Machsupport Forum
Mach Discussion => Mach4 General Discussion => Topic started by: Bob La Londe on January 04, 2026, 12:01:07 PM
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I asked about it years ago, and I was told I could use the hobby license for anything I want. I don't recall exactly what they said the difference was for the industrial license other than price.
Of course as we know policies do change.
Only thing I found beyond the AI result was this below. The AI result linked to a page that did not support what it said was the answer to the question.
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The industrial software version comes with greatly expanded customer support, including phone support for customers in a manufacturing environment where every second counts. Mach4 Industrial includes Macro B gcode programming, tool life management, screw mapping, and an advanced GUI editing tool.
Ah, just found this on the Artsoft website:
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A full featured software version to be marketed toward those interested in using CNC machinery for their own personal /non-business use.
So to be clear if I make a part for sale must I buy the Industrial version?
Currently I am running 4 machines with Mach 3, one with PathPilot (LinuxCNC under the skin) and one with a Masso controller.
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No, commercial use of a Hobby license is permitted, however if you use Mach4 commercially for multiple machines you are expected to purchase a Hobby license for each machine engaged in commercial use.
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No, commercial use of a Hobby license is permitted, however if you use Mach4 commercially for multiple machines you are expected to purchase a Hobby license for each machine engaged in commercial use.
So to be clear, are you are stating if I make any parts for sale I must buy an industrial license AND a hobby license, and an additional hobby license for each additional machine?
Okay.
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The Industrial License is not needed at all. It is about extra features and higher levels of support.
The Hobby License allows use on one machine for commercial use making products for sale.
If you were to run three machines making parts for sale you are supposed to own 3 Hobby licenses.
Other machines not being used to make items for sale do not require additional licenses.
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The Industrial License is not needed at all. It is about extra features and higher levels of support.
The Hobby License allows use on one machine for commercial use making products for sale.
If you were to run three machines making parts for sale you are supposed to own 3 Hobby licenses.
Other machines not being used to make items for sale do not require additional licenses.
That is not what your previous reply indicates, and not what they Art Soft website seems to indicate.
Commercial use legally and according to Webster would be using the software to make money. Using the software to run a machine to make parts for sale is commercial use. You said, and the quoted Artsoft website page said no commercial use.
It's the whole reason I asked now. Years ago I asked and was told I could buy the Hobby license for a machine and use the machine commercially (I think that was actually by Art around the time of the sale), but a discussion recently on another forum indicated that would not be allowed under the hobby license, the documentation seems to say no, and your previous response seems to say no I could not use a hobby license on a machine to make parts for sale.
https://cambamcnc.com/forum/index.php?topic=10751.15
Now this response seems to contradict that and say, "Yes I can use the hobby license on a machine to make parts for sale."
I was actually considering just using Mach 3 for a new machine and to re-retrofit an old machine since I have dialed it in to work fairly well and know how to set it up, but for just $25 more I was considering Mach 4. For $1225 more it's not worth it for me. It's at the point where selling off a couple Smoothsteppers and picking up some MESA IO cards starts to look more promising instead. (Actually, I have 1 spare Mesa IO card already) Maybe it's time I learned the ins and outs of HAL files.
My main reason for looking at Mach 4 was it looks like it supports and has cleaner support for some of the G/M instruction set. One of the things I like about LinuxCNC.
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You have interpreted my response incorrectly. The "No" in my first sentence was the response to your question "So to be clear, are you are stating if I make any parts for sale I must buy an industrial license AND a hobby license, and an additional hobby license for each additional machine?". The part after the comma in my reply states that " commercial use of a Hobby license is permitted".
I am unable to find the reference you mentioned on the Art Soft website. The closest thing I can find is a statement that Mach4 is "A full featured software version to be marketed toward those interested in using CNC machinery for their own personal /non-business use." This indicates that support is via forums but does not indicate that commercial use violates the license.
Again, the major difference between Hobby and Industrial versions is the access to ArtSoft support personnel and the addition of some advanced features such as Macro B in G-code.
I suggest that you try contacting support@machmotion.com for a definitive answer. They are the new owners of the Mach/ArtSoft family of products.
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A full featured software version to be marketed toward those interested in using CNC machinery for their own personal /non-business use.
I have used their contact form to request a clarification, but have received no response.
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The official line & current situation regarding the Masch4 Hobby licensing is as you have described… ‘A full featured software version to be marketed toward those interested in using CNC machinery for their own personal / non-business use’.
However, enforcing this rule would be pointless and many users do in fact use Mach4 Hobby for commercial purposes.
Tweakie.
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I can't see how a software licence which is essentially a copyright licence could extend its terms to an object made on a machine controlled by that software. By no stretch of the imagination could you say that the object was a "derivative work". On the other hand a commercial user depending on Mach4 for their business would demand a much higher level of support. In general companies don't get a good reputation by suing their customers and I doubt that NFS have the resources to do so anyway. Given the prices and the apparent lack of on-going support contracts I suspect the company revenue is based on one-off sales and can't be very large. A good principle with this kind of issue is "it is easier to seek forgiveness than permission".
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Ok.. I tried to hold myself but I simply can't... first there is no legal expectation, limitation or liability in DESCRIBING what you expect your target audience to be... none.. zero...zilch... so when they state they expect HOBBY to be for anyone not engaged in certain types of work, they are simply stating that they, the developer, simply expects that anyone using HOBBY doesn't expect much in the way of warranty or support.. since most businesses expect their purchases to function and be supportable, this isn't whom they expect the end users will be. When you purchase the product, the sale will either include the license agreement and limitations, or the seller must make the license agreement available, since this is the ONLY contractual agreement between the seller and buyer. So when they indicate you can only run on one machine, its done so you can't figure out a way to 'clone' your pc, and run the license to operate multiple machines, but only at the SAME TIME!!!! YOU could use your license on a single pc to run many many machines... but only one at a time (I am not actually sure that's a part of the license agreement). You actually don't have to run a machine at all... you could never use G-Code and write all sorts of wacky code in the background and make a audio recording. the license only stipulates that you can only run a single license of Mach4, on one pc at a time. So I have no idea who or what you are... but you should either HIRE a lawyer (if you are one, find someone else), go to Law school, or go to your local library and do some basic research on License agreements. Damn.... ::)
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and a software license can include a copyright restriction, but can include any other condition that the seller wishes to enforce... and the buyer wants to agree with. So go READ the license agreement... its not in the FORUM or up to the FORUM to determine what the licensing agreement states... all you need to do is read it. If it doesn't state anywhere you can't use the s/w for a specific purpose, or if there are specific conditions for the use of the s/w, then you are free to do whatever you want to do with it ... within the laws governing what you are doing however... ???
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Mach3 and Mach4 products are sold through the "ArtSoft" entity. Over the years this entity has been a freestanding company in Canada then owned by Art Fenerty, a division of NewFangled Solutions, LLC in Maine and now a division of MachMotion (aka Edge Solutions, LLC) in Missouri.
The word "license" in the context of software can refer to three different concepts.
A "license agreement or EULA" which states the rights and responsibilities of the buyer and the seller. It can be in the form of a signed contract or in the form of automatic effects such as proceeding to use a web site after notice is presented or opening a physical package with a notice on it. ArtSoft currently and historically has not used a formal "license agreement". Statements made in marketing materials or on a forum do not constitute a "license agreement".
A "license key" which is a mechanism to protect a software product which is designed to not operate fully if the license key is not present. This is the method that ArtSoft has traditionally used to protect their software. Mach3 license keys, when applied to the software, will show the buyers name on the startup screen so that it is possible to see if the name matches the user who presumably purchased the software. Mach4 utilizes a more robust mechanism that verifies that the license key matches the signature (PCID) or footprint of the characteristics of the PC for which it was issued, otherwise Mach4 runs in Demo mode.
"License policies" are restrictions presented or implemented outside of a formal "license agreement". These policies are often stated by the seller in their marketing materials and other documentation. Policies may interact with "license keys" to achieve control of usage. The "license key" for Mach4 is an example of this. A user of Mach4 Hobby is allowed to have up to 5 active "license keys" at once for Hobby use. If you already have 5 keys active, the license server will not generate a new license key until you deactivate one of the old keys. The license server also monitors activity to detect abuse of new key generation and may enforce management approval before more keys are generated. Mach4 Industrial and some optional software will restrict users to only one active license key at a time.
One policy that is stated in ArtSoft materials is that for commercial use (making money by using the software) the user is expected to purchase one "license key" for each machine that is engaged in commercial activity.
ArtSoft also suggests in its marketing that Mach4 Hobby is targeted at hobby users, but has never stated that commercial use of Mach4 Hobby is a violation of "License Policies".
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Hi,
very concise reply, thanks Steve.
I must say I feel somewhat guilty in that I have a Mach4Hobby license I bought ten years ago, and I use that in just one machine, but for commercial purposes.
By comparison to the cost of the machine, north of 30k USD by now, or even my yearly expense of carbide tools, about $750 USD/year, then Mach4Hobby is virtually nothing.
Its not that I'm doing anything wrong exactly, but the developers/owners of Mach4, whomever it is deserves credit for the excellence of their product.
I was very much opposed to subscription software until I subscribed to Fusion. I have, albeit reluctantly, come to consider the subscription model a very fair idea. I get, for my subscription,
a Pro level software that I could not afford to buy outright in a single purchase.
If any of the Mach4 developers/owners are reading this I would ask that they consider selling their 'best ever Mach4 variant' as a subscription. I would pay. Simply Mach4 gives me good value, and
it is MY BEST INTERESTS that the developers/owners of Mach4 get financial benefit of that. This would inspire further investment in the product. I note that MachMotion are making improvements to Mach4,
but excuse me for saying that the improvements are cosmetic, at least they seem so to me. I apologise if my ignorance has belittled others work, but it is my opinion at the current time. For this reason I have
not upgraded to MachPro.
I would pay, and pay well if Mach4 were to gain genuine RTCP. If Mach4, maybe as MachPro(industrial users), were to offer genuine RTCP, I would pay $500 USD/year as a subscription to be in on it.
I realise that Mach's roots are firmly in the hobby market, and most, if not all hobbyists would be appalled at my suggestion. Indeed ten years ago I probably would too, but now using Mach4
commercially inclines me to want Mach4 to grow and expand, and for that to happen there needs to be considerable investment in the product, and that in turn inspires my inclination to pay.....
as I've already said, it is in my best interests that I do.
Craig
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first, RTCP is nearly impossible under standard Windows... next.. I don't believe MachMotion can generate sufficient capital selling Mach4.. they are in the business of selling and installing entire CNC packages... so generating funds by selling s/w, and then trying to support this when the majority of users have only light knowledge of what is involved. If you charge for support, most users won't pay.. some will but at $150~$200/hr they will only get annoyed when their problem isn't resolved and their CC has a $850 charge on it... if you don't charge its a real losing battle... you can't sustain that for very long.
I emailed them with a problem I had with Mach4... I would pay for support but never received any response... I tried twice... support ain't coming at least for now.. so I told my client to find a different solution for 5~6 machines... something that is supportable. And we did.. and it didn't involve Mach4. ???
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Hi,
first, RTCP is nearly impossible under standard Windows
I am intrigued, as I believe that RTCP is rather like a post processor that 'processes Gcode' to accommodate the actual machine center being at some offset to the
nominal machine center about which the original (unprocessed) Gcode was composed by CAM. This does not require any realtime support, and therefore Windows would be highly suitable.
What is it that makes you contend that makes Windows unsuitable?
I don't believe MachMotion can generate sufficient capital selling Mach4.
I have long been of that opinion too, and that extends to the previous owners as well. That is why I suggest a subscription model as it provides a steady income stream which makes it worth while to continue
investment in Mach4. Unless there is a business case for investing in or growing Mach4 then Mach4 will not.
I recognise that most hobbyists will not engage in a subscription model, but full time users such as my self will. Thereby MachPro (or any other suitable moniker) would become exactly as the name suggests.
Craig
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that would be true... but i think from what i see in the forums that there are more 'hobbyists' and simply people of all sorts simply playing around... time invested seems not to matter much.. most can't program and many don't seem familiar with G-Codes... many don't know anything about electrical... or steppers... or servos either... how in any remote fantasy world can anyone support them without a $10k invoice? There will be some that will benefit... but I'd guess a small percentage... once you start paying maybe $300-$500 for a subscription, that still really won't cover a lot of support. So then you need to charge for support also... at that point, and with all the time savings, you probably better off letting MachMotion do it as a turnkey, or purchase a CNC controller such as FANUC or SIEMENS. :o
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Hi,
the thing is I seldom require support, and that I need has come from the forum. That is adequate......its not support I need, but capability, RTCP in particular.
This is largely a one-time investment. That is to say Mah4 owners, whomever they are, would engage three, four or five of their best developers, go hard at it for a month
or two, and sell the results. Aside from potential bug-fixes there should be no on-going development demand.
Lets say that the effort to code RTCP cost $50,000USD. Then MachMotion needs to recoup that at least and some more than that hopefully. Selling to hobbyists is unlikely to
generate that level of sales, and then as you so rightly point out then have to baby-step them through every step, a sure-fire money loser. Someone like me however will pay for the investment, be it
as a perpetual license one-time purchase or as a subscription, and beyond the initial set-up and learning curve not need any support. Naturally like everyone I want good value from any purchase,
but I'm not suggesting that MachMotion sell that capability cheap. That will pretty much preclude hobbyists but be an open invitation to serious CNCers. Pricing alone would suggest that only
serious CNCers would apply anyway.
My understanding was that Mach4 was to appeal to OEM manufacturers, and that New Fangled Solutions revenue stream would be dominated by that demand. How that panned out I don't know.
I do believe however that without RTCP then Mach4 will always lag other solutions.
Craig
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I would think $50k is not nearly sufficient.. if I had to take a guess, its probably closer to $300-$500k.
and the standard Windows environment isn't suitable... once you get out of that its difficult for 'novices' to work with.. so you're support goes way way up. And its almost a must to narrow down the h/w (i.e. controllers).. so you also need to get some of them onboard with the changes...
To make this really a useful product, it probably needs to be closed loop.. so go away from steppers.. that leaves a lot of users out in the cold... and if so, its probably better now to be in pulse and direction mode... so there goes the cheap stuff... so the casual user is gone... now you are just looking for a small fraction of the users of Mach4.. so MachRTOS won't succeed.
you are probably in a minority... I'm not sure what 'functionality' you require that necessitates a RTOS, but you can purchase a new cnc package, with all the servo's, etc. for under $20k. If you have a CNC business, not a CNC hobby or a CNC in my garage I make money on, and can't afford $20k, then you are not in business. Or probably won't be for long. You can't hire a plumber and pay him in yearly subscription fees, or an electrician, and I don't believe many auto repair places do that either. And most s/w companies went to subscription because no one really needed the updates... so they weren't purchasing new versions of Autocad, MS-Word, Excel, and many many others. Subscription nearly forces you to upgrade continuously and also costs you a lot more. And many of those s/w suppliers don't offer support anyway for a normal subscription. :o
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Hi,
I'm still intrigued by why you think Windows is unsuitable. My understanding is that RTCP is effectively a post process, it does not need to be realtime.
My machine is servo operated with the servo loops closed by the servo drive. Thus Mach4/ESS/BoB supply step/direction pulses to the servo drives and thereafter the
servos just do the business.
The vast majority of my work is three axis, but I have a trunnion/platter fifth axis that I use occasionally. Mach4 very handily produces a simultaneous five axis trajectory and my machine follows it
perfectly. So five axis machining with Mach4 is not a problem, but you need reverse kinematics if the machine center is not coincident with the assumed machine center when the five axis
tool path was composed by CAM.
I suppose you could do it 'live'.....that is to say that the trajectory of Mach4 would be modified in realtime, but just as Mach4's trajectory is not realtime, but a buffered control solution,
so would an RTCP module within Mach4 processes that trajectory, and it need not be realtime either. I had proposed that effectively the Gcode could be re-written, and thus the Gcode
would be processed before it ever got read into the machine.
Craig
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no... to be deterministic you either need a different OS, or there are certain extensions for Windows. Even so, if you are using an external controller, you would need to make your communications different... that why they offload all the actual motion to an external device... Mach4 doesn't actually 'control' any of the motion... it just tells the controller what the move should be...
But you haven't indicated why you feel you need an RTOS? :o
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I have a similar setup... Mach4... ESS... closed loop servos... that is actually not a real closed loop system, since neither the controller or Mach4 actually know the axis position.. they just assume it. I actually added a prox so i could make sure my 'z' axis was clear.. because if it wasn't I was going to rip the fixture apart, or rip the spindle off the machine... or both... not a good thing. But I don't do anything as complex as what you are stating... that's top notch stuff... but I don't believe an RTOS would resolve your problem. What actually is the issue? Kinematics or Reverse Kinematics (never heard of that) Do you mean 'Inverse Kinematics'? :o
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Hi,
Subscription nearly forces you to upgrade continuously and also costs you a lot more.
I was always adamantly against subscription software, but since getting Fusion I've had to reconsider that stance. Firstly I pay about $500USD/year for Fusion Basic.
The closest competitors that have the same features are $1500USD to $2500USD and with optional annual fees of $250 or so on top of that.
By my reckoning I pay (in subscription fees) the same as buying a perpetual license every four years. I consider that fair value......not cheap.....not expensive, but fair.
Were I to buy RhinoCAM (Expert) (for $2500USD plus $400 annual) for instance, then I'd almost be a fool not to get annual updates, otherwise I'd find in five or eight
years time that my software had slipped that far behind that I'd have to buy anew. Not very appealing.
So, no, I disagree with your contention that a subscription 'costs a lot more', over a medium term I think they are cost competitive with a perpetual licensed software
I, for a couple of years, also bought Fusion Machining Extensions, at a cost of about $1500USD/year. This adds full simultaneous five axis, collision avoidance and tool path editing.
BobCad, RhinoCAM (Premium) ($10,000USD plus $600USD annual) and other are all $10,00USD for a perpetual license plus $500-$1500USD optional annual fees.
Simply I don't have the cash to buy a perpetual license outright, and so Fusions Machining Extensions subscription gave me capability that I could not otherwise afford.
I'm 100% convinced that Autodesk know this and price their products accordingly.
I still don't much like subscriptions, but it does mean I can have capabilities that would otherwise be out of reach for me. The final thing which swings me in favour of Fusion is that it has
an Electronics module, and I use it daily for business. Additionally it can do FEA simulation, thermal simulation and generative design. I make only limited use (read hobby level) use of these later
capabilities but I do use all of them. It is these extra capabilities all in the one platform that appeals.
I do well believe bet that Autodesk know and understand all of this , and this is how they are trying to maximize their profit, and I am, in part, providing it.....but in return I get to use a very good,
perhaps to the best or first-in-class software but pretty damned good, in a manner I can afford.
Craig
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Hi,
What actually is the issue? Kinematics or Reverse Kinematics (never heard of that) Do you mean 'Inverse Kinematics'?
They go by different names but they all refer to the same thing.
Imagine a three axis machine. You touch of to a corner of your part and start the Gcode. If later you repeat the task but with fresh material and you clamp in in the vice
but not in the same location as previously. No trouble, touch off to the corner and start the Gcode running. The displacement of the material does not require any special handling
by Mach or your machine as the Gcode now runs about your newly aquired work zero.
With a five axis machine however if the material is displaced then you need to calculate not only the X, Y, Z axes anew but also the fourth and fifth rotational axes as well. If you rotate the fourth axis
by 10 degrees then that will affect the X,Y,Z,C axes as well. This is called kinematics. If you displace the material you can use kinematics or more correctly 'reverse kinematics'
to re-calculate the Gcode so that the part is still made correctly. The kinematic equations are not just linear translation as in the three axis case but contain sines and cosines of the rotational
axes as well. Sines and cosines occurr in forward kinematics, while arc-sine and arc-cosine occur in revers kinematics.
One of the quirks is that the sine of 45 degrees for instance is 0.7071, but then again the sine of 135 degrees is also 0.7071 and the sine of 225 degrees and 315 degrees is -0.7071
Thus with reverse kinematics you can get two (or more in certain circumstances) solutions, only one of which is likely to be correct for your machine. To call it a 'mind-f*******k'
is an understatement. Doable.....but definitely challenging.......ergo I want someone (MachMotion) to do it for me!!!! I have not lost my hobbyist credentials entirely!
There was a Aussie guy whom did this with Mach4, and I'll try to find the link. He did spend many months writing the code, but it was a module that 'processed' Mach's regular trajectory according
to the reverse kinematic equations. He also resolved the 'inflection point dilemma', which is the name for the phenomonon above.
Craig
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yes its normally referred to as Inverse Kinematics because of the way you specify the final position and the methods (calculations) required to get the individual axis' in position. Since in many cases the 'final' position can be achieved with the axis' in different states. Determining what the best state should be is a relatively difficult process. Yes, I am familiar and I would presume this would blow away most users. I'm glad I don't require. Does your CAM cover this or are you forced to do some of the calc's manually (sheesh!!!) :o :o :o :o
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and that is a common issue with defining the end point.. a point is a definitive position, but a true 5 axis machine (robot) can achieve lets say for example with the tool pointing up or down, and either to the left or right. Determining the best state also requires knowing where you are and determining not just the best way to move to the next state, but also how you expect to get to the following state. It can be a very very complex set of calculations and possibly rules that need to be applied. Again, glad I don't go there... :o :o :o :o
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but your problem isn't the lack of an RTOS... a five axis g-code program probably requires many truly minimal movements... the problem is one of computing power... given that the cpu might take a significant amount of time to compute the next movement.... so instead of a smooth transition from point to point you could have a more 'jerky' type of actual path. I would expect that most, if not all, standard pc cpu's would not be capable of meeting the requirements (that would still need to be determined) :o
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Hi,
yes that is a fair description of kinematics. It's not easy, but perfectly doable, and I believe even a modest Windows PC has any amount enough computing power.
Whether is has the computing power to do the kinematic translation 'live', that is to say at the same pace that Mach4 spits out trajectory data is less certain.
Even were it not the case and the tool path became discontinuous, it could be calculated PRIOR to the Gcode being loaded, and in that case that the PC is a too slow would
be no detriment.
I do not have any direct evidence to support my contention that 'live' kinematic translation this is within the capacity of a regular PC. I would note though that LinuxCNC does RTCP
without difficulty, assuming it is programmed to do so. LinuxCNC runs on regular PCs, albeit with an RTOS Linux distro. Still the calculations necessary for inverse kinematics still
happen on the same silicon processor that is in a Windows PC.
You are correct though, this is not a realtime constraint, i.e. no need for an RTOS, so assuming Windows had the compute power then it could still run as a buffered control system, exactly
as it does so nicely with three axes.
Craig
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the two items you are talking about, RTOS and kinematics, are not related.. RTOS is a Real Time Operating System.. basically you can determine when something will occur on the pc... Windows is not a real RTOS so you can't determine when the cpu will actually do something... You don't need an RTOS to simply calculate the kinematics, Forward or Inverse. An RTOS would be applied to be able to determine that the path is off by some amount and make corrections in real time...that's closed loop... something Mach4 on a regular pc can't do... if you've already calculated the positions, then you don't need the pc, RTOS or not, to determine the axis' positions on the fly. Now since the axis positions change, possibly dramatically, when a new part is loaded, you would only need to have a post processor of some sort, that you could call and then make the necessary corrections from one part to another. That is still possibly a good amount of calculations, and would depend on the cpu, what the machine mechanically is, and whether you could write the code to make the calculations (the actual equations might already exist). The amount of time it would require probably doesn't matter much if its an RTOS or not. So whatever time it required, whether 2 seconds or 2 hours or 2 days, is more a factor of the cpu and the equations, and not necessarily the OS. :o
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I read you previous reply... are you saying that Linux/CNC can calculate the necessary axis translation on the fly from one Gcode line to the next because its an RTOS? That doesn't seem correct :o
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Hi,
are you saying that Linux/CNC can calculate the necessary axis translation on the fly from one Gcode line to the next because its an RTOS? That doesn't seem correct :o
RTOS is not really the issue here. LinuxCNC can and does execute inverse kinematics on the fly, and there are videos of LinuxCNC machines doing just that.
I suspect the reason that LinuxCNC is favoured for this purpose is that the code is already written, and its just a case of importing it from GitHub........not that it relies in anyway on RTOS.
Five axis kinematics, either forward or inverse, are not especially computationally difficult.....very much less than serial robotic arms generally considered to have six degrees of freedom (DOF).
Five axis has 5 DOF, and only two axes are rotational.
I'm still very much learning about the theoretical and mathematical implications of RTCP.
If I understand correctly a 5 DOF system with two rotational axes can have as many as 4 inflection points, 2 for each rotational axis, 2 x 2 =4. A 6 DOF system but with 3 rotational axes
has a total of eight inflection points, 2 for each axis, 2 x 2 x 2 =8. Again, it is my understanding, and only my understanding.......that each rotational axis creates two infection points and as they
are multiplied with the inflections of other axes in effect double the total number of inflections.
This is a rather good resource:
https://linuxcnc.org/docs/html/motion/5-axis-kinematics.html (https://linuxcnc.org/docs/html/motion/5-axis-kinematics.html)
I have excerpted a couple of screen shots, and it is still matrix maths, neither is it overly complex.
I have been told, and can well believe it is deciding how to handle the inflections that adds considerable complexity.
Craig
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Hi,
note that the above were for a machine where the two rotational axes are coincident, namely the trunnion (A) axis is in the same plane as the platter (C) axis.
Therefore some terms drop out of the matrix formulation, i.e. the above matrix math is as simple as it gets.
I have attached a picture of my trunnion/platter. Note that the true machine center where the A axis and C axis intersect is a small (20.045mm by my measurement) distance
above the platter, but vertically above the center of the platter. i.e. Dz=20.0245mm
The same document outlines the matrix formulation for a machine where the center point is displaced by both Z and Y axes, Dz and Dy.
This is actually more realistic of my machine, its just that in my case Dy=0mm, and allows a minor simplification of the matrix formulation.
Craig
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while I'm not particularly up on the specific, I'd imagine it has to do with the fact that a rotational axis (and you shouldn't think round here) has at least two ways of getting to a single point. I ran into something like this with a SCARA robot.. you need to watch and make sure you tell it how to bend and articulate its horizontal... otherwise you will either smack into something or crash in the next move. So how you approach a specific point in space depends on where you are beforehand and how you got there.
I would imagine that if Linux/CNC is already doing kinematics on the fly, then the equations are already in place. So why don't you simply switch over? :o
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Hi,
I'd imagine it has to do with the fact that a rotational axis (and you shouldn't think round here) has at least two ways of getting to a single point. I ran into something like this with a SCARA robot.. you need to watch and make sure you tell it how to bend and articulate its horizontal... otherwise you will either smack into something or crash in the next move. So how you approach a specific point in space depends on where you are beforehand and how you got there.
Yes, that it it exactly. Further I understand it is very much the concern of robots. Five axis CNC machines are less difficult, but that does not make it easy either.
The matrix formulations I have excerpted do not resolve that issue, and there is I believe yet more to learn about the resolution of those conflicts.
I would imagine that if Linux/CNC is already doing kinematics on the fly, then the equations are already in place. So why don't you simply switch over?
That is a very good question....and the only real answer is momentum. I have been using Mach4 for ten years and daily for at least five years in business. 99.99% of all of that is three axis,
and for that purpose Mach4 has been excellent. My preference would be that Mach4 has RTCP natively, and that would allow seamless extension of my machine to four and five axis tool paths.
I do have twenty or thirty toolpaths that are four and five axis, so its not like Mach4 cannot do simultaneous four and five axis, but it requires a very specific set-up of your material in the machine
in absence of RTCP. RTCP would mean a easier migration to more complex parts, not that its absence precludes those tool paths.
Like any decent free loader/bludger/sloth.....I would like someone to do the heavy lifting for me!
I have plenty of projects on the go already, adding coding my own RTCP module for Mach4 is appealing, but is unrealistic at the moment.
Craig
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yes, I was confusing RTCP as it references CNC with something else.... yes, RTCP does what you are looking for ... that is calculate the required axis translations on the fly.. and that requires an OS with a deterministic operation. Its already been done in Linux/CNC so the modules are already available. I doubt that many hobbyists or even general users would require it. And it should be only utilized with a real closed loop setup.. not a 'closed loop servo' as the cpu doesn't know if the servo is actually where its supposed to be in real time. So there goes 99.8% of your users... its most likely too small a target group for that much effort and cost. :o
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and I would add... I've determined that Mach4 has some very basic flaws... and the programmers aren't even interested in correcting those... more colors and new screen development tools sell ... fixing problems doesn't but still costs $$ they can't recover. sounds like mach4 does a good job for you however. :o
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Hi,
that is calculate the required axis translations on the fly.. and that requires an OS with a deterministic operation.
No it doesn't. It can be calculated in exactly the same manner as the trajectory is, and that is used to fill the motion controllers buffer. It does not require deterministic behaviour
any more than three axis Mach does.
And it should be only utilized with a real closed loop setup..
No it does not. As I've already posted Mach4 does a perfectly excellent job of five axis tool paths, to whit I have several of them myself. WITHOUT RTCP it means that I have to place the material
in strict coincidence with the machine center point about which the Gcode was composed. It does not require closed loop (not just closed loop drives) servos any more than it requires closed
loop servo for three axis.
RTCP is solely to allow you to place the material and/or work holding in a convenient location in the machine and yet still have the tool path run AS IF the material had been placed
in strict coincidence with the assumed machine center.
Without RTCP, you could if you wish, you could translate the machine center in your CAM program to reflect the position of the material/workholding and then re-generate
the Gcode then post and run the Gcode as normal.
To date I've always placed my material carefully to be coincident with the machine center, save having to shag around with Fusion Machining Extensions all the time.
I've determined that Mach4 has some very basic flaws... and the programmers aren't even interested in correcting those... more colors and new screen development tools sell ...
Quite frankly, I think that stuff is a red-herring. Sure you can make it look nice, or maybe more convenient to operate, but Mach will go no faster, nor more accurately, nor anything else that
improves the parts coming out of the machine. RTCP would make five axis more convenient, and that would be nice, nice enough that I'd pay a $500/year subscription for it.
Can't really be bothered with cosmetic changes, what really counts for me is operational capability.....everything else is just 'gilding the lily'.
Craig