How to Engrave my CNC Tags

[kolias]

I built my own hobby cnc table mill all in 3/8" thick aluminum plate/flatbar, 36"x48" cutting area with 4 stepper motors and water cooled spindle. I can do a lot of things but I can't do engraving, never tried, so the ID tags for the buttons in the control panel are printed on paper and stuck to the panel with tape as per attached picture (very ugly). I use Mach3 to run the cnc.

I have a total of 8 tags I would like to make and searching its quite expensive just for 8 tags so I would like to give it a try to make my own and I'm asking what kind of software do I need for this job. No idea for the tags material, I'm guessing perhaps some kind of plastic or vinyl?

Many thanks

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[joeavaerage]

Hi,
I use Fusion. It has a number of letter engraving strategies, each of which generate a good tool path.
The attached pic is in die cast aluminum with a two flute 0.5mm endmill. The letters are 4mm (larger) and 3.5mm (smaller) high.
Took about 30 minutes to generate the tool path.

Craig

[joeavaerage]

Hi,
I see in your other post that Mastercam refused to generate a tool path 'cutter compensation failed'

My guess is that the tool is too big to fit in the letter font you used.

There are two types of letter engraving.

One is where there is a single line right down the centre of the letter. That single line can be used as a tool path. The width of the letter will then depend on the diameter of the tool.

The other type is a tool path that first goes 'up' one side of the letter and then 'down' the other side. Clearly the tool needs to be LESS than the width of the letter or it will not fit inside the letter
without breaking the over the letter boundary.

The example I posted is an example of this later type of tool path. That is why I used a 0.5mm tool so that it would fit within the width of the letter, and also means that there is a minimum size letter that you can compose
that will have a good tool path for a given size tool. In the case of a bold Arial font (pictured above), with a 0.5mm tool, the minimum letter size while retaining full definition is 3.5mm.

You need to experiment with the two types of tool paths. The single line type is most forgiving but with somewhat variable results while the 'up & down' type you get a better result, but the tool path requires
considerably more to generate and you must have a small enough tool to do the job, but the results are very pleasing.

I have attached a close up view of part of the tool path. Note how the tool goes 'up' one side and 'down' the other. Note also that I used a Ramp toolpath, so the the tool ramps down into
the material. I found this necessary to prevent tool breakage......0.5mm tools are very tender. The cut depth is 0.5mm or 100% of diameter and is a challenge for such small and tender tools.

Craig

[kolias]

Hi Craig, pretty nice engraving jobs you did. I will experiment with the information you gave me and hopefully I will get something acceptable

Many thanks
Nicolas

[routalot]

I use F-engrave and the standard single line font for engraving and I have only really used brass.The default post processor is for LinuxCNC which I use,but it may well work more generally. I bought a box of the 30 degree engraving cutters from ebay and they were adequate but needed a much slower feed that I anticipated.

[kolias]

Thanks mate for the help, I had forgotten f-engrave and just gave it a run and produced a gcode for a text sample. Tomorrow I will give it a test run and somehow I believe it will be good. Will post back the results and f-engrave looks simple enough to use

[routalot]

One word o cation about F-engrave,the default clearance heights and plunge rates can lead to a very slow job.Keeping the tool a bit lower and increasing the plunge rate a bit will speed things up.The actual feed rate could be something you may know to work or you may need to experiment a bit-with the risk of losing a cutter or two,I know I did.

[kolias]

I understand what you say, thanks. I got a good gcode and a .dxf file but when I try in my MCx5 to simulate the cut either using engrave or contour paths I get "the path cant be completed" and MCx5 locks and have to reboou the PC. I try various parameters with the same results. I'm in the middle of another project and I cant spend more time on it to solve the problem, will try another time

[joeavaerage]

Hi,
try Mastercam with a smaller diameter tool, say 0.5mm or even smaller. Its not that you actually have such a tool, but rather it might prove , or alternately disprove, the idea
that the tool path cannot be completed because the tool you have nominated is too big.

Craig

[kolias]

Good idea Craig, thanks, I will give it a try

[routalot]

I would have expected a single line font to run satisfactorily but with the risk of some messy details if the tool is too large.I'm really surprised that MCx5 can't generate a decent toolpath or run the code from F-engrave.Could it be a case of running it through a different post processor?I do know that the default F-engrave single line font isn't from the TrueType family and maybe searching for an alternative single line font would overcome the problem in both programs.

[kolias]

I would have expected a single line font to run satisfactorily but with the risk of some messy details if the tool is too large.I'm really surprised that MCx5 can't generate a decent toolpath or run the code from F-engrave.Could it be a case of running it through a different post processor?I do know that the default F-engrave single line font isn't from the TrueType family and maybe searching for an alternative single line font would overcome the problem in both programs.

Nothing wrong with the post processor and I tried different fonts with no success. When I finish my current project I will try again. Problem is that when MCx5 cant complete the path it locks the PC and I have to reboot which takes time and that never happened before. Normally when something is wrong with my parameters I can go back and change the parameters but not now. Thanks

[routalot]

I didn't think to ask the question,but did you convert the letters to curves?Most CAM programs require you to perform the conversion so they have compatible elements to work with rather than the raster format of the typical font.

[kolias]

I didn't think to ask the question,but did you convert the letters to curves?Most CAM programs require you to perform the conversion so they have compatible elements to work with rather than the raster format of the typical font.

That's a good question, converting letters to curves know nothing about it. Will have to find out how to do it. Thanks