5th axis required? 1

[pedrof]

I require 2 flat surfaces parallel to each other to be milled, with a straight sloped surface i.e. a long chamfer connecting the 2 planes. The surface finish is not critical on the sloped section and I can live with rads on the 2 corners. One machinist tells me this requires 5th axis, another doesn't. I would have though as long as the path of the tool is in straight line that this could be done without the need for a 5th axis machine. I've attached a sketch to illustrate the profile side on.
Just want to clarify if this does need 5th axis or not.
Thanks

 

[mcgyvr]

Does not require a 5th axis if you machine it with the top view being just as you have it sketched. You will get a radius (1/2 tool diameter) where it transitions from the angled slope to the flat again (inside corner only).

 

[NomLaser]

You could also machine it on a CNC mill. It will take some time to get a smooth surface but it can be done.

 

[pedrof]

Thanks for those responses. I just want to make sure I've explained this correctly. I think the pdf may have been 90° out.
Here's a pdf of a 3d model showing a tool and the blue faces are those to be machined, this is just indicative, I appreciate the tool is not very realistic.

 

[mcgyvr]

Autodesk Inventor right?
Why not machine it with the tool in the red axis (x axis)?

Doing it the way you have it you will have a wierd radius on the inner edge of the sloped face.

 

[mcgyvr]

Like I said above milling like you have in the second attachment showing the tool you will have this wierd radius.
see attached

 

[mcgyvr]

Machine this way (see attachd), then you only have the radius indicated in red... Which can be made really small with a final pass from a smaller end mill.

 

[pedrof]

Sorry, should have clarified. The milling has to be from the direction shown due to other features on the part not shown here. I think we could live with that 'wierd' radius as long as it's not too large. We have sheet metal which needs to have a lip to mount against, so we can cut this back to make sure it's meeting a flat surface i.e. missing the 'weird rad'. I guess overall it looks like it can be done without bothering with going to 5th axis but with some caveats..(...and yes, it is Inventor). I'm getting the 'can-do' machine shop to mill me a sample block so I can get a feel for surface finish etc.

 

[mcgyvr]

Surface finish should be fine if its just mating a sheet metal part on to it.. And that "wierd" radius can be made really small by simply making a second run through that radius with the smallest end mill they can.

Obviously if this is a 1 off there is no issues. But I would actually suggest them making the part in 2 steps if this is a production part. Run your top features, then turn the part. I bet it's faster n 2 steps depending on what you can live with as far as surface finish on the sloped plane.
If their CNC machine can actually turn the part (typically called an A axis I believe) during machining your even better.

 

[dicer]

A drawing in one plane is not helpful at all.

 

[pedrof]

Dicer,
.......which is exactly why I posted a 3d view with a mocked up cutter further down, see link above.

 

[larrylcoyle]

To clarify you original question, "NO" you do not need a fifth axis to machine this. You do need a fourth axis however so you can rotate the part to the proper angles for machining the flat surfaces. Are you planning to machine this in house?

Larry