Inconsistent 3D Finishing Cut

This forum is for general discussion about Aspire
User avatar
Phil
Vectric Wizard
Posts: 3026
Joined: Thu Nov 17, 2005 10:56 pm
Location: Pittsfield, MA

Inconsistent 3D Finishing Cut

Post by Phil »

For this frame I created two components. The recess was a two rail sweep and the oak branches were extruded along a centerline. The oak branches machined very well. The second drawing shows what I am questioning.
1. The outer ring did not machine flat; the lower left and upper right quadrants were not machined at all and the upper left and lower right quadrants were cut to a depth of .088. The transition along the ring was gradual. Why was it not consistent?
2. The inner edge was not machined smooth. The Z reading was consistently going up and down along the perimeter leaving a ragged edge. What could I have done to get a smooth cut?
I had the modeling resolution set to Very High.

Phil :?
Oval Window B Preview.jpg
Vectors B.jpg

User avatar
adze_cnc
Vectric Wizard
Posts: 4327
Joined: Sat Jul 27, 2013 10:08 pm
Model of CNC Machine: AXYZ 4008
Location: Vancouver, BC, Canada

Re: Inconsistent 3D Finishing Cut

Post by adze_cnc »

How about: don't let your 3D-finishing path go over the edge trying to cut the vertical wall---use a follow-up 2D profile pass instead?

BillK
Vectric Wizard
Posts: 594
Joined: Wed Mar 27, 2013 4:16 pm
Model of CNC Machine: CNC Shark Pro Plus
Contact:

Re: Inconsistent 3D Finishing Cut

Post by BillK »

Hi Phil,

Were the ellipses draw in Aspire or created from tracing a model? If the vector was from the outline of a model it probably has to many nodes in it. You can smooth it out with Bezier curves, applied a few times. Also can you show a shot of the model tipped at an angle? Looks like there is some peaks generated where two components are joined? You can try merging one of them instead of adding. To get rid of that.
BillK
https://www.facebook.com/CarvingsByKurtz

User avatar
Phil
Vectric Wizard
Posts: 3026
Joined: Thu Nov 17, 2005 10:56 pm
Location: Pittsfield, MA

Re: Inconsistent 3D Finishing Cut

Post by Phil »

Bill,

I've posted a preview at an angle. I drew the elipses in Aspire, there are only four nodes in each, including the centerline for the extruded oak branches.

Thanks,

Phil
Attachments
Oval Window C Preview.jpg

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: Inconsistent 3D Finishing Cut

Post by TReischl »

The two opposing corners being up makes me wonder if your wood moved while cutting.

How did you have it secured to the machine?

I don't see the issue in the preview, and we all pretty much understand if it doesn't show in the preview it is more than likely a machine/setup issue. In this case I would tend to believe it has something to do with how you set the job up on the machine.

Jaggies on an edge are pretty common. I see it fairly often when I am doing deeper models and there are vertical walls. A sure cure is to put a bit of draft angle on the model. I am not talking about jaggies caused by no modeling plane but rather the ones that can be encountered on the inside walls of a part.

Edit: One other thing, I never, ever, cut something like that out of a single flat board. I even avoid glue ups with wider boards when that much material is being removed. If I had to do it I would create a segmented ring using two layers for strength.
"If you see a good fight, get in it." Dr. Vernon Johns

User avatar
Phil
Vectric Wizard
Posts: 3026
Joined: Thu Nov 17, 2005 10:56 pm
Location: Pittsfield, MA

Re: Inconsistent 3D Finishing Cut

Post by Phil »

TReischl wrote:
Thu Feb 27, 2020 1:06 am
The two opposing corners being up makes me wonder if your wood moved while cutting.

How did you have it secured to the machine?

I don't see the issue in the preview, and we all pretty much understand if it doesn't show in the preview it is more than likely a machine/setup issue. In this case I would tend to believe it has something to do with how you set the job up on the machine.

Jaggies on an edge are pretty common. I see it fairly often when I am doing deeper models and there are vertical walls. A sure cure is to put a bit of draft angle on the model. I am not talking about jaggies caused by no modeling plane but rather the ones that can be encountered on the inside walls of a part.

Edit: One other thing, I never, ever, cut something like that out of a single flat board. I even avoid glue ups with wider boards when that much material is being removed. If I had to do it I would create a segmented ring using two layers for strength.
The variation in depth of cut that I was referring to was from the readout on my laptop. The difference, from .000 to .088 was seen on the Z level readout while the bot was machining the surface of the flat area on the frame.

Phil

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: Inconsistent 3D Finishing Cut

Post by TReischl »

The plot thickens. . . .

When you have the file loaded in Aspire and you move the cursor around the suspect flat area do you see a change in the z depth on the bottom of the screen?

Another question, is this a purchased model or did you create it? I am thinking that a purchased model may have been created with what you are seeing. If you created it then you should check the cross section vectors you used to create the basic frame.
"If you see a good fight, get in it." Dr. Vernon Johns

User avatar
Phil
Vectric Wizard
Posts: 3026
Joined: Thu Nov 17, 2005 10:56 pm
Location: Pittsfield, MA

Re: Inconsistent 3D Finishing Cut

Post by Phil »

]T, I checked the preview as you suggested, the readings areas I posted in the drawing .000" - .088". I created this frame myself. The vectors appear to be fine.

Phil

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: Inconsistent 3D Finishing Cut

Post by TReischl »

Sheesh.

Can you break out just the vectors you used to create the base frame? I am running an old version of Aspire, like 4.5 so if you exported them as EPS everyone can get a look at them. Honestly, you have been at this stuff for a long time so I don't think anything is wrong with your vectors but it always pays to double check and I believe in doing the easiest things first.

I am wondering if possibly the model height changed due to scaling or some other operation on the model once it was created, but I have never seen it do it unequally.

Was this a 2 rail sweep? Since I have not much to do today, waiting for shellac to dry, sanding, etc, I am going to create something similar and see what happens.

Back. I grabbed your image and recreated the base oval frame piece. All went well. As I was working on it something else came to mind. . . did you by chance use the fade or tilt commands on anything while you were modeling? If you accidentally had that base selected that could explain a few things.
"If you see a good fight, get in it." Dr. Vernon Johns

User avatar
Phil
Vectric Wizard
Posts: 3026
Joined: Thu Nov 17, 2005 10:56 pm
Location: Pittsfield, MA

Re: Inconsistent 3D Finishing Cut

Post by Phil »

Oval Window Vectors.eps
(1.61 KiB) Downloaded 57 times
I appreciate your help.
The modelling was very straighforward, two rail sweep, minimal number of nodes. No adjusting the model in any way, no fade, no tilt, no distort. The large oval is 33 x 24, small one is 24 x 16
The eps file seems to be too large to attach. 1.61 Kb

Phil

User avatar
mtylerfl
Vectric Archimage
Posts: 5865
Joined: Thu Jan 29, 2009 3:54 am
Model of CNC Machine: -CarveWright CNC -ShopBot Buddy PRSAlpha
Location: Brunswick, GA

Re: Inconsistent 3D Finishing Cut

Post by mtylerfl »

I imagine you’ve already made sure your spindle/router is trammed to your flat spoilboard?
Michael Tyler

facebook.com/carvebuddy

-CarveWright CNC
-ShopBot Buddy PRSAlpha CNC

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: Inconsistent 3D Finishing Cut

Post by TReischl »

Phil wrote:
Thu Feb 27, 2020 4:07 pm
Oval Window Vectors.epsI appreciate your help.
The modelling was very straighforward, two rail sweep, minimal number of nodes. No adjusting the model in any way, no fade, no tilt, no distort. The large oval is 33 x 24, small one is 24 x 16
The eps file seems to be too large to attach. 1.61 Kb

Phil
EPS file downloaded just fine. Popped it into my antique version of Aspire and it modeled up no problem. Everything flat like it is supposed to be. Just in case I am misunderstanding you, you are saying that when you run the mouse over your model it shows the discrepancy?

Something else, could it be that you lost steps on Z? A while back I had the nasty creeping Z axis problem, it only happened when I had really vertical moves with a high feedrate and I think I had the acceleration set a tad too high. Since I have no idea of the strategy you used. . . . just tossing out some ideas.
"If you see a good fight, get in it." Dr. Vernon Johns

User avatar
Phil
Vectric Wizard
Posts: 3026
Joined: Thu Nov 17, 2005 10:56 pm
Location: Pittsfield, MA

Re: Inconsistent 3D Finishing Cut

Post by Phil »

TReischl wrote:
Thu Feb 27, 2020 4:26 pm
Phil wrote:
Thu Feb 27, 2020 4:07 pm
Oval Window Vectors.epsI appreciate your help.
The modelling was very straighforward, two rail sweep, minimal number of nodes. No adjusting the model in any way, no fade, no tilt, no distort. The large oval is 33 x 24, small one is 24 x 16
The eps file seems to be too large to attach. 1.61 Kb

Phil
EPS file downloaded just fine. Popped it into my antique version of Aspire and it modeled up no problem. Everything flat like it is supposed to be. Just in case I am misunderstanding you, you are saying that when you run the mouse over your model it shows the discrepancy?

Something else, could it be that you lost steps on Z? A while back I had the nasty creeping Z axis problem, it only happened when I had really vertical moves with a high feedrate and I think I had the acceleration set a tad too high. Since I have no idea of the strategy you used. . . . just tossing out some ideas.
Yes, I see the discrepency when I run the mouse over the model.
I don't think it's a lost Z steps issue, that would have made all of the cut lower. This cut was consistently up and down over many trips around the surface. I was using a .125" bit at 10% stepover.

User avatar
TReischl
Vectric Wizard
Posts: 4596
Joined: Thu Jan 18, 2007 6:04 pm
Model of CNC Machine: 8020 48X36X7 RP 2022 UCCNC Screenset
Location: Leland NC

Re: Inconsistent 3D Finishing Cut

Post by TReischl »

Phil wrote:
Thu Feb 27, 2020 6:38 pm

Yes, I see the discrepency when I run the mouse over the model.
I don't think it's a lost Z steps issue, that would have made all of the cut lower. This cut was consistently up and down over many trips around the surface. I was using a .125" bit at 10% stepover.
So, something fishy with the model then. If you just model that frame up again, do you keep getting the same results? Yanno, import the vectors into a new job, sweep them and then check the heights?
"If you see a good fight, get in it." Dr. Vernon Johns

User avatar
dealguy11
Vectric Wizard
Posts: 2464
Joined: Tue Sep 22, 2009 9:52 pm
Model of CNC Machine: Anderson Selexx 510
Location: Henryville, PA

Re: Inconsistent 3D Finishing Cut

Post by dealguy11 »

I just tried modeling the figure using the vectors you provided and can't replicate what you're seeing. The ragged edges on the carving are caused by the vertical surfaces on the model, and can't really be cleaned up. Higher modeling resolution will reduce it a little, but won't get rid of it. You'd be better off adding some draft to get rid of the verticals.
Steve Godding
Not all who wander (or wonder) are lost

Post Reply