Trouble with radius toolpath Help please?

[ryadia]

Hello all,
I've got a 350mm long 41mm wide 31mm deep piece I'm trying to radius the 4 edges with a 10mm radius. No matter how or what I do I can't calculate the toolpath. I've chosen a 4mm ball end bit, drawn firstly an outer rectangle and tried to radius it and then made an inner rectangle, then tried using both rectangles and every time I get the same message when trying to calculate it.

"A toolpath was not created. Check that there is enough space to fit the entire profile across the rail contour without it overlapping itself."

Have I missed something here in not having a 'rail'? The help documentation is not helping me. Some of the descriptions like 'Rail' are not defined as a selection and I'm totally confussed. Any help will be gratefully recieved.

Thank you, Ryadia.

[Adrian]

Sounds like you're using the moulding toolpath.

The rail is the vector you want the moulding to flow around, the rectangle in your case and then you need a vector that is the shape of the moulding (radius) you want to create. A 10mm radius arc in your case.

You're getting the error because the software thinks you're trying to run the second rectangle around the edge of the first one. You have to select the rectangle (rail) first and then the profile (moulding) and it will calculate correctly.

[ryadia]

Thank you Adrian,
I'll add you to my Christmas list!

[martin54]

Using a small bit like that will take quite a bit of time to cut a radius around the edge, I wouldn't even use the CNC for a job like that. Much quicker on a router table. If you do have to use the CNC then using a profile cut with a round over bit will be much quicker or if you have to cut it using the moulding toolpath then a larger bit would reduce machining time

[ryadia]

Using a small bit like that will take quite a bit of time to cut a radius around the edge, I wouldn't even use the CNC for a job like that. Much quicker on a router table. If you do have to use the CNC then using a profile cut with a round over bit will be much quicker or if you have to cut it using the moulding toolpath then a larger bit would reduce machining time

Thanks for the reply Martin.
I don't have an auto tool changer and my spindle requires 2 spanners to change a bit. The item I'm machining is a pine 40mm wide x 30mm high strip that has a slot in the middle to take a piece of engraved perspex. Using the same tool to cut the slot and the radius (with rounded corners) saves me 3 bit changes. I can successfully run 100 mm per second with 2mm bites on everything except the radius. For that I have to use the moulding profile so its not a continious process but faster than changing and setting bit bottoms.

I've used a 10mm radius round over bit that has to be run in climb mode to prevent ripping the corners out. That needs 5, 2mm steps to get a decent enough finish to only need a mild sanding before stain and gloss. Unfortunately setting zero for all axis's and using a slower feed means to isn't much faster than running a 4mm bit flat out. My router table doesn't have any facility to cut a 90º round corner without it showing the mess created by trying that does. The sound proof area the CNC machines are in has no room for a cast iron router table that I could make a jig for to do sharp corners. Maybe when the positive vent room for the laser cutter is approved (everything we make for manufacture in Australia has to be approved) and I get that monster out of the quiet room I can consider something like that.

Sorry to take so long to reply but I had trouble logging on to answer you.
Kind regards,
Ryadia