very slow 3D carving

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very slow 3D carving

Postby AZRoger » Sat Dec 09, 2017 6:18 am

I'm doing a 3D project which is cutting very slowly. I have the cutting speed set to 200 Inches per minute.
There a couple profile cuts where the tool steps out at the specified speed.
It gradually speeds up (the half inch or so) at the beginning of the cut and slows before the end.
However for cuts that involve a lot of Z-Axis movement, the cuts are very slow.
I don't know if it's
(A) the stepper motors that can't keep up, or
(B) the controller can't command the stepper motors fast enough, or
(C) the USB port can't send the compiled G-code fast enough (USB-1?), or
(D) the control panel application can't keep up, or
(E) the cuts are so short that it's always running in the "speeding up" part of the cut.
I'm guessing it's either (C) or (E) that is causing the slowness.
Anyone else experience this? Is there anything I can do to speed things up?
Thanks in advance for your insights.
AZRoger
 
Posts: 30
Joined: Fri Sep 30, 2011 7:47 pm

Re: very slow 3D carving

Postby SteveM » Sat Dec 09, 2017 12:53 pm

Try slowing down the cut speed to something like 50 ipm.
I don't even know if you can actually cut at 200 ipm with the Shark. That seems to fast.
I would think normal cut speed should be the 50-60 ipm when V- carving.
SteveM
 
Posts: 134
Joined: Thu Sep 08, 2016 1:29 pm
Location: Franklin, Wisconsin

Re: very slow 3D carving

Postby AZRoger » Sat Dec 09, 2017 5:37 pm

Stewart,

To respond directly, It tried the defaults first (40 ipm X/Y, 10 ipm plunge and 12,000 rpm. It was very slow.
I don't know if it's actually doing 200 ipm on the profile cuts now but it is pretty fast - lots faster than the default
I forgot to mention before that I set the Z axis plunge speed to 50 ipm.
The tools are spinning at 20,000 rpm - this is about double the default.
The X and Y speeds are about 5 times the "default" speed from the Vectric Aspire tool database.

I've heard it said that you speed it up until you get poor quality or break tools, then back off a little.
The cutters are all solid carbide. There is no squeal (starving the cutter) or chatter from vibrations or
"off-line" tool cuts due to excessive tool pressure, and I'm not breaking tools. So, not too fast yet.

The cutting sequence for the trim pieces (see attachment) is a follows.
(1) profile cut with a 90 degree cutter two horizontal channels to remove bulk material from near the top and bottom.
(2) profile cut with 1/4 inch ball nose to take the inside corners off the channels and some meat off the very center of the piece.
(3) 3D finish carve the whole piece with a 1/4 inch ball nose carver using Raster Horizontally.
(4) 3D finish carve the whole piece with an 1/8 inch ball nose carver using Raster Vertically.
(5) 3D finish carve the whole piece with a 1/16 inch ball nose carver using Raster Horizontally again.
(6) 3D finish carve the right and left sides separately with a 1/32 inch ball nose carver. These last cuts use Raster parallel to the valleys.

The parts come out looking very good. But, all the raster cuts are pretty slow, climbing up and down the hills...
Attachments
Rope Center.JPG
The job
AZRoger
 
Posts: 30
Joined: Fri Sep 30, 2011 7:47 pm

Re: very slow 3D carving

Postby tonydude » Sat Dec 09, 2017 8:42 pm

The z movement will only go as fast as the feedrate you set in your toll data base.When doing 3D carving you have a lot of up and down movement therefor, it will only move at the slowest setting. Look at the attachment I have for my .125 ball nose bit.

Tony
Attachments
feed rate.JPG
Buffalo,NY

"What will matter is not what you bought but what you built; not what you got, but what you gave”

Aspire 9.014, photo vcarve, cnc mako shark extended bed, control panel 2.1
tonydude
 
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Location: Buffalo,NY

Re: very slow 3D carving

Postby tonydude » Sat Dec 09, 2017 8:45 pm

I've been doing this for 6 yrs now with the original shark and I also have a extended bed also.

Tony
Buffalo,NY

"What will matter is not what you bought but what you built; not what you got, but what you gave”

Aspire 9.014, photo vcarve, cnc mako shark extended bed, control panel 2.1
tonydude
 
Posts: 1441
Joined: Tue Aug 17, 2010 9:23 am
Location: Buffalo,NY


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