Wood everyone sign in? :-)

[Mayo]

Was just thinking it would be cool to see everyone's faces in wood.
Here's mine:
http://www.difsupply.com/mywoodie.jpg

It was my first attempt using the shopbot tiff converter. Some of the lettering was the same color as the area behind it, and wasn't defined well, but you get the general idea. A heavier black outline around the letters would have made it better.

Also, this was done in soft pine, and a hardwood might have allowed a finer more detailed image.

[gkling@jdweb.com]

Mayo,
I really like your face in wood. How about a quick summary of the steps involved and settings used.
Jerry Kling

[Mayo]

I didn't write down the settings for the above picture, so I made another picture tonight and wrote down the settings.
You can see the original picture at http://www.difsupply.com/zack.tif
and the routed PVC plastic at http://www.difsupply.com/zackpvc.jpeg

The original picture was color, so I converted it to grayscale in Micrografx Picture Publisher ver. 8. I then played with the contrast and brightness settings to enhance the differences between light and dark. Then I sized the image to fit on the material scrap I intended to use. It's approx. 4.25"x4.75" It was 150 DPI.

I saved the file as a tiff file and then opened the shopbot software and used the file convert function on it. The settings were as follows:
Image is 420x473 by 8 bits.
Resolution is 113x113 (I have no idea how/why it got changed from 150)
226 Levels of gray
Starting X and Y coordinates were 0
Safe Z axis height was 0.20
Pixel size in inches was 0.009 (this made it slightly smaller than the original - it became 3.78"x4.25")
White depth was 0
Black depth was 0.0312

This file was too big for a floppy, so I used WINZIP to compress it. It compressed about 85% and fit on a floppy very well afterwards.

I then brought it into the other room and loaded it on the old 486 computer which controls the shopbot. I unzipped the file and ran it, cutting the picture into half inch PVC. The bit I used was a Bosch "Sign bit" which is 60 degrees and comes to a real point. It's also got 3 cutting surfaces on it.

When the job started cutting, I immediately realized there was a problem with the plastic bonding back to itself (from heat?) after being cut. I continued cutting anyways in the name of science. :-)

Some time later (the file had over 140,000 lines) when it finished cutting, I tried sanding off the surface but it didn't work. Then I tried wire brushing and that was a little better but still there was hardly any image visible. I put wood stain on it and rubbed away the highlights but it didn't work right. Finally out of frustration I used a screwdriver and scraped off all the cut PVC and the amazingly detailed image was revealed.

Had I been more careful, I'm sure the image would have looked even better. You can see the stray marks here and there left from the flat tip of the screwdriver.

I'm going to experiment with faster cutting speeds to see if the plastic will fly off the background before welding back to itself. My router was set at it's slowest speed (10,000 rpm) and I was cutting at 1" per second.

I took the same original tiff file and then saved it at 75 DPI, and converted it in the shopbot software and noticed it's about half as many lines as the previous conversion that started at 150 DPI. I'll see if it cuts any quicker.

[wdyasq@yahoo.com]

Mayo,

When I was cutting acrylic, I found the bonding problem similar to what you describe. A partial remedy was an airstream on the bit. A near perfect cut could be made with a 'mister', placing air and a very light water mist on the bit.

I am told the secret is slower bit speed and faster cutting speeds. The 'big guys' who do a lot of plastic tell me there are different sharpening angles that help......

Ron