Printable View
Hello everyone! you can call me J.
I currently have a 5-axis CNC with a DDCS Expert V1.1 controller.
I recently discovered that the controller does not have the ability to move all 5 axes continuously, nor does it have RTCP. This is why I am looking for a controller for my machine that can operate with these requirements.
Thank you very much!
Hi,
I use Mach4, and that can easily move six axes simultaneously, but cannot do kinematics.
I can draw the part in Fusion CAD, and then generate a toolpath with Fusion CAM, but the origin of the part has to be coincident with the centre of rotation of the machine.
There are controllers that you can touch off to a part in the vise, and the machine will automatically alter the Gcode necessary to match it to the centre of rotation. This last feature requires that
the controller be able to do kinematics.
Mach4Hobby and Mach4Industrial cannot do that, or at least as shipped from the manufacturer, although some users have programmed it to do so. To my knowledge there are few hobby grade
motion controllers that have this feature. I don't know whether LinuxCNC has it as standard, but it can certainly be programmed into it.
It seems that the majority of industrial controllers (Fanuc, Siemens, Mazak, Mitsubishi, Heidenhain etc) that can do this thing are all very expensive, not really hobby class at all.
I have nearly finished my trunnion fifth axis. I will continue with Mach4 but realise that I will set to set material in the vise such that it corresponds to the machine center of rotation. This might
be considered a limitation, but for many years all five axis machines were like that. I don't think it will prevent me from using simultaneous five axis toolpaths. When I built the fifth axis I was very
particular that I left the centre of rotation free so that I could touch off to it and set the work coordinates of my machine.
If this works then maybe I'll try writing my own kinematics module......but that's down the track aways yet.
Craig
Hi Craig - so for touching off the machine centre are you going to make a fixture that goes to the rotary? Then centre, then swap to the part then check centre? Do you have a procedure in mind? Peter
Hi peteeng,
yes, I have a procedure in mind, of course I've yet to try it, so this is my intention rather than a fixed procedure.
The center of rotation of the fourth axis (trunnion) is 20mm (actually 20.32mm) above the fifth axis platter. The centre of the fifth axis is of course is the centre of the platter, and that centre is precisely located as it is the centre
of the part as I made it in the lathe.
My intention is that when the vice is in place but without the material fitted in the vice that I can push the tool down between the open jaws of the vice to pick up the centre.
Excepting the Z axis, which is variable by virtue of variable tool stick-out, the centre of rotation (in X and Y) will remain the same....unless the whole trunnion moves. Thus I should be able to touch off the
the rotation centre and then have it fixed in machine coordinates for months at a time. This will rely on me being able to home the machine in X and Y repeatably. With the Home switches I am using
I claim 0.02mm repeatability. That claim will come under strict test in the months to come.
Craig
Hey J. You'll want to look into LinuxCNC 2.9. That'll drive a real-time 5axis TCP/RTCP with customizable kinematic effortless. Recommend a MESA fpga hardware, open or closed loop that is.
Hi Macanix,
I've posted my timeline. I will be using Mach4 without any kinematics to start with. I already have it and have done so for eight years accumulating many
thousands of hours with the solution.
Once I gained familiarity with 3+2, 4+1 and 5axis simultaneous THEN I'll make my decision. Firstly 'do I truly need TCP?'. Just because a feature is available does not mean
that it is essential.
If I decide that yes I want TCP.... THEN I'll decide whether to continue with Mach4 or consider another solution, and LinuxCNC would have to be a top contender. There are at least two Mach4 users whom have written kinematics
modules, so its far from impossible. Additionally I imagine NFS (Mach4 manufacturer) would welcome such an effort as it would extend their products applicability to a wider market. Indeed its is far from impossible that NFS
produce their own module....Mach4 has steadily developed over recent years.
Either way that decison is some way down the road. In the mean time I shall certainly check out LinuxCNC2.9.... research is free.
Craig
Hi Joeavaerage. Slight confusion here, my suggestion was to OP, who've requested to be called J. Unless you're both the same user/account then my bad.
Noticed he's geared up with a proprietary DDCS Control, one of those commonly wired-up and easy to retrofit for a scalable solution like Linuxcnc 2.9. My recommendation is based on experience with the real-time kernel and a closed loop w/ feedback implementation. I'd like to think that Linuxcnc (with FPGA powered) blows the competition by worlds distance; Sinumerik Fanuc Heidenhain etc. In terms of scalability it certainly wins anyway.
Can't comment on Mach4 neither compare to it. Never used it.
All the best and apologies for the J/naming confusion.
Hi Mecanix,
apologies, I thought your post was directed to me.
LinuxCNC is certainly a way forward for OP. Having said that LinuxCNC certainly favours strong programmers and scares non or weak programmers off.
There is no way that LinuxCNC with TCP kinematics could be said to be turn-key.The only solutions that I know of which are turn-key or nearly so are Sinumerik, Fanuc etc.....
and none of them are hobby class.
Craig
No worries, J! I have the Sinumeriks 828 (4ax mill) and a 808 (2ax lathe) at the large'r shop. Both on the v4.5 firmware. They are great real-timers nanobits and all, sure, but man... p r o p r i e t a r y l i c e n s e d e v e r y t h i n g. Don't you ever think of enhancing those controls it'll cost ya 3k per feature minimum.
At home, in the much greater shop (a 20sqm garden shed!), everything is on Lcnc 2.9. That's where prototyping is carried and one-offs are made. Note that Linuxcnc is pre-compiled for users (no specific environment required) although the source code is made public domain for those who wish to scale it up to their needs. HALs and INIs (examples?) are also public domain along with an amazing knowledge base/forum online community supporting it. Shall you be stuck with anything.
Also happy for you to PM if you're diving into this route. Wish you all the best of luck with your implementation and projects in a meantime. Thumbs up on your 5ax trunnion add-on, looks awesome.
For inspiration only. And to debunk the assumption about the non-turnkey solution. Here's one full turn-key solution for 5ax RTCP, among countless others I am aware of. Includes everything, hardware (FPGA), and all the HALs and INI to get it setup along with step-by-step documentation.
https://i.postimg.cc/65KTGLdD/RTCP.png
https://i.postimg.cc/8c9HtXNB/O1-CN0...1915437044.png
https://i.postimg.cc/cCpRQKBF/O1-CN0...1915437044.png
Full implementation documentation and supportive software & configs. Full Turn-Key here (5.000Mhz example, no f joke!!).
https://pan.baidu.com/s/1SAy18L9lHsv...O92AA?pwd=syen
*no affiliation, no seller links*. Just to inspire really.
Hi,
sorry, just more Chinese junk. If it suits and works for you well good luck to you, but I will not be buying it.
Craig
Of course it works. Nothing Chinese there, all ICs and passives from foreign manufacturers. I can also see differential pairs, properly terminated comm trace ends, nicely spaced routing, high quality nylon connectors etc etc. All highly professional stuff, Joe biden would prolly disagree though, but then his cult is the cult to be!
MESA is open source, not chinese man. Just happens that this dude kindly/generously provides a full "turn-key" solution to the community.
All the best of luck.
Consider a Dynomotion KFLOP / Kogna Controller with Free KMotionCNC GUI and Kinematics :)
https://youtu.be/szZka9htlHM
This is another choice: https://rosettacnc.com/en/index.html#
RosettaCNC is an industrial CE certified CNC for multiaxis RTCP or TCP movements made totally in Italy with Fanuc G43/G43.4/G43.7 commands.
Also in this case you have only to connect to drivers, set axes parameters and RTCP pivot points.
You can use STEP/DIR drivers signals, EtherCAT drivers or old analogic/encoder drivers.
https://youtu.be/Z3eIsawFVQo?si=FP-XWhgXi9gSbnVi
Some video: https://www.youtube.com/@thoth2487/videos