I have been making some plastic labels using the sheet material that is a layer of black, with white plastic base. Using a 60 deg. engraving bit, when going about .025 deep, the letters show up clearly in white, against a black background. The material comes in 1/16" and 1/8" in various colors as well as black.
Using "WRITE", all words have a X/Y start position box in the upper left corner. If the X and Y position are both 0.000, the word will be written with the lower left corner at X 0.000, Y 0.000 home position.
In my labels, the dimensions are 1.500" long, x .500" high, with two screw holes at each end. Cutting the outside of the label leaves a nice white border.
Print the desired word in the program. Select the font; in my case I used the Helvetica as it is plain and readable, and input the "Height" setting as .160.
Output the word to Mach3. Then enlarge the view of the word until it nearly fills the window. Your X/Y home line is on the screen view
tangent to the word on the left,lower corner. Jog your X axis until it is just tangent to the last letter right side. Write down this X dimension, as that is the physical length of the word.
In my case, my label plate is 1.500" long. Subtract from 1.5 the word length dimension, and divide the result by 2. This will give you the starting "X" position, leaving equal amount of space on the right and left side of the word.
In my labels, there were usually two lines. The upper line start "Y" dimension worked out at .290", and the lower line start "Y" at .050"
This had to be derived by trial and error, but once you arrive at what looks good, this can be a constant.
Each particular word has a specific length, and it is not just a fixed horizontal length for all letters or numbers. You must do each word separately.
Since I made many different label plates, each finished label program contained a heading like this:
(PUMP)
(x st - .471)
(y st - .050)
(Helv- .160)
This helped ID the program. Remember to "Save as" when your program is finished, with the label name, as the original program is saved by "Write" as write.txt.
Some words, or multiple words don't look just right depending on the first and last letters. You can just edit the starting X position until it is visually pleasing.
Hope this helps.
John