To be honest I don’t really think we know as a company - but as it’s high end furniture/office fit out joinery we tend to work with small tolerances, around 0.2mm
I was talking more of an overall sizes of the object, like does it matter if that curvy desk is 5mm wider than shown in the drawings. Or is just a concept pic and you are the one creating the drawings?
ah i see, generally we receive drawings from architects and have to follow them as close as possible. A few mm may not be a problem, unless they clearly state on their drawing a dimension they require.
I drew this using splines in the end, however our CNC department prefer to work with arcs, but i managed to get around this by exporting the 3D parts out as a DWG CAM metric file.
That’s another subject which i’m not 100% sure on as well. The best way to get my 3D parts to our CNC guys. I know Rhino files open in mastercam, but I’m not sure this is the best way to transfer the files, do you know much about this Asterisk?
Yeah, CNC software hates splines, 'cause the G or NC code doesn’t do splines. They get converted into lines and arcs by CNC software that generates the code for the machines and sometimes the conversion fails, so the production comes back to you asking to convert the geometry into simple arcs and lines. We use Panel Builder here. It’s AXYZ software if I’m not mistaken and it deals with splines nicely or is it our Rhino exports that are already fixed?.. Don’t know.
You can make Rhino export splines as arcs and lines into DWG. It’s in the Export scheme settings.
That depends entirely on the quality of your “CNC Department” personnel, their software and their machines. I’ve been CNC’ing spline-based curves for over 20 years with no problem. Decent CAM software will do the conversion to line segments in the background based on tolerance, decent CNC machine controls and motor circuits will not stutter even with lots of relatively fine line segments.
True, it usually comes down to them (business owners) not wanting to spend money for a competent software and pay people who actually know what they’re doing.
@Jed_Chaplin
This setup seems to work for us. (this is in inches)
You can change splines to this too.
We use Mastercam x9, which i believe is quite old? It would be perfect for me if the CNC guys could convert my 3D parts with spline lines in their software. Maybe its worth us upgrading?
I started with Surfcam 7.0 which is even earlier than that (I think). It handled splines just fine back then. The problem is probably not the CAM software, but rather the (older) machines and CNC controls which can’t handle lots of fine line segments (approximating a spline) in the G-Code.
We have old KOMO machine sitting in the shop (still works, but not really used). It’s got whooping 64KB of RAM. If G-code file is larger than that - it has to be split just so machine could actually load it. XD
Hi,
We check exported dwg files in Autocad LT or Draftsight before sending to a supplier. Normally splines is ok for export to Lasers and punching machines. We only had issues with dwgs, that were converted to small polylines. Wrong export parameters can lead to funny results! Too many points, and some Cam Softwares stop working…
familiar picture.
