Sorry yo have to rotate your head for the polargraph print! You can start to see the tiger body and the tail but it's certainly not tight shading. I had the smallest grid size etc.

Hello, welcome! There's a couple of issues with the drawing that I can see:

1. Lack of density in the waves. Kong is right that it's easy to forgot to actually send the "send pen tip size" command. The mistake I tend to make is to send it when doing my paper set up and trials, but then reset the machine for some reason, and forget to re-send it. Remember that the pen tip size is NOT saved in the machine - it needs to be re-sent after every machine reset.

Assuming it's not just that, the pen width test is your friend here (on the setup tab), http://www.instructables.com/id/Polargraph-Drawing-Machine/step25/Pen-thickness/, try that and see what the real thickness of your pen is.

Using such a small grid size makes any pen-tip-size problems worse. Looking at this image in the controller program, with a similar grid, it's not really recognisable either. One other thing is that this is exactly the kind of image that the pixel rendering style is really bad at - thin dark lines and big areas of colour, it's easy for the lines to slip between the pixels, so play with the "sample area" setting to blur them a bit. It also helps to draw them really big.

You will definitely have better luck if you get a copy of the original vector artwork of the logo (an SVG), and can then plot the edges out using the "draw vector" function.

2. Distortion - you didn't mention this, so you might not be worrying about it yet, but it looks like the left-hand motor has dropped a lot of steps when pulling the pen back up. That's why the patch is a weird shape - the bulgy bit on the top right (with the tiger's tail in), looks correct, but it gradually gets more and more distorted after the 7th row. Without knowing about your hardware setup, can't suggest anything sensible, but drawing lower down, drawing more slowly, less weight on the gondola, more weight on the counterweight might help.

3. Pen holder, or board angle - based on the wave patterns, it looks like you've got lots of friction on your pen tip, and it's dragging behind the gondola a bit. Again, without seeing the setup, difficult to suggest and remedy, but you didn't ask about that anyway - I'm just being picky 🙂

cheers!
sn