CamBam / FreeCAD 2D/3D MOP question Please help

[dudz]

Ok. I can mill 2D objects no probs.

I wanted to mill a simple semi circle slot along the horizontal plain of the material. The circular slot is to be 120mm long / 11.113mm deep
12877

This picture is just an example I made so you can see what I am trying to do. I have milled the object all apart from the slot on the left.
What is the simplest way to do this ?. I have today tried to create a 3D version in FreeCAD software, but when imported to Cambam, I have no Idea what to do with it. Especialy as I only want the slot. Maybe there is a way in Cambam, that lets me do this without getting into 3D ?

[irving2008]

whats the radius of the slot? or is it a true semicircle so diameter = 22.226mm (spurious level of accuracy aside), or 7/8". Maybe you can find a 7/8" ball nose cutter.

[dudz]

Hi irving,
The Dia is 7/8" . I have 6mm ball nose cutters. I can't fathom out how to cut a semi circle slot. Cambam just creates a rectangular pocket. Obviously I am missing a vital bit of info. My DOC is only 1.5mm in aluminium




whats the radius of the slot? or is it a true semicircle so radius = 11.113mm (spurious level of accuracy aside), or 7/16". Maybe you can find a 7/16" ball nose cutter, like this one (http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Milling-Cutters/HSS-Ball-Nose-End-Mills) (scroll down 1/2 way)

[irving2008]

Edited my post, but not quickly enough.. got my radii and diameters confused (its the heat). Don't think cambam can do that. If you can find a 7/8 cutter and get it in your spindle the doc isn't an issue, just go round and round.



Hi irving,
The full circle would be 7/8". I have 6mm ball nose cutters. I can't fathom out how to cut a semi circle slot. Cambam just creates a rectangular pocket. Obviously I am missing a vital bit of info. My DOC is only 1.5mm in aluminium

[dudz]

Hhhmm chinese spindle. I dont know if the speed will cope too low with such a large endmill . If Cambam wont do it, what software will ?

Or maybe something inside Mach3 ??

[Robin Hewitt]

But you aren't trying to cut a semi-circular slot, you are trying to cut a semi-circular slot with something at the ends so the software knows what to do when it gets there. The tool needs to know where it can overhang.
Given half a chance any self respecting software will not view this as a pocket sinking exercise. That way it can cut the outline when it reaches the end. Simples.
The easiest way is to write a quick program that spits out a G code, that way you can be sure you get a finishing cut that increments to the face rather than the depth.

[dudz]

OK thx.

I just tryed the trial version of Meshcam. It was simple to do (on the pc)
Pitty I cant get Cambam to do it though.

[FatFreddie]

OK thx.

I just tryed the trial version of Meshcam. It was simple to do (on the pc)
Pitty I cant get Cambam to do it though.

Have you tried the CamBam forum? There are some very knowledgeable people on there.

[phill05]

I wanted to mill a simple semi circle slot along the horizontal plain of the material. The circular slot is to be 120mm long / 11.113mm deep
12877

This picture is just an example I made so you can see what I am trying to do. I have milled the object all apart from the slot on the left.
What is the simplest way to do this ?.

I would draw the slot as a line longer than you need draw a semi-circle to the size you want and extrude the semi C along the line, create your tool path using a bull-nosed cutter, using center line of where you want to put slot across the part, use this as XYZ = 0 set your cutter & g-code to run from there, it should cut a semi-circle across the part.

Phill

[dudz]

I would draw the slot as a line longer than you need draw a semi-circle to the size you want and extrude the semi C along the line

Phill

This is the bit, Im not sure how to do ?

[phill05]

Take a look below.

12878
first draw a line longer than you need so you have overcut of the part, then draw a semi circle like the one in red in your software look for extrude, pick the line as your length of cut, then pick the semi C as your profile and merge them together, you need to orientate your part or the drawing to cross your part using the top face of the part as the XYZ =0 you end up with a semi circle cut into the part as shown.
Hope it helps, if not give me the exact sizes of the part you want to cross and the size of the semi circle and I will do you a code to cut.

Phill

[dudz]

ah that's probably why. I don't have "extrude" in my CAD software. What software are you running for example ?
looks like vectric

[phill05]

Take a look at the 4th paragraph down Extrude.

http://www.cambam.info/doc/plus/cad/DrawSurface.htm

Phill

[dudz]

pick the line as your length of cut, then pick the semi C as your profile and merge them together
http://www.cambam.info/doc/plus/cad/DrawSurface.htm

Phill

Ok found the Extrude in Cambam. I managed to make a 3D circle , but I am now stuck on how the merge them together. and I cant get the circle/cylinder to follow the same axis as the line.

Sorry for my lack of understanding here !

[phill05]

disregard my first idea as this was done in Vetric, in Cambam first create the semi circle then extrude upwards to the over length you require then follow the instruction to rotate the part.

(To create extrusions along other axis, the shape must first be extruded in Z, then rotate the extruded surface object to the required orientation.
The Extrude operation will first prompt for an Extrusion Height. This will be the Z height of the extruded surface. A positive height will extend toward the positive Z axis (ie toward the viewer when drawing is in the normal orientation with the XY plane parallel to the screen). A negative height will extend the surface along the negative Z axis (ie into the screen).

[dudz]

Ok. This is going to raise answers that probably are obvious that it is not the correct method to do this, but still I want to try.

I want to cut 2 slots (2mm wide and 30mm deep from 2 sides / length around 35mm) though the 6082 T6 billet. Using a single or 2 flute 2mm endmill, I know the DOC is going to have to be tiny maybe 0.25mm ?. I am using flood coolant.

I think 10mm is probably the max flute length for any 2mm dia endmill. Maybe I can find one somewhere that will stretch to 15mm, but I doubt it.

[Robin Hewitt]

What you need is called a rib cutter. The sides of the cut support the tool, only the very tip is fluted. It cuts the slot that puts a rib onto an injection moulded component.

[dudz]

What you need is called a rib cutter. The sides of the cut support the tool, only the very tip is fluted. It cuts the slot that puts a rib onto an injection moulded component.

Sounds interesting. I have searched but cannot find them available for purchase online in metric

[EddyCurrent]

I wanted to mill a simple semi circle slot along the horizontal plain of the material. The circular slot is to be 120mm long / 11.113mm deep

Dudz, did you get this sorted ? there's a thread here just like your issue; http://www.cambam.co.uk/forum/index.php?topic=4338.msg31125#msg31125