'Safe Distance' why is it needed?

[Fabbunny69]

Hi All,

I have scoured the forums and read many posts to try and understand  why you need 'Safe Distance' (found under the linking tab). Doesn't 'Retract Height' & 'Feed Height'(found under heights tab) cover all clearance scenarios?

If 'Safe Distance' is set higher than "Feed Height' then 'Feed Height' is ignored and 'Safe Distance' becomes the height the tool feeds down from.

PS> the below post from 2018 was related but no Reponses were made😶

https://forums.autodesk.com/t5/fusion-360-manufacture/not-understanding-purpose-of-quot-safety-dista...

[daniel_lyall]

Sometimes a safe distance is a need as you noticed it is an override.

[Fabbunny69]

Thanks for that but cant you achieve all the safe distances you need using the heights tab?

I know 'Safe Distance' must have some functionality, I am having trouble conceptualizing it. I have lost a fair bit of time wondering why my NC program was ignoring my feed height, only to find out that the safe distance amount set from a previous setup was overriding my feed height.

That's OK, live and learn, but I just want to understand why 'Safe Distance' is even necessary?

[mattdlr89]

I think this is needed to set how much distance it will feed in at when starting a cut below the top of the model. For example at the moment I am doing a parallel machining strategy (as a semi-finishing op). If I have the safe distance set to 2mm, when I simulate I get collision warnings that the tool will rapid into the stock. This is because it is going 2mm off the start of that pass which may not be at the model top. 

If my understanding is correct the safe distance is setting the distance that it feeds in at before doing a G01 lead in move. Whereas the retract plane is a set plane above the model. See the bit of toolpath between the red lines in my shot below. 

This is my understanding of it anyway. I generally leave it at 2mm until I get warnings or collisions in the simulation.

[Fabbunny69]

Thanks @mattdlr89 just the kind of guidance I'm looking for in trying to understand this. 👍

Flat out at the moment, later on I will knock up a test job with different levels and play with it and hopefully the sun will start to shine!

Will let you know how I go.

[Fabbunny69]

x

[Fabbunny69]

I would like to thank you again and at least now after some testing the clouds seem to be clearing a little! But there seems to be variance with some tool paths to others on how this works 

An extract from my notes:

SAFE DISTANCE: Only used when a toolpath needs to leave material and move over to another feature and re-enter the material within the same toolpath (LINKING). ie. letter to letter in engraving, pocket to pocket, surface to surface, cut to cut.
NOTE 1: If LINKING is effective in a toolpath then the greater of SAFE DISTANCE or FEED HEIGHT will be used on initial tool approach. See BRG/ROPE PULLEY for clarity.
NOTE 2: If features are on a different plane then retract position will be ignored when moving over and tool will be sent to clearance position.

Does this seem correct to you?