Ramping issue

[gstanczak]

Hello, I am having an issue ramping down into a circular pocket toolpath. Essentially, there is no apparent ramping. I have attached a crv file. I understand this scenario should result in a spiral ramp, which would be fine, but the tool plunges straight down to the full depth of cut, at plunging feed rate, but without any lateral movement. It is also apparent in the g-code file that no ramping movement is present.

Am I missing something?

Thanks,
Greg
VCarve Desktop 10.507

[dealguy11]

Looks like a question to send to support@vectric.com.

[sharkcutup]

Interesting --- create a 1" diameter .2" deep pocket using a 2" downward ramp on the Z-axis in .25" thick material

Is there any special reason for trying to get VCarve to create a spiral ramp on a pocket toolpath? Especially on one of this small of a diameter!

Sharkcutup

[scottp55]

Funny...It works as expected in VCP10.022 ?

[adze_cnc]

In version 9.519 if you use a larger area clearance tool only it ramps (see image). That is with the offset path—I didn't try raster.

two-bit ramp (worth what you pay for it?)

[scottp55]

At least in VCP10.022 it allows for stepover of the tool diameter Steven:)
Lets me use my best pocket bottom FEM Downcut(which you really shouldn't plunge!)
Enough area so my DC would get chips out usually.
Something Vectric missed maybe?
Should at least be mentioned to Support.
(Things like this keep me running VCP10 on my control computer)

[dealguy11]

Sending it to support@vectric.com is the first thing to do in a situation like this. If the software does something different in a standard function from one release to the next, then that's the best way to get resolution as soon as possible.

[scottp55]

Just sent it to Support Steve
(had to play with it a bit first:)
scott

[gstanczak]

Thanks all. I appreciate the responses. I have since sent an email to vectric support and received a quick response, however, I'm not sure I understand the explanation and supposedly it is working properly.

One thing I've noticed is that if the ramp distance is shortened sufficiently, there is a point where a ramping spiral move does then emerge.

[scottp55]

Hello Scott,

Many thanks for your inquiry.

I see identical results on your file in both V10.0 and re-calculating in V10.5
Did you try your file in both versions?

I answered a ticket to support from the original poster.

The reason that the ramp does not work with his file, is that the circle that he drew,
is smaller than the one that you drew. As the ramp is a spiral one, there is a mathematical limit
at which a spiral becomes a straight line. as you increase the ramp length you decrease the
diameter of the spiral.

If you increase the Ramp length on your file to about 6 inches you would see the same result
(in any version of the software).

I hope that this helps.

Regards,
Mark.

I'll have to play with it some more:)

[gstanczak]

Interesting --- create a 1" diameter .2" deep pocket using a 2" downward ramp on the Z-axis in .25" thick material

Is there any special reason for trying to get VCarve to create a spiral ramp on a pocket toolpath? Especially on one of this small of a diameter!

Sharkcutup

Thanks, Sharkcutup. I use a spiral single-flute bit for almost everything but it doesn't plunge worth anything. So, I ramp every move with it. Using your example, if you shorten the ramping distance incrementally, at about 1.568", a ramping spiral emerges instead of a straight plunge.

-Greg

[gstanczak]

Hello Scott,

Many thanks for your inquiry.

I see identical results on your file in both V10.0 and re-calculating in V10.5
Did you try your file in both versions?

I answered a ticket to support from the original poster.

The reason that the ramp does not work with his file, is that the circle that he drew,
is smaller than the one that you drew. As the ramp is a spiral one, there is a mathematical limit
at which a spiral becomes a straight line. as you increase the ramp length you decrease the
diameter of the spiral.

If you increase the Ramp length on your file to about 6 inches you would see the same result
(in any version of the software).

I hope that this helps.

Regards,
Mark.

I'll have to play with it some more:)
[/quote]

Thanks, Scott. Shouldn't a spiral of increasingly length just have more revolutions? In any case, it seems problematic that at some unknown threshold your ramping spiral will flip to a straight plunge without warning, especially when that threshold is not that extreme. For example, I first noticed this issue on a 0.86" diameter hole, with a 1/4" bit, 0.040" step over, 1/2" ramp distance. This seems like a pretty realistic pocket to cut without anomaly.

Thanks again,
Greg

[scottp55]

That's the way a Profile cut/inside the line/ with a spiral ramp works Greg...
I'm cutting right now, but definitely want to play with that and find some parameters...
Seems it could bite me sometime, IF I didn't preview!
Gotta run to shop after that 30 second coffee jolt:)
scott

[gstanczak]

From this I have also learned that the light blue line in the preview simulation is the plunging (ramping or otherwise) toolpath.

And just to reiterate, shortening the ramping distance does in fact solve my ramping problem.

-Greg

[gstanczak]

Attached is another crv file and screengrab where there are two circles of different size, each cut out clear through to the bottom with identical toolpaths. The smaller hole has a good spiral ramp, the larger hole has a bad spiral ramp. It seems that whatever the inner most circle of the toolpath happens to be has an impact on whether there's a good spiral ramp or not.

Circular pocket ramp issue_2.crv

(101 KiB) Downloaded 41 times

-Greg