Back feed motion in dynamic milling

[Pitka_Guru]

 

Just watching a webinar from Inhouse's about new features in X8. 

 

I've noticed when dynamic milling on a part shape similar to this one,  that my feed move is quite smooth but the back feed movement stutters like crazy. Mainly on the first passes from the outside of the part where it has to get back to the starting point by making a near 90 degree turn. Has anyone noticed this? I've avoided this by telling the tool to retract when avoiding a boundary but it seems silly that I should need to do that.

 

 

[Chris Rizzo]

Your filter is on? Can you reshoot that screen shot and have points displayed too? I'm curious.

 

Also, that first pass offset and feed reduction is a great add-on. It still will over-engage when morphing 90 deg corners, but this helps with some of it. I like to experiment and push the f&s to the limits, and the first pass was always the limit.

[Pitka_Guru]

I can't, thats a screenshot from inhouse's webinar  

 

But I did notice it on a bunch of parts I was doing with X7 and I had my filter on. I had to set my retract to avoid boundary and to a distance of about 150mm. Chris, you have some Haas machines, is that correct?

[Chris Rizzo]

Haas and Okuma currently at my disposal. Run all sorts of stuff though. 

[K2csq7]

What is your min toolpath rad set to?

[Pitka_Guru]

I completely missed these posts. My min TP radius is usually 10 - 20 % of the tool. Its smooth in most areas except where I mentioned previously. I'm trying to work out if this is a HAAS problem or Mastercam.

 

Chris, do you notice anything like this on your HAAS' and what post are you running? I'm wondering if my post and control def settings could be the culprit here? I'm using an edited version of Mpfan.

[Jayson Kramer]

What is the feed rate of the back motion and what year is your Haas?

[Pitka_Guru]

My feed is was 16,510mm/min and back feed was set to the same. The machine is 2014 VF4ss. I can send a copy of my post if needed. 

[Jayson Kramer]

Well you have the SS so the high speed look ahead should be on and you are running the back feed the same as cut. so my thought is out the window.