Halftone image in HPL

Hello everybody,
This is my first post here so I will do a short introduction of myself.
My name is Willem Loman, I live in the Netherlands. I have a X-Carve for hobby use since may this year.

Last weekend I tried to carve a halftone image out of a sheet of white HPL (Trespa) (because MDF was too soft and because HPL is already black inside).
I created the g-code with halftoner 1.7 from Jason Dorie. The carving proces went ok and the result was nice but afterwards I noted that all the holes were smaller than was calculated in the halftoner software. Thereby the image was too light. The reason for this was that the material was probably too hard or I used the wrong settings/v-bit. Everytime the bit touched the material I saw that the whole cariage was lifted a little bit.

I used a standard (cheap) 2 flute v-bit that I already had and which I used before in my plunge router. Does anyone have any advice on which v-bit I can use best? I saw Whiteside already in other posts but maybe there are more good bits.

I used a feedrate of 1500mm/min but I think that’s probably too high.

Any advice is appreciated


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I don’t have experience with that material, but you could simply lower your zero a smidge

welkom op het forum trouwens :slight_smile:

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@RobertCanning So looking at the bits on the link you provided… should I be looking at a or a1 for the required angle?

lets say I want a 60degree bit…

look at a

Are you talking about play in the z-axis? Can you turn the guide wheels by hand? If you can, they need to be tightened.

Are you talking about play in the z-axis? Can you turn the guide wheels by hand? If you can, they need to be tightened.

No, actually also the Y-axis and X-axis were lifted (bending). That’s not a good thing so I will first buy a new v-bit and I will lower the feedrate to max 1000mm/min before I start another testsession.

Last week I bought two new bits from CMT and that made a big difference. The machine wasn’t lifted up anymore and it carved the holes with exactly the diameter I designed them.
So the conclusion is: it was a doll bit that caused the problem. Here is a photo of some testholes with the new v-bit. Very sharp edges. Next week I will make the halftone again.

Are you using solid High pressure laminate?

or is the hpl made with a pvc or hdpe core?

It is solid HPL.
I had not used it before but it is a very cool material. The results with MDF were very poor compared to HPL.

oh awesome yeah I wish I could get my hands on some of that lol thats pretty expensive material

It’s not that expensive. I bought a sheet of 300 x 130 cm (10’x 4,25’) and 6mm (1/4") thick for €85,- ex VAT ($99,-)

I made a second attempt and it turned out much better than the first time. Maybe the speed is still a little bit to high(1500 mm/min) but that will be finetuning