[Cheeseduck]

My first CNC was a mess, so I've decided to build another. I made an earlier advice asking for advice and got a number of great responses (http://www.cnczone.com/forums/diy_cn...ign_start.html); I've since begun its construction.
As a high school student, I don't have too much engineering and machining experience (or cash, for that matter). If you have any suggestions, I'd love to hear them.
With any luck, the final product should look a bit like this.

[Cheeseduck]

(Most of the parts have already been cut out/machined, so this build should hopefully go fast)
The base came together quickly thanks to sheet metal screws (I'm not sure if they were ever meant to go through 1/8" thick steel, but it happened nonetheless ). It, in a nutshell, is made out of two sections of 1.5" (1/8" thick) tubular steel with a slab of 3/4" plywood bolted on top.

[Cheeseduck]

I also began assembling the gantry of the machine. My homemade bearings worked out surprisingly well!

[Cheeseduck]

The legs of my machine got put on next along with a few 2x4 reinforcements on the underside of the bed. A few (unshown) braces were also added to stabilize the legs.
I might add two extra legs to the center of the machine later on.

[Cheeseduck]

I completed the carriage next and installed it on the gantry. I also stuck the (incomplete) Z axis on it.



The bearings look a bit on the tight side; should I keep them like that, or loosen them up a bit to prevent fatigue?

[Cheeseduck]

I got a bit of work done on the gantry and added its side panels along with a second set of bearings along the bottom.


I also encountered my first major problem; after an unsuccessful fight with a harbor freight drill press (I sadly don't own a lathe yet), I've managed to bore both of the gantry AT5 pulleys off center. The only solution that I can think of is to get two more bored to the right size from Misumi, but that'll cost me another $50. Either that, or I get two more 0.25" bore pulleys from Econobelt and try to find someone with a lathe to do the job right.

[pippin88]

It's looking pretty decent.

Haven't you reduced your Y axis travel a lot by having the stepper mounted in board like that?

[Cheeseduck]

Yep, I did lose 2 1/2 inches from that decision. I have 23" of travel, though, so I can still work well with 2x4 sheets (which was its main purpose).

[Devastator]

Yep, I did lose 2 1/2 inches from that decision. I have 23" of travel, though, so I can still work well with 2x4 sheets (which was its main purpose).

Putting it out-board would only take some longer screws and stand-offs. Definitely worth it if you can pick up 2 1/2" on the Y travel. That's an extra 120 square inches of cutting area for your machine and you can use all of that 2'X4' sheet and a bit to spare. And it will look better engineered.

[Cheeseduck]

@Devastator: I can't change my design now since all of my parts are already cut, but I think that fix will be my first cut when I finish this!
I've added the first belt to the gantry, and added the 4 belt holders for the belts that move the gantry itself. I've also added all of the drivers, and hooked up the X axis. The X axis now has movement (!), but is pretty noisy since not all of the bearings have contact; I'll have to tram it soon. The Z axis nut is also in place. All I need now are the two gantry pulleys and a shaft coupler to get my machine fully operational.
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Oh, and one last question: My belts are steel reinforced Brecoflex 16mm AT5 belts. How much can I tension these?

[pippin88]

Looks like it's coming together nicely

I'm interested as to why you chose to put the stepper drivers at the stepper? My thinking it's that it adds weight and exposes the driver to a harsher environment / risk of damage compared with having the drivers in a case and running cable to the steppers.

[jckstrthmghty]

Perhaps at the time is seems easier to wire up the stepper but in the end you have to run wires to the bob. Centralizing the electronics in one location in a protective box is the way to go.

Very cool build.

Looks like it's coming together nicely

I'm interested as to why you chose to put the stepper drivers at the stepper? My thinking it's that it adds weight and exposes the driver to a harsher environment / risk of damage compared with having the drivers in a case and running cable to the steppers.

[kennl]

Nice build, like the bearing trolley design you used. Been puzzling over this one for awhile, need to change out my x axis rails and bearings for something easier, stiffer and adjustable. This maybe exactly what I'm looking for. Hate to spend money on a ready made solution.

Keep up the good work :cheers:

[Cheeseduck]

Alright, I'll find an old box or something similar and put the electronics in that. Watching a $42 driver shake itself to pieces doesn't sound like fun to me.
On a bright note, I finally received my $3 chinese shaft coupler in the mail and finished up the Z axis. It is slow since it uses allthread, but ACME is on my list of future addons.



On a not-so-bright-but-expected note, my router screams like a banshee at full speed. My neighbors will not be happy with this.

[Cheeseduck]

I finally got my pulleys bored out and installed. In addition, I got most of my electronics bundled up on a separate board and hooked them up to all of the axis. I then battled my way through hundreds of bugs and small fixes to cut out new belt holders since my old ones were rather flexible. I guess that they could be considered my first cut! I then installed homing and limit switches along with a cardboard estop and added a shelf to hold it all. Although fully functional at this point, my machine still needs some form of workholding and cable management. I've been thinking of embedding Tee nuts around the perimeter of my table since T-slot is too expensive for me and hanging my cables off of a piece of spring steel. Any suggestions?
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