Project 1 from EmptyNester. Category: Custom Shop Tools - CNC Table

[EmptyNester]

After using my PP50, I found that my hand isn't nearly as smooth or coordinated as I'd like. So, I'd like to build a CNC table.

Having mostly finisihed the Hovercraft project after a year and a half - I wanted to do something that would be quicker. But, almost any project would be quicker than that!

My goal is to do the project for as little money as possible since this is more of a toy than a needed tool. And, to limit initial cash outlay, I wanted to do the project in stages so that I wouldn't have to sink too much money in all at once.

In my work life, I write embedded control software (currently for medical devices), so I'm comfortable with the electronics and software side of the project. I figured I could save the most money on the drive control if I went the E-bay route and I'm fairly confident that if the parts are functional, I'll be able to get them to work.

I have about 8 hours in on the electronics and 8 hours in on the table (just started this week).

I got a four axis drive kit Wantai Motor with:

• (4) Nema 23 428 oz dual shaft motors
• (4) 4.2 ampp stepper controllers
• (2) 36 vokt, 350 watt power supplies
• (1) breakout board
• (1) parallel cable

I didn't necessarily want the dual shaft motors since I don't plan on adding encoders, but this kit shipped from a US warehouse. So, I went with this for $406.

The first thing I did was to do a quick/temporary wiring job to make sure all the components worked. Using the demo version of Mach, I could spin all the motors, so I figured that was good enough to continue with the project. With that done, I picked up my steel on Monday.

I'll post the drawing I did for my table when I get a chance (it's in Visio and I only have that at work).

I'll post pictures and prices since I'm trying to build a "hobby level table" at "garage project prices".

I'll go into more detail on the electronics side, since that information is harder to find when you try to do research on the internet.

[Rambozo]

There is a free Visio viewer you can use. I use Visio all the time for quick drawings. However, with each new version it seems to be moving more and more away from technical drawings. Back from before Microsoft bought it and the was a specific technical edition.

[posixPilot]

Google sketch up is a good alternative to Visio for this type of drawing, since does dimensional material do well (I.e. lumber, tube, etc.). And it's free to boot!

Cheers
Mike

[EmptyNester]

I now have the table put together and right side up. I still have to weld what was on the under side.

This is only my second big welding project, my welding skill is progressing but I really have a problem with consistency.



I'm planning on putting 2" angle around the cutting area so that I can get up to 4" depth for the water table. I have 3" flat stock I'll use for the supports and just put it in notches I'll cut in the angle.

I'm planning on puttiing heavy duty casters on with a leveling foot with each one. That way I can move the table around without help and still be able to get it stationary and level. I kept it low to the ground so I wouldn't have to lift metal as high to get it on the table.

I'm not sure if I'll need to add support in the middle. The inner dimensions of the table are 52" x 76". I expect to lose a couple inches due to carriage dimentions. I assuming I'll have about 50" by 70".

Rege

[EmptyNester]

I got my carriage kit from Precision Plasma ($325). I originally saw it on EBay, but then went to his web site to find out more.

I liked the iPlasma tables he had, but buying a pre-built table wasn't in the budget.

The kit contained the carriage plates and all the bearing and hardware necessary, as well as plans for a portable cutter (just carriage rails, no table).



Two of the completed carriages are below, one X and one Y.



Based on the plans that came with the carriage kit, and a discussion with Ron at Precision Plasma, I went with 14 ga 2" square tube for the table and 16 ga 2" stainless for the gantry.

[acourtjester]

Great start empty
I built a table my self and it was a great project, there is tons of info on the web about CNC tables you may look at CNCzone for one. One thing you need to remember is the size of your water table and the volume of water it will hold and its weight.
Look under hobbyist projects you will find mine (DIY CNC table plasma cutter) and seanMurphy256 posts about builds. PM if you have any questions I will see if I can help.

Have fun
Tom

[EmptyNester]

Great start empty
One thing you need to remember is the size of your water table and the volume of water it will hold and its weight.

Tom,

I have seen Sean's, but I'll take a look at yours.

Is there some specific concern about structure and weight of the water? The water weight should be about 400 lbs.

Thanks,
Rege

[acourtjester]

Just the added weight of the water and the tank needs to be considered when building the table frame. The size of the legs, cross bracing for stability and depth of the water. So guys put chemicals in the water to keep the funk down.

Have fun
tom

[EmptyNester]

Here's the layout for my table. I based this on other tables I had seen and trying to maximize size for materials. I also wanted to not overbuild it so that I could still move it around and handle it while building. (Since this is my first major steel project, I figured the table may be replaced quickly as I learn more. The stainless rails and carriages are the bigger investment and can be reused, if necessary.)

I only have the table about 2' high on purpose. I knew I'd have to lift any steel I want to cut from floor height, so I wanted to minimize the lift distance.



Based on recommendations from Ron at Precision Plasma (where I got my carriages) - I'm using 14 ga 2"x2" steel tube for the table and 16 ga 2"x2" stainless tube for the gantry.

The table used:
(2) 2"x2"x24' hot rool
(1) 2"x2"x20' stainless
(1) 2"x2"x1/8" angle (used for the bottom braces between the legs)
(1) 2"x1/8"x20' flat bar
(1) 1 1/2" x 1 1/2" x 1/8" angle
(1) 5' x 8' x 14 ga sheet
(3) 3" x 1/8" flat bar (for support slats)

The flat bar iswelded to the under side of the 2" sq table with 1" protuding toward the center. This gives me a good surface to weld a 14ga steel sheet to for the bottom of the water table.


Table Cutting List - (2) 14 ga 2"x2" square tube
Feet - Inches
6 - 4 table side
6 - 4 table side
6 - 10 center support
2 - 3 mid table support
2 - 0 leg
Total 23 - 9

2 - 3 mid table support
2 - 3 mid table support
2 - 3 mid table support
5 - 4 long end
5 - 0 short end
2 - 0 leg
2 - 0 leg
2 - 0 leg
Total 23 - 1

Leg brace cutting list - (1) 2" x 2" x 1/8 angle
Feet - Inches
6 - 6 table length brace
6 - 6 table length brace
5 - 0 table width brace
5 - 0 table width brace
Total 23 - 0

I also reinforced the corners of the cutting table with 28 1/2" pieces at a 45 degree angle underneath the table on each corner. I used 1 1/2" angle for that.

Corner Brace cutting list - (1) 1 1/2" x 1 1/2" x 1/8 angle
Feet - Inches
2 - 4 corner brace on the bottom of the cutting table
2 - 4 corner brace on the bottom of the cutting table
2 - 4 corner brace on the bottom of the cutting table
2 - 4 corner brace on the bottom of the cutting table
Total 9 - 4


I have basic construction done and have already "learned a lot" (code for "messed it up"). I post some pictures later.

[sportbike]

Looking good Nest.

I assume you are going with a gear rack drive for both axis?

What was the cost of teh gantry kit parts? Looks like a pretty nice package.

[EmptyNester]

Thanks.

I did get gear racks for both axis.

The gantry kit was $325. In hindsight, it seems a little steep and I may have gone other directions since I've learned more.

I've had a couple issues with the basic table construction. The first was the inconsistancy of my welds. It took me a while to figure it out, but it turns out that if I'm not sitting or standing upright with a good brace for my hand, my welds suck. But, it's a learning project.

The other problem I've had is that when I put the 2" flat bar on the bottom of the 2" square tube, it cause the tube to bow up (away from the welded side) by 3/4" to and 1" in the middle of the tube. I'm planning on putting a piece of angle on the top of the tube to extend the depth of the water table and to hold the slats. I'm hoping that welding that on will help reduce the bow.

[EmptyNester]

Here's the table as its current state in the garage.



I've been going back and forth on how much support is enough for the water table. After talking to my brother in law (long time fitter) and my daughter (materials science engineer doing her post junior year internship in a metalurgy failure analysis lab) - they both think I'll have sufficient support.

The urge is to to support the table bottom more, but with water 3" deep there will be about 400 pounds of water. That's less than 1 pound per square inch. My reasoning (right or wrong) is that the table to leg weld it more of a concern for stress failures than the sheet that is the table bottom.

I'm willing to take a chance. That's the fun part - it's never interesting without the chance of a dramatic failure!

[EmptyNester]

I finished construction of the basic table. I haven't done the mounts for the rails yet.

It has both wheel and anti-vibration feet on it. This will let me move it around the garage by myself. It's worked well for moving it in and out of the garage.

This picture is while I was draining the table after the water test. Unfortunately, I have some work to do on fixing leaks.



What was interesting is the two leaks in the photo below. If you look closely, where the arrows are pointing, you can see a gap in the heat affected zone. This is just where the leaks are.



For the drain I just used a 1/2" black pipe coupling on the bottom of the water pan and threaded a ball valve on it.

[zoama]

For the drain I just used a 1/2" black pipe coupling on the bottom of the water pan and threaded a ball valve on it.

May as well put a garden hose adapter on it http://www.amazon.com/Anderson-Metal...094267-8385652 (link is only for illustration)
You could fill it the same way... slowly with no fountain.

[SeanMurphy265]

I would add some support in the middle, but if you not cutting over 1/4" it will probably work fine.

[EmptyNester]

I would add some support in the middle, but if you not cutting over 1/4" it will probably work fine.

I probably won't be doing anything heavy. (I just wouldnt' be able to lift it.) I'm planning on more decorative/artsy stuff.

If you look at post #12 you can see the cross pieces I put in. Would you put in support in addition to that for heaver work?

[EmptyNester]

Zoama,

You've become my idea man! That would work out well for filling and draining.

(I just got the mandrel for my hovercraft muffler. That's was another great idea from you. - Thanks)

[Rambozo]

That is so not what I meant when I said I wanted a pool table.

[EmptyNester]

That is so not what I meant when I said I wanted a pool table.

Unfortunately, its a little leaky as pools go. I went through one round of patching holes but still have some left.

I probably shouldn't have painted it until after I tested. Now I'm not sure how I'll get the paint out of the corner that needs "patched".

[ShaneJackson]

Just get some of that liquid rubber spay they sell on TV. It will fix anything.