[bobcad guy]

hey guys, I had a problem with a part I am cutting. the problem was, I used advanced rough to cut the profile of the part, and in one area, with advanced rough the tool doesn't go to .100 above part to rapid to next position, it only rapids to .100 above last depth cut, unless it thinks it will hit the part, and bob as well as predator did not show any tool hitting, but, my problem is the tool was hitting the part as it was rapiding to the next cuts start point. I don't think bob is at fault here. I think its a machine fault. is there a parameter, or a setting, or a G code that makes the machine synchronize the X and Y rapids so they travel in a " straight" line, arriving to a point at the sametime? as if they were feeding. I believe the tool was hitting because the Y axis was getting to its position before X. I know this can be done on most machines, but I don't know all the Haas systems very well, its a VF4, any help would be great.

[Machineit]

I have both BobCad and a Haas. The problem you are having is with Bob-Cad, not the Haas. It is normal for the Haas to rapid as you have described with the short axis distance getting there first.

You might want to post the part here for others to look at. If the tool does not hit the part in the simulation, it should not hit during the actual machining.

Mike

[aldepoalo]

dog leg rapid.....

[jrmach]

If it does not show in Preditor,that is a problem.
I am curious as how "" I used advanced rough to cut the profile of the part,"""
Advanced Rough and Profile seem an odd combination of words used together.
Upload file,you gots me curiousity up.

[aldepoalo]

one solution is not to use G00 moves but instead use G01 moves with a "rapid" feed rate. I haven't done this to a post processor yet but want to. doing so will eliminate dog leg rapids and allow you to back plot or simulate what will happen on the machine. because of the G00 short cut the back plot and or simulation doesn't accurately represent your rapid moves.

[jrmach]

dog leg rapid.....

Maybe Preditor needs something for this?I never have encountered anything though,just like machineit has said.A file to look at will tell.
As far as dog leg rapids,if you need info of what and how these are,Google has many hits for "dog leg rapids haas"

Like I said I never had a problem because of this,because software was smart enough I guess.Where knowing when,how,and why these happen,,help a lot for obstacles like clamps and such.But still,Preditor seems to get it right,at least when I needed to know.

[jrmach]

Hey Al,never noticed this.Guess had no reason to.
Do tell,,is Preditors days going bye,bye soon??????

[aldepoalo]

there is a setting on the haas to eliminate the dog leg rapid. maybe yours is turned on....

[bobcad guy]

im working on it, the guy from Haas seems to think we change change this, and is looking into a cure. ill update when I know the how too.

[bobcad guy]

[QUOTE=jrmach;
Advanced Rough and Profile seem an odd combination of words used together.


ummmmmm, advanced rough is a wizard within bobcad, where as a profile, is the outer configuration of any article with mass. it is a synonym for the word "shape" atleast in this case

[SBC Cycle]

I posted this reply in this thread: http://www.cnczone.com/forums/bobcad...eg_rapids.html

It is an option on the Haas control to use Linear style rapiding, it isn't on my Fadal.

The G01 trick for rapids works "ok". I don't have a separate post, I use the search and replace function on the control G0 ---> G1 F300.

It just feels dirty. I'm pretty risky with the new Feed plane option but I'm also pretty good at spotting when it's going to clip a corner by not "jumping" over a corner that the toolpath thinks that it will clear. I've only had one or two "oopsies". I mentioned this early on when the Feed plane was introduced but didn't feel the need to bring it up again. But since you asked Al...

I try not to bring these topics up that have been ongoing for years, but when someone else feels the same pain I do I'm glad to jump in.

Yesterday I got a sales call about the Simulation Pro add on. This was one of the many reasons I won't upgrade to it. I need backplot of G-Code and I need an accurate simulation. The current sim does neither, for me. Individual results may vary.

Predator DOES have an option for dog leg rapiding BTW....

[SBC Cycle]

im working on it, the guy from Haas seems to think we change change this, and is looking into a cure. ill update when I know the how too.

Parameter 315:23

"Enables straight line rapid moves. Normally, during a rapid move of two or more axes, the axis with the shorter distance will finish first. When this parameter is set to 1, the control will treat rapid moves as high-speed feeds, and all axes will complete their motion at the same time"

Unfortunately, broken tools is the only option in my Fadal.

[bobcad guy]

im kinda thinking im gonna try to set my rapid plane to a height that is just bigger than the cut depth, of course this means enourmous inches of rapid added in a big roughing op, but I cant be risking hitting the part. I guess if I set the one particular tool that hits, to a rapid plane of 1.95, as im cutting 1.88 deep, it shouldn't hit. although ive already hand edited it to miss, i'll wait till next time I have an issue. hass told me to get a better cadcam system, the others will allow for this. if bobcad just made the rapid plane between cuts go to .1, above zero, instead of .1 above last cut depth. end of issue. just sayin

[bobcad guy]

I actually tried setting the rapid at 1.9 height, and I found that you have to also set the feed height to 1.9 also. but since its advanced rough, it rapids in z every move anyway, so a 1.9 feed plane never kicks in. so its not perfect, but it beats hand editing, and trying to figure out when its gonna hit, and when it isn't, hopefully someone finds this helpful

[SBC Cycle]

I actually tried setting the rapid at 1.9 height, and I found that you have to also set the feed height to 1.9 also. but since its advanced rough, it rapids in z every move anyway, so a 1.9 feed plane never kicks in. so its not perfect, but it beats hand editing, and trying to figure out when its gonna hit, and when it isn't, hopefully someone finds this helpful

Right, well that's the nature of the problem. If BobCAD "thinks" it's going to miss clipping the part, it uses the Feed Plane. If it thinks it will clip the part, it will jump up to the Rapid plane. Problem is that it really has no clue if it's really going to hit the part or not because BobCAD toolpaths always assume straight line rapids. Neither of my machines work that way.

Be aware of changing the parameter I mentioned above. See this thread: Out of control Rigid Tapping.

[BurrMan]

hass told me to get a better cadcam system, the others will allow for this.

That's funny.... I can find this issue in HSMWorks-MasterCAM and all the other forums. I can find just as many people stating that it's a Haas Issue on "Crappy Haas Machines"..... It certainly is curious that "your Haas guy" would try to rub this off as a "BobCad issue".... I would ask him about the parameter they have on their machines for dealing with this, that they state "But don't use that parameter though....." There is also much talk about Backplotters not really being able to deal with this exactly also...

Seems to me it is an industry issue with various ways of handling it...Choose your poison.

[SBC Cycle]

Maybe Preditor needs something for this?I never have encountered anything though,just like machineit has said.A file to look at will tell.
As far as dog leg rapids,if you need info of what and how these are,Google has many hits for "dog leg rapids haas"

Like I said I never had a problem because of this,because software was smart enough I guess.Where knowing when,how,and why these happen,,help a lot for obstacles like clamps and such.But still,Preditor seems to get it right,at least when I needed to know.

Predator's backplotter will most definitely do a dog leg rapid, even with a Level 2 license.

[Machineit]

That's funny.... I can find this issue in HSMWorks-MasterCAM and all the other forums. I can find just as many people stating that it's a Haas Issue on "Crappy Haas Machines"..... It certainly is curious that "your Haas guy" would try to rub this off as a "BobCad issue".... I would ask him about the parameter they have on their machines for dealing with this, that they state "But don't use that parameter though....." There is also much talk about Backplotters not really being able to deal with this exactly also...

Seems to me it is an industry issue with various ways of handling it...Choose your poison.

Referring back to the original post, he said that the tool is not being withdrawn to the clearance plane: .100", but just .100" above the last cut-----then it rapids! In all the time I have used BobCad, it has never performed a rapid non-cutting move while "in" the part. Even on my "Crappy Haas Machine!"

Best that I can recall and figure, whether you make straight line or dog tail rapid moves, your are not supposed to make them "in" the part. I think the simulator is looking at cutting moves only for interference.

Mike

[SBC Cycle]

Referring back to the original post, he said that the tool is not being withdrawn to the clearance plane: .100", but just .100" above the last cut-----then it rapids! In all the time I have used BobCad, it has never performed a rapid non-cutting move while "in" the part. Even on my "Crappy Haas Machine!"

Best that I can recall and figure, whether you make straight line or dog tail rapid moves, your are not supposed to make them "in" the part. I think the simulator is looking at cutting moves only for interference.

Mike

I will dig up a file for you to look at where BobCAD will only lift to the Feed plane (I believe) before rapid motion to another cut. It is very scary to watch but very, very fast. That's why I don't want them to change it, as long as I backplot the code I can catch it if something gouges. Then I can back off the rapid moves and give my self Z clearance.

[BurrMan]

Referring back to the original post, he said that the tool is not being withdrawn to the clearance plane: .100", but just .100" above the last cut-----then it rapids!

Thats a HS thing... And relates to how the HAAS is running that move VS what you see in the SIM "OR" a backplot. Did you follow through with Al's post?

Whats being brought up is that his HAAS will handle that rapid "differently" than what is shown in the SIM or a backplot, and "hit something"...