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p1lts
30-01-2011, 12:48 PM
Chaps

I am entirely green to the world of CNC. I would like to be able to machine thin alu plate.

I've seen this machine advertised, but it seems particularly cheap. Is it, as I suspect, too good to be true?

http://www.premiersign.co.uk/proddetail.asp?prod=BC-300-200

Thanks

Ian

blackburn mark
30-01-2011, 02:28 PM
hi ian
looks pretty tidy for the money
i dont think it will cut through 1mm alli in one go without complaining but if your not in a big rush i would have thought it would get you there in the end

with unsupported rails you will get sympathetic vibrations kicking in at some point and giving poor finishes (vibration will kick in no matter what rails you use however if you think of unsupported rails as EXTRA large guitar strings and your cutter+cutting force as a plectrum youll get the idea of how this works) this pricipal applies to the whole stucture of course but on this machine the weakest link would be the X axis rails then the Y axis rails then probably your gantry sides, on a machine with supported rails the weakest link would very likly be the gantry sides


changing spindle speeds may help by knocking the vibration out of phase but i would have thought light cuts high spindle speed and single flute cutter would be the way to go on a machine like that

if you take the gamble youll have to report back here, it would be interesting to see how well a £700 ready to go machine would perform :smile:

stirling
30-01-2011, 05:43 PM
remarkably similar looking to the Chinese stuff on ebay - Not that I'm suggesting this is Chinese, nor that there'd be anything wrong with it if it was...

p1lts
30-01-2011, 08:59 PM
Thanks for the replies guys.

There are a few videos of similar machines on youtube. It seems to be capable of doing everyhting that I would desire of a CNC mill.

Now for the next question:- I already have access to Autocad and I am pretty proficient with this software. However, what other software would I require? From my limited reading, I think I may need two separate pieces of software. One to drive the mill (Mach 3???) and another to convert the Autocad drawing files into something that Mach 3 can import.
Am I on the right track??? Any recommendations?

Thanks

Ian

p1lts
03-02-2011, 06:53 PM
The machine posted in my first link, is supplied with A 300W spindle. That doesn't sound very powerful to me. My main useage would be thin plate alu. Do you think it would cope?

FatFreddie
03-02-2011, 07:25 PM
Thanks for the replies guys.
Now for the next question:- I already have access to Autocad and I am pretty proficient with this software. However, what other software would I require? From my limited reading, I think I may need two separate pieces of software. One to drive the mill (Mach 3???) and another to convert the Autocad drawing files into something that Mach 3 can import.
Am I on the right track??? Any recommendations?

Yes, the process is...

CAD creates drawing of part
CAM creates NC control file from drawing
Controller (Mach3 / EMC2 etc) Takes the NC file and makes the machine move according to the instructions therein.

You always need the controller but you can create the NC (AKA gcode) file in a text editor.

Autocad is fine for the drawing, the CAM program really depends on what you want to make and what your budget is. I tend to recommend CamBam which is fairly cheap, easy to understand, will import DXF files from Autocad and has a 40 go full function trial. If you need to take complex 3d models from Autocad and create the NC code directly from them then you may require something (much) more expensive but CamBam is a good introduction to the basic process so time spent looking at it won't be wasted.

blackburn mark
03-02-2011, 08:17 PM
The machine posted in my first link, is supplied with A 300W spindle. That doesn't sound very powerful to me. My main useage would be thin plate alu. Do you think it would cope?

it looks like a reasonably chubby motor so i would have thought the torque would be quite good but i guess there is no real way of saying without knowing more about it/ how its wound

iv an outrunner that looks a similar diameter and will happily cut 0.5mm depth in alli 3000rpm 3mm single flute, the power supply is 350w but im pretty sure its drawing nowhere near that

edit: the one you show in the link will only run as low as 5000rpm not perfect but i would have thought doable with small tooling :)

p1lts
03-02-2011, 08:29 PM
Hi Mark

Apologies. I am now looking at the slightly larger machine http://www.premiersign.co.uk/proddetail.asp?prod=BC-400-300 which has the 300W motor and a variable speed of 1-9000rpm.

I'm just a little concerned how easy it would be to change the spindle to a different type if I had too at a letr date.

Thanks again for all the help

blackburn mark
03-02-2011, 08:47 PM
speed of 1000-9000rpm


ahhh!! that sounds better :) i would have though you would be fine with that

if you have access to a lathe making your own spindle would be a cheep option.. easy to make one to fit whatever spindle housing you already have, its not rocket science and they work quite well, there are a couple of threads on here that will talk you through the task but unless your after using larger cutters and heavy cuts im pretty sure the spindle on the BC-400-300 will be fine