Does anyone have a buyer’s guide, or some recommendations for controller boards? Seems that there is no concise comparison of boards, only individual companies hawking their wares.
Looking to do a 4-axis router. Will likely need 5 outputs as I hope to have a slaved pair driving the x-axis.
I don’t have a buyer’s guide, but I do have a recommendation. I would highly recommend PMDX (http://pmdx.com) and a Ethernet Smooth-stepper if you are looking at anything more than a light weight (~1HP/3-axis - wood only) platform. I own two CNC machines, one a CRP-4848 48"x48" CNC router, and a Sieg X3 converted to CNC. The CRP-4848 runs with a PMDX-126/PMDX-107/PMDX-134 and a Ethernet Smooth-stepper. No noise problems and I have had no other problems with this combination. I am planning to convert the Sieg X3 to the same combination, the boards are in hand I’m just waiting for the time to do it.
FYI - PMDX is rumored to have a PMDX-426 which includes full six axis support with ethernet connectivity and on-board spindle control coming in February, that supports everything I listed above minus the PMDX-134 support (the Gecko driver motherboard). It will also handle 5v and 24v control voltages. I’m really tempted to lay a side the the boards I have as spares for the CRP-4848 and use the new PMDX-426 on the Sieg X3.
I think PMDX boards are the best on market for the price point. You have spend a lot more to get better. I have been nothing but impressed with their support.
In my opinion, you haven’t really offered enough information for the people that could help you to give you good ideas. The size of the machine should dictate lower limits on supply current for each stepper.
@Freeman_Pascal Thank you.
@Kyle_Kerr , do you mean the size of the cutting area? I was planning in 1200x1200mm. I will mainly be focused on hardwoods although the occasional bit of aluminum
would be nice. I have a 220V power supply if that matters. Other than that I have very few details as I am just planning out my build.
maybe depending on your system . You may contact the dealer
List up a few suggestable controllers please with out the need to show off what you own or not, just some names and maybe links ? thanks !
GRBL over Arduino UNO and Tiny-G over Arduino DUE are two inexpensive USB-based firmware choices. You can get Tiny-G board including drivers too. Smoothieboard/Smothieware is another good choice… You can repurpose 3D printing firmware as Marlin or Sprinter too.
All these are open-source choices.
@Paolo_Pinsone That’s the controller of your machine . you may show some photos
Having just gone through this process, I think you need to first work out what steppers, etc. you will be using. That will give you an idea about what power drivers you will need. Then, think about what hardware you are going to run your CNC on - desktop/laptop, PC, Mac, micro (Beaglebone, R’Pi, etc.), Unix. What sort of interface - USB, Wireless/Bluetooth, Parallel, Ethernet… all of those will dictate what you eventually buy. And price - your budget will have a big input to your choices. And then there is where on the technology curve you want to be - safe and secure with lots of support, or bleeding edge.
In my case, I wanted to have a choice of drivers, but with a decent driver built in to start with. I wanted to be able to run from any platform - PC, Mac, Raspberry Pi/Unix, Web/dedicated, laptop/desktop. I wanted to be on the leading edge of technology and I wanted a board that did its own g-code decoding. I wanted to be able to be wireless and I wanted to use ethernet or USB, not a dedicated board or parallel, and SD card, if possible. I wanted 4 axis, because my machine has dual y-axis steppers and I didn’t want to share a driver. And I wanted to be able to talk to the board in a way I was familiar - so JSON, TTY, HTML, that sort of thing.
That meant I was already at a short list of only a couple of boards - The Smoothieboard and the TinyG seemed to fulfill most of what I wanted. I ended up with a TinyG, although in hindsight that isn’t the right decision for me - I traded off connectivity for algorithm. I am happy with it because it gives me wireless comms, it uses state-of-the-art tech, it is open (ish) and extensible, it uses the motor drivers I wanted to use (Ti DRV8811s) and is easy to get around.
I will probably buy a smoothieboard to try out at some stage, when I have finished spending shedloads of money and have something coming back the other way.
There are good reasons I didn’t want to use a breakout board or something like the Gecko, Planet CNC, GRBL, CNC shield, etc., but harder to quantify.
For you, with 5 axes, I wouldn’t bugger round - just buy the Smoothie 5XC http://robotseed.com/index.php?id_product=13&controller=product&id_lang=2
You won’t regret it and it will save you money over assembling the various boards, drivers, etc.
I took the advice of @Mike_Thornbury and went through the exercise of figuring out my desired motor size. My hangup has always been starting with the machine and figuring how hard to push it later. This time, I can start at the max I’d probably ever do: Milling 6061 Aluminum.
I started with the excellent Feeds and Speeds at http://zero-divide.net (CNC Speed and Feed Calculator and Formula). I figured the most I’d ever be doing was making more structural bits using a 12.7mm end mill. Plugging in all the parameters, and a 2cm deep cut I get a spindle speed of 3975, a feed rate of about 0.58m/min and most importantly a cutting force of 279.79N. 0.7Hp, totally doable.
I used this information to feed into the motor selection tool at Oriental Motor (Motor Sizing Tools). I assumed a 30kg gantry with a 0.1 friction co-efficient. 80% efficient 16mm ballscrews and a 3Nm breakaway torque (isn’t this changed via pre-load?). My External force is that from the previous calculation and I chose the simpler Variable speed operation of 0 to 9.66mm/s (instead of m/min). Using a half a millimeter of stopping accuracy, I get that the required torque is to be 6.133Nm, and a load torque of 4.09Nm
So that 6.133Nm max torque is about 868.5oz-in (which seems to be what most stuff is listed for on ebay), and the load torque is 579.19. So in this cutting example, my best case Aluminum cutting needs a feed rate of 0.58m/min and with 5mm per revolution I’d need that load torque at 2900RPM. So, I’m going to bet I’ll need some high voltage, and it also means I’m looking at like a 2kW “Medium inertia” system (http://www.automationdirect.com/static/specs/sureservolowmed.pdf). The problem now is that for $832 It’ll cost me to do one axis I can buy a whole mill from harbor freight.
Now this analysis is all bunk, as there is no way I’d buy steppers that large. More likely a smaller bit, more cuts and push it less. I will avoid the ‘size my system’ upfront and go back to trying to find the lay of the land. Right now I’m looking at more of a holistic approach to just see what is out there. What controllers are good at multiple axises, which are easy or hard to configure, which people have had success with, and which I should avoid. In the end, I’m going to have to make a lot of decisions regarding rigidity, speed of cutting, accuracy, cost, etc. Right now, I’d like to just know what is out there. Thanks to @Freeman_Pascal (PMDX) , @Miguel_Sanchez (GRBL/TinyG) and @Mike_Thornbury (Smoothieboard) for giving up some suggestions.
Hey, I’m a TinyG guy - but my next controller will be a Smoothieboard… 
And… I think your ideas about cutting 2cm of aluminium plate are way out - with a ‘hobby grade’ machine, you are much more likely to be cutting 2-5mm at a time. I cut mostly ply and MDF, I have decent 450oz steppers and a 3kw spindle and wouldn’t even cut MDF at 2cm/pass. Typcially, for 18mm ply I am making three passes of 6mm.
It takes a hefty commercial-grade machine to cut 2cm passes… with a hefty price tag.
Sorry @Mike_Thornbury , my sarcasm did not come across very well. The last paragraph was the crux where I said I really just want a survey of what people were using or a buyer’s guide so I could get a better idea of what is out there.