Author Topic: Acrylic-in-Acrylic Inlay - first shot  (Read 18212 times)

Offline airnocker

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Acrylic-in-Acrylic Inlay - first shot
« on: June 21, 2016, 20:12:39 pm »
I must say, for a first attempt at doing inlay lettering for a small sign (.75" x 3.0") with letters .50" tall I am surprised I got as close to good result as was done.

I used a 30 deg. v-cutter for the letter pockets in .120" thick white acrylic to a depth of -.075" and declaring the bit diameter to be .015".  My first test cut used a bit diameter of .036", the actual trigonometric calculated diameter at a depth of -.068" and I didn't get contiguous pockets on each letter as their thickest width was .047".  Hence the reason for reducing the bit diameter parameter in the MOP.  This produced good contiguous pockets in all letters at the cost of "fattening" up the letter strokes.

The letter profiles were cut using the same bit in .068" thick black acrylic.  Here my first test cut (shown in the photo) was to a depth of .068" while declaring the bit diameter of .001".  As a result although the letters fit in their pockets they need to be a bit "fatter" to more closely match the pocketing adjustment.

I used a material hold-down method I learned on this forum shared by a number of our most learned, distinguished and highly skilled forum members (and you all know who you are  :D ).  A .75" thick piece of HDPE lightly surfaced, sprayed with Krylon Easy Tack, also applied to the backs of the paper-backed acrylic material.  I removed the paper-backing from the side I milled.  This hold-down method was PERFECT!  Thanks for this tip guys!

My first instinct for making this lil'o sign was to pocket the letters then fill the pockets with black enamel, wipe of excess and sand off any excess paint and buff the white surface back down to shiny.  I made two pocketed white backgrounds, the first is my inlay trial, the second will be paint filled.

So, is there a way to use Profile MOP with an outside offset that results in cutting outside the line by the offset amount?  I don't see the parameter in the Profile settings.  And I've thought of scaling the font "up" which seems an alternative method but very trial and error.
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Offline dh42

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #1 on: June 21, 2016, 20:54:56 pm »
Hello,

Quote
So, is there a way to use Profile MOP with an outside offset that results in cutting outside the line by the offset amount?  I don't see the parameter in the Profile settings.  And I've thought of scaling the font "up" which seems an alternative method but very trial and error.

You can use the "roughing clearance" property of the profile MOP.

at the right side, a profile with 1mm roughing clearance (positive) .. RC can also be negative.

++
David

« Last Edit: June 21, 2016, 20:56:35 pm by dh42 »

Offline airnocker

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #2 on: June 21, 2016, 21:02:59 pm »
The very thing I'm looking for.  Thanks David.
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Offline EddyCurrent

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #3 on: June 21, 2016, 21:27:41 pm »
Black epoxy putty makes a good job of filling inlays if you want the surface to be flat.

Also this plugin; http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/InlayCalculator.html
but you might want to read the forum thread to get a handle on it first.
« Last Edit: June 21, 2016, 21:30:21 pm by EddyCurrent »
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Offline airnocker

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #4 on: June 21, 2016, 22:31:21 pm »
Hi Eddie, thanks for the tip. Turns out I had download this plugin and forgot I had it.  Will read forum posts.
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Online Dragonfly

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #5 on: June 22, 2016, 10:28:54 am »
@airnocker

When the discussion about the 'Collision detection plugin' was going on I raised a question about the possibility to use the principle for making inlays.
I've seen the inlay MOP in a Vectric made program - Aspire.

The idea is by using a given fixed tool diameter to transform the actual shape so that all corners get a fillet equal to tool radius. This way one can produce bot the male and female parts with a perfect fit. Otherwise such fit is impossible - where there is a sharp corner on the male insert there will be a rounded corner in the female pocket.
Rouging clearance also plays its part in assuring a tiny amount of looseness to assist fitting.
But the main problem with inlays are the corners.
Here is an example - left normal letter 'A', right - prepared for inlay with a 2mm tool (fillet radius = 1 mm). Done in CorelDraw. I think based on accumulated work and experience by our plugin writers a plugin for CB is not impossible.
« Last Edit: June 22, 2016, 10:34:19 am by Dragonfly »

Offline airnocker

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #6 on: June 22, 2016, 17:52:43 pm »
Dragonfly - I read the forum posts you refer to and found it useful when planning my first attempt here. Thanks for illustrating the challenge in CB for doing inlay work.

« Last Edit: June 22, 2016, 17:58:33 pm by airnocker »
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Offline EddyCurrent

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #7 on: June 22, 2016, 20:09:06 pm »
The way I understand it, this plugin, http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/InlayCalculator.html in conjunction with the V-Engrave plugin, http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/Vengrave.html
do the same thing that Aspire does, albeit in a less polished manner.

Link to Vectric instructions, http://www.vectric.org/video/aspire4-vcp7/2d-25d-techniques/D07/VCarve_Inlay_Description_and_Procedure.pdf

compare it to Bob's thread here; http://www.cambam.co.uk/forum/index.php?topic=4065.msg27844#msg27844
this is where the plugin came from.
« Last Edit: June 22, 2016, 20:15:38 pm by EddyCurrent »
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Online Dragonfly

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #8 on: June 22, 2016, 22:10:58 pm »
I know and have been through those threads.
But I am talking about flat inlays. Male inserts from thin material and female shallow flat bottomed pockets. Using a cylindrical tool, not V-engraver.
I have done only one such thing for an auto service board - 400 mm tall letters from 15 mm thick white PVC (foamed). On each PVC letter there is a 3 mm deep pocket, offset inward from the edges where red acrylic inserts fit. As a final result we get 3D red faced letters with white border. Prepared the letter shapes in CorelDraw.
Here is another example. The CAM was done for me with Aspire. This is a different kind of inlay where the male part is inserted from the back, has a wider base to prevent it from falling. New central caps for the wheel covers of an old RR.

Offline EddyCurrent

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #9 on: June 23, 2016, 07:46:08 am »
Yes, I see that now, "Auto Inlay Toolpath"
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Online Dragonfly

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #10 on: June 23, 2016, 07:54:49 am »
Exactly! :)

The collision detector finds the corners where the given tool will not fit. Next step is to modify the shape to fit the tool. Tool path generation in CB does it too and I have thought as an alternative to use imported back tool paths.
« Last Edit: June 23, 2016, 07:58:27 am by Dragonfly »

Offline dave benson

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #11 on: June 23, 2016, 14:26:04 pm »
HI Dragonfly
I'll have a look over the weekend to see what can be done, Although I might not be able to code it straight
away as I'm currently finishing of the code for a 5 Axis patterning device for my  carpet\rug machine that I've working on, 30 mb so far.See below.
Dave

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #12 on: June 23, 2016, 17:30:22 pm »
Wow! You have taken to quite a job. And I envy you somewhat. I am working here on a small project with an AtMega MCU and I found  I've become so-o rusty ... :)

I think inlay shape generation will be a nice useful addition but it's not urgent.

Offline dave benson

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #13 on: June 23, 2016, 23:01:43 pm »
Hi Dragonfly

The Arduino Echo-system is a fantastic way to start with microcontrolers, I've been using them (Atmel chips) since before Arduino burst into the scene in my projects.

Atmel Studio 7 is the way to go for challenging projects (Reading Encoders in real time) ect, as it gets you closer to the hardware.

This project has pushed the limits of what is possible with an Atmega2560 (Limited Very Basic AI) and I have been porting the code to an Due until recently when I found out that Arduino.cc are retiring it.
Arduino.org have a new board that’s even more capable than the Due with the same form factor.

I've been researching the Beagle Bone Black Industrial Board which is essentially a small format Linux computer with built in programmable real time units, and until recently they (the real time units were difficult to program) But now can do it "C" now with the new Code Composer V6 compiler.
Anyhow if you run into any programming issues with your mega, I'll be glad to help if I can. :)

Dave

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Re: Acrylic-in-Acrylic Inlay - first shot
« Reply #14 on: June 24, 2016, 16:28:20 pm »
I've been working with microcontrollers for quite a long time - I discovered them for myself about 12 years ago. Doing my own projects or reproducing someone else's. And I prefer to make my own development boards - knowing the architecture of the MCU and its peripherials I try to stay as close as possible to the hardware. Even in 'C'.
The problem is that if there is a pause many things sink down into my memory and I have to go back to the manuals and online help :) :o
My elder son bought recently one ARM based Arduino for himself and one 2560 which he gave to me. I have an idea about the Arduino project but haven't sat down to learn the keywords, functions and the syntax of its 'C++' slang. Maybe because coding with WINAVR and GNU-C suits my needs ATM. I am still with v. 4.xx of AVR Studio. Read something about changing the WINAVR relationship and decided to stay with what I know.
As for GUI programming I stopped being an active programmer just before Windows started to shape and missed the opportunity to go into it. Some small things with VBA but noting more complicated.