[MichaelHenry]

From the "Jogging bug..." thread:

P.S. And at the risk of a hijack, I'll answer MichaelHenry from several days ago: When I am milling very small details, SprutCAM will create a command for an arc, but will put zero for the radius. Mach will load the program and display it just fine, but will stop on that block and croak when I run it. The fix (for me) is to edit the program and replace all occurrences of zero radius with a small number (like 0.0001). The saddest part is that I usually find out after the part runs for a while, so I usually start from that line after I fix the problem. It's always a nail biter to restart like that, especially with very small tooling.

Are you using lead in or out on any of the ops where you get this error? I recall getting the same thing before and have a nagging memory that it was related to the lead in parameters on at least one occasion. In other cases I think it may have been related to the radius on the corners of a rectangular pocket and that increasing the design corner radius to something a little over the size of the cutter resolved it.

For example if using a 1/4" end mill to mill out a 2" x 4" pocket, I'd specify 0.251" radius on the corners of the pocket in the Alibre design.

Of course I could be mis-remembering all or any of the above.

I'm absolutely positive that it annoyed the heck out of me every time it happened.

Mike

[StephanWenger]

That radius would be right for an 1/2" (diameter) cutter, right? For a 1/4", you would use a 0.126" radius?
Stephan

[ger21]

Yeah, that sounds right. And I believe he's talking about cutter comp, G41/G42.

[saabaero]

I do know that when using an arc as a lead-in or lead out (even without compensation G41, G42) that the radius of the arc should be slightly larger than the cutter radius (otherwise there might be an error). However when I am machining a pocket with a corner radius smaller than the cutter radius there is just extra material left in the corner that isn't machined away. If I were to follow up with a smaller dia. cutter it would clean up and the result would be the correct radius.

[mactec54]

Michael Henry

The problem is in your Cam program Not in Mach control if your posted Gcode has a 0.0000 corner radius & you have a cutter that has a .010r it will not go past that line of code because your cutter is to big to do a 0.0000 radius

[MichaelHenry]

That radius would be right for an 1/2" (diameter) cutter, right? For a 1/4", you would use a 0.126" radius?
Stephan

Yep - it should have been a 0.126 radius.

Mike

[MichaelHenry]

Michael Henry

The problem is in your Cam program Not in Mach control if your posted Gcode has a 0.0000 corner radius & you have a cutter that has a .010r it will not go past that line of code because your cutter is to big to do a 0.0000 radius

I hadn't thought about corner radius since most of my designs and end mill so far have used square-cornered wall/floor intersections and my end mills are almost all square cornered (so far as I know). If the features and end mills are both square cornered and the CAM software carries that info forward, Mach shouldn't have a problem, should it?

Come to think of it, it seems to me that on one or two occasions I got the radius error in the middle of a job at least once, restarted it from the beginning and the error did not repeat. Unfortunately I was in too big a hurry at the time to make notes of circumstances or settings at the time. If it happens again is there anythings special I should look for in the G-code?

Mike

[mactec54]

Mike

I would love to see a Endmill that can cut a inside square corner, it can not be done there will aways be a radius in the corner of at least half the dia of the cutter

You can go around the outside of a part & have a square corner but when cutting around a pocket you need to draw a radius in the corner of your part, or the control will stop every time it comes to a corner because the cutter can not fit around a 0.00 corner

The control will only let the cutter go were the Gcode is telling it to go in your case a 000 corner is going to stop .000 is no ware you have to tell the cutter to go around the corner

Like/say corner radius being .126 in your part, A .250 EndMill will then go around your corner

[philbur]

My CAM just ignores the square corner of a rectangular pocket with zero radius corners and goes into the corner as far as the cutter diameter will allow. I though this was kinda standard procedure for any CAM program.

Phil

Michael Henry

The problem is in your Cam program Not in Mach control if your posted Gcode has a 0.0000 corner radius & you have a cutter that has a .010r it will not go past that line of code because your cutter is to big to do a 0.0000 radius

[mactec54]

philbur

That is correct most cam systems will do what you are saying, & will let the cutter go into the corner as far as it can, this is usely a choice that you have to make when you select the tool path you want to do in your cam program

[philbur]

What other choices are there?

Phil

philbur

That is correct most cam systems will do what you are saying, & will let the cutter go into the corner as far as it can, this is usely a choice that you have to make when you select the tool path you want to do in your cam program

[MichaelHenry]

Mike

I would love to see a Endmill that can cut a inside square corner, it can not be done there will aways be a radius in the corner of at least half the dia of the cutter

You can go around the outside of a part & have a square corner but when cutting around a pocket you need to draw a radius in the corner of your part, or the control will stop every time it comes to a corner because the cutter can not fit around a 0.00 corner

The control will only let the cutter go were the Gcode is telling it to go in your case a 000 corner is going to stop .000 is no ware you have to tell the cutter to go around the corner

Like/say corner radius being .126 in your part, A .250 EndMill will then go around your corner

Sorry - by corner radius I meant the corner of the cutter. I know that some end mills have a radius or chamfer on each tooth and thought that was what you were referring to.

Mike