[5artist5]

How would I go about cutting a part this shape?

I have bobcad V21 and it seems to have three cutting path strategies.
1) A linear back and forth pattern.
2) a Radial pattern that moves from the center out to the edge or vice versa.
and
3) A spiral pattern

So these are my questions.
1) Is there some way to do this easily with just the G code? I have done some basic G coding. The straight line parts of it I get how to do, but can I say, "do a straight line from this point to that point then make 90 degrees of a .250 radius and then go to this other point?

2) Is there a way to have BobCad actually follow a path like that?

or 3) Can I just use a small cutter and use say the radial pattern and have it cut that notch that way?

It is a gasket channel, so it should be pretty smooth...

[Thorpydo]

What's the part look like? Did you forget to attached a picture?

[5artist5]

What's the part look like? Did you forget to attached a picture?

Yep, thanks for the heads up ;-)

[Kipper]

I'm a lazy sod and would just specify the dimensions in Mach.....Although that part is a doddle even for a noobcake like me in Bobcad.....What dimensions is it?

[5artist5]

it's 2" per side. The channel in .125 wide.

The part is just a test for a much more complicated part I want to make. But I want
to make sure I get how to do this part of it, either via bobcad or by injecting the appropriate G code into the script that bobcad spits out.

[Journey_Man]

Hey There! Is that an O Ring Groove? If it is, You should use a Ball End Mill. It looks to be .250 Wide? You Could offset all of your lines to 1/2 of the width and run your toolpath with cutter comp.off;picking the center line as your tool path...but you should know the size of the O ring first. They have specs for width/depth ect. Here is a site that has that sort of info. Navagate to the O Ring Sizing Chart.
http://www.marcorubber.com/

[Kipper]

Try this Bobcad file if it helps. It has the toolpath and geometry in it (Metric though)

[SCzEngrgGroup]

How would I go about cutting a part this shape?

I have bobcad V21 and it seems to have three cutting path strategies.
1) A linear back and forth pattern.
2) a Radial pattern that moves from the center out to the edge or vice versa.
and
3) A spiral pattern

So these are my questions.
1) Is there some way to do this easily with just the G code? I have done some basic G coding. The straight line parts of it I get how to do, but can I say, "do a straight line from this point to that point then make 90 degrees of a .250 radius and then go to this other point?

2) Is there a way to have BobCad actually follow a path like that?

or 3) Can I just use a small cutter and use say the radial pattern and have it cut that notch that way?

It is a gasket channel, so it should be pretty smooth...

I don't know BobCAD, but I'm sure it must have a way of doing that. However, if you want to program it manually, you need to use G02 or G03 commands. The arguments are the endpoint of the move, as X/Y coordinates, and the centerpoint of the arc, as the I/J parameters. I/J as usually specified as relative offsets from the starting position, but this is settable in Config->GeneralConfig. G02 cuts a clockwise arc, while G03 cuts a counter-clockwise arc. For example:

G02 X2.00 Y0.00 I1.00 J0.00

If you start a X0.00 Y0.00, the above will cut a 180 degree arc starting at X0.00, Y0.00, ending at X2.00, Y0.00, with the arc center being at X1.00, Y0.00. The I parameter is added to the current X position to give the X coordinate of the centerpoint, while the J parameter is added to the current Y position to give the Y coordinate of the centerpoint

Regards,
Ray L.

[5artist5]

Ok I think I get it, so then if I do this:

G01 X-0.75 Y0.9375
X0.75 Y0.9375
G02 X0.9375 Y0.75 I0.75 J0.75
X0.9375 Y-0.75
G02 X0.75 Y-0.9375 I0.75 J-0.75
X-0.75 Y-0.9375
G02 X-0.9375 Y-0.75 I-0.75 J-0.75
X-0.9375 Y0.75
G02 X-0.75 Y0.9375 I-0.75 J0.75

I will come out with that shape then?

Thanks guys. That G2/G3 thing is exactly what I was looking for.
Also I looked at that bobcad file and that seemed like what I was looking for too

Thanks for all the help!

[SCzEngrgGroup]

Ok I think I get it, so then if I do this:

G01 X-0.75 Y0.9375
X0.75 Y0.9375
G02 X0.9375 Y0.75 I0.75 J0.75
X0.9375 Y-0.75
G02 X0.75 Y-0.9375 I0.75 J-0.75
X-0.75 Y-0.9375
G02 X-0.9375 Y-0.75 I-0.75 J-0.75
X-0.9375 Y0.75
G02 X-0.75 Y0.9375 I-0.75 J0.75

I will come out with that shape then?

Thanks guys. That G2/G3 thing is exactly what I was looking for.
Also I looked at that bobcad file and that seemed like what I was looking for too

Thanks for all the help!

Close, but not quite. What you want is:

G90
F200
G01 X-0.75 Y0.9375
G01 X0.75 Y0.9375
G02 X0.9375 Y0.75 I0.00 J-0.1875
G01 X0.9375 Y-0.75
G02 X0.75 Y-0.9375 I-0.1875 J0.00
G01 X-0.75 Y-0.9375
G02 X-0.9375 Y-0.75 I0.00 J0.1875
G01 X-0.9375 Y0.75
G02 X-0.75 Y0.9375 I0.1875 J0.00

G00/G01/G02/G03 are all modal, so whichever one you used last, persists until you specify another explicitly. Also, I and J are incremental, from the starting point of the arc.

You can load this into Mach3, and "run" it with the machine turned off, or on a PC with no machine attached at all, and see the result in the toolpath display.

Regards,
Ray L.

[5artist5]

Oh ok I see.

Thank you so much for the lesson!

I really think it is amazing that there are boards like this with people who are willing to help people to learn things that may otherwise be difficult to figure out. I am ma member of several different types of boards and I think that this kind of information exchange is really the most valuable type of resource that the internet and possibly technology itself has to offer.

So thanks everyone, I really appreciate it!

[fretsman]

Oh ok I see.

Thank you so much for the lesson!

I really think it is amazing that there are boards like this with people who are willing to help people to learn things that may otherwise be difficult to figure out. I am ma member of several different types of boards and I think that this kind of information exchange is really the most valuable type of resource that the internet and possibly technology itself has to offer.

So thanks everyone, I really appreciate it!

Ray's not only a smart cookie, but he's a good dude as well-

Thanks for the lesson, as well, Ray-

Dave

[SCzEngrgGroup]

Ray's not only a smart cookie, but he's a good dude as well-

Thanks for the lesson, as well, Ray-

Dave

Dave,

Thanks! :-)

Regards,
Ray L.

[hoss2006]

That G2/G3 thing is exactly what I was looking for.

Here's a cheat sheet I've kept on hand for a long time, it's for the typical G17 XY plane.
Hoss