for engraving on aluminum and working softer materials like wood.
You could work on aluminum with this but very slowly.
Neither system includes the coolant you might want for working aluminum.
You could retrofit this into a 3D printer but the Z axis depth might be a limit to consider.

Neither system includes any kind of dust collection or enclosure.

[Rohawk1]

Originally Posted by IanW

I should have made it clearer, but I was in part asking whether the parts produced from a low to mid-range consumer printer would be at all comparable to the high end consumer printer (uPrint SE) that I have experience with.

Are you looking for the same print quality? And what are your limitations on build space? I have the privilege to be an intern at the Manufacturing Demonstration Facility, a part of Oak Ridge National Laboratory, in which I mainly work with a variety of consumer printers. We have two uPrints, and the quality is amazing, but I have found that the Afinia printer can have almost equally amazing print quality and it is below your range in price. Although, the build space is only 5x5x5 in, so it depends on what you are working on. As far as structure goes, I have been using HIPS, or High-Impact Polystyrene, with the Afinia for a while now and it works great. It isn't Ultem, but I think it is an upgrade from ABS. It takes minimal tinkering, and fits very well in a dorm room. Also, I have quite a bit of experience with the Makerbots and the Solidoodle 3rd gens, so if you have any questions, feel free to ask.

[JamesCH95]

Speaking as someone who has used a CNC router table to do MIG welding development... it's not a very good idea. The arc root can jump around, the material is laid down in a non-uniform profile, and there isn't much of a practical way to make 'filler' to support cantilevered features. Weld beads simply aren't consistent enough to get a decent part or hit any meaningful tolerance.

Robotic welding is used quite a bit in industry, in very but "not 3D welder printing."

As other's mentioned, printing in metal means SLS or another comparable process using powdered metal. Though this area is ripe for innovation...