2nd Build - Steel and Al 3'x5'

[Woodbutcher-59]

Hi Group,

Here's my new CNC Router project and it's my second build. I learned all I needed for the first one here on the Zone, so thanks to everyone for the new addiction, it's the best one I ever had.

Cutting area will be 3' x 5' with a 6" Z Axis. This size is as much as I can sacrifice in my garage shop.

It will be Steel and Aluminum, Steel Base Frame with 80/20 Extrusions and Alum Plate for the Router itself.

In the pictures, the red parts of the base are 3"x3"x 1/4" wall square tubing with some 1/4" plate for attaching to the 8020 at the four corners....I'll put some big shock absorbing leveling feet on the bottom of the legs.

The Router frame will be 15 series 3060 extrusion from 80/20 for the X axis rails, 5 pcs of 1530 for the table cross beams and a piece of 3/4" MDF for a sacrificial tabletop that will be on there most of the time.

I used 2 pcs of 10 series 2040 stacked vertically for the Y axis gantry beam. I did the beam this way mostly to get my slides for the y axis a bit farther apart. I plan on tying the two together so it acts as one solid beam. I'm thinking some sort of keyway kinda deal in the hollow where the extrusions meet to lock them together and then pouring the whole cavity with the 'key' full of epoxy of some sort. Maybe a TIG weld here and there first....

The gantry sides will be 1/2" aluminum plate and I'll do some cutouts to shave some weight off them...

All Three Axis will use Linear Rails and Blocks - THK in the Z axis and Bosch/Rexroth 20mm rails for the X and Y.

My Z Axis is a Linear Positioner by Robostar... 6" travel with Linear Rails and Ballscrew... 1:1 Belt Drive with a Nema 23 Stepper
It's all packaged in a hefty Alum. extrusion, even has limit switches built in ! Ebay score

For drive on the X (longest) axis and the Y axis I plan to use the Nema 23 R & P drives from CNCRouterparts.com and I will buy the 4 Axis Motor Kit with the Gecko G540 Driver from Ahren as well....and some rack clamps while I'm at it...

I've got the Y Drive on the backside of the gantry and 2 drives for the X axis under the tabletop mounted on what I call
the connector plate, which will be 3/8 aluminum with some cutouts for more weight removal....

I'll use Igus E-chain for wire management although it is not shown on my drawings.

For the Spindle I plan on a 2.2kw water cooled Chinese job and I'll go with the Hitachi X200 vfd. Thanks again to all you guys for the wisdom on this... I think I'll cool it with the 5 gal bucket and pump method.

Software will be Mach 3 and Vectric Aspire, which I already use. Check out Vectric if you have not already, Great Software !!

Well, with all that said, I'm starting this thread hoping to get opinions from you guys. Please pick it apart and give me the brutal reviews I know you're capable of.... And of course I'll take any good comments too....

Keep in mind the pictures don't show every little piece mostly cause my Sketchup talents are a bit limited,
but I am getting better at it.

I have started to gather parts, I've got the Z Axis and the Linear Rails for X and Y......and I hope to have enough $$$ to get this done by years end or so....it'll be painfully slow I think...

So what do ya think ????

Jeff

[CarveOne]

Looks like it's going to be a real nice machine design. Will be watching it come together.

I couldn't fit a 12' CNC machine in my work shop either - so I moved things around until it did fit.

CarveOne

[spoiledbrat]

At the base of your gantry walls, where they meet the plate, I recommend some triangular gussets for rigidity. As large as space allows.

I would not worry about weight for the gantry... it is duel driven. Plus, mass is class. I think most machines of this size, and driven with geckos, do not really suffer from too much weight when it comes to speed and acceleration. Trying to help you avoid chatter when making anything more than a light cut.

If you can manage to lose the pulley on the Z axis, you may be better off. Direct drive is stiffer.

Just my thoughts. I do like the design, and wish you luck getting it finished.

Rob

[gd.marsh]

I'll add a couple more suggestions to spoiledbrat's for gantry strength.

Perhaps lengthening the gantry sides below the bearing trucks would be a way to allow for some nice beefy gussets between the sides & the connector plate. With your double stack beam on top & some gussets at the bottom your aluminum sides should be plenty rigid in the Y axis.

Also, I would suggest that you make the width of the gantry side plates as wide as you can at the bottom .. Yes, it does require a little more length in the table to facilitate the cutting parameters you've set .. but with the investment you're already putting into this machine, it will be well worth it in the end.

The weakest link on most home built machines is the gantry. Racking shouldn't be a problem with a dual drive design .. but X & Y flexing could still be in your case under heavier use.

Edited: Looking at it again .. it seems as though you might be able to just add a piece of angle iron to the inside joint of the gantry sides & connector plate. 2X2X1/4 or possible 3X3X1/4 with maybe 4 or 6 bolts in each leg of the angle to spread out the clamping force and make the joint as solid as possible.

[Woodbutcher-59]

Thanks guys, For the kind remarks.....

Carveone, I spent the better part of 5 evenings reading your MASSIVE build
log...Was like a good novel...couldn't put it down...

I think I read in there you've got 30' x 40' for your shop ??
Nice.... Color me green !!
The only thing I could move to fit a 12' machine would be WALLS !!!
I've got a pretty complete shop stuffed into 15' x 22' with another 12' x 22"
for the overflow....Supposed to be for the wifes car....love ya honey...

Spoiledbrat, I agree on the gussets at the bottom of the gantry ends...I have had a few ideas like the pic below...
I feel encouraged by your confidence in the Gecko drive system and am not so worried about the gantry weight...Point taken on the mass...I am trying to get as chatter free as possible as it is one of the shortcomings of my current machine....I may even bump up the thickness of the gantry ends and the gussets to 3/4"... Nice and meaty to tap and bolt together. I have also considered filling the extrusions and the four legs of the base with something for dampening effect, anyone have thoughts on this ??

As for the belt on the Z axis, it is pretty stout and I hope will be as good as the belts on the X & Y Pinion drives...plus I dig the way the motor hangs on the right side This would be easy enough to change later if it does turn out to be less than ideal....couple of pics of the Z axis below...

gd.marsh...I also agree that the X axis blocks should be as far apart as possible...I've been playing around with between 8" and 12"....the pictures show 8" now...it's really a matter of how much I care to lose on the X travel...I already have the slides...66.5 inches long they are. A couple of lost inches is not gonna kill me.

As far as the joint at the gantry/connector plate....check out my idea for gussets below and I'm also thinking of making the connector plate thicker and put a dado in it for the gantry sides to fit into...with a bunch of bolts...I'll show this in a yet to be done drawing update...

Thanks again for the feedback.....Jeff

[spoiledbrat]

Your outside gussets will do the trick nicely. As far as the mass not being an issue, I may need to retract that. My first router is similar, but uses DC Servos, and ballscrew drive.

Would be nice if someone can step in and speak for the stepper motor/gearbox/pinion perspective.

3/4" will add some cost, but it is worth it. When thinking about all of these expensive components we fit into these machines, it is nice to invest a little more into the structure.

Making the lower gantry plate longer (spreading out the X axis bearing blocks) will certainly add rigidity to it. Since you are duel driven, we are not worried about racking in the X-Y plane. But this would prevent/minimize tilting and vibration in the X-Z plane. Disclaimer: I am calling the long axis the X axis!

So... get back to work! You will be happy with this machine in the end.

Rob

[Woodbutcher-59]

[QUOTE=spoiledbrat] Your outside gussets will do the trick nicely. As far as the mass not being an issue, I may need to retract that. My first router is similar, but uses DC Servos, and ballscrew drive.

Would be nice if someone can step in and speak for the stepper motor/gearbox/pinion perspective.

3/4" will add some cost, but it is worth it. When thinking about all of these expensive components we fit into these machines, it is nice to invest a little more into the structure.

I think even with the thicker plate I will still be well under 100 lbs. on the gantry weight, I need to estimate this a bit closer...and the cost is not a huge problem...hoping to get it done for around 4 grand...

Making the lower gantry plate longer (spreading out the X axis bearing blocks) will certainly add rigidity to it. Since you are duel driven, we are not worried about racking in the X-Y plane. But this would prevent/minimize tilting and vibration in the X-Z plane. Disclaimer: I am calling the long axis the X axis!

I'll be looking at this too, gotta decide what X travel I can live with. As it is, I'll be a few inches shy of 60" actual cut size. Not a big deal as my size requirement is derived more from available space in the shop, not an actual need for a certain capacity. And X is the long one to me too...

Thanks and stay tuned.....Jeff

[CarveOne]

Thanks for the compliment Jeff. It's much appreciated. Trials and tribulations throughout isn't it? I completely lost track of how much money I spent on the thing since the beginning of the build log. I don't regret one minute of it.

I've been thinking of an add-on to the rear of the work shop so I can put the CNC stuff all in one room and get back my work shop space. May never happen, but the thought is definitely there.

CarveOne

[spoiledbrat]

The hell with 100 lbs. Try to keep it below 200, and you should be just fine.

Also, my first CNC has 60" of X travel. I have only cut a part that big once... in 5 years. Design for your mainstay products/interests. If you see yourself making everything 5' long, then shoot for that. Otherwise, 60" is a useless number, and should not be a design factor at all.

I am currently building a new one, 5' x 10'. I will rarely cut anything longer than 4'. But I would like the ability to stack up a lot of product on the table at once (32 products, rather than 8), so that is what drove me to go bigger.

In the first 3 years with your machine, your CAD/CAM skills will grow exponentially. You will also learn a lot about machine operation, and come up with very creative ways to get your ideas published in 3D. And you will collect ideas of what you want to put into your next build.

My advice is to look at this as your starter machine, and design for approximately 52" of travel. You could then have a few years using it to determine what you really want to get into later. I think most of us around here end up making a second machine.

Good luck!

Rob

[Woodbutcher-59]

Rob,

I'm thinking you may have missed the title of this thread....This IS going to be my second machine build.

I've been into this for about 3 years (good guess) and you are correct,
the knowledge does grow quickly as one goes along. I feel I have a pretty good grasp on the software side, I'll try and posts some project pictures
as time allows.

This build will be to correct some deficiencies in my first machine, and I figured while I'm at it, might as well be as big as I can fit in the shop.
I should get a solid 36" Y travel and around 55" X travel, which is just fine.
Like you said, I think most of the room will get used for multiple parts more often than LARGE parts. I am hoping this will be the last machine I'll need, but we all know how that works out.

After all, we have Carveone for inspiration and if he can add to his shop
then so can I, right Dear ??? Honey ???

Anyways, thanks for reading...

Jeff

[Woodbutcher-59]

Ok,

I made a couple of changes based on everyones comments...I bumped up the thickness of the gantry ends and the bottom connector plate to 3/4".

I added the gussets to the connector/gantry joint and also the dado in the connector plate. The gussets will be 3/4" and bolted in place, I just didn't draw all the bolts yet....

I also beefed up the top mount for the Z axis which also mounts the R&P drive on the back of the gantry. Then I moved the pivot point of the drive down a bit so the whole thing is closer to parallel with the rack itself. It just seems to me like it should be that way....

And I changed the spacing of the X axis linear blocks from 8" to 10"...I may still play with this more as I refine the design of the gantry end plates.

Here's a few pictures....

Jeff

[spoiledbrat]

Looking great!

I think that the dado in the bottom connecting plate should only be 0.100" deep. Deeper does nothing for you, only making assembly more difficult, and weakening the bottom plate (that the gussets are bolted to).

The extra 2" spacing on those bearing blocks is a good change.

Rob