[tbl]

Hey all,

I've been lurking on and off for a while, made an account today.

So I'm thinking of putting my christmas bonus towards my very first CNC. I've decided I, like most, don't have the money/space for a 4x8 machine. But I refuse to let my dream die. I've decided to go with the FLA200 and gecko 540 package to get this project off the ground.

I'll be using this primarily for wood, and hopefully a some aluminum. I currently own a bosch colt and a porter cable 7518, does anybody use these? Or do I need to purchase a 'normal' router?

My question is this:

Will any of this be reusable for a machine cutting cabinet parts out of a sheet of plywood(my eventual goal)?

Should I just use this as a learning experience and worry about it later? Or would some nema 34 sized motor be powerful enough? Anybody on a 2nd or 3rd or 10th machine still using some original components? I'm sorry if thats too many questions, but everytime I get close to jumping in I get scared if I spent a little more money now I could save myself a lot later.

Thanks for your insights.

Drew

[jerry426]

A few quick thoughts:

I am building two machines at the moment - one of which will be a 50x50x8 inch wood router - and will likely become the parts donor for a machine to handle 4x8 foot sheets. At the smaller size - the components we're putting into it are total overkill. The second machine is described here.

If you start with the G540 package now you are limited to 50 volts and 3.5 amps to the steppers.

Something like the G203V is good up to 80 volts and 7 amps. But then you still need a breakout board (can be cheap or "robust" up to perhaps $120) and if your design has 4 steppers, then you need 4 of the G203V units.

If you start with steppers best suited for 50 volts, then they won't be optimal for 80 volt use later. Then there's the cost difference between smaller/larger stepper motors.

If you know you want to reuse the parts later in a larger machine - if at all possible start out with the larger NEMA 34 640+ oz-in motors, larger power supply, breakout board, and G203V units now instead of smaller ones. That way you don't worry about being stuck with smaller components.

All that said, you can still build a very capable machine using a G540 package and appropriate steppers on the smaller budget - and gain experience in the process - and keep it running forever - and still build the monster machine later.

[ger21]

If you start with steppers best suited for 50 volts, then they won't be optimal for 80 volt use later.

Just because the G203 can use 80V, doesn't mean you have to. The need for higher voltage is related to the motors inductance. Typically, better performing motors have lower inductance. Which have lower voltage requirements.

But that's really irrelevant imo. Build the small machine using the components you need for the small machine. When you want a bigger machine, sell the small one.

Well built CNC routers have very good resale value.

If you used some of the parts for a larger machine, you'd have at least half of a machine with little value. If you sell the machine, you should be able to recoup more than you'd be saving by using some of the original parts. Does that make sense?

[brtech]

I have the FLA-300, which is 4 x 4. It's easy to upgrade that to 4 x 8: all I need to do is extend the frame and rack. I'm not sure end butting rails will work, but that wouldn't be expensive to replace.

I have a G540. You can definitely run a 4 x 8 on it, so that investment is good for the future.

You can reuse the entire Z axis from an FLA-200.

The gantry beam from the -200 is going to be throwaway. The frame and Y look similar to my -300, so you should be able to replace the stretchers and widen to 4'. It uses the same R&P double drive as mine, so you can re-use that, and extend it the way I would.

You would need a new gantry beam, you can either get a new piece of rail, or if you replace the Y rails with 8' lengths you can use one of your 4' on X. The 4' X uses R&P, so your screw and bearings would be replaced. You can reuse the motor, but you would need a new R&P drive. Need another 4' piece of rack for X.

So, bottom line, you should be able to expand your 2 x 4 to 4 x 8 without too much throw away.

[tbl]

Thanks for the input.

So I've concluded that the kit is of quality resale value. It seems however that I may be able to transition the electronics. Couldn't I theoretically use the 540 with some 34 size motors, on the 2x4 machine. Then later on the 4x8 add a 4th stepper onto the X axis to deal with the size increase? The Y & Z wouldnt be that much larger/heavier. As I understand it rack and pinion has less friction than lead screws, so maybe I could switch that out as well.

I guess what I'm hoping for is 250-300 IPM? I'm just using my planers feed rate of 24= 288 ipm FPM as a reference point. I would be pretty happy with 1/64" accuracy Am I in the ballpark for this? Is this what I should expect out of the FL200 kit?

I've been looking at the Keling web page as an alternative, but I have yet to comprehend all the specs or what the advantage of dual shaft is. Is there any reason to not mix and match steppers?

I guess I'm just not totally clear on how to figure out how fast I can move how much weight with the different steppers specs.

I image an FLA200 kit assembled with no electronics would be of intereste to quite a few people as well?

[DIYaholic]

tbl,
I'm going to do a 3' x 4' 80/20 machine utilizing CNCRouterparts components. The X-Axis will be 3' dual R&P, Y-Axis will be 4' R&P and the Z-Axis will use Acme. Later, all I will have to do is modify the X-Axis to 8' with minimum added expense. I'll reuse the Y-Axis gantry and Z-Axis as is. There won't be any need to upgrade any of the motors or electronics. I will need to purchase additional 80/20 and longer linear rails, longer cables/wire and a few fasteners. At least this is my plan to make upgrading to a larger machine as inexpensive and easy as possible. Just my $0.02.

Randy,

[jerry426]

re: the G540 with 34 sized motors - Keling even has a kit just like that with 465 oz-in motors having the optimum inductance value for 50 volts.

re: accuracy? If you go with rack and pinion, and for sake of discussion your pinion gear is 1 inch pitch diameter, you have a pinion circumference of 3.14 inches. Dividing that by 2000 steps per revolution (200 step motor with 10 microstep drive), you have a resolution of 0.00157 inches - 10 times better than 1/64 inch and still very good even after you allow for backlash and gantry flex (assuming your gantry is sufficiently rigid).

re: IPM? if you only spin your pinion gear at 100 RPM, your moving at 314 IPM (100 * 3.14 inches per revolution of the pinion gear). You should be able to get WAY more than 314 IPM from it - rate of mass acceleration notwithstanding.

re: how much weight can you move how fast? Without digging deep into calculations, think of it this way: If you use two steppers to move your gantry, and if those steppers are the 465 oz-in models I mentioned earlier, and your pinion gear is 1 inch pitch diameter, then you have a theoretical holding force of 58.125 pounds (465 / 16 * 2). Looking at the typical torque/rpm curves I've seen you will have plenty of power available to fling the gantry up and down the rails at a fairly impressive rate of acceleration/deceleration, and max IPM. Once the mass is moving, then you only need enough continuous torque to overcome minimal rail friction and drive the cutter into the workpiece. Plus you can tune the acceleration rate in software as needed to ensure no lost steps.

[tony kendal]

Future proofing.. now there is a topic..I have a 48v set up with Keling 460oz drives. I have a 4 axis mill, but I have individual gecko drives and 6 of them and 6 steppers. Reason, I can gang/slave them if ever needed for a router etc. The drives are all plug in and interchangeable. The two spare ones are about to go onto the lathe. All within the same control box, which also has zero switches on all drives and 'disable' on all drives.
All the Keling drives are dual shaft, which permits the old hand wheels to be used and gives the possibility of mounting the drive in the table center and drive both sides of the table from one motor. As they are all the same drives, then they are 'hot spares' if needed.
The old Inch Per Minute chessnut.....ultimately the feed rate is determined by tool RPM, tool dia, depth of cut and spindle power,,, also throw in stepper power, waste removal and tool/job heating. Generally, my cutting of alloy is about 150-200mm/minute, but my traverse is 10 times that. NOTHING beats getting to the next cut at max traverse and then cut at the cutting rate. It's all a balanceing act. My interface is Smoothstepper via a usb. I have no breakout board, all the limits and zero's etc are onto the smooth stepper. I also have a CNC4pc spindle speed controller ( don't forget to have AN ISOLATED DC/DC CONVERTER TO POWER THE CNC4PC card ) and a small flat panel meter ( like a VU meter ) to monitor the speed output. If you can't future proof it by getting the hardware right, then future proofing is all about how much money you throw at it down the track.