Buying a NM-200

[kvom]

After a couple of weeks of emailing Khai at Novakon, I have decided to "pull the trigger" and order a NM-200. This will be for hobby use primarily, as my goal is to build a working radial engine (probably Edwards 5).

I am ordering the CD-100 upgrade with an integrated motherboard, which will hopefully avoid any Mach3 install and configuration issues. Because of space considerations I decided not to order the coolant system, so initially I will be using the machine without coolant.

I will need to decide on a CAD-CAM package. The mill comes with BobCad V21, so I will do some experimentation with that. I'm currently taking MasterCam training, so I am pretty new at CAD-CAM. However, I have taken courses in g-code programming, and most of the small engine parts I have made manually in the past I can program in g-code. So I'll get acquainted with the machine via hand-coded programs at first. I do want to be able to do some engraving and similar 2D work, so a package will be a necessity. CamBam looks interesting.

I'll try to update this thread with some photos when the machine arrives.

I currently have a manual mill with an R8 spindle and an air-operated drawbar. I suspect that changing tools manually will get old pretty soon, so I will be considering a quick-change system at some point.

[urbanimports02]

i would strongly consider the bobcad v23 upgrade. at $350 it is a killer deal. it is much much better then v21. i am not to saavy on the cad side of it yet, and so far do not like it much, but the cam side is very nice for the money. for cad i have both solidworks pro(very spendy) and alibre design standard. i love alibre for general use. it is very easy, and very quick. i use it on my lap top then export files to the cd-100 into bobcad and works like a charm. for more complex stuff i use my solidworks. i use it for everything from simple parts up to race car body work and chassis design, but it sounds like you will not need anything like that especially when it costs almost as much as the nm-200! if you look around and download the free trial version of alibre, they will start emailing you offers. they eventually offered me the full program for $99, and recently offered me to upgrade to there newest version for $99 as well.
also, request that novakon test your machine with your controler. i suspect they did not test my machine with my controler as it did not have a novakon xml intsalled and the y axis was running everything upside down which was fixed in mach3 telling me my cd-100 was not used to test my machine.

[fourwheeler]

i would strongly consider the bobcad v23 upgrade. at $350 it is a killer deal. it is much much better then v21.

Very good advise...V21 is not to my liking either but I am starting to grasp it better. I downloaded a trial version of V23 and it is much better to work with.

[SpeedsCustom]

I plan on upgrading an purchasing the nm-200 within the next year and half. Will be saving for it. I can't wait for the day

[kvom]

It's supposed to ship today. We'll see if it gets onto the truck.

[ihavenofish]

congrats. i use an nm200 sometimes and its a pretty nice machine.
i increased the speed to 125ipm on it and it runs very well.

[urbanimports02]

do you mind sharing your settings to get 125ipm? i tried that, and it was stalling and losing steps big time! do you use more conservative acceleration numbers or something? also, how is your circular interpolation? my machine produces circles that are out of round by more then .005" that is using 3 flute solid carbide cutters and i have even tried rerunning the program to clean it up, and still out of round. otherwise i like the machine. i ran it hard all day yesterday and produced 7 of my parts, running at 4000rpm pretty much the whole time, hope the spindle is up to the task!

[ihavenofish]

do you mind sharing your settings to get 125ipm? i tried that, and it was stalling and losing steps big time! do you use more conservative acceleration numbers or something? also, how is your circular interpolation? my machine produces circles that are out of round by more then .005" that is using 3 flute solid carbide cutters and i have even tried rerunning the program to clean it up, and still out of round. otherwise i like the machine. i ran it hard all day yesterday and produced 7 of my parts, running at 4000rpm pretty much the whole time, hope the spindle is up to the task!

the one i use is the older blue one with the gecko controller. i dont know how different it is form the new one, but heres some tips...

1: you need to increase the mach core clock for more speed. i think i set it to 45k, possibly 60k.
2: 125ipm is tops. above that the motor torque drops to 0. so 150ipm for example doesnt work... at all, motors dont even want to turn with no load.
3: acceleration on mine is at 40, which is HIGHER than stock, and lower than i wish it was. faster speed is useless without the acceleration to get there.
4: the stalling is due to pulse timing in the motor tuning panel. i had to adjust them and test a longish program over and over with straight lines to get stall free running.
5: the timing settings arent going to be the same on every pc / machine, so giving you mine wont help. i tried changing khai's CMTS demo machine at the show and it stalled with my settings. you will need to experiment to find the perfect match. i had to do the same exercise on my gecko g540 controlled nm-070. it seems to be the nature of paralell port and drive variability at higher pulse speeds.


6: if you are getting out of round circles, this may be due to another separate issue, especially if the "flat" sop is always in the same axis. try running mach in sherline half step mode. this fixed a similar issue on my gecko g540. the nm200 cuts dead perfect circles (within .001"). this is aparently a difficult to track "bug" in the gecko drives. if you manage to isolate it to a single drive, gecko will warranty it through novakon, but theres no absolute guarantee the new drive wont do the same. the only "perfect" fix ive found is the half step mode, which doesnt seem to have any reall effect on performance and accuracy, though theoretically the motors are moving less smoothly.

also make sure theres no backlash in the system of course. check the screw bearing supports, gibs, and such.

[kvom]

I just got an email from Khai that my mill was shipped today.

[fourwheeler]

I just got an email from Khai that my mill was shipped today.

Ah the anticipation....

[urbanimports02]

congrats, when your machine arrives, try the settings below from ihavenofish. i owe you big. changing the kernal speed to 60khz and increasing rapids seems to make everything happy. i test ran a program with rapids at 120ipm(just going a little more conservative) and accel at 40, and walla! it is moving a lot faster, almost scary on short rapids, it sounds like the table is jumping, thought for sure it was going to lose steps. finished the test run and rezeroed with edge finder, and it was bang on. ran the program on eight parts with a work stop on the vise, so no rezeroing, and all parts cam out perfect and the circles are now within .0005" i guess the 60khz must have done it as i did not do the sherline half step mod? whatever it is, i am pleased as punch and appreciate the insight. oh, and i have the current novakon cd100 control with internal pc. i will also try to post some pics of my $40 flood enclosure, it is working great, just need to improve the "door". i made a simple upper square tube frame and attached .020" marine vinyl(for boat canvas windows) using office depot 1" capacity paper binder clips. the vinyl just hangs inside of the coolant containment tray and works like a charm. it is kind of the shower curtain idea, only heavier material. between this and the other mods i made to the flood cooling system, i have this thing working pretty good, and filled a 8 gallon trash can with aluminum chips in 2 days time without any clogs or anything. i enjoy this nm-200 more everyday, but already looking forward to a sharp 2412s.

[ihavenofish]

woot. glad that all worked well.

the sharp.. mm.. yeah. i actually saw the new haas tapping centre at the cmts show and have been wanting one since. at $50k though... its more than i can justify for such small travels.

maybe we can all hound khai to make a novakon 20x40 tool room mill, hahahah.