3D Edge Cut Scallops

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Goozler
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3D Edge Cut Scallops

Post by Goozler »

Need a little input for rough edges.
Experiencing scallops on edge cut but bottom surface is great. Any thoughts to get rid of scallops on edge without sanding?

Milling a fishing lure mold, materail .50 Delrin. I attached a photo which shows edge cut.

My conditions and perimeters...

3D Roughing- .1250 ball end mill, .0625 depth of cut, step over 0.0025 2% ,30 IPM ,Machine allowance (.02), Z level (Raster X), Profile-(Last)

3D Finish- .1250 ball end mill, .0625 depth of cut, step over 0.0013 ,40 IPM ,Raster (45 degree)


Your thoughts are appercaited. Thanks.
Attachments
image.jpg

JoeM
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Re: 3D Edge Cut Scallops

Post by JoeM »

100+ looks and nobody has any hints?

If it was me, I'd change the roughing tool to something else. The purpose of the roughing tool is to hog out the waste so the finishing tool can do its job quickly and cleanly. Maybe a 1/4 or 1/8 endmill instead of a round ball. That should save a bunch of time. And drop the machine allowance down to .01 - let the roughing tool do more of the work.


As for the scallops - what does it look like in preview with the resolution cranked up to as high as possible? If it shows in the preview, it's a problem in the toolpath setup or choice of tools. It could be an artifact of using a ball on both the rough/finish, might be that the ball can't get up close enough to the edge to finish that cut. The pic is too small to really see - I can't even tell which way it's curving.
If that's the case, maybe playing with the boundary offset will give you enough room, otherwise you can try finishing with a smaller ball. I just did some parts with a 1/8" and they looked decent.

If it doesn't show in the preview then it's a machine thing. Got any play in your spindle mount?

PaulRowntree
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Re: 3D Edge Cut Scallops

Post by PaulRowntree »

How smooth is the exterior shape? Any glitches there will show, especially with the raster toolpath. Have you tried a spiral path?
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esteeme1
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Re: 3D Edge Cut Scallops

Post by esteeme1 »

Paul is on the mark with that. I had this problem resurface with me. I extensively retuned my machine and nothing helped. Someone reminded me to look at my model one more time. If you look at your bounding vector (the vector you used to create the toolpath) you will most likely see hundreds of nodes. I would try to smooth out the bounding vector by selecting the fit vector to curve tool on the drawing tab. I use bezier curves most of the time. Also delete any unwanted nodes that don't correspond with a smooth transition from one node to the other. The other thing I recommend NOT doing is use an offset vector to create your toolpath, UNLESS you fit curves to vectors.

This condition will not show on your preview but your machine is registering the nodes and creating some lashing problems.

Just work on cleaning up the nodes first then you can try to adjust your control setting. if using mach3 there are smoothing controls you can adjust. Go to the down load sight and there is a tutorial there.

Also your acceleration factors can be set to high.
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Goozler
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Re: 3D Edge Cut Scallops

Post by Goozler »

Thanks all for your input. So I understand correctly, the model view after simulated cut will be some what accurate as far a edge detail?

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esteeme1
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Re: 3D Edge Cut Scallops

Post by esteeme1 »

Goozler wrote:Thanks all for your input. So I understand correctly, the model view after simulated cut will be some what accurate as far a edge detail?
The preview is an excellent representation of what is programmed to be cut. I look at your situation like this (because I'm illiterate to G code). Every time your machine is regretting a node it translates it to noise. when it hits one it doesn't know what to do so it creates a jerking motion. You should be able to see this in the action of the router as it reaches the edge of the piece.

Here are a couple things you can do.

1. Make sure the model you are cutting is of hi resolution.
2. Insure that the model fits/fills the working material block as possible.
3. Make sure your bounding vectors are clean and devoid of unnecessary node.
4. Check your machine for backlash (slight movement in all axis) Adjust setting accordingly
5. Slowing down your feed rate may help but….Check with the control manufacture about adjusting your acceleration factors

From what I see I would focus on steps 1, 2 and 3 for a quick fix and work on the rest after you get going.
Jim Darlas
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esteeme1
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Re: 3D Edge Cut Scallops

Post by esteeme1 »

Each one of these divots were repeatable and later associated with nodes. After cleaning the bounding vector the file cut clean.
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Jim Darlas
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Goozler
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Re: 3D Edge Cut Scallops

Post by Goozler »

Thanks again. Utilized node edit and removed quite a few nodes. Attached is the preview after roughing and finishing operations. So, will the scallops and rough edges shown in preview be mirrored in actual finish product? or is this the laptop resolution pixels? I am trying to establish a base line to compare what is on screen and what is actual finished material product.
Attachments
Screenshot.jpg

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esteeme1
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Re: 3D Edge Cut Scallops

Post by esteeme1 »

It's possible that they will translate. Aspire does not do well with 90 degree edges. Try giving them a slight angle on the edge by utilizing the draft function and or the smooth tool.
Jim Darlas
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dealguy11
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Re: 3D Edge Cut Scallops

Post by dealguy11 »

If you see it on the screen you will most probably see it on the part. Vectric products are very much "what you see is what you get".
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