Thinking about building my first cnc plasma need advice.
Need advice in picking my electronics. I'm wanting to use 4 nema 23 425 oz motors. Can someone please point me in the right directions as into what electronics is the best. I am looking to spend around 300 to 500. I have found some on eBay I like.
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Re: Thinking about building my first cnc plasma need advice.
Most of the stuff on ebay is junk. Try the Geckodrive G-540 http://www.geckodrive.com/geckodrive...ives/g540.html . It's the top pick around here for driving 23-frame motors. Look at the inductance on those motors - if it's over 3 mh, get something that's lower, or they won't perform well without more power than the drives can handle.
[FONT=Verdana]Andrew Werby[/FONT]
[URL="http://www.computersculpture.com/"]Website[/URL]
Re: Thinking about building my first cnc plasma need advice.
OK thanks man it's odd you say get the g540 because I was looking at them. I think im going to go with the kit that has everything minus the motors and the box. I found the kit for around 450 has the wires, gecko unit, power supply. I like the fact that they are american made, and the fact that people say they have good customer service. Also im new on here how do I find my post that I have put on here, I have to go threw today post section to fine my post and see the reply's.
Re: Thinking about building my first cnc plasma need advice.
Well, I happened to disagree with that generic, blanket statement. I guess you mean "most of the CHEAPEST stuff on eBay is junk". Because remember... you get what you pay for, even from China, and eBay stuff in itself is not equal junk.Originally Posted by awerby
Re: Thinking about building my first cnc plasma need advice.
I think on that low budget you MUST look at eBay. The most important thing is not to buy the cheapest stuff, but quality is not necessarily expensive. The Gecko 540 most people speaks so warmly about may be very good, but a bit outdated and it is my understanding that it can be tricky to get it right. Not only that, but it needs extra cooling, at least a decent heat sink. I am also a firm believer that individual drivers are better than "all in one" integrated like the Gecko. So, my advise is:
Low inductance motors + DQ542MA drivers + BoB + a decent, non switching, analog power supply.
I have a similar kit like this one bought from the same seller, but have 5 drivers and a BoB like this one (not from the same seller as the link) I bought my motors also from Wantaimotor some time ago. Everything works fine, the drivers never get hot but have integrated heat sinks anyway. Originally I bought a switching supply also, but that's going to be replaced by an analog supply, based on a thoroid transformer. I bought the parts and will build it myself, but I am pretty sure those can be bought readily built as well. Not that it is too complicated to build one, but some people don't want to work with soldering irons and want to buy them readily made.
Anyway, if you are on a tight budget you should not be afraid of, or avoid eBay, just as long as you check out want you buy and ALWAYS avoid the cheapest stuff.
Re: Thinking about building my first cnc plasma need advice.
Yeah part of me wants to build mine, but I have never done it before. Yes i am electrical incline person so shouldn't be to bad. And also i like the drivers being separate myself. I do believe I need to read up on software thou. To my understanding you have a cad/cam software that is were you design it and there is another software that actually communicates with the machine like mac 3?
Re: Thinking about building my first cnc plasma need advice.
In that case you should have no problems building a CNC, even the power supply. I bought the power supply parts from a German company called CNC-Plus. fast delivery and very good quality, though they are mostly Europe oriented, so I don't know if their transformers can be used with your 120VAC mains. Basically, the mechanical parts of a CNC are quite simple, but you must be careful when drilling and assembling it, so that the machine stays squared as well as that is possible to avoid later problems, once you start milling. The most challenging part is the electrical part, but if you have no problems with that then the rest is pretty simple.
You can have a cad program which you use for design, but if you are good at understanding low level programming then you can create G-code by hand. It needs some practice but it is fun. G-code is pretty simple, basically some simple commands with or without parameters, some just instruction, some with X, Y and Z coordinates, or other values. There is plenty online documentation, just google "G-code" and you'll get many hits. Of course, for more complex things, manual coding is inefficient since you need to do also a lot of manual calculations, so a CAD software is advisable. I am using a very old CAD software which I bought cheap in a grocery store (yes, it is true) over ten years ago. It was on sale at that time for something like 20$ and considering the price it is very advanced, contains a lot of modules for very sophisticated design, even 3D. It is no longer available on the market, so no updates, but it can generate dxf files which enough for me. I import the files into a freeware called "dxf2gcode" which generates the code. Some manual action is still required, but it is pretty straight forward. After that, once the G-code is generated it is just imported into Mach3. So to start, you actually only need Mach3 and even the free version should be enough to get the feel of it and to learn how to use a CNC and to see if it is something for you or not.
Good luck. CNC is fun to use and can be very rewarding challenge to build.
Re: Thinking about building my first cnc plasma need advice.
Actually, you don't always get what you pay for. Just because a seller decides to charge more for a product, that doesn't make it any better. And Ebay makes it easy for sellers to dump and run; that's why I generally avoid it, especially for items on which I will need post-sale support.
I've built a control box with the G-540, and was pleased by the way it went together and worked. Having the breakout board integrated into the board seems like a good idea; I don't see the disadvantage of getting the drivers and BOB as a single unit. If an individual driver has problems it can still be replaced separately, and wiring it up was simplified considerably. Yes, you do need to provide a heatsink and fan, but that's pretty standard for this kind of equipment. Getting the motors separately is good; that way you can look at the specs and get something appropriate for your drivers and power supply, not just whatever the seller found that was cheap. I second the recommendation of a non-switching toroidal power supply; the G-540 is best matched with one that puts out 48VDC at 10 amps or more.
To find the conversations you've gotten involved in here, go to the second line of the menu bar, where it says Quick Links, and click "Subscribed Threads" in the drop-down menu.
[FONT=Verdana]Andrew Werby[/FONT]
[URL="http://www.computersculpture.com/"]Website[/URL]
Re: Thinking about building my first cnc plasma need advice.
Yeah I have read a lot and watched a lot of videos on both set up and i don't think either really is any better then the other electronics wise. But I would like to have some support the first go around with messing with these. Also will any electronics accept any software? Like do all units use the same software.
Re: Thinking about building my first cnc plasma need advice.
andrew werby thanks for the advice for finding my post
Re: Thinking about building my first cnc plasma need advice.
I ALWAYS disagree with blanket statements because they are ALWAYS wrong. Generic, simple truth are far too simplified and NEVER true.
I didn't say that the most expensive is always the best, did I? I also happen to disagree that you generally don't get aftersales support from an eBay seller because that very much depends on the seller. I agree that it is difficult to get support from China from many sellers, but hey, the price reflects the support as well. They can be Harvard or MIT educated, produce high quality documents, give you H24/7 support, follow every regulation on earth and sell the stuff you want cheap at the same time. If you want all that you must pay extra for. That's why it is more expensive to buy stuff locally, not from far away. Again, you take the worst cases as some kind of reference. That's nonsense. On eBay you will find crappy sellers from USA as well as from China, but you will also find honest and good sellers from all over the world, also from China. ...and another thing... Yes, you can find horribly priced stuff there as well, from very dishonest sellers, but come on, we are supposed to be adults so do your home work, find out what is reasonable and don't buy anything from those sellers. I have the last ten years bought several hundred items from different eBay sellers and never got disappointed so far, got always everything as expected and the very few times I didn't receive the items I always got my money back. Some times I have received the wrong items and those times I received honest compensation, either 100% or a reasonable reduction. I am not defending any jerky seller, but I have not yet met one, only heard about them, so I continue buying through eBay whenever I feel like. Of course, once again, I don't always chase the cheapest stuff, but I am not afraid to buy anything, at least up to about 1-2k$ value. There are items I prefer to buy from known sources, or locally or at least from Europe, but in general, I don't mind if it comes from China.
Yes, it is up to the seller to set the price, but really, it is up to me to pay for it, and if I'd pay several times over the "normal eBay" price, well, so be it, it is my own fault for being stupid and not checking out or not waiting for a better deal.
That's OK, if you like the "all in one" solution, that's fine. I prefer individual drivers for each motor. Also, not every driver gets hot, so really, fan and heat sink is not always necessary. I can run my DQ542MA drivers with my NEMA23 3A motors for ever without the drivers getting hot. The heat sinks are necessary, but not the fans. My understanding is that the Geckos definitely need both heat sink and fan because they are always hot. I don't know why, probably because the holding current is the same as 100% motor current all the time, or it is simply a design fault. Also probably the compact package for all four axes are too compact and heat up because of that as well. Anyway, the good thing is that there are several options, what suits your needs may not suit mine and vice versa.
