The more I read, the more lost I get. Help me suite my first build. [Archive]

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eurikain

12-09-2015, 07:20 PM

Hi everyone,

--------- This is the WHY

I have been building a 2m x 1.5m MDF router for the past couple of weeks. While, on the side, playing around with SW to come up with new concepts, just for fun. Some of you may have read my build log "All steel, nut and bolted". That is a project ahead of me that i'll try to keep working on in the next few months. I thought that I'd first finish my latest first real build, get it running, learn from it and then move on to the next build.

I have been reading this forum, cnczone.com, and other websites on the internet for a few months now, researching about different setups, how to calculate what motors you need, what voltage you need, PSUs, control panels, etc. Honestly, the more I read, the more lost I get and the more complicated it seems :(

As my old electronics (blindly bought 4 years ago from buildyourcnc.com, when I didn't know much about CNC and was just a young boy too excited about buying some electronics and jumping into an unknown world) died some time while resting in my attic for the past two years, I'd like to replace them with new ones so I can finally get this MDF lady running. So, since I'm lost in the gigantic mass of info out there, I'd like you to enlighten me.

--------- This is the HOW

I got an MDF machine, for woodworking purposes. Footprint 2m x 1.5m roughly. Driven with 2m SBR 20 on X, 1.3m SBR20 on Y, 0.6m SBR20 on Z, coupled with 2 x 2m SFU2010 on X, 1.3m SFU1610 on Y, and 0.6m SFU1605 on Z. Gantry weighs 60kg (yes, it's a big lady, I'll start a build log when I get time to show you what has been going on for the past few months). Z weighs about 20kg with spindle. Spindle is 2.2kW Chinese water cooled. Now you've got a general idea.

I want to make this reasonably cheap. I know, CNC is not cheap by definition. I want something simple. I'd like a very very basic setup with which I can just run GCODE, control all axis, MAYBE switch on/off the spindle, so just run a simple machine, nothing fancy with Mach3 spindle speed control, smooth stepper, $300 bob, etc.

So, I need to choose a BOB, motors, PSUs and drivers. That's where we start.

1. BOB

I've seen about 1000 different models out there. But honestly, for a very basic setup like I want, I think the following BOB will work like a charm:
http://www.aliexpress.com/item/High-Quality-Upgraded-5-Axis-CNC-Interface-Adapter-Breakout-Board-For-Stepper-Motor-Driver-Mach3-USB/32265339603.html

The only thing I don't get about this board is what the female plugs behind the axis screw blocks are meant for. Anyone can explain that to me ?

I think CNC4YOU uses those boards in their 3/4 axis kits, so I'm guessing they're not too bad. Plus, $9.5, free shipping, hard to beat :)

2. Stepper motors

I've already got some. I don't know if they all work, as I haven't figured out what went wrong with my old electronics yet, but I think that it's worth trying to keep them. They are 60BYGH303-13 from buildyourcnc.com. They're rated 2.8A, 3.1Nm, 7,5mH, 8 leads. What do you think about them ? Overkill ? Worth keeping ?

I need to complete those 3 motors with a 4th one, so if you think they're good enough, which motor could complete this set ? I was thinking about a SYS60STH86-3008BF from Zapp Automation. They're on sale right now, so for 50 Euros (shipping included) I can get them here. My only worry is that they're rated 4.2A wired in parallel. That's quite a lot compared to the 2.8A I've got. I know that they're rated more than half the mH, and I'm guessing that A and mH increase / decrease in opposite directions. Pus will be greatly impacted by this.

3. Stepper drivers

Well, there I'm lost. Honestly, there are a billion ones out there. I know you guys like AM882 or Gecko equivalents. But I think that would just be an overkill for the purpose of this machine. I know that CNC4YOU uses CW5045 in most of their kits. I can get them for $40 free shipping. Is that an option ? What is your opinion ? Keep in mind that I am trying to have something between a Lada and Mercedes, so let's say Toyota.

4. PSU

With the motors I've got, ideal calculated voltage is roughly 80V, but I might be wrong or have done something wrong in the calculator. But honestly, do I really need that much ? I was thinking more of something like 50V 10A regulated. Is it necessary to DIY an unregulated 80V 12A PSU like recommended by Boyan and Clive on a thread I started a few weeks back ?

So... let's summarize. I think the BOB choice is quite modest. Of course, I'm ready for some bad feedbacks about this board, as it's probably incomparable to other $100 BOBs.

For the rest, I'm guessing it's just a compromise. AM882 and unregulated DIY 80V 12A like Boyan suggested, or some other route ? I'm lost guys, please get me out of this huge pit !

Once we've agreed on a good setup, I'll buy everything needed, set up wiring diagrams and everything you require to guide me in the right direction.

Thanks a lot for your patience, forgiveness and help !

Clive S

12-09-2015, 11:22 PM

The only thing I don't get about this board is what the female plugs behind the axis screw blocks are meant for. Anyone can explain that to me ? I think you will find that they are an alterative connection for the drives dir/step pins.

You don't say what your driving the machine with ie ball screws etc slaved axis etc. ?
.
The steppers you have have a high inductance and the Zapp ones will be much better http://www.zappautomation.co.uk/electrical-products/stepper-motors/nema-23-stepper-motors/sy60sth86-3008b-nema-23-stepper-motor-48577.html
If you are going to build another machine and want to use the bits again go with AM882 at least as they have stall detect and run them at about 70V. Some of the newer drive can be run from AC as well.
Building your own PS supply will cost about £45 ish

cropwell

12-09-2015, 11:57 PM

http://www.qiannipicture.com/pic/Uploadfile/eBay/SKU062631/769D1313369A2353CE4CD213C6CF43D2999DF36693D2239999 93D2C50333CF9D9E66CC43C42616CAC7A093.jpg

cropwell

13-09-2015, 12:05 AM

eurikain

13-09-2015, 01:07 AM

Clive - you are right about the line of 5 sockets.

If anyone wants the Engrish language version of the BoB manual PM me with your email address and I will forward it to you. For some reason I can't upload it as the Adobe plug-in crashes on the uploader - Lee comment ?

Rob

Thanks so much ! I attach to this post the PDF you sent me :)

You don't say what your driving the machine with ie ball screws etc slaved axis etc. ?

I have 2 x 2m SFU2010 ballscrew on X, 1.3m SFU1610 ballscrew on Y, and 0.6m SFU1605 ballscrew on Z. I think X is oversized, but I had to go with 2010 because lengths were higher than 1.5m. Fred @BST Automation even recommended SFU2510, but I didn't think that binding would be a problem for an MDF machine. Turns out the screws don't bind at all, unless you push on them obviously. I can't say anything about whipping as I haven't tried them on yet.

The steppers you have have a high inductance and the Zapp ones will be much better http://www.zappautomation.co.uk/electrical-products/stepper-motors/nema-23-stepper-motors/sy60sth86-3008b-nema-23-stepper-motor-48577.html

Well noted. I'll keep those (or CNC4YOU, whichever one is cheaper) in mind :)

If you are going to build another machine and want to use the bits again go with AM882 at least as they have stall detect and run them at about 70V. Some of the newer drive can be run from AC as well.

Sounds good ! I think you're right, thinking long term good quality is a better money saver.

Building your own PS supply will cost about £45 ish

Right, as we discussed in the other thread. I have done some more research on the forum but apparently I don't use the correct terms (I searched "unregulated power supply", "diy power supply", but searches with words of less than three letters don't work... for the software engineer and web developer that I am, that's a key thing missing on the forum !). I found a thread where someone built his own unregulated PSU for 4 x CNC4YOU Nema 23 3.1Nm and 4 x AM882 (which would most likely match my case), but I found it hard to find the right information throughout the discussion. I think we should add a "DIY unregulated psu tutorial" thread to the forum, with wiring diagram, simple formulaes, links to parts and pictures of how to make it. If this already exists, can you point me in the right direction ? I can always start such a thread when I make my PSU, but would rather see someone with much more experience doing it :/

Neale

13-09-2015, 10:21 AM

JAZZCNC

13-09-2015, 10:36 AM

I think we should add a "DIY unregulated psu tutorial" thread to the forum, with wiring diagram, simple formulaes, links to parts and pictures of how to make it. If this already exists, can you point me in the right direction ? I can always start such a thread when I make my PSU, but would rather see someone with much more experience doing it :/

Mostly the reason why you'll struggle to find a full start to finish guide is for the legal side of things.
Now with due respect to Mycnc Forum members, who are ALL obviously highly intelligent by the fact they joined, but I know there are still lots of Muppets out there who watch but don't fully read or take time to ask or understand what's involved but instead jump in with both feet eyes shut.!!

Not something that is advised or I would want to be partly held responsible for when it comes to electricty that is often used in a dry dusty enviroment just itching to catch fire.!!!

Yes I help people build there own PSU and have done so for many but I do it privately and make sure they fully under stand before proceeding.
So if you get no joy just ask and I'll gladly help but I won't post it here. PM me then just you, me and one other will read it.!!

eurikain

13-09-2015, 12:03 PM

What you are looking for is "linear power supply" as opposed to "switch mode power supply". Might help in a search. Commercially, the kind of thing you are looking for is "PS806-12 Linear power supply" from Zapp. I'm sure that you could build one for less, as already suggested, but the Zapp supply is the kind of specification that you need. I'm currently running an MDF router with one of these supplies, three SY60 motors, and M752 drivers. These drivers are old analogue boxes, now superseded by things like the AM882, but the combination is fine for this class of machine. The MDF structure can't take much more power anyway!

Thanks ! I've been struggling with this for a while. Are you sure that Zapp's will work ? It says it's 68V 6A. I think I would need something like 12A (=4.2A * 4 * .7) ?
I just checked and the M752 is very close to the AM882, but for $8 difference I think I'd rather go with AM882 :)
How heavy is your MDF machine, what is the area ? My gantry is a 1500 x 350 x 140mm torsion box (1 horizontal rib and 6 vertical ones) made from 22mm MDF. Approximated weight with Z and spindle is about 60kg. I think I overbuilt this haha.

Mostly the reason why you'll struggle to find a full start to finish guide is for the legal side of things. Now with due respect to Mycnc Forum members, who are ALL obviously highly intelligent by the fact they joined, but I know there are still lots of Muppets out there who watch but don't fully read or take time to ask or understand what's involved but instead jump in with both feet eyes shut.!!
I understand 100%. But a disclaimer is enough to warn people, right ? Plus, it legally protects you from being held responsible of anything. Too bad that shops like Zapp's won't make those tutorials, since they commercially sell those things.

So if you get no joy just ask and I'll gladly help but I won't post it here. PM me then just you, me and one other will read it.!!
That didn't fall on deaf ears ;) I will PM you some time this week. First need to finish my "stepper problem" thread :) Then will order BOB, AM882s, and motors. Maybe I'll ask Fred at BST Automation if he can get those for me.

Thanks to everyone for their kindness and the time they spent replying to me ! It's nice to see this lively community, that I will try my best to give back to when I get the opportunity.

cropwell

13-09-2015, 01:19 PM

I understand 100%. But a disclaimer is enough to warn people, right ? Plus, it legally protects you from being held responsible of anything. Too bad that shops like Zapp's won't make those tutorials, since they commercially sell those things.

In legal terms disclaimers mean diddley squat :stupid: Everything is biased towards protecting the stupid consumer - ask any retailer !!

eurikain

13-09-2015, 01:23 PM

In legal terms disclaimers mean diddley squat :stupid:
Couldn't find a correct french translation for that slang one :/ I'm guessing you're saying "not worth anything" ;)

cropwell

13-09-2015, 01:25 PM

Couldn't find a correct french translation for that slang one :/ I'm guessing you're saying "not worth anything" ;)

Even less than that mate !

eurikain

13-09-2015, 01:36 PM

Huh, weird, I thought they were commonly recognized, like open source licenses (GNU, Apache...). I'll give a call to my lawyer when I get time, I'm interested in the subject :)

Neale

13-09-2015, 05:13 PM

Huh, weird, I thought they were commonly recognized, like open source licenses (GNU, Apache...). I'll give a call to my lawyer when I get time, I'm interested in the subject :)

...and if your lawyer knows something about electrical things as well, you'll be laughing:)

The problem here is that a simple linear PSU is about a simple an electrical circuit as you can get, but the consequences of getting it wrong are serious. Get a proximity switch or BOB-to-driver wiring wrong, and you're unlikely to do anything much more serious than pop a fuse or give yourself a serious bit of head-scratching to do. Get mains wiring wrong and fatal shock or significant fire hazard are possible. In principle, it should be easy to describe but I wouldn't like to explain how to identify the wiring on a toroidal transformer with twin 110/220V primary windings. If you understand it, then you don't need the explanation and if you need the explanation, then you probably shouldn't try it! Which leaves the question about how you do learn through experience, and Jazz's suggestion that it needs a private one-one conversation that can be tailored to exactly your set of components, not some bunch of kit that someone else might buy randomly from eBay, is the way to go.

eurikain

14-09-2015, 10:48 AM

...and if your lawyer knows something about electrical things as well, you'll be laughing:)
Haha, my lawyer won't probably know anything about electricity, but may be about disclaimers :D

The problem here is that a simple linear PSU is about a simple an electrical circuit as you can get, but the consequences of getting it wrong are serious. Get a proximity switch or BOB-to-driver wiring wrong, and you're unlikely to do anything much more serious than pop a fuse or give yourself a serious bit of head-scratching to do. Get mains wiring wrong and fatal shock or significant fire hazard are possible. In principle, it should be easy to describe but I wouldn't like to explain how to identify the wiring on a toroidal transformer with twin 110/220V primary windings. If you understand it, then you don't need the explanation and if you need the explanation, then you probably shouldn't try it! Which leaves the question about how you do learn through experience, and Jazz's suggestion that it needs a private one-one conversation that can be tailored to exactly your set of components, not some bunch of kit that someone else might buy randomly from eBay, is the way to go.

Words of wisdom :) I'll contact Jazz in a few days. Thanks a lot for giving me the heads up !