Trouble engraving plaques

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Yewleaf wishes
Posts: 1
Joined: Fri Feb 09, 2018 1:43 pm
Model of CNC Machine: Denford Micro router CNC

Trouble engraving plaques

Post by Yewleaf wishes »

I use my Denford micro router compact everyday to engrave hardwoods with perfect results. For this I typically use a traditional v bit, either 30 or 60 degree pencil tip.

The plaques I have been having issues with are 7mm x 25mm in size with text around 3mm - 10mm. The material is ABS plastic with a metallic coating (TROPHY Metallic 1.6mm). I have been using a single flute solid carbide engraving cutter, with a 30 degree angle and 0.235mm flat tip.

I am using Vcarve desktop to create the gcode. I set it up using true type text, then creating the toolpath with a quick engrave.

The results I am getting are quite poor. There is a lot of scalloping to the text, despite only using 8% stepover. The depth of the engraving is 0.4mm, but I have experimented with 0.8 - 0.2mm and the results are the same - rough edging the the text!

Finally I am using a t-slot mdf bed with clamps the hold down the material, I have heard the Seklema mat is supposed to be the optimum method, so I am wondering if this may be a contributing factor as well.

Is the machine I am using just not good enough? Or am I doing something wrong?
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adze_cnc
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Joined: Sat Jul 27, 2013 10:08 pm
Model of CNC Machine: AXYZ 4008
Location: Vancouver, BC, Canada

Re: Trouble engraving plaques

Post by adze_cnc »

If you're going 0.4mm and greater in depth why not use the v-carve toolpath with 0.4mm (or deeper) as the "Flat Depth"?

As far as I'm aware quick engrave is merely for scratching the surface of something rather than doing deep cuts.

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martin54
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Joined: Fri Nov 09, 2012 2:12 pm
Model of CNC Machine: Gerber 48, Triac PC, Isel fixed gantry
Location: Kirkcaldy, Scotland

Re: Trouble engraving plaques

Post by martin54 »

Took me a while to get the hang of machining engraving laminates, with these types of material speed & feed setting seem to be more crucial than they do for wood, good chip evacuation is also important to ensure the chips don't weld themselves back on lol
My biggest problem was actually hold down, the substrate wanted to bend & bow all over the place when I tried clamping it to the table. You may find that is happening with even quite small bits if you clamp tightly & are using the 1.5mm thickness :lol: :lol:

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