diy build help

[iTaurus]

I plan on building the indymill CNC and I'm not sure if I either want to go with nema 23 closed loop hybrid motors 2nm with mach 3 control board or go with standard nema 23 motors and use an offline controller like ddcs v3.1? I'm trying to budget so it's one or the other. Plan on cutting woods and some aluminum as a hobby.

Similar Threads:

• New Machine Build- DIY Router Build
• Build Thread- CRP PRO 48x24 DIY Custom Build. First CNC Build.
• New Machine Build- diy build
• Is this feasible as a DIY build?
• Newbie- First DIY Build

[joeavaerage]

Hi,
all development ceased on Mach3 nine years ago. Notwithstanding that it works and has a loyal fanbase its obsolete. I've been using Mach4 for nine years and its
light years ahead in my opinion.

Mach4 all but requires an external motion controller. I use an Ethernet SmoothStepper, and my own breakout borad. I could recommend an MB3 breakout board (by CNCRoom),
all three ports developed, good balance of inputs and outputs, well developed spindle control circuits. Its sophisticated, but not cheap, none the less is good enough to justify the cost.

Mach4Hobby License $200
Ethernet SmoothStepper $225
MB3 breakout board $196
Cheap and cheerful second hand PC to run Mach4 $200

TOTAL $821.

There are other choices that could reduce that total somewhat, but I think the $821 (for a Mach4Hobby solution) figure is a good place to start your comparison.
For instance if you have one of the kids cast-off school laptops, that would save you having to buy another PC. Other choices are much cheaper and simpler
breakout boards, a C25 for example at $31. I would argue penny pinching on a breakout board is false economy....but then I don't have to justify the cost to
your wife either!

You need to be a little careful about making a decision on price alone.

You might think that my choice of Ethernet Smoothstepper and Mach4Hobby, with my own design breakout board is not the cheapest solution.....and you'd be right.
I've been using Mach4 and an ESS for nearly ten years. If I amortise over that ten years the CNC software and motion control hardware cost me less than $50/year.
I spend at least $500/year on carbide tools. One servo costs $438 plus another $156 freight (to NZ)....and I have five of those. I have a Fusion (Basic) subscription
and a Fusion Machining Extensions subscription (for four/five axis) and the two cost about $2000/year.

The point being that the CNC software and the motion hardware (ESS and breakout board) are actually the cheapest part of CNC. Don't penny pinch to get
a useful, flexible and expandable solution....its far from the most expensive part of CNC. Get a good or at least sound solution right from the start....and you'll never look back.

Craig

[joeavaerage]

Hi,
you might ask 'well are there other solutions worth looking at?'. Yes there are.

I've already expounded why I like Mach4, but UCCNC is a strong and direct competitor to Mach4, both performance and cost.
Another more commercial solution, almost turn-key, is Centroid Acorn.

No CNC software discussion would be complete without talking about LinuxCNC. LinuxCNC is open source and free, which is very appealing. There are motion boards by Mesa in the range $200-$300
which are very capable. LinuxCNC is very good especially if you can code in C. Certainly worthy of your investigation.

There are a number of Gcode senders, of which the most mature is GRBL. I cannot say that I know a great deal about them....but I can say I tend to regard them as 'toys' by comparison
to Mach4/UCCNC/LinuxCNC/Centroid Acorn. This will likely infuriate various GRBL users...but there it is.

Craig

[hfjbuis]

For a hobby router you don't need the max performance so you don't need closed loop. That saves money and probably some problems getting the closed loop drivers tuned.
There is no financial reason to use the old analog drivers anymore. Go for the modern digital drivers like DM556T, DM542. If the max (not peak) current of your stepper is 2A or less, you could even use TMC2209 stepstic drivers if you use a fan for cooling.
A ddcs v3.1 is not a real budget thing. If you have an old (used) pc/laptop/tablet a cheap MKS-TinyBee with grbl-HAL or FluidNC firmware would do a great job at a lower price.

[peteeng]

Hi IT - Consider CNC3D's commander/knighthawk controller system. All in one box, plug and play and excellent support. Also Buildbotics fits as well and it has excellent motion control. I'd choose Dynomotions controllers as they are scalable and offer exceptional motion control. I prefer not to use discrete components and controllers and velocity planners as there are too many wires to connect, too many variables and not enough cross support if things go wrong. Using discrete parts is doable and done by many hobbyists but all in one solutions offer lots of advantages, done both and the one box, one sup-plier solution now wins for me... ... Re: motors - I personally can't see the extra value in using hybrid steppers, better off putting the extra $$$ into bearings or other stuff. I've run std N23 steppers for many years without issues. If I loss steps its my fault; a crash, pushing the tool too hard, expecting too much from the machine etc. Peter

edit - by the way the "indymill" is not a "Mill" its a small kit router, you'd better check it will do what you want before you commit to it. Especially its ability to cut aluminium. Looking at the DDCS for $300USD you get the controllers and drivers and software from CNC3D for less.... I've used the Knighthawk and its an excellent system... for $500AUD or $332USD Knighthawk beats the DDCS hands down.

so I've looked at Indi - some comments 1) it uses a twin gantry tube design. These usually require bracing to gain stiffness especially in torsion. Most twin tube gantry designs get reinforced quite quick if you look around at this type of design 2) I've worn out two 500W DC spindles and broken ones shaft. The shaft is small and fatigues fast. Being small it can also bend which once you straighten it, its life is seriously shortened. 3) I'd use a 1.5kW or 800W AC round spindle not a square one. I'd go 800W on that small gantry so it weighs less. You will have to adjust your spindle height occasionally to cope with tall or very short jobs. The square type is difficult to adjust. The round type you undo the bolts slide it to where its needed and when done slide it back to its usual spot, so go round spindle 4) The columns are flat steel and will not be stiff under side loads and they can vibrate. They need webbing or stiffening or to be much thicker to match the structure 5) Some parts are plastic 3D printed and they will let you down... so have a think. Now is the time to sort your design, once you commit its hard to change...Peter

[joeavaerage]

Hi peteeng,
I know you are keen on Dyamotion motion control and are planning on getting one. What CNC software are you going to use?.

My understanding is that the Dynamotion boards have libraries from which you 'construct' your own GUI. Plenty of coding in C to do there!
There is also a Mach3 plugin.
There is also KMotionCNC by Dynamotion.......its quite limited. It does not have canned cycles and stuff like that. Cant see any Probe Gcode either?
Rather looks like you have to code your own???? It might be a bit of a come down from UCCNC.

https://www.dynomotion.com/Help/KMot...KMotionCNC.htm

Craig

[peteeng]

Hi Craig - I've been reading the manuals and looking at its forum. I'm interested in it due to its excellent motion control and its open & scalable so I could implement input shaping, active shaping or use the usual feedback loops (jerk control) for motion control. As usual until I get into it and play with it I won't really know. Tom the owner and developer is very active and the Dynomotion controllers have been used on all sorts of machines and robots. So this looks good for my 5 axis machine and the 6-7 axis robot I want to build.... Just need more time to get everything done.... I've never programmed in C and its been 35+ years since I've coded in fortran. But always up for something new....I've been asked to run a CNC Routing/Machining course later this year for a company and tomorrow I'm doing a test run with 4 people to test the curriculum. So the last 2 weeks I've been busy designing and documenting the course and timing test demos (and upgrading Brevis my portable demo machine, it's a 1655km drive to their site!).... My builds have suffered lately but I can see next week I can get them rolling again...RE - UCCNC, I think Dynomotion will be streets ahead of UCCNC once I get into it... Peter

[joeavaerage]

Hi peteeng,

UCCNC, I think Dynomotion will be streets ahead of UCCNC once I get into it... Peter

BS. You are confusing the motion control and the CNC software.

You may be correct that the motion control offered by Dynamotion is way ahead, but the CNC software of Dynamotion is scarcely a patch on UCCNC or Mach4.
Both UCCNC and Mach4 are CNC programs that provide the GUI, the Gcode interpreter and trajectory planner. The motion control converts that trajectory into
pulse streams.

A Dynamotion control board is as 'useless as tits on a bull' without having some CNC software to feed it the trajectory, and that trajectory is composed on a PC. If you want S curve and input shaping
then you need to provide that trajectory. Evidently Dynamotion comes with a whole bunch of libraries....but you still have to write your own CNC software.

Basically you cannot use either UCCNC or Mach4 to run a Dynamotion control board. You have to write your own GUI OR use a stripped own GUI in KMotionCNC OR use a Mach3 plugin.
That means the Mach3 is the trajectory planner and all that stuff about input shaping goes out the window.

Craig

[arturod]

For a hobby application, you are going to find a PC based system to be more user-friendly and will provide more tools.

Considering the price drop of the closed-loop steppers, I would say is the way to go for a hobby setup. The price difference with open-loop is not significant and you can have the peace of mind that your system will stop if an axis loses position.

We can help you spec up a system for Mach3, Mach4, UCCNC, ACORN or MASSO: https://cnc4pc.com/contact

Arturo Duncan
https:/cnc4pc.com

[peteeng]

Hi Craig - I assume by "CNC Software" you are describing the Machine controller (MC). My interpretation is that the MC is (take UCCNC for instance ) the GUI, gcode interpreter and something like a UC100 is the trajectory planner. You also say that it needs a trajectory. The actual trajectory and the original path are slightly different. The original path is the gcode stream created by in my case Fusion CAM. That path will be modified by UCCNC to conform with its tolerance settings, then the UC100 will modify the velocities so it conforms to the new path created by UCCNC and the set limits on velocities and accels. Dynamotion boards does all of this. It is a machine controller. Just feed in gcode and it will do the rest. Sure it may need tuning just like other machine controller systems... and its GUI maybe sparce but it is fully programmable to your own preferences. I generally don't like programming GUIs but until I dig into it I don't know. Once I dig into it I'll know more.... I have not looked at the M3 module. I think it exists so the front end can be easy for someone to migrate to from M3 but the workings are not M3.... Until I go down the wombat hole I can't say much more....Wombat holes are much bigger than rabbit holes. They can consume utes and Holdens.... Peter

[joeavaerage]

Hi,
the CNC software, UCCNC for example is NOT a machine controller. The UC100 is however a machine (or motion) controller.

The software plans the trajectory, which as you say may vary slightly from the exact path. The trajectory, series of closely spaced positions at very small time intervals, is communicated to the motion control as blocks of numeric data.

then the UC100 will modify the velocities so it conforms to the new path created by UCCNC and the set limits on velocities and accels.

No, that is incorrect. The UC100 calculates the pulses necessary to satisfy the motion from its existing location to the next trajectory point. It does not modify in any way the trajectory.
It is assumed that the CNC software has composed the trajectory such that the max velocities and accelerations are met.

Dynamotion boards does all of this. It is a machine controller. Just feed in gcode and it will do the rest.

This too is incorrect. The Dynamotion boards DO NOT UNDERSTAND GCODE AT ALL. All it understands is that it is at location x,y,z,a,b,c at a given instant and 1millisecond later it needs to be in position
x1,y1,z1,a1,b1,c1. It will calculate and produce pulses necessary for the motors to get there. If the the distance between x and x1 say is too large and the motor cannot possibly accelerate fast enough to get there
then simply: IT WILL NOT. It is the job of the trajectory planner to ensure that at all times the motion between any two consecutive locations can be physically achieved.

Note that all the KMotion libraries are not stored on the Dynamotion motion board, they are libraries installed and stored on the PC. They are used by the CNC software (on the PC) to generate the trajectory. There is no
way they libraries can be executed on the motion board. It is, in the main, an FPGA.....not a general purpose computing platform....that is the PC speciality.

I have not looked at the M3 module. I think it exists so the front end can be easy for someone to migrate to from M3 but the workings are not M3....

That is incorrect also. If you use the Dynamotion Mach3 plugin it takes the trajectory as planned by Mach3, and remember Mach3 has a second order planner, so no S curve or input shaping, and the Dynamotion
board executes that trajectory. Mach3 is the GUI, the Gcode interpreter and trajectory planner. Whatever limitations the Mach3 trajectory planner has will be reflected by the Dynamotion motion board.......all it does and can do
is faithfully execute the numeric trajectory it has been commanded with. You might say the trajectory is the 'workings' of Mach3.

This is a different style of control to GRBL. In GRBL and similar systems Gcode is indeed sent directly to the GRBL controller, and that controller can digest alpha-numeric Gcode and produce pulses from it.
A motion controller like the UC100 cannot do that, nor does either of the Dynamotion controls or my Ethernet Smoothstepper as another example, and do not in fact do that.

You need to buy one of the Dynamotion boards and try it out. Your understanding of what they actually do is flawed.

Craig