[Action-KAT]

Hi all
I have done my first drawing for a router build just need some constructive input, If you can see any problems I might have with the design before I comit to buy the parts.

The cutting area is not set in stone just the parts I can get at a fair price.
I will be using Ali extrusion 90mm x 45mm sections for most of the build
1605 Ballscrews/Nuts/supports
20mm & 16mm Supported rails
10mm Ali plate

Electrics most likley from kellinginc
-G540 4 axis package (One G540 + Four
KL23H284-35-4B (1/4” Dual shaft with a flat) 387 oz-in + one KL-350-
48 48V/7.3A 115V /230V power supply: $544.95

I would like to add a 4th axis later on,
so would like to try & keep a spare input on the G540 for the 4th axis.
So what would be the best way to run the twin ballscrews.?

I am new to this building game but would love a cnc to do bits on just can't afford to buy one & been waiting to long for one to come up on fleabay

any help in pointing errors out before I start would save me loads of time money no doubt.
Cheers for any input:drowning:

[Trucks]

Looks good, i HIGHLY recommend the G540, and not to put any bad words to kelling, but Ahren over at CNCrouterparts.com, has the plug and play set up for the G540 and the motors, and let me tell you that is so nice to just plug everything in, NO SOLDERING!

My machine has worked flawlessly and i am in the process now of going to a 4th axis, and building a second machine that will do 4 x 8 foot sheets.

Second not on the twin ball screws, best way is to run a belt and pulley system, just probably have to gear it a little so the motor has a little more tourque, which you would lose a little speed but its ok. I have had great luck with B and B Manufacturing (http://www.bbman.com/) great service and help, fast shipping and the products are so nice.

Let me know if you have any questions, just PM me

Andy

[Crevice Reamer]

Hi Action!

FYI: Keling "kits" are mix & match. The individual parts cost the same as the kit, and he doesn't always select the best matches. I would go with the KL23H2100-35-4B 381 motors, because they are currently the most efficient to use with G540 and will give better performance than either the 387s or the already soldered motors from cnc router parts.

Hey Trucks: How long are the cables that come on those motors?

CR.

[Trucks]

The motor cables are about 1 ft long, but i bought the extension cables that he sells as well, and i think those were 12ft long, and they just work out so nice.

[Crevice Reamer]

Thanks Trucks!

Here's the link to those motors:

http://cncrouterparts.com/product_in...products_id=42

Certainly a nice option if you don't like to solder--But adds $16 to the cost of each motor for the extensions.

Don't get me wrong, the 387s and these motors are good and will run well, but since they are 65V motors, just not as well on 50V as the 53V 381s.

CR.

[Trucks]

I understand where you are coming from, for what i paid, and the time it saved me, i went with them, and they work great for me. I plan on ordering a bunch more for my larger machine.

[Crevice Reamer]

I understand where you are coming from, for what i paid, and the time it saved me, i went with them, and they work great for me. I plan on ordering a bunch more for my larger machine.

I totally understand that. Business money spent to save down time and get into production faster is money well-spent.

CR.

[FandZ]

Thanks Trucks!

Here's the link to those motors:

http://cncrouterparts.com/product_in...products_id=42

Certainly a nice option if you don't like to solder--But adds $16 to the cost of each motor for the extensions.

Don't get me wrong, the 387s and these motors are good and will run well, but since they are 65V motors, just not as well on 50V as the 53V 381s.

CR.

CR do you know how much would be lossed by going with the 387's vs the 381's ? Does it work out to a 15% drop in efficiency?

[Crevice Reamer]

CR do you know how much would be lossed by going with the 387's vs the 381's ? Does it work out to a 15% drop in efficiency?

Not a lot. Voltage dif is 20%, but I can't quantify that into performance yet until I do some comparison tests. I just think--if you are starting from scratch, get the most efficient motor.

The Iron Man certainly performs well with 387s:

http://www.cnczone.com/forums/showthread.php?t=77409

CR.

[Action-KAT]

Cheers Trucks & Crevice Reamer for the info on the G540.
I think I will take a look at the 381's.

Trucks when you say "best way is to run a belt and pulley system"
you mean a tooth gear, not to clued up on this so I will have to look that up.
would a 2:1 ratio be enough say 10 teeth & 20 teeth. Is there a calculation for getting the right setup of lenght and teeth.
(chair)I don't even know which way round to put the gears!
I think maybe a little more reading is needed.

Thanks for the input, I'll try to update the design adding a pulley system to the twin ballscrews.

cheers all

[Crevice Reamer]

Servos can deliver full power at high RPM, so they are often geared down to trade RPM for torque.

Steppers produce max torque at rest and start losing it from RPM #2 up. Gearing down steppers is an excercise in futility because the gearing WILL produce more torque, but the stepper loses as much or more torque by running faster. Best to use 1:1 gearing with steppers.

CR.

[Crevice Reamer]

Take a look at this torque/speed curve for the 387:

http://kelinginc.net/KL23H284-35-4BT.pdf

The driver is a Keling, and the microstepping is set to 8X, so the motor needs 1600 pulses to turn one revolution.

At 20000 PPS,(Pulse Per Second) or about 750 RPM, the motor has lost 1/2 of its torque. Suppose you had geared it 2 to 1. Now the motor is running 40,000 PPS, but only has 1/4 of it's torque left. Theoretically with the gearing, the motor should be again producing 1/2 of its torque--But with this driver and microstepping, mid band resonance will set in and the motor will probably not be ABLE to run at 1400 RPM.

The G540 drivers increase speed and power by 1. eliminating mid band resonance and 2 morphing from microstepping to psuedo full step. Still way better to gear 1:1 though.

CR.

[jsheerin]

Gearing down steppers is an excercise in futility because the gearing WILL produce more torque, but the stepper loses as much or more torque by running faster. Best to use 1:1 gearing with steppers.
CR.

You want to gear them up if anything on screw drives (larger motor pulley than drive screw pulley). That can redistribute some of the force from low speeds to higher speeds at the expense of resolution, screw critical speed, and nut velocity on plastic nuts. If you go rack and pinion, then you typically want to gear down a bit on the motor because you've already geared up on the rack and pinion with typically used sizes.