CNC Lettering

#Woodworking #CNC #Vectric #Aspire





I am trying to dial in my process for carving fonts.

Rather, cutting lettering into wood not cutting out the actual letters. These past few days have been a learning experience. From what I've learned so far these are the my options:

  1. Using a V-bit with a V-carve toolpath

  2. Using a V-bit with a Profile toolpath

  3. Using an endmill with a Profile toolpath.


Test 1

Settings: Bit: 90 Degree V-bit Front: Pacifico The machine settings were mismatched with the Vetric Post Processor. I am not sure if this matters. My machine is set to MM and the Vetric Post Processor was set to Inches.

The cut seemed quite aggressive.

These were the settings. I now know that these settings are completely inappropriate: The I believe the feed rate and the plunge rate may be too aggressive.



This is how it looked:

Observation: Aside from the text not fitting onto the wood, I feel like the finished product wasn't as clean as I wanted it to be. The inside of the carve seemed rough.


Test 2

Font: Yellowtail I thought that my issue may have been the with the font selection so I tried something else Yellowtail this time.

At this point my machine settings were still mismatched. I believe my feed and speeds were too aggressive (I didn't change them). I was using whatever Vetric set as the default for a 90 degree V-Bit. This is how it looked:

Observation: It carved but it's not the look I was going for. I want a deeper / cleaner cut.




Test 3

For this test I actually updated my tool library to reflect the bits that I own. I also changed my feeds and speeds and changed the font to Survivant. I should stop changing so many factors in one iteration lol.


Also, this test was run right before Test 4. I was also testing weather it was better to stain the wood first and then carve or carve and then stain.


This is how it looked:

Observations: I adjusted my feeds and speeds. As it was cutting it didn't seem as aggressive so this was a move in the right direction. Changing the font to a more blocky font was a probably not the best idea. The machine felt like it handled this cut better but I still thing that I will tweak this later.

Test 4

Test 4 had the exact same settings as Test 3 but for this one I stained the piece before cutting.


This is how it looked:

Observations: This one appeared to cut much deeper despite the fact that I am running the exact same code. I think what happened is that the piece wasn't laying directly on the bed. I use cam clamps to sandwich the workpiece between the fence and the clamp. I think when I was tightening the cam clamp the piece lifted off the waste board. In regards to whether to stain before or after. Even though Test 3 (stained after) might look more pleasing to the eye the stain wasn't crisp. I was using a fabric with a pile and that caused the stain to get into the groove. I think Test 4(stain before) would have looked better if it was carved properly!



Test 5

For this test I changed the bit to a 60 degree V-bit.

It cut deeper than I wanted it to. These were my settings:

This is how it looked:


Observations: I lost detail in the lettering, especially in the center of the O, the M and the A. To fix this I will have to set the bit to make a more shallow cut when I am creating the toolpath.



Test 6

I switched things up. I went for a simple font: Ariel I used an 1/8 endmill instead of a V-bit and I tried using a 2D Profile toolpath set to inside/left. I was pleased with the results. Again though, I think I need to reduce the feed rate. It cut just fine but I didn't like the way it sounded.

This is how it looked:





Test 7

I tried to run a Vbit on a Profile/Contour toolpath around the letters. I had the plunge set to 0.05 inches

And this is what I selected for the toolpath:


The simulation looked like this:


My project looked like this:



Observations:

It went way too deep. I didn't expect this because I thought that because it's a profile cut the bit should plunge to the depth I set it at and run a long and cut a v groove.



Test 8

I ran the Vbit with a profile toolpath. I decided to go with a really shallow depth. I want to see what this looks like. I want something that pretty much just carves the outline.


The bit settings are the same as Test 7. The only thing I changed was the depth of the toolpath.

This is what the simulation looked like:

This is what the cut looked like:



Test 9

The test was to run a V-Carve operation with a flat depth set.


These were my bit settings:



This is what my toolpath settings were:



This is the simulation:

This is what the cut looked like:

I had to abort this cut because it made an aggressive gouge into the wood. At the time of running the Gcode I had no clue why this happened. The settings looked pretty good and the simulation matched up with my expectations. I know the zeros were set correctly because I ran Test 8 a minute before and it was as expected.



Test 10

This test is using a V-bit with a single line font and a very shallow depth.



This is what my toolpath settings were:

This is what the simulation looked like:

This is what the cut looked like:



This cut really gouged the wood and I quickly aborted it. I ran Test 8, 9 and 10 in the same session. Test 8 worked perfectly. Test 9 and 10 both gouged the workpiece. My assumption regarding the cause of the gouges doesn't have to do with the operations chosen because this test was using a 2D profile operation and Test 9 was using a Vcarve operation.


The only things that were different on this test and Test 9 were the Cut Depth and the Pass Depth. I THINK it's because my cut depth for my toolpath was set to .015 inches and under the Cutting Parameters for the tool I have the Pass Depth set to 0.05. Maybe the fact that the past depth is greater caused it to gouge the material. I for my next attempt I will made sure that the Pass Depth is less than the Cut Depth.



Test 11

This is my re-attempt of Test 9: The test was to run a V-Carve operation with a flat depth set. This time I am setting my Pass Depth to less than my Cutting Depth to see if it still gouges. Everything else is still the same as test 9.

This is how it turned out:

Test 12

This is my re-attempt of Test 10.

This test is using a V-bit with a single line font and a very shallow depth.

This time I am setting my Pass Depth to less than my Cutting Depth to see if it still gouges. Everything else is still the same as Test 10.


These are my bit and toolpath settings:

This is how it turned out:




Lessons Learned:

  • Make sure the Vectric G-Code Processor matches the setting on the CNC. My machine is set to MM so my processor should be set to MM.

  • Add/Edit tools in the tool library. Don't just use the default settings. They are too aggressive for my machine.

  • Set the Pass Depth to less than my Cutting Depth.

  • V-bit CAN be used for wide fonts without cutting too deep using a Flat Depth. (Test 11)

  • V-bit can be used for a profile path but the key is to make sure the depth is shallow (Test 8)

  • V-bit with a single line font and a very shallow depth looks quite nice (Test 12)

  • An endmill using a 2D Profile toolpath and a single line font looks great as well. I think a 1/8 or 1/16 endmill is appropriate.

  • Stain piece before!

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