[heavycnc]

I'm in the process of making a cnc table. It'll have a cutting surface of 6' x 11'. Since I work in the metal industry, I find good deals on large heavy pieces of steel. My bottom beam will be made from 10" I-beam and have 6" I-beams running across the table. The top plate will be 1/4" thick. It's all heavy steel but that's the point. I'm trying to avoid the table from flexing even a little bit. I know the characteristics of metal very well. It doesn't take much welding for metal to start warping on you. I wish I had a nice CAD design to share the final design but I don't have the time or skills to make something decent and more importantly, understandable. I'm planning for my cnc table to be multipurpose. It'll be designed so that the head can be interchanged with different cutting components. I plan to make attachments for routers, plasma, engraver and and let's see what else I can come up with. There will be more to follow as I progress.

[Woodbutcher-59]

Hi Heavy....

We don't need no stinkin' CAD drawings, just lots of photos !!!

Sounds like a cool build.

Jeff

[spoiledbrat]

Heavy,

Download a copy of Rhino3D, and start drawing. Although you can program manually, you will, at some point, rely on your CAD to make the GCode. Also, your machine will have multiple parts bolting into it (bearings, drive mechanism, etc.) I have a hard time imagining building a machine like that without CAD. Sounds old school.
Heavy sounds good... mass is class.

Good luck on your build!


Rob

[mactec54]

heavycnc

As I said in my build, the base of the machine is the most important part to get right, so mass is good, you will have a great machine

spoiledbrat Glad you have some free time to look at the Zone, still at 10,000 feet

[heavycnc]

In the picture below I layed out the 6" I-beam to get a sense of how big and how much space the cnc table was going to require.

[heavycnc]

There are a few things to notice in this picture. I'm showing the 10" I-beams sitting on top of the the 6" I-beams. The table is actually upside down the way it's layed out. The 5" pipe sitting on the 10" I-beam is one of six leg posts which will also have a leg leveler added.

[heavycnc]

I made some custom leg levelers since I didn't like anything I was finding locally or on the net. The solutions was to buy some lower ball joints made for a 2003 Ford crown victoria and make a few modifications. The process to make these leg levelers was very time consuming but they are heavyduty and overkill, just the way I like it.

[heavycnc]

Hi Jeff,

I'll keeping adding pics as I do something worth taking a picture of. It almost feels like CNC Porn, lol

Heavycnc

[heavycnc]

Hi Rob,

When I first learned about cnczone I studied lots of people's designs. I almost was going to start my build until I ran into your thread. What an awesome machine. I had to scrap my plans and think big. So your machine had a big influence on my design. Thanks for posting it.

I'm looking into Rhino3D


Heavycnc

[heavycnc]

Hi Mactec,

I figured using heavy steel solves and avoids problems with straightness and strength. Considering how much time and money is involved with a project of this size, it's not a bad investment to add heavier steel.

Your build is coming out really nice, almost too nice, lol

Heavycnc

[giz]

Saw that you are using the DMM servos. I'll be looking forward to experience with those.

[heavycnc]

Hi Giz

My biggest concern with starting this project was the electronics part. I have no issues with making the table, installing the servo motors, running the wires and fine tuning the gears. The part where I was clueless was how was I going to make my computer run the servos. After lots of research and some luck I run into a system sold by DMM Technology. Then I saw a cnc router running with DMM AC Servo motors and I was sold. I bought it, prewired all of it together outside the case and made it run. At that moment I knew this project was as good as done. It's as close to plug and play as you're going to get.

Heavycnc

[1234567]

Im just starting my machine bulid too.What are you going to use for ball screws?And how many oz motors are you going to use

[wcarrothers1]

Like the crown vic ball joint /foot idea that is very inovative..

Will be curous as well with the dmm servos. Wondering if they will have enough mussle for what I'm guessing will also be a heavy weight gantry? Guess that all depends on how you gear them

b.

[heavycnc]

Hi 1234567,

I'll be using a rack and pinion setup for the X & Y axis and for the Z axis I"ll be using a ball screw with an anti-backlash nut. For my servo setup I bought a

Peak 7.2Nm(1015 OZ-In) high torque AC servo motor, 3 Axis CNC kit
- 3 x Peak 7.2Nm(1015 Oz-In), rated 2.9Nm(408 Oz-In), Peak power 900W, AC servo motors


heavycnc

[heavycnc]

How do I calculate IPM?

My motors rpm is 1000
gearbox will have a 10:1 ratio
So what size pinion do I need to achieve 1000ipm?

[lgalla]

At 100 rpm you need 10"travel per revolution for 1000 ipm
Pinion diameter would be 10/pi=3.18"
Larry

[jsheerin]

And you would have resolution of 0.0006", and accuracy in the 0.0024" range if you're using the 14bit absolute encoder.

[heavycnc]

Thanks Igalla for the math equation, seem obvious now that you explained it.

[heavycnc]

Hi Jsheerin,

What ipm do I need to achieve .001 accuracy? Can you please include the formula

Thanks,
Heavycnc