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Hello,
I am new to the world of CNC, so have limited knowledge, and am essentially looking for advice to daft questions as I learn.
I am just completing a build of my own CNC machine based on plans from the woodsmith magazine. At this moment it's built and able to 'jog' around, which I am very proud of.
Cheers
Andy. - Knee deep in Fusion 360 and Mach3 software!
Welcome, Andy,
There are No daft questions except the ones you don't ask so fire away.:thumsup:
Hi Andy WQuote:
Originally Posted by AndyW
Wow, that is one sturdy piece of kit - It looks like it weighs a tonne
WoodKnot
Hello,
Thank you for the positive response.
Yes it weighs a lot! I did manage to 3d print a few parts so that had to save at least 4grams! I was very new to the cnc world and just decided to have a go at building a machine from an article I read. It's mostly baltic birch ply. After I started to learn more I realised about 80/20 aluminium. Perhaps that will be mk2.
I am just waiting for the router bits in the post, then it will be a case of revisiting the calibration in Mach3.
I think I maybe having a unit metric vs imperial problem as I have done the sums regarding steps, revolutions and distance travelled but I am getting odd results.
Secondly, it is a nema 34 8.7nm stepper on the axis (approx 1200mm 20mm dia 5mm pitch ) looking at the x axis motor movement profile what are suitable velocity and acceleration speeds? - (a nagging thought about being mechanically sympathetic)
Thank you.
Andy.
What odd results.?Quote:
Originally Posted by AndyW
However, it's a simple enough calculation. Take the Micro steps set on the drives and divide by the pitch of the ball-screws taking into account any ratios if you have any. So let's say 1600 micro-steps and 5mm pitch, then 1600/5=320 Steps per MM.
This is what you enter into Mach3 steps per setting. This will give you the correct movement so if you are getting different results in the commanded distance then it's coming from elsewhere which could be from a number of places.
Now that's not easy to answer because several factors come into play that determines how to set up the machine regards motor tuning and unfortunately it looks like you may have fallen foul of the "bigger is better" assumption when it comes to motors and this will now be robbing you of speed.Quote:
Originally Posted by AndyW
NEMA 34 motors of this size require lots of volts to get any decent speed from and I'd put a small wager on it you probably have less than 50V which will limit the RPM and torque, which when combined with a 5mm pitch will result in quite slow speeds.
Give more info on the electrical side ie: Drive make and Volts to drives, Micros steps set on drives.
Sorry AndyQuote:
Originally Posted by AndyW
So the frame and plates are all birch ply? It looks like steel?
WoodKnot
Hello,
WoodKnot: No need to apologise. Yep it's all birch ply. This process has felt like I need a cnc to build a cnc. Aluminium would have been fab but I am one man in his shed!
Minor success this weekend - I've printed the 100+ pages of the mach3 manual and started to read it. After having enough of reading I decided to revisit the calibration again. My thought process was as you described regarding steps and pitch. For some reason this time it is happy in metric and moves as requested. Perhaps I was not saving the settings before exiting or even the classic reboot of the software????
What are peoples thoughts on Mach3 or Mach4. I have a UC100 interface and it seems as if the difference at cost is $25.
Jazzcnc: With regards to the speeds, Yep your right, I did think bigger is better because of the length of the bed at 1800mm and was concerned about torque etc.
Nema 34, 8.7mn stepper driven by a cw8060 (6.0A 80v) Being supplied by a 480W 48V 10A PSU. 200 steps stepper motor and dip switches set at 1/10th.
It jogs along nicely but I was concerned about not over stressing the the whole system. I didn't want to drive it apart being over zealous.
My next task it to produce a spoil board.
Andy W.
If you have the UC100 it's a no-brainer to use UCCNC it's so much better than mach3, it's much more reliable and stable, the action is smoother and better still it's still supported and getting better. Mach3 is no longer supported and Mach4 is full of bugs and best avoided at all cost's. Also, UCNC is much cheaper than mach3 or 4.Quote:
Originally Posted by AndyW
I have used mach3 for nearly 20yrs and know it inside out and I can tell you with 100% confidence that UCCNC is the way to go.
Yes as expected and it's a common mistake for new builders to make. However, you do have spare room on the drives to up the volts and I recommend you do, I'd run them at 70V. You will see a marked difference in performance and power.Quote:
Originally Posted by AndyW
Hit the nail on the head with this one! "This process has felt like I need a cnc to build a cnc".Quote:
Originally Posted by AndyW
I'm switching to UCCNC. I'm still working on my control box. License was bundled free with controller and boards.
On paper it looks far superior.
Mach4 is out of my budget.
Quote:
Originally Posted by JAZZCNC
I bought a new 80vac/110vdc capable driver for my Nema34. Now running it on 80vdc to get a ltte more velocity. Maxed out at 2000mm/min on the mill Z with 60v.
I put 60v on my x,y nema24's and they fly. I did have 34 all round but it turned out the 24's battered them in terms of performance!!.
Andy,
I think you'll find plenty of people have cut their teeth on machines built from wood and are ether happy with what they can do or use the confidence gained from the experience to push ahead with a more capable machine built from steel or aluminum. What sort of things are you planning to make? Decorative signs and carvings or more complex items with multiple pieces that will need to fit accurately together?
Re the controller: I used LinuxCNC for several years and was happy with it, but the parallel interface suffered interference problems and I've recently changed to using an AXBB-E controller whch is Ethernet connected a laptop running the matching UCCNC software. It proved simple to install and has worked without any problems so far.
Kit