Thread: Gecko G540 or?
Im putting together my first 4-axis CNC. I was thinking of using a Gecko G540 kit but its quite expensive and i wonder if there are any other kits out there with a good price/performance ratio?
eBay is full of them but its hard to know which ones are good.
Anyone with a recommendation? The size of the mill is roughly about 1000x600 mm.
I live in Sweden so anything from UK or Germany would be nice...
I don't think that any of the experts on this forum would want to specify hardware based on your specification! There are too many people who have bought the wrong items at the beginning of a project and created a lot of problems for themselves. Often, they have bought cheap kits from eBay/China, and suffer from poor performance or unreliability or both. Once you have finished your design to the point that you can safely specify the hardware, then a couple of good UK-based suppliers that I have used are Zapp Automation and CNC4You. They probably will not be as cheap as you might find via eBay for what sounds like similar kit, but they are good people to deal with and sell decent quality goods. There are others but I only have personal experience of these.
So, get a good understanding of what you are trying to do (what do you want to cut, home/industrial use, etc), get a design put together, and post on this forum for comments. You will get plenty of useful advice!
Last edited by Neale; 16-10-2014 at 01:46 PM.
Neale is correct it's a little premature to be recommending or even thinking of buying anything yet if you haven't even designed the machine.
The Gecko G540 is a nice bit of kit but it does have some limitiations like restricted to 3.5a motors and still use all it's features, Plus restricted to less than 50Vdc for running motors.
Machine your size if robustly built will most likely be best run on nema23 motors which if sourced in Europe will most likely be 3Nm and 4.2 and for best performance you'll want to run them on 75-80V drives with 65-70Vdc PSU.
The G540 can run 4.2a motors but you loose the Idle current reduction feature which means the motors get hot when at stand still. Also your restricted to aprox 42-45Vdc to leave a safety margin for back EMF.
So my advice is to look at individual drives and don't buy anything yet. Save and wait until you need them then buy good quality Digital drives along with correctly sized PSU.
If you do want a decent all-in-one drive that's slightly higher spec than the Gecko then look at the Leadshine MX3660 which is only 3 axis but as 60Vdc digital drives along with inbuilt BOB and spindle control. http://www.zappautomation.co.uk/elec...ng-driver.html
Thankyou for your comments guys.
I have been thinking about this for a long time and i have a design. I fell pretty Confident about the design (mechanical engineer) but i do have to admit that im not that good with the Electronics part and i havent done my homework calculating how much torque i need and so on.
I was kind of hoping for some Quick advises and your comments above was very enlightning, especially the part about idle current reduction.
I was looking at zapps page and i would like to get my parts there but i got a bit confused and didnt know what products to choose.
The design looks like a machine thats called "high z 1000" if you want to check with Google.
Size would be about 1000x600 mm. The machine should be allround, Wood but also alu.
So, if you got the time i would gladly take some further recommendations. 4-axis, idle currrent reduction would be nice and so on.
It may well look ok and scratch it's way thru aluminium but it's far from ideal and much better design could be made that isn't much more work.
Suggest you post your idea or drawing.!
It was a bad idea to bring up the High Z. Should have stuck with just saying 4-axis machine.
I can say this much that im going to use supported rails mounted on 2 pcs of alu extrusions. These two sides will be held together by two (dont know the English Word for it) but two end pieces, watercut alu... Theres much more, i will post something when ive got something solid.
I got this, im sure of it... If not, ill ask you guys... ;-)
EddyCurrent; Yes, i will gladly take some advise for the Electronics part. Thats why im here...
Regards electronics then really it boils down to one standard setup for this size machine to get best performance and it goes like this.
3Nm 4.2a 8 wire low inductance Nema23 motors wired in parallel.
75-80Vdc digital drives
16mm 10mm pitch ballscrews on X & Y
16mm 5mm pitch on Z axis.
Good quality BOB
And if you want the very best performance and reliabilty then external motion control card to get away from parallel port.
Yes you can calculate the torque required and probably get away with lower NM motors and possibly use 50Vdc drives along with smaller PSU but the above setup won't cost much more and will be well on top of the workload giving maximum performance while at same time giving redundencey which prolongs life of components as they are not working near there limits all the time.
Brilliant answer! Now i got something to work with.
Im gonna check out the Zapp site to start with...
Hi there, fellow swede!
I agree with what jazz says, trust that guy.
I'd suggest getting the leadshine am882 drives. I recently finished my build (check my blog at tumblebeer.com) and I used a mix of dm542a cheap drives from an old build and the leadshines, and I can tell you to never ever use anything but digital drives. My leadshine motor spins happily and completely quiet at 3000rpm at only 36v, while the analog drives are resonating and screaming at barely 500 rpm.
As for motion control, I'm using a plcm-e4 from purelogic and I'm very very happy. No need for an external bob, it's packed with optocoupled inputs and mains relays.
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