5' x 5' CNC Router Build

[Darren Wright]

I've been collecting parts over the years and I think I'm ready to start a new cnc table this spring, still working on the exact design since it will be based on the equipment I have collected.

The rails and screws I recently ordered are 1500mm long, so just under 5', so the usable area will be more in the 4' x 4' range. I'm planning to use a ball screw on each side of the Y axis (table length) and one on the X axis (gantry width).

I really like the Legacy brand of CNCs which accommodate the 4th axis sunk into the bed area of the cnc and usually an adjustable end section for doing dovetails and such on, such as this...


I just can't afford their machine.

I'm thinking I'd like to have a removable bed section to fill in where the 4th axis is, when not in use.

I'm planning for a steel frame, but may go with aluminum plate/extrusion for the gantry parts. Though I do have a plasma cutter, so could cut some parts out using templates.

The stepper motors will probably come from the current cnc, which are Nema 23's 425 oz/in, but I'm open to feedback on if these seem too small.

I'm looking at a water cooled VFD controlled spindle, probably in the 2.2Kw range. Again, would like to hear of experiences with this size of spindle.

Running it on my current copy of Mach3. Probably will go with a usb controller, but may spring for the ethernet connected one.

 

[Brent Dowell]

 

[Don Baer]

The stepper motors will probably come from the current cnc, which are Nema 23's 425 oz/in, but I'm open to feedback on if these seem too small.

I am having the same debate..... The CNC Routerparts web site states that a Nema 23 motor is what you need for 250 IPM cutting and 500 Rapid and states that a Nema 34 is needed for a 500 IPM cutting and a 1000 IPM rapid. I don't plan on during heavy routing and 500 IPM is like 8 inches per second rapid that mean I could got from side to side (48") in under 6 second in the rapid mode. Most cutting is done at slower speed. Of course this machine is rack and pinion not ball screw. The other side of the coin a full for axis stepper motors and driver on Amazon is less than $750 .https://www.amazon.com/Nema34-Stepp...4+axis+cnc+kit+nema+34&qid=1577837382&sr=8-37
(there goes my 3D printer budget).
decisions decisions

 

[Darren Wright]

Yeah, a lot of it will have to do with the weight of the new gantry. I will be using two Y axis motors rather than one, so that will compensate for some of it, but the z axis carriage will be a bit heavier too, so may have to upgrade the X axis motor at least.

I'll also be going from acme thread to ball screws too, so hoping the 425 oz/in will suffice.

 

[Leo Voisine]

At one time I was thinking about buying the CNC routerparts 48 x 48 machine with the NEMA 34 Pro package.

What I ended up with is the Chinese machine that I currently have. No Regrets at all.

I have the rack and pinion X-Y axis and a real ball screw on the Z axis with Nema 34 on all 4 axis's The Y axis has 2 NEMA 34 steppers to drive the gantry.

Glad to have it. Glad to have it.

My 24 x 24 machine started with smaller NEMA 23's but I upgraded them to NEMA 23's in the 400-500 oz-in range. It had lead screws all 3 axis's. It worked OK but I would not want to outfit my larger machine that way.

Carol landed on NEMA 34. I have not seen a serious machine in that size range with NEMA 23. My friend Ted home built a 48 x 24 machine with NEMA 23 and he said it's OK, but I believe if he did it again he would go NEMA 34.

You are just moving more mass around. Maybe the NEMA 23 425 oz-in will be OK. If it were me I would go NEMA 34.

Keep in mind that the screw on the Z axis is a tremendous mechanical advantage.


On the spindle - ER20 collet will hold a 1/2 shank cutter. I use that a LOT. A larger spindle is a lot heavier.

I have installed a door 3" OGEE cutter with 1/2" shank on my machine to cut door panels. - I do have a video of that. I also cut rail and stile cuts. Best way I have ever made doors. I WILL do it again.

With a larger machine table you WILL want to do some larger stuff with it. It opens up a whole new world.

I have cut a Walnut slab at 500 inches per minute with a 1.500 diameter cutter.

I DO NOT run my machine as fast as it can go. Generally I have my rapids set to around 800 and I generally cut between 150 - 250 IPM. I also run my spindle generally between 8000 to 12000 RPM. I also don't drive my car at max speed. I just like running my machine on low to mid to make it last and keep it problem free. I CAN cut well with spindle at 8000 - other spindles would stall. The steppers have the power needed to push through the cuts. I am not so sure a lighter duty setup would perform as well.

All I am suggesting is that if it at all possible - go for the gold. If it is NOT possible, then do the best you can with what you have.

Congrats on opting for the larger machine. You will NOT look back.

I have a 10" working "Z" -- wish it was 12" or more.

 

[Darren Wright]

Thanks Leo, that is food for thought. I may just bight the bullet and go with the nema 34s. I could always build a better frame for the old table and maybe sell it to recoupe some costs. That or build a plasma table using its parts, speed and weight shouldn't be as much of an issue for it.

Sent from my SM-G965U using Tapatalk

 

[Ryan Mooney]

Great discussion, definitely learning a lot (assuming I'll remember it when needed - one hopes).

That or build a plasma table using its parts, speed and weight shouldn't be as much of an issue for it.

 

[Don Baer]

Great discussion, definitely learning a lot (assuming I'll remember it when needed - one hopes).

for me it's a trip down memory lane. For over 20 years from the mid 70 I was the western regional manager for Cleveland Machine controls (Now Cleveland Motion Controls) working with machine builder applying motors and controls for machine automation. Most of our machine work was with large HP D.C. and AC motors and closed loop servos but I still had to have a grasp of stepper and their operating characteristics. I am now having to recall a lot that I had filled away in my mental archives. My next mental exercise when I have to start working with G codes and M codes,etc. and remember all that stuff I have long since forgotten. In the 70 there were no CNC's they were only NC's no computer. They were programmed using paper tape, just like the early computers. Oh well good mental exercise for this 70+year old man.

 

[Darren Wright]

I found out this morning that I have a co-worker that is building a 1500 x 1500 mm CNC also. H'e doing much of the same setup as I am by using linear rails and ball screws, but is using the 425 oz/in nema 23 motors. He said he'll having his complete in about a month and he's planning to use it mostly on aluminum. I'll be watching his build closely to see how the motors perform, but I'm also thinking I should probably go with the attitude of "only cry once" and get the nema 34's.

 

[Leo Voisine]

Much like Don, I spend my career in the industiral world of machines and cutting metals.

I have used the industrial machines right up to 10/2019. I have been in G-code and CNC all the way throughout the years. I am quite familiar with that world.

However, this new world of light duty CNC machining with Stepper motors and light duty build and light guide ways is a bit different than the industrial world I am used to.

My tidbits from owning 3 different light duty CNC machines since 2007 and having many years of industrial machines is this:

HIWIN linear guides ----- same as what is used on Cammaster
YAKO 2811 drive
YAKO YK86HB118-06OANEMA 34 (1200 oz-in) steppers --- best brand in China --- Leo's take> Good stuff
Rack and pinion X-Y rails > good stuff
Italian Ball Screw on Z axis > good stuff
3.2 KW (4 hp) ER20 HQD brand Chinese water cooled > good stuff

My machine has a Mach3 BOB --- it's OK - but a CNC4PC BOB is a better choice. I will upgrade some day.


When I was researching on a machine I wanted most of what is listed above. Some stuff is better, some not.
I also have an integrated 4-th axis, so my machine is fully 4 axis - no axis swapping.

Welded steel base
All steel gantry

When I was doing the pricing - the Chinese machine was the BEST VALUE by far.
This is why I ordered it


ONE BIG reason to want the more powerful steppers is this one thing.

Steppers and industrial servos are different animals.

Servos will generally have encoders, which feedback actual position.

Steppers work on pulses and count number of pulses to estimate position - no actual feedback (though I think encoders can be used)
So - if the controller sends 500 pulses to the stepper, thinking that is 1" - but for some reason the motor slips 250 of the pulses the actual position is only half inch - BUT - the controller does NOT know that and will continue. That is called lost steps, sounds like gears miss meshing. It can ruin your day. If you have sufficient power the steppers can overcome some irregularities and not lose steps.

You CAN put servos on your machine.

So the question is - Are Steppers in-accurate?
NO ----- My machine is repeatable to seriously less then .001 -- more like .0005 or better. Watch my video.

 

[Darren Wright]

Thank you Leo, I appreciate all the feedback.

I'm pretty sure I'll go with the Nema 34's. I'm already planning on doing steel for the rigidity, and for my main purpose of mostly cutting out parts from sheet goods, I think I'll need the extra horsepower.

Can I ask how they've powered your new CNC from the factory? Are there individual power supplies on each driver/motor or is there one large one for all? The drivers you pointed to look to go to 110v, so wasn't sure if they may have been directly wired to mains or not too?

I do plan to have a dedicated 4th axis on this one also, just haven't decided on the controller to use yet.

Years ago I had planned to build a 4x8 table and prices for just one set of linear rails was astronomical, and ball screws were completely out of the budget. Now I can get all of the screws and rails for under $300.

The price of the steel is what has surprised me, it's gone up a bit since I last bought much of it. It's made me re-think my design a bit to use the heavier stuff only where needed, but probably needed to do that anyway since I'll probably be moving this thing some day.

 

[Darren Wright]

Still need to to add some braces and clean it up, but this is close to what I was thinking. Having all the parts to measure will make a difference. The z axis is a bit short, just used one from the 3d warehouse.

 

[Dan Noren]

this is going to make my 32x52 shapeoko 2 look positively dainty by comparison.

 

[Brent Dowell]

And with a welded frame, holy cow. I'm gonna need a bigger shop.

 

[Darren Wright]

this is going to make my 32x52 shapeoko 2 look positively dainty by comparison.

Ha! Yeah, my little 15" x 24" is going to have a complex

And with a welded frame, holy cow. I'm gonna need a bigger shop.

Welded, but going to put flanges on most of the cross members/supports to allow disassembly if we decide to move in the future. Should also give me some room to square things if my welding isn't up to par.

I'm also planning for for expansion, can always add another section to the front, install longer rails and screws. Will leave enough slack in the cables to reach too.

 

[Leo Voisine]

Looks good - BUT

I would make the 4 corner legs on the base square stock. It will be stiffer. I would also make the gantry uprights beefier. Mine are 1" thick steel.



On the 4-th axis. It is nice to make X-Y&Z axis moves, in addition to having the A-> rotational axis available. If you want a flat surface to create a 3D relief on - then "index" to a new rotary angle - all 4 axis's are needed. Sure there are work arounds, but it sure is a nice to have.

On my axis drives - there are 4 very large drivers. One for each axis. The 2 Y axis motors are driven by one of the axis drives. I would not expect them to be 110v that is not at all common in China. They are with much of the rest of the world with 220v. There is nothing 110v in the machine.

One of my videos is a work around of my machine, in pretty decent detail.

EDIT IN CORRECTION >>> There are FIVE axis drives for the motors - not 4 as mentioned above.

 

[Brent Dowell]

Any thoughts on adding some sort ability to use coolant with it for machining metal? Not sure of the terminology.

 

[Darren Wright]

Looks good - BUT

I would make the 4 corner legs on the base square stock. It will be stiffer. I would also make the gantry uprights beefier. Mine are 1" thick steel.



On the 4-th axis. It is nice to make X-Y&Z axis moves, in addition to having the A-> rotational axis available. If you want a flat surface to create a 3D relief on - then "index" to a new rotary angle - all 4 axis's are needed. Sure there are work arounds, but it sure is a nice to have.

On my axis drives - there are 4 very large drivers. One for each axis. The 2 Y axis motors are driven by one of the axis drives. I would not expect them to be 110v that is not at all common in China. They are with much of the rest of the world with 220v. There is nothing 110v in the machine.

One of my videos is a work around of my machine, in pretty decent detail.

EDIT IN CORRECTION >>> There are FIVE axis drives for the motors - not 4 as mentioned above.

Thanks Leo, I'll have to see what voltage I want to run this at. I have 220 available now, but may have to think about where it's going in the future. I probably will go with 4x4 square tubing for the legs. I was planning to box the gantry sides with square tubing to beef them up and thicken the mounting plate for the linear bearings or use square stock there as well. I just remembered that the ball screws come with a mount for the nut, so the sides of the gantry will probably extend down for those to mount on.

Any thoughts on adding some sort ability to use coolant with it for machining metal? Not sure of the terminology.

I've done some aluminum on my old one, but just used a hand sprayer with soapy water to mist while cutting. I screwed a box lined with a trash bag then screwed a spoil board on top of the bag, but still got some leakage. I'm sure I could do a more permanent pan/misting system if I do a lot of it, but don't feel the cnc router is really the tool for doing metal all the time, though I guess it could.

 

[Darren Wright]

Leo, Thanks for posting the walk-around of your machine, that is quite a beast! Those gantry sides look like they were cast and machined.

I'm curious if you might be able to get a pic of the transformer's label? Just curious what it's output is and if it's a toroidal power transformer.

 

[Darren Wright]

Parts have been trickling in this week. I decided to get everything so I could work on finalizing the design with accurate measurements. I've gone with the SmoothStepper Ethernet controller, Nema 34 1206 Oz/In motors, DM860S Drivers, and 70v power supplies, one for each driver.

The longer (1500mm) rails and ball screws arrived yesterday. They don't seem quite as long in person, but should do.
.

I also ordered a 300mm Z axis. Which I'll need to do a few minor modifications for it to work with the rails and bearings I have. When I get the new spindle I'll verify the placement and amount of travel I'll actually have. I may actually need to add another set of bearings and longer mounting plate for it to be stiff enough.