Straight line rapids

ARB · Apr 4, 2009

I think this was discussed recently but I can't find it.

Is there a setting that will force the Haas to rapid in a straight line?

I just got hosed because of the rapid both axis at the same speed deal. :angry:

tc1999 · Apr 4, 2009

I'm pretty sure you can't change that. According to the manual, there is nothing regarding changing how the machine performs a rapid move.

Matt@RFR · Apr 4, 2009

Parameter 315. 0 for dog leg, 1 for straight line rapids. This is on an '07 control.

ARB · Apr 4, 2009

Thanks Matt,

My old girl does not have that option.

Oh well.

I just posted the code to do a full retract and not rapid down inside the part. :eek:

Ox · Apr 4, 2009

Sure it does.

G1 X10. Y6. Z2. F800.

-----

Think Snow Eh!
Ox

ARB · Apr 4, 2009

Ox said:
Sure it does.

G1 X10. Y6. Z2. F800.

-----

Think Snow Eh!
Ox

If I was writing the code long hand that would work well.

But in this case the rapid moves is in the middle of a program that consumes the entire memory of the machine. This is a mold cavity and the code is spit out by Gibbs.

I am going to check with Gibbs to see if it possible to get these moves posted as feed moves but I am not betting on it.

In this situation i was able to repost the code with full retracts to avoid the problem.

You can have your damn snow.

It is snowing right now. :willy_nilly:

I'm ready for bike weather.

SeymourDumore · Apr 4, 2009

Arb

Can you edit your post in Gibbs?
See if you can change it by checking to see if you're below Z-clear, and if yes then change all G00 moves to G01 with high feed.
It is possible in FeatureCam. As it is I don't do any 3D, but all my 2D operations start and end in the Z-rapid plane, below which all G00-s are eliminated and are G01 X.. Y.. Z.. F200. instead.
ACtually even the F200. is using a local variable of P1, which can be overwritten per operation if needed.

Matt

I did not know about Setting 315, very cool.
Do you get any speed penalty when set to straight?

Mud · Apr 4, 2009

You might be able to reconfigure your CAM so that it shows the rapid move correctly. I can in edgecam and smartcam. At least the gouge would show up in your verification that way.

ARB · Apr 4, 2009

Seymour,

Right now I am using a PostHaste post. I will look into your idea. The PH post is editable so i can mess around with that .

I will talk with Gibbs on Monday and see what they have to offer. If they have a canned solution then I will go that way.

Matt@RFR · Apr 4, 2009

Seymour, I think it is a little bit slower but I haven't proven it. Most of my parts are small enough that I doubt any rapid moves actually get up to 1400ipm anyway.

HuFlungDung · Apr 5, 2009

I've wondered how much slower an interpolated rapid move would actually be. I played around with this setting on my Mits lathe, but found it difficult to clock the difference. I prefer the straight beeline between points.

I suppose the velocity of the interpolated move is computed at maximum rapid along the vector, which means that each component vector must be less than max rapid velocity. So this begs the question, if the machine is doing a dogleg move at 710 ipm in each axis, the resultant vector along 45 degrees is at 1004 ipm? Or does it interpolate (and restrict the vector speed to 710ipm) along the 45 degree segment of the movement anyway?

SeymourDumore · Apr 5, 2009

Hu

I don't know about the Mits, but on a Haas the rapid speed does not equal the interpolated speed.
If I'm correct the older controls had a 720 IPM Rapid and a 400 IPM feed ( interpolated) speed.
Truly have no idea what they are nowadays, I think the rapids are up to 1000IPM or so.
In either case, if the straight mode was selected by the settings, it would by definition mean "interpolated" rapids, therefore 400 IPM on the older controls.

Would it be a big difference? Probably not too big, I would likely not notice it too much on the mills. I would however certainly do so on the MiniLathe, where the large qty small dia turning stuff goes and cycle time is ... well... timed.

ARB · Apr 5, 2009

There is good news. It appears that Gibbs as already rectified this with an update.

As for the rapids on this old girl. I think they are only in the 500 ipm range. It looks pretty slow compared to the Sharp at 1180. On this type of work I typically don't care about rapid rates. They amound to a very small part of the program time so if it moves a 250 vs 500 it is of little concern.

SIM · Apr 5, 2009

I thought Gibbs was supposed to offer help 24/7...

Matt@RFR · Apr 5, 2009

I just ran this program with both styles of rapids:

G90 G00 G53 X0. Y0.;
G53 X-29.5 Y-15.5;
G53 X0. Y0.;
G53 X-29.5 Y-15.5;
G53 X0. Y0.;
M30

So that's going from corner to corner (close to it, anyway) on my VF-2ss with rapids advertised as 1400ipm.

In dog leg mode, I figure the total distance traveled is 143.68". Interpolated distance is 133.28".

The cycle time timer on the control said the dog leg rapids took 6 seconds, and the interpolated rapids took 8 seconds. I ran both several times to make sure it was consistant, but I realise this is not really accurate.

So, if my math is correct (somebody check it please!):

Dog leg: 143.68" / 6 seconds = 23.95"/sec, or 1436.8IPM.

Interpolated: 133.28" / 8 seconds = 16.66"/sec, or 999.6IPM.

Dog leg video.

Interpolated video.

Joe788 · Apr 5, 2009

Matt@RFR said:
I just ran this program with both styles of rapids:

G90 G00 G53 X0. Y0.;
G53 X-29.5 Y-15.5;
G53 X0. Y0.;
G53 X-29.5 Y-15.5;
G53 X0. Y0.;
M30

So that's going from corner to corner (close to it, anyway) on my VF-2ss with rapids advertised as 1400ipm.

In dog leg mode, I figure the total distance traveled is 143.68". Interpolated distance is 133.28".

The cycle time timer on the control said the dog leg rapids took 6 seconds, and the interpolated rapids took 8 seconds. I ran both several times to make sure it was consistant, but I realise this is not really accurate.

So, if my math is correct (somebody check it please!):

Dog leg: 143.68" / 6 seconds = 23.95"/sec, or 1436.8IPM.

Interpolated: 133.28" / 8 seconds = 16.66"/sec, or 999.6IPM.

Dog leg video.

Interpolated video.

Very interesting videos. The acc/dec of the interpolated (also known as G00 Slope Constant in Fanucese), is DRASTICALLY slower than the Dog Leg. On a machine with equal X and Y rapids and acc/dec rates, the time should be exactly the same either way, and should hinge solely on whichever axis has the longest distance to travel. The tremendous reduction in acc/dec rate on your interpolated video, tells us the VF2SS has very weak Y axis acceleration and deceleration rates relative to the X axis.

I'd guess this has something to do with the surface finish problems that seem to pop up rather often with these SS machines.

Haas apps guy - "Boss, all of our SS machines leave coining marks on the floor of a pocket when the table changes directions. Should we redesign the frame of the machine to make it stiffer?"

Design engineer- "Nahhhh, we'll just turn the gain way down on the Y axis servo so that the direction change of the table doesn't make the column bounce up and down like a jackhammer......" :cheers:

Perry Harrington · Apr 5, 2009

The Haas is only deccelerating *1* axis at a time with the dogleg rapids. The issue at hand probably has more to do with axis allowable error. When dogleg rapids are on, I *know* that exact stop mode isn't on. However, I would bet that with interpolated rapids on, they just alias the command internally to a G01 with exact stop turned on. With dogleg rapid moves, you have more time to allow the axes to settle before reaching the end point of the vector.

The trick would be to test the following iterations:

Dogleg: exact/no-exact
G01 dogleg path: exact/no-exact
G00 Interp: exact/no-exact
G01 Interp: exact/no-exact

I know that on my VF-0 the gain values are identical for each axis. What I *have* noticed is that Haas has the overshoot (D) clamping turned way up, and this is very noticable while jogging the machine with the handle.

Mohawk72 · Apr 6, 2009

Nope, No editing of Gibbs Posts.

You can however modify them to an extent by using Post Haste to modify your code after posting the code.

What I do is grab, Swap, Trade posts at every gathering I go to. Just to give me a chance to put out good code.

I have switched to FeatureCAM for that reason mainly.

But ARB, There is an option in Gibbs that will allow you to input code anywhere in your program and this stays with your program.

Go to the the right side Machining Op Tile at the part you want to modify and right Click tile.

Now select "Operation Data"

At the Bottom of this pop up window, See the Boxes, At Op Start? And At Op End?

You can input code in these boxes to do anything you want.

And the cool thing is this code stays with your part.

Here you can also add an Operation Comment to explain things to your operator or setup man.

I have done some strange moves right here and they worked.

Also SIM is right. Gibbs will help you if you pay for the Maintenance Agreement.

I inherited this mess and our company now is such poor condition I am without Maintenance on ANY software. But I got you guys now. Grin

Just Lucky to have the job as this company has gone from over 3,000 Employees to less than 300 Now.

It's like a ghost town here.

C Ya L8tr

Mohawk

sderyck · Jan 29, 2019

Oddly, we have a 2018 VF2 and it's setting number was 335 for straight line rapid

Straight line rapids

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