Lithophane cutting tips

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bradders
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Lithophane cutting tips

Post by bradders » Thu 22 Nov , 2007 13:08 pm

I would be grateful for some pointers to improve the quality of the red Perspex lithophanes produced on our new Denford Model 2600 PRO software version 5 / 17 (Serial no H08071). I have made my settings as per the tutorial, except I have set the depth of cut at 1.5 mm. The picture reduction I am using is 27% and the picture size is about 55 mm x 75 mm. This gives about 21000 lines of data to work from - the raster step over is 15% and the cut depth 1.5 mm, leaving 0.5 mm thickness from the bottom. Feed is about 600 and speed is 23000. One of the areas that may be a problem is the cutter. I have the picture cutter mounted which I think is 140 - 45 - 0 (BI00811Y). It was not in its packet when I first saw it and there is no packet available with the number on it to verify that this is the cutter being used. My tool settings indicate that a 1/8" engraver cutter with a flat bottom is in use. The cutter in use is quite fine and pointed to the touch. The machined preview itself does not show good sharp features around the face, but small circles, whereas the contouring on the pre-posted design seems fine. The result is that the quality of my finished product does not remotely compare with the Mona Lisa example shown during a demonstration. I would also be grateful to know what the dimensions for this tool as stated on the packet. Thank you in anticipation

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Post by bradders » Thu 22 Nov , 2007 13:08 pm

From Denford Technical director

The tool definition is what is important.

If you have a photo engraving cutter you will see there is a very small flat on the bottom of the cutter this should be about 0.5mm across.

You should add to your tool library a photo engraving cutter and set it up as a 0.5mm slot drill.

Then re run the design through Quick CAM and make sure you select the 0.5mm diameter tool. Put the settings to 40% stepover with a feed of 3000mm/min and 24000RPM

As you have used a 1/8” engraver in the cam package the program detail will be greatly reduced as the tool would be unable to fit into many areas without machining other parts away.

You must have the correct tool defined in the machine and QuickCAM. First add the tool to the tool library of VR milling then open Quickcam which should now show the tool you have added.

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Post by bradders » Thu 22 Nov , 2007 14:55 pm

Thanks for your speedy response. The tool you have described is not listed as a standard tool - the nearest is a 1.5 mm slot drill, as seen on a pull down menu.

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Post by bradders » Thu 22 Nov , 2007 14:55 pm

You are correct it does not appear in the library.

You have to manually add a tool or add a library tool then edit it.

Add a 1.5mm slot drill then edit the diameter to 0.5mm

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Post by bradders » Fri 23 Nov , 2007 10:45 am

Thanks for your assistance. It worked really well. What would you say would be a practical number of lines of data to aim for to produce a typical lithophane? That is to say the program I ran to make it was lengthy!

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Post by bradders » Fri 23 Nov , 2007 10:45 am

I have run programs in excess of 1,500,000 lines. The better the picture the better the result and the shorted the program.

If you crop the background you can reduce cycle time.

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