How to eliminate lines when using a diamond drag bit with acrylic

[Rustic_Designs (Trevor Pottelberg)]

Hi Guys,

I’ve been making some acrylic items using my 90 diamond drag bit. I noticed that I always have lines in the final result. I thought that was normal but I’ve seen many results online that don’t have any lines and looks smooth. Is it a setting that I need to change?

[AndyP (Badger)]

A few thoughts,

• reduce the step over , try half again
• try cross hatch: second pass at 90 degs
• keep the line definition but use an offset rather than straight line pattern, it might be a look that you like without the extra time needed by the smaller step over or reoeating at 90 degs
• use a flat end mill rather than drag bit

[Borgorl]

I gave up on acrylic because I could never figure out how to get a clean cut on it. I used a 0 flute acrylic bit too

[Rustic_Designs (Trevor Pottelberg)]

Thanks for the suggestions Andy! When you say use an offset rather than straight line pattern, where do I find that? I don’t think I have a flat end mill in my bit set at the moment.

[AndyP (Badger)]

What software package are you using?

[suprak (Alex ❄)]

Anybody make any progress with Acrylic and 1F?

I’ve experimented with the JTech 24w laser and it’s not been great.
Exploring etching options using drag bits.

Wondering what learnings others have developed.

[Echd]

I used the default settings in vectric without any issues at all with the Carbide “mc etcher” bits. I have been quite happy with the results.

I use the 120 degree bit in acrylic and 90 in aluminum.

[suprak (Alex ❄)]

Ended up getting the 90 degree MC Etcher myself.

I thought I could get away with using LightBurn, since it has rudamentary Z axis support. But turned out the way LightBurn optimizes it’s toolpaths, it does not raise the Z, just turns off the laser, which doesn’t work for drag etching since we need to physically lift the tool off the workpiece.

Since I was already using Fusion360 for general CNC work, I was able to utilize the 2D Trace and Face operations to achieve my desired look.

Tips-and-Tricks:

• You will need to create your etching bit as a flat-end-mill, otherwise you will not be able to use the Trace/Face operations, here are my values for MC Etcher
  

  

• The Face operation allows you to specify the Pass Direction as well as the Stepover. The angle controls the direction of the face relative to the selected axis (defaults to X) and the step over controls the spacing between the drag marks. Duplicating the Face operation and changing the angle allows you to create a cross-hatch pattern.
  

  

• Experiment with the stepover value to find the effect you’re looking for. I like 0.03 in for cross hatching and 0.01 in for filling in.

• In order to get the Trace command to neatly trace your fill, you will need to tweak the “Sideways Compensation” setting.
  

  
  
  
  By default, the “Sideways Compensation” in the latest Fusion360 is set to “Center”.
  
  However this disables the ability to control whether the select contour is traced on the inside vs outside.
  You can see in the above triangle trace on the left, is the default trace. On the right is the trace after setting “Sideways Compensation” to “Right” (or “Left”) and then toggling the contour direction using the “Reverse” checkbox or the red arrow on the model,
  
  
  

• By default, the Face command links it’s passes with a transition you may want to tweak as well.
  

  
  
  
  In the above samples the left is the default “Smooth” transition and the right is the “No contact”,
  
  

Overall, I am very pleased with MC Etcher and the kind of effect and acrylic capabilities it unlocks!
If you use Fusion360 this will hopefully help you get start and with the above tweaking, can help you achieve results like this,