Please Help - In depth technical advice requested. Longish read

Mostly Printed CNC - MPCNC Advice
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Hello everyone, i’m Hunter. First time poster on the V1 forum and of course I go for the help thread. Sorry about that, i’m sure its annoying for you veterans in here. I do plan on being an active contributor in here, but I don’t have the experience to give any valuable input yet. This will probably be a long post, but I am humbly asking for advice and opinions from you guys, so please stick with me here and offer what you can.

Some backstory - I have been debating on making this thread for about a week now. At times I can be very hard headed, particularly when it comes to asking for help. I say that to follow up with this, I have scoured the internet as well as this forum to try and find answers to my questions. I have easily spent 100 hours in the last 2 weeks researching, sourcing parts, agreeing with myself on the build then finally finding a new piece of information and tossing it all and starting over. I have a need to build this for use in a business. I am rather young, 28, I have been a business owner since I was 19 for many reasons. I have taken the last 2 years off to be a stay at home dad in what I could best describe as a mid-life crisis. I have been mildly successful in that I haven’t had problems with making money, but I have been miserable(business wise, being a stay at home dad is awesome, but our savings will only take us so far). So these last 2 years I have been spending time with my family and myself doing some serious soul searching to find what I really want to do with my professional life for the next 40 years, and I finally believe I have a direction. At this point I am over examining, over planning, and over complicating. Please excuse me if this is TMI on the personal end for this place, but it felt good to vent a little bit and I felt its relevant to state. Long story short, i’m not asking lightly, and not without doing my due diligence before coming for help.

My technical knowledge is not extensive. Software or electronics are not my strengths, only because I haven’t dedicated a substantial length of time in the field. I have dedicated quite a bit of time to 3D printing, along with completing projects in several other mediums. I have 3 3D printers and an good set of tools. My base of knowledge is sound for me to move forward in my opinion. My problem solving and learning abilities are exceptional, in this case i’m having trouble finding a direction. A dozen softwares, a dozen firmwares, a dozen control boards, VFD or no, spindle or router… you guys know the struggle. Cost is not really a problem for the MPCNC build, but if its going to end up in the 3-4k range I might as well just buy an in the box CNC. I would like to list what I have settled on for sure, my requirements for this machine, and some questions and go from there.

So first, what are my requirements for this machine?

  1. Dimensional Accuracy - The machine must be accurate. From what I have read, this machine has little problem with this. I’m not talking aerospace grade tolerances, but within 1% or so. I don’t believe that’s hard to do with this machine.
  2. Materials - Needs to handle everything up to aluminum with no issues as far as mechanical capability goes. I understand this will be more of a hurdle on my end than that of the equipment.
  3. Reliability - The machine must be reliable. I understand things break from time to time, it is inevitable. Breaking down every other day is unacceptable. User error is a different story, but I am setting time aside for the learning curve, and I know it’s going to be a steep one. That’s ok.

What have I agreed upon(mostly)?

  1. Footprint - I want to build this to have a 30"x30" working area.
  2. Tubing - 1" material with the thickest wall I can find, I have found several sources online and in my area. Stainless or DOM. I have considered filling the interior with either epoxy or closed cell foam to increase rigidity, but that’s just an idea I’ve been throwing around. I can get enough material to do it for free from local sources, along with epoxy I have on hand.
  3. Dual endstops - This will improve accuracy and help me achieve my goals. The cost and effort for the benefits is worth it in my opinion.
  4. Router - Makita RT0701C. I feel I have settled on this for my tool. I don’t believe the added cost for a VFD along with a high quality, reliable spindle will be beneficial enough to justify the cost. I can upgrade later should the need arise, but in the beginning I think the makita would be my best choice not only for cost, but to help simplify the set up. Lots to learn and I believe simplifying this portion would be better for me to focus on the other areas, while still functioning as I need it to. Sound is not an issue, make it scream.

That’s pretty much what all I have agreed upon. I have several questions about electronics, software, and firmware. If you feel anything I have said or am about to say is wrong, please tell me. I would much rather be wrong than continue to be ignorant.

  1. Stepper motors? There are lots of choices here. I have seen ryan and jeff say several times that making this machine effective is really a balance of the parts working together. What would be optimal for torque and accuracy and why? This likely seems like a simple decision, but there is alot that I only have a very basic understanding of here as it relates to how this machine works. It seems to me the steppers in the Primo kit that V1 sells are sufficient for my purpose, is there an alternative that would be better for a slight increase in cost?

  2. Main board - Holy crap. So many, I don’t even know where to start. I use the SKR Mini E3 V2.0 on my 3D printers, and thats what is sold in here (i’m pretty sure), but I feel that’s not the best choice for a dedicated CNC. The choice of this relies on the choice of firmware and software.

  3. Firmware and software - Again, holy crap. I have experience in fusion 360, but I wouldn’t consider myself an expert by any means. Would something like Rhino coupled with RhinoCAM be a better direction to take with a dedicated CNC? If not that than something comparable? I do not mind spending a larger sum in this area since I believe from what I understand this will have a larger impact on the outcomes than the hardware. Not entirely I know, but my understanding thus far leads me to believe this is likely the most important piece of the puzzle as long as the rest is of sufficient quality. What other choices are there and why do you prefer then for CNCing? I know OF Grbl and Estlcam, but i don’t know them. Are they the most popular because they are free or cheap?

  4. Printed parts - Has anybody experimented with printing the parts in anything other than PLA? Like a CF Nylon to improve rigidity? Haven’t researched into this a whole lot, but it has been on my mind. I don’t believe the benefits would be substantial, but I don’t have the experience you guys do with this platform.

I’m not really worried about the platforms being difficult to learn or for advanced users or whatnot. I am seeking function over form so to speak. I’m more than willing to put the time and effort in to learning all of this. I would be ecstatic for any responses I can get on whatever topics you feel like discussing here. I’m sorry the post was long, and i’m sorry if you’ve heard the same crap 900 times here. I have read and read and read, here and elsewhere, but I just didn’t feel like I got the answers I was looking for. Thank you.

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Hunter,

Welcome to the (crazy) forum! Like you said the choices and permutations in this place are almost too much to wrap your head around. Your TMI and circumstances are important information to understand your intent for your machine.

But, I think you’ve left off an important piece: What is the main “mission” of the machine? As you can see from the many threads, it really matters whether you’re planning on making mostly wood, or metal, or occasionally planning on attaching a laser or swivel knife.

In my case I want to do wood, thin fiberglass panels, laser cutting of thin plywood and vinyl cutting. So far I’ve been able to do that with a larger than recommended MPCNC Primo unit (24x36), Rambo 1.4, and a Dewalt 660. About the only thing I want to add is a variable speed control to slow down the router.

I know you said cost was not the driving factor, but you probably have seen incredible things done with the simplest setups of these machines. You can also see that many, if not most, of the participants in the forum are “tweakers” and hobbyists, in that they are always upgrading, or building something new. That often means that the initial cost can be modest, if you’re will to do upgrades in the future. It also means the low-cost route in the beginning does not limit your future machine. And the smaller, low-cost machine will be better for the learning curve (cliff) you’re going to climb.

I don’t know how much that helps, but I know you’ll find an impressive group of supportive individuals here on the forum.

Mike

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Welcome to the forums.

Lots of what you ask about has been discussed in these forums in the past. Top recommendations:

  • I doubt anyone here will flat out say “No - don’t do that” since we’re almost all tinkerers at heart and love getting the most out of our individual machines. It’s your machine, you’re free to do whatever you think is interesting with it and to it. You will hear “others have tried that already” in a couple of cases.
  • Rigidity is king for working with metals - smaller footprint increases rigidity. 30"x30" is probably large for metalworking but would be fine for other materials. Keep Z travel as short as you can get away with.
  • Build it as recommended first (with regards to materials, etc.) then once you’ve got some time on your own machine consider changes/upgrades. The current Primo design represents a lot of learning from previous models and a wide variety of experimentation both by the designer and by lots of forum participants. You get the benefit of learning vicariously from other’s trials and errors rather than your own school of hard knocks.
  • For the MPCNC, several folks have tried other materials (PETG, ABS, CF) and found that either rigidity was poorer or the extra cost wasn’t worth the marginal benefit. Bottom line is that the cutting forces transferred to the machine are well matched to the capabilities of PLA. On the Lowrider, some folks have machined aluminum (or even steel) assemblies to replace some of the parts, but that’s a different animal.
  • Performance is going to be a balancing act between rigidity and the mass/momentum that has to be fought when changing direction as the tool moves around. The recommended tube materials and thicknesses achieve the required rigidity without extra weight. I’d avoid going for thicker walled material than is specified - you’ll end up with more weight and more sag, so less rigidity and slower possible speeds.
  • There are several examples of pipe filling experiments on the forums. Consensus seems to be the juice wasn’t worth the squeeze, but a little searching will allow you to look over the data that those testers provided.
  • The biggest issue with steppers is to make sure you’ve met or exceeded the force they can provide. Here again, bigger = heavier, which is not a benefit as the motors are part of the moving machine. There are great options available in the V1 Store, at a good price. Redesigning for a larger format stepper (e.g. NEMA 23) is possible - folks have done it, but again, a lot of work for not much, if any, measurable benefit.
  • You can use any controller you’re familiar with, but to get up and running with the minimum fuss, go with one from the V1 store. If buying fresh for this build, I’d go with a 32-bit board. When I built mine, I pulled an older Arduino/CNC Shield out of my spare parts box and it’s done just fine, but I like messing around with grbl so wasn’t afraid to find my own path. Support on the forums for the boards from the V1 shop is excellent.

I think the MPCNC is a great fit for the road you’ve decided to travel. The great thing about it is you are joining a journey others are already on, so you can benefit from their (our) experiences, and still get support for whatever new capabilities you want to explore.

Best of luck. Let us know how we can help!

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These two requirements seem like the hardest to meet. I would decide which one is more important to you and either make a 18x18x3" aluminum build or a 30x30x3" wood build. Once you have a machine for a while, you will quickly learn what is important to you, and decide if you need a second MPCNC, a Low Rider, or some expensive workhorse.

The preferred SKR used here is the Skr Pro v1.2. The mini is different and the 2.0 has not been picked up for use here. The Skr Pro v1.2 is a great board for many things, including an MPCNC.

This machine will be yours and you can do what you like with it. The goal of the docs and Ryan’s advice is to have a “yellow brick road” you can follow to have some success. This includes using Marlin firmware. You will have a good chance at success, but a grbl board, either the esp32 variety or just a CNC shield will work fine.

My recommendation is to just try it with PLA first. It is a very rigid material, and very inexpensive. Things like PETG are more flexible and work. Nylon is not something I’ve used, but my impression is that it can be a pain to print and is expensive.

This really is a “Choose your own adventure” project. But if you are looking for no nonsense, reliability, and to hit the ground running, then you should follow the yellow brick road, get a kit from the store, follow the estlcam basics and consider the machine an investment in your brain. Once you’ve spent a few dozen hours on the machine, you will be able to tell where to go next (moar v1 machines, bigger CNC machines, etc.). You may also decide to change the size, replace the controller, or spindle, or print some parts in nylon, but you will do that with the first hand knowledge of using the MPCNC for your business.

Just don’t fall for the hype. You don’t have to spend thousands to have a machine that can make you money and you don’t have to buy expensive software to control a 3 axis router. Any CNC router will have failed workpieces. Any CNC operator has a lot to learn. I would rather learn and make those mistakes on a $500 machine than a $10,000 machine. The $10,000 machine can probably cut bigger items in metals, and it can probably cut faster, but not 20x faster.

You will need a healthy dose of confidence and some patience. It sounds like you’ve got that already.

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Having built several of these, and following the excellent feedback above, I don’t have a lot to add.

30x30 is OK, but aluminum will be painfully slow on it. I built a 10x12 (teeny tiny burly) that did great on aluminum and even cut some steel, but I think I could have gone as high as 12x18 without losing anything. I’ve also cut 1/8" aluminum on my 2x4ft primo, but only from much smaller sheets (about 1x2).

You should come in well under 3k for your build and tooling. In fact, you could build several mpcncs for that, and really, that’s a great way to increase your output compared to buying a faster machine.

A while back i looked at tormachs for a comparison. That’s what I would consider an actual step up from diy cncs. Something like 15k to start, not counting tools and tool holding, work holding, etc. On top of that, the envelope is quite small (8x12, from memory). Maybe the maintenance is less frequent, i don’t know, but unless you are turning out part after part after part, that’s A LOT to pay for. I added another build to my shop for a very specific type of job and increased flexibility, and I’m in it for about 2500 usd now. The machines “in a box” under 4k that I’ve seen are not substantially better than the mpcnc, just perhaps more flexible as larger machines. Again, i think you can build 2 for under 1k if you’re careful.

If you need flexibility or high output, definitely plan for multiple machines. Smaller machines are easier to learn on, but a few of us have used larger machines to make placement holes for the legs on smaller machines.

For software, download the programs you are interested in and see what you like. Estlcam is simple and easy to learn, lots of support here. Freecad is comprehensive and improving, but the sketch tools suck. Fusion is free-ish but unless you subscribe it is fairly crippled (depending on what you need) and have shown that they’ll pull the rug out from under you if it suits them. Solidworks is solidworks, and a while ago I think you could get a free or discounted copy of you were in an aviation club (which was cheap) but that may have changed.

In terms of rigidity, in most cases the plastic will flex before the tube so don’t sweat it too much. I had a 2x4ft primo, and epoxied some 1/2 in conduit i the longer gantry tube. The difference was noticeable and measurable (hanging weights) but that is extreme size and probably not applicable to appropriately sized machines.

The recommended steppers are plenty. Your machine WILL flex before you lose steps as long as your tools are in good shape.

In terms of boards… I’m still running mine on a mega/ramps and don’t feel limited.

And finally, don’t hesitate to make a post and ask questions. Even if you want to learn it for yourself, there are tons of really smart people here and many of them can point you to resources if that suits you better. This crew really is the best, and it’s been a long time since i was in a community that was even close.

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The main mission of this machine would be 60/40 Aluminum/Wood. I plan on putting 2 more of these together as a separate laser cutter, and swivel knife(maybe, it will probably end up being a second setup of one of the other two), and/or a lowrider for the full sheet/large format capabilities. Variable speed control seems to be almost a requirement for cutting aluminum, and i’m not sure the best way to go about that yet besides spindle and VFD. I think the best results I have read about with variable speed have been with the makita. I’m completely open to rebuilding and upgrading in the future, that’s why i’m insisting on this platform because the possibilities are endless when it comes to size and ability.

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Yeah, I don’t see anyone saying “don’t do that” around here. I’m not dead set on 30x30, and I understand what you’re saying about smaller=more rigid, I was trying to push the envelope a bit there. Z travel will likely be the recommended height or just above it. I don’t plan on cutting 5" thick material or anything, and if I ever do I can alter the machine as needed. I have dug through a bunch of the lowrider threads, love what they did in that regard. This whole project reminds me of the Dave Gingery book series, thats how I got into this kind of thing when I was a teenager. Build your own metalworking shop from scratch. This is basically that with computers and I love it. The mass/momentum in changing directions I understand from 3D printing. Usually referred to as jerk settings in cura and has other names in firmwares like klipper. It should be the same with a CNC except you have to account for extra weight and rotational force, correct? I know that’s something that will come with learning how to use everything. I have seen it said in many places that it is a balance with the frame/hardware. Grbl or estlcam is kinda what I was aiming for, something catered to CNCs.

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I think most of the major points have been hit already, but I’ll throw in my 2 cents.

This is a DIY setup by the very definition of it. You can get away with not knowing a lot about electronics by using the pre-built kits and getting basic help here on the forums. But keep in mind that the kits and instructions are NOT to make a 100% complete CNC machine! Yes, it takes care of 90% of it, but you still need to engineer a few things yourself. That includes cable management to keep wires organized and out of the way, plus a way to hold down your material being milled/cut. Thats not to say that you can’t use other’s ideas (some even offer their down designs you can print up), but its not as straight forward as building the MPCNC itself.

My suggestion would be to check out a ton of the threads made by us that built our own already and get an idea for the cable management and material mounting before diving into this at full throttle. Its honestly not that hard, but you’ll have to have a bit of engineering skill in you to build a 100% functional CNC machine.

Touching on a few questions you had…

Great choice. It can handle most if not all of the materials you want to attack. I have one myself and its perfect. You’ll only need a more powerful spindle if you want to go faster, but that will introduce new problems. Start with the Makita and you can always swap out tools later.

I bouught the 5-pack off of Amazon that is linked in the directions. They go up to 2 Amps which is the highest power you’ll get from these sized motors with the exception of VERY expensive custom models. As others said though, these motors are more than powerful enough. Keep in mind that the X and Y axis are powered by two motors each.

Second to software, this will be the biggest option to pick from. I personally don’t have a stand-alone board, but rather have a whole PC running LinuxCNC that connects to a driver box I built, and it controlls everything. There is even the option to use a Rapberry Pi. Lots of options.

Same as above, if not more complex with options. You’ll see a lot of people talk about EstlCAM, which also prefer. But still, there are a ton of options.

Be prepared to build and disassemble the whole system at least a couple times. When I first built my MPCNC, I thought I was doing it perfectly. Then I ran the machine. I ended up almost completely taking it apart and rebuilding it with better adjustments.
Its certainly a journey, but worth it in the end. The MPCNC is an amazing piece of machinery, but it has a learning curve. Build it, research the electronics/software, and start cutting!

You’ll fit in just fine :rofl:

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Not a lot to add, but welcome!

I have a 25X37 Primo. I am not planning to use it for aluminum in this configuration, but now I have a LowRider, so I plan to reduce the size on the Primo so that I can use it for harder materials, like aluminum. Both my Primo and LowRider use the Makita RT0701C

In general we move the router pretty slowly when cutting, so acceleration isn’t as complicated as all that.It is set lower, but when we’re going to a lower speed. Since we’re basically using 3D printer software, we use the same settings, just set slower. The default V1 firmware is plenty reasonable.

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I don’t think anyone else has addressed this yet… I don’t think you’ll have any issues staying well below this cost. If I remember correctly, I think my total out of pocket was around $500 to build the entire machine included a base.

I’ll second most of the other statements. 30x30 and aluminum go against each other. I’d start with the 30x30 knowing that it will do well with wood. Then build a smaller, stronger MPCNC for tackling the aluminum.

I would recommend going stainless. I went with DOM and am thinking of replacing my tubes. This is partially for the more regidity, and partially because my DOM tubes were ever sow slightly bent.

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The makita will be great for aluminum. I’m using a dewalt 611 and rigidity is the limiting factor. They both have a speed control that maintains the rpm for you, so as long as you know the set rpm pretty close (within 1krpm or so) it will be close enough for the chipload to work out well.

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It seems to me that it would be better to build a smaller platform that will machine aluminum and wood, then build a larger one for just wood when it is needed. 30x30 is still rather small IMO, I know it’s not for what is being built but the machine obviously has its limits. I have considered an expensive workhorse, but the only reason I can really find to buy something like that is for something like a diabase 5-axis small platform. More would be better but it gets into big money really fast. It just doesn’t make sense to me to buy a $5,000 “workhorse” with practically the same capabilities as an MPCNC or a lowrider. There are a lot of variables to that obviously but for the most part I haven’t found them to significantly outperform what has been done with these for what I intend on using it for. The game changes when you get into 4 or 5 axis machining but I don’t really see a need for that anytime soon. Thank you for the input.

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Thank you, this is the direction I was hoping this would take. 12x18 would be ok, but damn that’s small. I was really looking to get the first build nailed down (if that’s even possible) electronics wise, then build more. 15k is about what I have to play with machine wise, and 10 MPCNCs sound way better to me than 1 or 2 pre-built machines. I find the platform here is miles above the mainstream hobbyist offerings, for both laser cutting and CNCs. I like extreme size and inappropriately sized machines, that’s what this platform is for, pushing the limits right? Do you have a link to that thread if you made one?

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Yeah I understand. I believe the kids here are designed to maximize access for everyone, so cheap simple and effective. There are just so many options and alot of the threads on many of these topics are so old, half of the information isn’t even valid. That’s not always the case, but I have found it to be the case enough to worry about it. Technology is just moving so fast it’s unreal. I’m not nearly as intimidated by minor engineering tasks surrounding the machine as I am the sheer number of options that are available these days in terms of electronics and software/firmware. There’s alot, so I was just kinda hoping what everyones experience was from basic to professional softwares. Such as the comparison between using EstleCAM and RhinoCAM Professional. Not necessarily exactly that comparison, but you get the idea. I would be very very interested in knowing more about your LinuxCNC/Laptop setup. I would be super happy to go for that. My wife has wanted a new laptop anyways and her old one would be perfect for this project. I remember when I started 3D printing and did exactly that 3 or 4 times until I was satisfied with the build. I enjoy doing it so i’m really looking forward to that part. Thank you for the input.

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The videos are old, and I should really get around to making new ones, but I’m in a temporary housing situation for the last year. Not ideal for anything.

2x4 prior to epoxy tube

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If I were starting over, this is what I’d have done.

The 25X37 platform that I have isn’t actually quite big enough for some projects that I’d like to do, but it’s getting pretty big for a Primo. That’s why I built a LowRider. My LowRider isn’t as big as it gets, but it’s bigger, and enough so that I can do the couple of things that the Primo wouldn’t quite take. If I ever need it bigger, I just need the table to put it on. Or, say a 4X8 sheet of plywood and a couple of 10’ 2X4s…

So I’ll be cutting down the Primo to a smaller size, so I can start playing with other materials.

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Welcome to the madness!!
After all the great replyes I don’t have much to add. Just that I started with a Burly that was 24x48 ( I know way to big for a Burly) after that, Ryan was Kind enoth to let me be a Beta tester for the Primo build. The primo was cut down to a size 18x18 ish, with that size I’ve been able to cut wood, aluminium and Steel also I add a laser to it. For the bigger stuff I built a Lowrider that is big enothg for all I do so far… 32"x60".
I do agree that you will need a little bit of engenuaty when it comes to cable management, other then that this machine is a no brainer.
As far as Cad goes, you have a buch of opitions, I use Fusion 360, but you also have OpenSCad, FreeCad, Onshape just to name a few and for the CAN side EstlCAM is a good starting point.

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You got a lot of great advice already but no one has really addressed the business side of things. Save your 15k nest egg build a basic machine and start getting orders. A good quality mpcnc will run you $500-$600.

Just buy a kit and be done with the thinking part save that for your second machine once you get your head around the basics. You need to focus on getting business into the shop first and honing your skills second. A small, stock machine is easier to do that with. We hobbyists enjoy playing in our spare time but you have bills to pay.

Let the work define your machine requirements. Start with an inexpensive vanilla machine. Something like a 12x30 is rigid enough to cut your teeth on aluminum and do some signs etc. it also fits on a 2x4 sheet of ply which makes it portable in your workshop. It’s a days work and a new set of pipes to refit the mpcnc to a new size if you get larger projects or build a second machine if start doing a lot of aluminum.

Once you get enough business you may outgrow the mpcnc and be thankful you have $14,400 left in the bank as a down payment on the next step.

Just my $.02

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Not really. Especially for the MPCNC.

At this point, we know most of the limits of the MPCNC. Pushing the limits have already been done. What we’ve already discovered is that cutting aluminum needs a smaller machine. We’ve also learned that 30"-36" is pretty much the max you can go with a MPCNC. It’s why the LowRider was designed in the first place.

There’s not a lot of sense trying to push the boundaries of an MPCNC at this point. You’ll waste time and money trying to get the machine to do something outside of it’s scope.

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I think where the limits are being pushed is in the addition or expansion of interesting tools rather than in overall machine size. Lots of interesting laser work, cardboard cutting and scoring/folding, vinyl and fabric work leveraging a variety of tool heads and the “universal” mounting system that makes it easy to adapt for mounting whatever you can imagine.

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