Tips For Machining Photos On Acrylic (Lithophane)

Home User Forum Tips & Tricks Tips For Machining Photos On Acrylic (Lithophane)

This topic contains 0 replies, has 1 voice, and was last updated by  Steve Stevenson (Iconic Inc.) 4 months, 2 weeks ago.

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    We gets lots of questions about the best techniques for creating lithophanes (photos machined in plastics such as acrylic and backlit). We have made a few of these but don’t necessarily consider ourselves experts but we are happy to share our experience.

    For those of you who have never seen a lithophane here are two links showing a photo machined in acrylic. The first link is a photo machined but not backlit and the second of the same photo backlit. You will see what I mean.

    http://lesjorgensen.com/wp-content/uploads/2010/01/IMG_1795.jpg

    http://lesjorgensen.com/wp-content/uploads/2010/01/IMG_1747.jpg

    So now that I have you excited about making one of these let me share a few tips.

    1) Material: I have seen these created using a few different types of plastic. Corion is one that is popular but I have pretty much stuck with acrylic or plexiglass. There are two different manufacturing processes used to make acrylics, extruded and cast. Extruded has a lower melt point and is prone to melting on the tool. The best choice is definitely cast. You may need to specify this to your supplier. If they don’t know then expect to get extruded. I am sure there are lot’s of thicknesses available. I have tended to stick with 3/16″ – 1/4′ or 4-6 mm.

    2) Tooling: The best tool I have found is the 1/32″ conical carving bit that comes with your ICONIC machine. This creates outstanding detail.

    3) How long to they take to machine? Well you can’t be in a hurry on these projects. Because the machine utilizes a raster (or linear) machining strategy this makes machine times quite long. Depending on the size of the image they can range from an hour or so (small image like a 3″ x 5″) up to several hours for a larger image (maybe 12″ x 12″)

    4) What software program should I use? The easiest program to use for lithophanes s definitely iPicture (supplied with your ICONIC machine). It literally takes just a few minutes to learn. Here is the link to the video on our website that will teach you all you need to know. http://iconiccnc.com/training-videos/. Select iPicture from the menu and choose Machining on Plastic. You can also do lithophanes using ArtCAM Express (also supplied with your ICONIC machine). To do so you can import the photo as a relief just like any 3D greyscale model. It requires a bit more skill but is still reasonably easy to learn.

    5) Lighting: Well this is where you get to be creative. LED lighting seems to work best but the intensity and location of the lighting is pretty subjective. Try a few different ways and you will see it changes your image. I guess it all depends on what the expectation is. Have some fun with this part.

    6) Should I display the project face up or face down? Again it is personal preference. I prefer the machined portion to be at the back (keeps it a bit more mysterious I guess) but others prefer it the other way where the exposed machine portion faces out. Note that if your machined portion is facing back that you need to flip your image left horizontally before you import it or the whole image is reversed (trust me on that one, I have done it more than once).

    7) How deep should I machine? It is explained in the video bit the general rule of thumb is to machine to within .050″ of the bottom of the material. So if you are using 1/4″ thick acrylic then set the depth to .20″. The deeper you machine the better the contrast because more light passes through the thinner portions (lighter areas).

    If you need more information on these feel free to post on this thread and I am happy to help or if you are lucky someone way smarter than I will chime in.

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