Reply with Quote20mm supported rail will be fine for a machine this size.
Now I wondered... are the 20mm in diameter supported rails enough to hold on the weight of the whole gantry? Or it might be just better to use 25mm supported rails... Which one would be optimal choice in your opinion ?
20mm supported rail will be fine for a machine this size.
I've just looked closer at your sketch up. . . . Can I suggest that you position the rails for the X axis(longist) flat on the top of the box section instead of on the sides, this will help support the load better and lessen the stress's on the bearings slightly it will also allow for your gantry to be narrower and thus stronger.
Look at this machine it's very similiar but use's profiled linear rail instead of round rail but mounts them in the same way i'm suggesting.
http://www.cnczone.com/forums/diy-cn..._router-7.html
It's a very nice machine well built machine and it cuts guitars.
I was thinking also about mounting the round rails on the top side of the steel profile tube... that lasts the question about angular joints of the gantry sides and the bottom piece of the MDF...
And how do you like the idea of the lead nut - I mean the PA nut in the rail support.. I figured it out just for prototyping... would it be enough to test the motion of the machine ?
Last edited by Tomov; 12-10-2010 at 03:18 PM.
Originally Posted by Tomov
I was pleasantly surprised after I looked at the Gecko Drive G540, but included in a kit, along with 3x 380 oz.in motors, cables and the included switching power supply. Also I think that the price is a bargain
After some modifications on the construction - ballscrews and nuts instead of the ISO threaded ones and supported rails for the Z rail I am looking to buy that kit:
- 48V 7.3A switching power supply
- Gecko G540 4 axis stepper motor driver
- 3 High-torque Nema 23 380 oz-in stepper motors. These motors already have the current set resistors installed in a pro-grade metal shell. No soldering or crimping required. These are optimized for the G540 -- don't get caught up in the stall torque game, since your motors don't run at stall! These motors use all of the 3.5A the G540 has to offer.
- 3 High-performance flexible motor cables: (1) 6'and (2) 12' cables
I think it's the best at the comparison price/quality(functionality).
Any weak spots in this kit ??
P.S. Here our mains voltage is 220V/50Hz.
I bought that kit and it is very easy to hook up. At first I thought it would be complicated, but as you'll see in this thread and videos, it is pretty much plug-and-play like that site says: http://www.cnczone.com/forums/diy-cn...ecko_g540.html
Yes the Nut will be ok for testing purpose's just dont expect to much speed or precision/repeatabilty.
1.5mm pitch is very fine and at the very very best you will only get 2mtr/min rapids and if you are lucky enough to get these speeds then the nut will wear out very quickly due to high friction of threaded rod if it's not highly cleaned up and polished. One of the problems with using threaded rod as lead screw is thread pitch is not often consistant along it's length which mess's up the repeatabilty and precision.
If your aware of this, run lower feeds and dont expect high precision threaded rod works ok for testing and learning purpose's.
Brace the gantry angles has much as you can and the stronger you can make it the better and the less chatter you'll see on your cutt. Dont worry too much about the gantry weight being too heavy because the extra Mass works for you when cutting and the motors will handle more than you probably realise, better being a fatty and slow than skinny and weak.! . . . . . Well thats what I keep telling my self when i'm stuffing MacDonalds down my throat. . Lol
Wow, I was working on the CAD of the machine, placing the long rails on the top of the steel profiles (longest axis). For now I'll leave the threaded screw for just learning purposes (very nicely said btw)... we'll see how the gantry will move w/o the threaded rods and the steppers installed first - it has to be precise and smooth. And when it's ready for the lead screws and nuts I'll post some photos. I'll try to do my best to show in steps the cutting of the frame, the clamping, welding, painting of the metals, etc. Hoping it will be interesting experience to show
And hemsworthlad, yes the more the merrier... says I.. and stuff that double cheeseburger... Cheers
CNC_Lurker, very nice photos, mate.. look better than the websitereally
Hey, guys
Besides, talking about mechanics, what do you think about my machine ?
It's one of my older PCs, it's equipped with:
Intel Celeron CPU - 2.66 GHz,
512 MB DDR RAM (400MHz)
64 MB (Radeon 9200) Graphics Card
80 GB Hard Drive
And it has on-board LPT Parallel port.
Is the configuration OK to run Mach3 or similar CNC CAM software ?
Ooo.. one more thing... I bought not very long ago, from my local hardware store - LPT to USB adapter cable - it came with it's own drivers cd.
Will it be able to connect the Gecko Drive to the USB port of my laptop ?
Or it depends...
Hey, guys
Besides, talking about mechanics, what do you think about my machine ?
It's one of my older PCs, it's equipped with:
Intel Celeron CPU - 2.66 GHz,
512 MB DDR RAM (400MHz)
64 MB (Radeon 9200) Graphics Card
80 GB Hard Drive
And it has on-board LPT Parallel port.
Is the configuration OK to run Mach3 or similar CNC CAM software ?
Ooo.. one more thing... I bought not very long ago, from my local hardware store - LPT to USB adapter cable - it came with it's own drivers cd.
Will it be able to connect the Gecko Drive to the USB port of my laptop ?
Or it depends...
I recommend adding another 512Mb of ram. Bring it up to 1Gb and it will be fine. Maybe later you will want to add a second hard drive but 80Gb is enough for a while.
Others will verify it but I don't think the LPT to USB adapter will do you any good with CNC controllers.
CarveOne
CarveOne
http://www.carveonecncwoodcraft.com
Just to add to be clear, the PC will be ONLY for the use of Mach3 software, without any CAD/CAM apps. It will be only to load the G-Code and control the steppers. But just in case I'll add another 512 MB of RAM (or probably single chip of 1GB).
Is the processor enough powerful to control the motors (about frequency, ipm, etc.) ?
Yes, it is. Your machine is equivalent to a Dell computer that I'm using. Mine has a 320Gb hard drive that is gross overkill but it was not being used at the time I set up this particular older PC for CNC uses. It has Mach3, CamBam, and Vcarve Pro on it and little else. No internet connection and automatic updates are disabled.
CarveOne
CarveOne
http://www.carveonecncwoodcraft.com
Hi,
The PC spec is fine, like C1 says a little more ram wont hurt. To be honest thou the main issue's people have is not with the PC speed or spec but the quality of pulse's the parallel port gives. Even high spec PC's with very fast processors can have rubbish PP's causing poor running motors and no end of mind mending issue's enough to drive a person crazy.
Mach as a PP driver test I suggest you run it, this will give you a better idea of how good or bad your PP performs.
One thing I can tell you is dont try running mach at too high a Kernal freq if you want stable performance, 35K is usually good enough for most motors.
I was sitting and thinking about how to fit all the electronic equipment for the CNC machine and was hit by the idea. The Gecko drive, along with the switching power supply will fit into one of them metal boxes, designed for (don't know the word in English - about that measurement device which measures the energy consumption (in kWh for example):
On the front panel of the box will be mounted power switch, maybe Amp-meters to monitor the motor currents, Voltmeter for the mains voltage (sometimes it's not exactly 220V (210-240) here) and one E-Stop button along with the indication LEDs. On one of the sides will be the connectors to the steper motors and outputs of the relays for spindle, vacuum, light and others and brackets for mounting one or two 80 or 120mm fans for cooling.
The case is all metal, and of course - grounded.
How do you like the idea ?
Looks perfect to me..
Does anyone have any experience with the Switching Power Supplies, made by MeanWell ?
I'm talking about that: New Regulated Switching Power Supply 48V DC 7.3A 350.4w - eBay (item 310233059911 end time Jan-06-11 17:29:17 PST)
The price in eBay is good I think. But how will it work...
Meanwell make nice PSU's I have a 24V that powers my limits,relays etc.
If the specs are enough to suit your motors needs then it will work fine.
At the Kit with Gecko 540 and 3 stepper motors, the power supply is just that 48V/7.3A == 350W Then Mean Well it is. I think when I finish the mechanical works I'll buy the PSU from eBay. From CNC Router Parts will be the motors and the Drive. Here I found some pretty nice cables which are 4 wires with shielding foil (4 x 0,75 mm2) or sometning between 20 and 18 AWG. Also I found and cable which is 6 wire - 6 x 0.5mm2 which I think is just 20 AWG - the same gauge which is used in the Gecko drive kits. It will be just cosmetic work to solder the DB9 connectors to the both ends of the cables, I think. As soon as I get my E-Stop switches and limit switches, I'll post photos of them and both of the cable models.
You will also need current set resistors to limit the current, I think the cables that are in the kit have them wired into the DB connectors but it's not a difficult job to do if your handy with the soldiering iron.
I thought that the current set resistors were mounted somewhere in the stepper motor ?! Or am I wrong ?
CNC Enthusiast.
Not sure if they are in the connectors of the cable or the motors, I would guess that they are at the motor connector.?
