First time 3D tool path strategy

[Anonymous]

I have done a fair bit of 2D caming but this is my first 3D milling project. The model will be milled out of brass. 

In my first tool path I decided to use a 2D contour operation. This way I could physically remove the 3 triangular  brass sections before moving on to the scallop tool path. In my mind, this would minimise unnecessary milling and wear and tear on the end mill. I'm getting an odd tool path:

Also, I'm not sure if my strategy of 2D contour followed by a scalloping operation followed by a parallel milling operation is the right way to go. 

In addition I'm confused about where and how much stock to leave for a high quality finish.

I'd appreciate input!

Thank you.

Gunter

[seth.madore]

It seems to be the Smoothing that is tripping this up. Turn it off and you'll be all set.

I'll log this as a defect and get it into the system.

Regarding your other question;

Your approach should yield acceptable results. If you have access to the paid Extension, Steep and Shallow would be a good choice as well (this is only available to EDU and commercial accounts). As for the "Stock to Leave", I tend to favor values of .005" (inch) axial and radial.

[Anonymous]

@seth.madore - Thank you Seth, that worked.

I still have a question about the 2nd operation which is scalloping. Won't the end mill go too deep into the stock since I do not have a 3D adaptive clearing operation?

[seth.madore]

What I would recommend:
1) Use 2D Adaptive on the OD and three triangular windows. Simple and effective.

2) Use 3D Adaptive with "Rest Machining - From Prior Operations" and remove the excess

3) Alternatively, you can also use 3D Contour with Stock to Leave and do a decent job (Ordering Bottom-Up)

Scallop would be my preference for finishing the part, or you can use parallel on the straighter sections. Scallop would be the better choice, imo. Turn on "Contact Point Boundary" and turn off "Contact Only" and "Machine Areas using Boundaries"

[Anonymous]

@seth.madore - Thanks for the advice Seth. I did as you suggested but have a couple of questions:

1. In the final scalloping operation there are some weird tool path bumps which are not only visible during simulation but also during actual milling.

How do I get rid of these or rather, why are they there in the first place?

2. In my current set up, I did a test on mdf. I plan to mill this out of brass. For the final finish, I used a 1mm ball end mill with a 0.2mm stepover. Which end mill would you suggest?

Many thanks in advance!

Gunter

[Anonymous]

Update..

Over the weekend I played around with some tool paths. Using the scallop path to finish, I got an excellent surface finish on the circular part of the model but quite a lot of striations on the 3 straight triangular sections. This despite using a step over of only 0.2mm. I thought I'd like to keep try parallel finishing for these sections but I am unable to pick all the faces: 

 1. Could you please explain how to select specific faces for different tool path strategies?

2. I noticed that in 3D Adaptive Clearing, there is no step over option. Is the equivalent Maximum Roughing Step down in the Passes tab?

Many thanks,

Gunter

[johnswetz1982]

1. I think your were having trouble because the contours meet/overlap at a common point. Select a contour. Hold Alt and select that contour again. You will get a pop box where you can select open or closed contour (closed in your case). then walk around picking all your edge contours. Select the "+" sign to accept your selection.

2. Adaptive does not have maximum step over because that values constantly varies (thats why it is adaptive). What would be your absolute highest stepover is your "Optimal load" setting. That is the max that it can engage/stepover.

3. I'll add to maybe try machining only one of the wings/points at a time and adjust the pass direction to be either perpendicular or parallel with the point, or try clicking the perpendicular passes option. 

 

[Anonymous]

@johnswetz1982 - Thank you for your detailed explanation. As you suggested, I think I'll try one spoke at a time and see how I go.

Much appreciated 🙂

[johnswetz1982]

Just do one, when you are happy with that, put that operation into a Circular pattern of 120 degrees. That way you only have to alter on set of parameters that are then duplicated for the other wings.

[Anonymous]

@johnswetz1982 - Not sure how I would do this... "put that operation into a Circular pattern of 120 degrees" ? 

[johnswetz1982]

See image. You create a pattern. Give it a type (circular). This will create a folder in you operations tree. You would then drag you parallel operation into that folder. Its real useful for anything repetitive or symmetrical.                                                                                                                                  .

[Anonymous]

@johnswetz1982 - Thanks so much, I didn't know that! This is super useful 🙂