Newbie- My first CNC machine - Build

[clocksandblocks]

Hey there every one! I'm new around here but I thought I would share some info about my first CNC router build. I have learned a lot from reading posts here so hopefully I can contribute in some small way.

I'm not an engineer from a background standpoint, I'm actually a finance manager at a car dealership. On my days off however I LOVE to tinker in the garage. I have a small milling machine and a mini lathe from harbor freight that are well loved and well used, but after seeing my cousins CNC router he built from scavenged parts I decided I HAD to have one, so here I am!

This router is designed from the ground up by myself and will be built mostly from steel, with a little aluminum and wood thrown in for the Z axis and the cutting table surface. Here is a picture of the CAD drawing I made for the machine:

As you can see I am using thompson style bearings and shafts and 16mm ballscrews for linear motion. The motors and drivers are the "green monster" from Probotix and the spindle will be a 2hp Dewalt router.

In the above image you can see my Z axis finished. The rails and bearings are 16mm and I'm using a Lovejoy coupler to connect the 1/4" motor shaft to the 1/2" shaft on the ballscrew. (I turned the ends of the ballscrews down from 16mm to half an inch on my mini lathe. Note to self - turning hardend steel ballscrews on a mini lathe is a major pain in the butt!)

Here is the big pile of steel that will make up the bulk of the router! Most of it is 1/4" and 1/8" thick wall tubing and angle iron depending on where its going and what it is doing.

Here you can see my Gantry done! The project really is moving right along. The long rails are also 16mm in diameter just like on the Z axis. There will be 33" of effective cutting area on this machine.

Here you can see how the ballnut connects the the Z axis to move it side to side. All these parts where cut free hand on my milling machine and bandsaw. I can't wait to be able to use the router on stuff like this!

That is as far as I have gotten, next up is building the base and the CNC controller box!

-Jerome

[Jesse B]

That's looking fantastic so far! What are you planning on cutting with it? Those rails aren't overly thick, so if you're cutting hard materials, with that type of length you might get a bit more deflection than would be ideal. If you're just sticking to wood and plastic it should be fine, however. Just letting you know.

[clocksandblocks]

Thank you! I'm mostly going to be cutting wood and lexan with it, but i'm planning on some aluminum as well. Each rail is supported fairly well by the 2" wide, 1/4" thick steel angle iron that makes up the length of the gantry. A picture is worth a thousand words so here you go:

The whole assembly feels VERY rigid (if a little heavy) so hopefully it will not flex to much =) the rails that the gantry will rid on are not shown yet, and they are 20mm in diameter to help keep them from flexing. After gettting all the rails in the mail I wish I would have gotten 20mm for everything but since I already have these I hope they will work! =)

-Jerome

[Jesse B]

Oh, those are supported rails. Those small images were a bit hard for my eyes to see that. Should work fine then

[RomanLini]

Looks pretty good so far!

Just a tip with turning the ends of the ballscrews, if you grind them with an angle grinder you can chew through the hardened outer layer in a few seconds, then your mini lathe will have an easy job with the soft core.

I clamped the angle grinder in a vice, then held the ballscrews in hand and rotated them as the grinder took off the outer "screw" part, about 5/8 inch on each end. It was easy and neat, well neat enough.

[clocksandblocks]

You know, I have both a bench grinder and a 12" disc sander that probably would have worked great for doing that! Getting through the threaded part of the ballswcrew was the hardest part, once I had that turned down is was smooth sailing from there on out! I only have one ballscrew left to do but I may try that to save some of my lathe cutter inserts from the garbage can!

Tommorow is my day off so another long build day on the router awaits!

-Jerome

[RomanLini]

Angle grinder will be quicker, unless your bench grinder is a big one. Looking forward to seeing more build pictures.

[clocksandblocks]

I think just about anything would be faster than taking the threads off with the lathe!

On another note I worked for several hours yesterday on the machine. First thing I had to do was make an area for the completed machine since I didn't have a work bench big enough to hold it! The picture below shows the addition to my work bench.

After I got my work bench modified I started to cut the steel that will make up the base of the machine. The rails running from front to back are 1/4" thick by 3" wide angle iron (HEAVY stuff!) the the front and back rails are 3" x 1" x .125" wall steel tubing (Pretty heavy, but not as heavy as the angle!) In the picture below you can also see I placed the Gantry in the frame to make sure everything is coming out correctly. You can also see the a can of Mt Dew (The official drink of my garage!) in the front corner to show scale. Its funny how much bigger stuff feels in real life compared to on a computer screen in my Cad program! More to come.

[Jesse B]

Looks good. Finally starting to take shape!

[rcbamm]

Man that machine is looking nice!

Where did you get your supported rails? I just ordered 6 supported SBR16 rails from this ebay store > http://stores.ebay.com/linearmotionbearings. I got two 1400mm, two 880mm, and two 380mm SBR16 rails with 12 bearing blocks for $326 shipped. Looks like your 16mm rails are the same thing I ordered. I'm building a CNC machine to cut mostly foam, and wood. Although I came to a thought the other day, "you know, it might be nice to cut aluminum too!" so I'm still trying to figure out what I'm gonna do to connect the x,y,z axis to the steppers. I ordered the probotix probostep 3 axis kit for the drive setup, but I'm trying to choose if I need ballscrews, or if belts will do just fine for the kind of cutting I will be doing.

[clocksandblocks]

That is the same ebay store I got my stuff from, I was very impressed with their service and the bearings and ballscrews are great for the price! I got both 16mm and 20mm rails from them and 16mm ballscrews. (Which have
VERY little, if any backlash)

The Green Monster Probotix set up I got seems top notch, I even got the relay board so I can turn my spindle and dust managment system on and off with my G-code =)

I would go for a machine that can cut as many things as possible, then you won't have to build another one for a while!

-Jerome

[rcbamm]

So I guess when one of Chai's ebay listing say "end machinings" on the ballscrews that means the ends of the ballscrews are machined to fit the bearing block? (reading that you machined your ends) I wanted to get a whole package of SBR16 rails and ballscrews but I'm lost as to what to buy from him. His desctription of the ballscrews is to vague, and I tried asking if if he knew what I could possibley use for my CNC table and he said he didn't know.

Probably for around the price as buying 3 ballscrews for my x,y,z axis plus shipping, I can get enough timing belt and pulleys to drive both right and left slides of my x axis and all the other slides. I think I'm still gonna go with belts..