Projecting engraving onto a surface

twforeman
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Projecting engraving onto a surface

Post by twforeman » Sun Nov 23, 2014 2:14 am

I want to start doing some engraving, but I don't want to do it on a flat surface.

Is there a CAD or CAM program that will import an STL file, project text or 2D lines onto the surface so you get a consistent depth, and then generate the G-code?

Thanks!
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chomdh
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Re: Projecting engraving onto a surface

Post by chomdh » Sun Nov 23, 2014 2:45 am

I know solidworks can make a cut offset from a surface a specified depth - to get a consistent cut depth on a non-flat surface. It's all in how you define the cut properties.

But I've never done any 3d surface milling so I'm not sure how to go from a Solidworks model to g code. I'd like to learn though (using free software if possible).

Hope this helps.
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aam
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Re: Projecting engraving onto a surface

Post by aam » Sun Nov 23, 2014 9:45 am

Is this what you are looking for?
Rhino has the functionality to project curves to a selected surface. You can then export in various file formats to a cam program of your choice
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RobCee
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Re: Projecting engraving onto a surface

Post by RobCee » Sun Nov 23, 2014 12:18 pm

The chap that created F-Engrave has produced some software that can do this (slowly) by taking gcode generated for a flat surface and then using a probing routine to identify the topology of the surface you are engraving/carving onto and reworking the gcode to match.
I have not tried it, but it looks interesting for this sort of thing.

This functionality takes the AutoLeveler code for PCB design and extends it for more varied surfaces.
gcodeRipper

Here it is in action on a simple example and towards the end, on a more complex one. This video extract was taken from Schorch's blog page which explains a bit more about how it works: Auto probing with gcodeRipper

Back when I was involved in selling 3D CAD, this was one of the most difficult things to manage accurately as you really want the projection to be 'normal' to the surface topography, rather than parallel to the viewing angle, which is what usually happens. The maths is much simpler in the parallel viewing angle method, but you can get horrible distortions, even in high end CAD systems.
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DanMc
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Re: Projecting engraving onto a surface

Post by DanMc » Sun Nov 23, 2014 2:19 pm

Ditto for the Rhino, bonus if you're a Mac user because it's still in WIP status and free for Mac users.

DeskProto will do this as well, they give you a 1 month free trial which should give you enough time to figure it out.

Edit: both of these options require you to have the surface that you want to project onto in a format they can use.

Schruminator
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Re: Projecting engraving onto a surface

Post by Schruminator » Tue Dec 02, 2014 4:01 pm

What material are you engraving and how "not flat" is "not flat"? I've heard of some people using spring loaded engravers to keep the tip in constant contact with the material they are engraving. I believe most of (if not all of) the examples I have seen of this if folks engraving onto a metal with a very sharp, pointed endmill.
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twforeman
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Re: Projecting engraving onto a surface

Post by twforeman » Tue Dec 02, 2014 8:23 pm

Schruminator wrote:What material are you engraving and how "not flat" is "not flat"? I've heard of some people using spring loaded engravers to keep the tip in constant contact with the material they are engraving. I believe most of (if not all of) the examples I have seen of this if folks engraving onto a metal with a very sharp, pointed endmill.
Wood mainly and "not flat" depends on what I'm engraving. It's mostly pistol grips that have radii on the sides that the engraving should sort of wrap around.
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lioramsalem
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Re: Projecting engraving onto a surface

Post by lioramsalem » Wed Dec 03, 2014 5:28 am

Maybe using something similar to PCB probing done in chilipepper using some special probe tool? I saw many of these on eBay...

This way you'll probe the stock and have equal depth all across.
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picengravertoo
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Re: Projecting engraving onto a surface

Post by picengravertoo » Fri Dec 05, 2014 12:17 pm

I have done this with KeyCreator and then generated the gcode with there intergraded CAM "Machinist".

http://kubotek3d.com/

http://kubotek3d.com/Products/KeyCreator-Machinist.aspx

You can trial the full version for 30 days. Generate as many gcode files as you can in the 30 days and then it will time out. :-D

They were the first 3D cad program that was offered for use on personal PC's (Cadkey). I have been using it since there DOS version and it's very user friendly.
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aldepoalo
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Re: Projecting engraving onto a surface

Post by aldepoalo » Wed Jan 07, 2015 2:28 pm

Projecting geometry on to surface(s) and then using 3D engraving is how it's done in BobCAD.

This video shows the work flow, where a projected pattern in engraved on a knife handle.

http://youtu.be/UBzMSxei66g?list=UUL7tk ... IWholtT9cA
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