Settings & Controls
The NewlyDRAW software supplied with my laser cutter is capable of controlling a number of different models so it is vital to set up the configuration as per the information supplied with the machine. This configuration includes details such as the cutting bed orientation and dimensions; so it's important to have it right.
I was also supplied with a manual in .doc format. There appeared to be something wrong with it as I couldn't see the pictures. After some searching I found it on the web in .pdf format and have reproduced it here (812kb), for your convenience. It's not great, but it's worth reading.
Bed Dimensions
A printed sheet that came with my machine suggested:
TopLeft X: 21
TopLeft Y: 307
Width: 210
Height: 205
However, as can be seen from the image below, my machine came with a metal mesh in a frame that can be used as a cutting bed to give better results.
With the co-ordinates as given the beam will go over the edges. So I adjusted these settings:
Starting with the TopLeft settings, I clicked the "To TopLeft" button. This put the head over the frame. I added 2 to the value of "TopLeft X" and hit the button again. Having observed the direction that the head moved I was now in a position to guess a value for TopLeft X that would move the head in the appropriate direction and put it over the mesh. Then I did the same for TopLeft Y.
With TopLeft on the mesh I put a piece of material in place and test fired the laser. I repeatedly adjusted the values, clicked the button to move the head, and fired the laser, until I got TopLeft exactly where I wanted it.
To set the height and width I started with low, safe, values and used the "To BottomRight" button to move the head. Repeated value changes, head moves, and test fires enabled me to set appropriate height and width values.
Height Adjustment Knob
Something to watch out for is that, as you can see from the image to the right, the bed height adjustment knob can foul the cutting head if you leave it in place. Initially I considered choosing values for the bed size that would prevent this, but in the end I decided that it made more sense to keep the knob separate, only putting it in place when I actually need to adjust the bed height and removing it immediately afterwards.
Bed Height
I do read manuals but somehow I managed to miss the page describing the optimum height to have the bed below the head. I did a number of experiments, raising and lowering the bed to find the point at which I got the finest cut line. When I finally noticed the instructions in the manual it confirmed what I had found by experiment.
From what I've read elsewhere it seems that the lenses generally have a focal length of 54mm however as shown in my manual, when I found it, it is easier to measure to some convenient place on the head assembly. On my machine the distance from the top of the material to be cut, to the top of the metal plate with the sticker (as shown in the image to the right), should be 57mm.
Power Settings
The fact that NewlyDRAW can control other cutters caused me some initial confusion. NewlyDRAW screens imply that you can draw with different coloured lines and allocate a power setting to each colour. However with the Rabbit40 selected in the configuration, most of these parameter boxes remain greyed out. With the Rabbit40 you can choose a cut speed (from 1 to 10) within the software, however the power is set via the knob on the machine itself and not through the software. This is not a major drawback but it does mean that if you want to etch and cut on a Rabbit 40, you'll need to perform two separate operations, with a separate drawing for each.
Speed Settings
Speed is set via the software and the blurb that came with my machine suggested speed 2. Something that I didn't twig at first is that this is the speed of the motors and not necessarily the speed at which the cutting head moves. If the head is moving in the X direction at speed 2 and, at the same time, is moving in the Y direction at speed 2, then the head is moving diagonally at speed 2.8 (consult Pythagoras or take my word for it). Consequently the laser will cut less deeply when moving diagonally (because it's moving faster) than when moving in the X or Y directions alone.