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Page Updated November 2, 2012
Khloe, Jada and Kruz Lithophane
FINISHED
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This is my third Lithophane and in my opinion the best yet. First of all I chose to rout my own frame completely out of black acrylic. Second the backlight I chose not to make myself but instead purchase. They are in fact LED backlights from standard LCD displays use for many commercial display products. I found a company in china that were able to source manufacturer rejects where the LCD part was faulty, too many dead pixels etc. I simply removed the LCD part and am left with an absolutely superb backlight system, much better than I could ever make. Then for the third and most important part I experimented with some different acrylic and found that ACS-402 White improved remarkably the final result. Overall I think I would find it very difficult to improve further on this design. Again the photographs below look remarkable but the reel thing is quite stunning and definitely has that wow factor. I have included an image that shows the difference between the acrylic I was using to the ACS-402. Some people say that machining acrylic with small cutters is difficult and have melting problems. I experience none of this, you just have to get your speed and feed rates right. I will tell you what my settings are later. Again I use Vectric Aspire to process the image and generate the CNC G-Code.
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This is a comparison between the acrylic type I used to use to what I used for this Lithophane.
So these are the finished shots. The first one being the original photograph.
The engraving process using my CNC Router
The first Roughing pass used a 2mm Ball Nose Cutter. The 3D finishing pass used a 1mm Ball Nose cutter.
The first Roughing pass used a 2mm Ball Nose Cutter. The 3D finishing pass used a 1mm Ball Nose cutter.
This is the black acrylic frame.
The front is routed from 10mm acrylic and the back from 6mm acrylic. Following the routing and putting in the M6 Brass threaded inserts, I secured the back to the front, masked it to protect the faces then linished and polished the edges as one piece. I first machine linished the edges, then used a 100 followed by a 320 sanding block, finishing with 1200A Wet & Dry paper, before polishing. The more time spent on preparation the better the polished result. I also show here the LED backlight panel & all the components.
The front is routed from 10mm acrylic and the back from 6mm acrylic. Following the routing and putting in the M6 Brass threaded inserts, I secured the back to the front, masked it to protect the faces then linished and polished the edges as one piece. I first machine linished the edges, then used a 100 followed by a 320 sanding block, finishing with 1200A Wet & Dry paper, before polishing. The more time spent on preparation the better the polished result. I also show here the LED backlight panel & all the components.
Final assembly and attaching the stand that I made.
The stand is slotted at the two securing points so that it can be moved up and down a little to change the angle that the frame sits. I put a 1mm grove across the point where I wanted to place the bend. Using a fine hot air pencil I was able to achieve a rely neat bend.
The stand is slotted at the two securing points so that it can be moved up and down a little to change the angle that the frame sits. I put a 1mm grove across the point where I wanted to place the bend. Using a fine hot air pencil I was able to achieve a rely neat bend.
These are the specs as setup in Aspire:
Modeling Shape Height: 3.5mm, Base Height 0.0, Combine with other components...: Select Subtract from Previous Components.
This is if the imported image is a positive, selecting this option should turn it into a negative image and that's what you want.
It means that the light/white parts of the image will be cut the deepest and the darker to blacker parts will be raised. So then it is lit from behind it will revert into a positive image just like the original. The deeper the cut reduces the thickness and more light will come through. That's the whole principal of how Lithophanes work.
CAM Tooling setup:
Roughing Pass: Ball 2mm, Pass Depth 1mm, Step Over 50%, 1200RPM, Feed 1000mm/min, Machining Allowance 0.3mm, Boundary Offset -1.5mm
Finishing Pass: Ball 1mm, Stepover 10%, 1200RPM, Feed 1000mm/min, Boundary Offset -1.5mm.
To shorten the finishing pass time a Stepover of 15% works fine, most of the time that is what I have used in the past.
The time for the Roughing Pass is about 90 minutes.
For the Finishing Pass about 3 Hours and 15 minutes.
The Boundary offset of -1.5mm is there to provide a consistent height border edge to fit up against the inside corner of the frame.
Modeling Shape Height: 3.5mm, Base Height 0.0, Combine with other components...: Select Subtract from Previous Components.
This is if the imported image is a positive, selecting this option should turn it into a negative image and that's what you want.
It means that the light/white parts of the image will be cut the deepest and the darker to blacker parts will be raised. So then it is lit from behind it will revert into a positive image just like the original. The deeper the cut reduces the thickness and more light will come through. That's the whole principal of how Lithophanes work.
CAM Tooling setup:
Roughing Pass: Ball 2mm, Pass Depth 1mm, Step Over 50%, 1200RPM, Feed 1000mm/min, Machining Allowance 0.3mm, Boundary Offset -1.5mm
Finishing Pass: Ball 1mm, Stepover 10%, 1200RPM, Feed 1000mm/min, Boundary Offset -1.5mm.
To shorten the finishing pass time a Stepover of 15% works fine, most of the time that is what I have used in the past.
The time for the Roughing Pass is about 90 minutes.
For the Finishing Pass about 3 Hours and 15 minutes.
The Boundary offset of -1.5mm is there to provide a consistent height border edge to fit up against the inside corner of the frame.
For images of some of my other Lithophanes go to the Other Lithophanes project page.