Design phase question -- Clearpath SDSK + Acorn

[pfmcnamara]

Hi everyone, I've been lurking for a few months on the Forum and have found it incredibly valuable. I'm about to build my first CNC machine and was hoping to get some advice/opinions regarding motor control. First a bit about me and then a bit about my machine.

I'm an amateur luthier with 20+ years of hobby experience who is turning pro when I retire in a few years. Even as a pro, I will remain a low volume producer (15 to 25 unit per year). I work mostly in wood, but also build tools and fixtures in Aluminum. My necks and bodies require 3D organic surfaces. I've been using a CNC machine (ShopBot) for a few years at the local TechShop, but I now want to own one (for a lot of reasons). I've got an engineering and computer science background and I'm reasonably comfortable with electronics. I'm willing to spend a bit of time building from kits, but anything more than 40 +/- hours assembling a control system gets to be a bit too much.

At first, I was planning to order the CNC Router Parts Pro4848 with the plug-n-play NEMA 23 control system and the plug-n-play spindle. But I've been reading a lot about the Clearpath SDSKs. I'm entertaining the idea of SDSKs, Centroid Acorn Control kit, the CNCPro Pro4848 and the CNCRP Plug-n-Play spindle. But its turning into a real budget-buster. The SDSKs + Acorn + Centroid power supplies + NEMA enclosure + misc supplies is ~$3000 vs $1549 for the CNCRP plug-n-play motor control + $175 for Mach3.

So my question is: what are the real benefits of the Clearpaths and Acorn vs the Pplug-n-play NEMA 23s? I understand the "features" -- higher torque, quieter operation, faster rapids, etc., but I'm unsure whether those features would translate into real-world benefits given my use case (guitar building). I produce relatively small parts so I don't do long traverses. I don't hog huge amounts of material. My machine utilization will be ~200 hours per year. For me, "benefits" would be things like more precise guitar parts, faster job completion times, better surface finish, reduced maintenance (since constantly battling entropy seems to be one of the complaints with Mach3). I will say that once I get something working I absolutely hate fiddle futzing with software components simply to keep it working. So software stability is worth something to me. I'd be interested in hearing people's thoughts.

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[ger21]

I'm willing to spend a bit of time building from kits, but anything more than 40 +/- hours assembling a control system gets to be a bit too much.

The time factor is the biggest issue. Building a control box takes time, especially if you've never done it, and don't know exactly what you need. This makes the CNCRP plug and play packages very nice options for most people.
But building your own control has some big advantages.
Imo, the main issue with the plug and play kit is that it's built around an Ethernet Smoothstepper, which locks you into Mach3.
While tens of thousands of people are using Mach3, it's obsolete, and has been for a while now. There are several competent Mach3 replacements available, with the Acorn being one.
Mach3 development stopped over 5 years ago, and while it works fine for most people, it has a lot of bugs, and other options perform better.
In addition to the Acorn, other options would be UCCNC, or LinuxCNC. A lot of longtime Mach3 users are migrating to UCCNC.
I don't think there's any reason for any new CNC user today to be using Mach3, when there are much better options for the same cost.

Let's forget about the Clearpaths for now.
One thing you can do is buy the plug and play Nema 23 kit, and swap out the Ethernet SmoothStepper for an Acorn or other control. You should be able to easily sell the ESS for $125 or more on Ebay. You'll also save the $175 cost of the Mach3 license.
The Acorn and software is about $470, but you'll be saving $300 by ditching Mach3.
This leaves you with a lot of the wiring already complete, but you may have to move some things around in the box.
One thing about the Acorn, is that is has a lot fewer Inputs and Outputs than the ESS, so you may not be able to connect everything back up that's in the box.
UCCNC, with a UC300ETH and a UB1 breakout board,gives you about the same amount of I/O as the ESS.

Now, if you were going to go the Clearpath route, you should look at your options.
Since Clearpaths would require building your own box, consider building your own higher performance stepper control.

You can get stepper motors for $60 each. https://www.automationtechnologiesin...-640-oz-in-55/
Stepper drives for $100 each https://www.automationtechnologiesin...-motor-driver/
https://www.automationtechnologiesin...k-is-included/
Good quality power supply. https://www.automationtechnologiesin...c-duplicate-3/
There are a lot of little things that also need to go in there, but these would be the major components, in addition to the motion control board.

Basically, for the same $1500 as the plug and play kit, you can build a Nema 34 setup for the same price that would give much better performance.

I think the Clearpaths are overkill for your application, and their cost really only makes sense when upgrading an existing stepper powered production machine.

[pfmcnamara]

One thing you can do is buy the plug and play Nema 23 kit, and swap out the Ethernet SmoothStepper for an Acorn or other control.

This is an interesting idea. I need to spend a bit more time to map the Acorn ports to the CNCRP connections to make sure everything would be supported. Acorn supports 4 axes whereas CNCRP supports 5 -- but I don't anticipate needing 5. The proximity switches, e-stop, and spindle control are all supported. They have relay controls for external devices (although my dust collector is 220v so there is a little extra complication). And they support probing (touch plate in my case).

What I like about Acorn is that the control software and control board are tightly integrated.

[wizard]

Ger covered some good points but I might suggest that you are getting a little to deep into the controls end of the machine before you have finalized what size and type of machine you will be building. A mechanical design that meets your needs is very important and what you build has an impact on your controls implementation.

The first thing to get a handle on is machine size. Interestingly to me any ways is that you say you are interested in musical instruments manufacture but then say you don't need a big machine. At least in my mind a machine big enough to do guitar necks, via 4 axis machining needs to be rather large. For example if you plan to machine between centers on the 4th you will need room for the drive end and the dead end. Like wise if you prefer to machine on a trunion table. In either case you will likely need a higher Z clearance than many machine posses. I'd be putting a lot of thought into this as you want to have confidence that the machine you build can deliver what you hope to get off it.

When it comes time for CNC controls there are more options for low end machine than at any time in the past. This includes full blown CNC controllers from China that are very FANUC like to GRBL derived systems at the other end. Centroids Acorn is a very interesting new entry into the market and frankly it looks to be well implemented, if you are interested I'd suggest following threads here and on other forums that cover implementations of this controller in various machines.

The discussion about servos vs Steppers can get very involved but in my opinion steppers are easier for a person new to CNC to implement. Well to a degree anyways, the new servos and the tools available to tune them make life far easier than it was in the past. Still tuning a servo is far easier if you understand just a bit of control technology so I think it is fair to say going servos requires a higher commitment to do your own engineering.

[ger21]

What I like about Acorn is that the control software and control board are tightly integrated.

UCCNC is as well, as it's one company developing both hardware and software. Other competing products do as well.

Mach3 (and Mach4) are the only control software(s) that rely on third party hardware manufacturers.

[1Jumper10]

If you go with Clear path SDSK's I'd recommend their NEMA 23 versions. The 34's are overkill for a 4848 CNCRP machine. Plus you'll save a little money on 23 size CNCRP motor mounts versus the 34's.

I'd also recommend something other than Mach 3. I use UCCNC and a UB1 board and it's working well.

Each of us has our strengths and weaknesses when designing/building a router. And Ger21 gave some really good advice. You have to decide what you want to buy already built, and what you want to build yourself. Whatever your decisions may be, there are numerous good examples here that you can get ideas from. Good luck.

Sent from my Pixel XL using Tapatalk

[pfmcnamara]

UCCNC is as well, as it's one company developing both hardware and software.

I was not aware of that. That's good to know. Its hard for me to figure out who is actually behind UCCNC -- is CNCDrive Motion Controls the original publisher of UCCNC? Is it open source or proprietary?

I think my choice of control software is a pretty fundamental choice. At this point, I'm not burdened with any legacy, so maybe I should start by picking the software. My impression (and this might be wrong) is that Centroid is an incumbent in the higher-end space who is now trying to win over the maker market. So Acorn is mature, battle tested software taken from higher-end products with some features stripped out. It looks like they have a bunch of good tools for config and integration with 3rd party gear. UCCNC seems to have gotten a strong start in the maker world and is now moving upmarket by adding more and more features. My guess is that it might be a more modern architecture (but its hard to know its lineage). Is this a good view of things?

I've now taken a closer look at UC300ETH and the i/o is impressive.

[pfmcnamara]

If you go with Clear path SDSK's I'd recommend their NEMA 23 versions.

Would that be the CPM-SDSK-2321P-ELN?

[ger21]

Yes, CNC Drive is the creator of UCCNC. It's not open source. A license is $60, and is tied to the motion controller.
CNC Drive started out making motion controllers for Mach3. Their original controllers were the USB UC100 and UC300. Due to many outstanding issues with Mach3, they decided to create their own control software, which resulted in UCCNC. I think UCCNC was introducerd about 5 years ago, and initially, was pretty basic. In the last 2 years, they've added a lot of new features, to the point now where it's nearly comparable to Mach3 feature wise, but far superior performance wise. I wouldn't say that they are moving upmarket. Just a natural progression of their software.

The Acorn is actually the motion board, not the software. The software is the same (or similar to) the software on their $2500 systems. Centroid has been in the higher end CNC control market for a very long time. They came out with the Acorn board to try to get into the hobby market.
Since the acorn itself is very new, I wouldn't say that either one is a "more modern" architecture. I think they are just different approaches.

I wouldn't be surprised if the Acorn is a little better in the motion department, due to their many years in the industry. But UCCNC is very good, and constantly improving.
If the Acorn supported 6 motors, and the same amount of I/O that UCCNC does, I'd probably be testing one now. But it's too limited for me in it's current form.
But, I'm very happy with UCCNC. Their support is outstanding. Ton's of I/O. Excellent customization options.
Check out the UB-1 motherboard and UD-1 daughterboard for the UC300ETH. These are what I'm using, and are outstanding products as well. These are made by CNC Room in Thailand.
UB1 [UB1] - $180.00 : CNCRoom, The Room for CNC'ers, from Mini to Big machine, from Hobbyists to Gurus - ????????????????? ???????????????????????????????
UD1-U [UD1-U] - $104.98 : CNCRoom, The Room for CNC'ers, from Mini to Big machine, from Hobbyists to Gurus - ????????????????? ???????????????????????????????

[pfmcnamara]

The first thing to get a handle on is machine size. er forums that cover implementations of this controller in various machines.

I'm thinking about the 48 inch by 48 inch pro machine by CNC Router Parts. My neck blanks are 30 inch long.

[1Jumper10]

Would that be the CPM-SDSK-2321P-ELN?

That's the "P" model, I would recommend the "S" model: CPM-SDSK-2321S-ELN. Its their high torque version and will accelerate faster than the "P" model at the expense of some top speed. But the "S" model will be plenty fast enough. At 3:1 gear reduction (CNCRP Rack & pinion NEMA 23 drive units) you'll get over 900 IPM rapids pretty easily.

[mactec54]

Hi everyone, I've been lurking for a few months on the Forum and have found it incredibly valuable. I'm about to build my first CNC machine and was hoping to get some advice/opinions regarding motor control. First a bit about me and then a bit about my machine.

I'm an amateur luthier with 20+ years of hobby experience who is turning pro when I retire in a few years. Even as a pro, I will remain a low volume producer (15 to 25 unit per year). I work mostly in wood, but also build tools and fixtures in Aluminum. My necks and bodies require 3D organic surfaces. I've been using a CNC machine (ShopBot) for a few years at the local TechShop, but I now want to own one (for a lot of reasons). I've got an engineering and computer science background and I'm reasonably comfortable with electronics. I'm willing to spend a bit of time building from kits, but anything more than 40 +/- hours assembling a control system gets to be a bit too much.

At first, I was planning to order the CNC Router Parts Pro4848 with the plug-n-play NEMA 23 control system and the plug-n-play spindle. But I've been reading a lot about the Clearpath SDSKs. I'm entertaining the idea of SDSKs, Centroid Acorn Control kit, the CNCPro Pro4848 and the CNCRP Plug-n-Play spindle. But its turning into a real budget-buster. The SDSKs + Acorn + Centroid power supplies + NEMA enclosure + misc supplies is ~$3000 vs $1549 for the CNCRP plug-n-play motor control + $175 for Mach3.

So my question is: what are the real benefits of the Clearpaths and Acorn vs the Pplug-n-play NEMA 23s? I understand the "features" -- higher torque, quieter operation, faster rapids, etc., but I'm unsure whether those features would translate into real-world benefits given my use case (guitar building). I produce relatively small parts so I don't do long traverses. I don't hog huge amounts of material. My machine utilization will be ~200 hours per year. For me, "benefits" would be things like more precise guitar parts, faster job completion times, better surface finish, reduced maintenance (since constantly battling entropy seems to be one of the complaints with Mach3). I will say that once I get something working I absolutely hate fiddle futzing with software components simply to keep it working. So software stability is worth something to me. I'd be interested in hearing people's thoughts.

You should watch this video before you consider the Clearparth, this is a good comparison of what other choices you have, you will have a much smoother running machine with the DMM Tec system, Dmm also have a Video with Centroid Acorn controller setup