I must not understand the product!

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dbchamber
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I must not understand the product!

Post by dbchamber »

Hello,

I have read all the posts and have carved about thirty different projects and none of them are even recognizable as what's the picture showed.

I have a cnc shark and I use the shark post processor. I have tried engraving bits, 30 60 and 90 degree v bits and depths from .005 to .0400 inches. I have tried stepovers smaller than the bit width top two times bigger. I machine the material flat with a half inch end mil before going to work.

The examples posted by Woodart are marvelous and I would love to get that kind of quality but right now I am simply trying to get an engraving that is recognizable.

I have used maple and charity and sometime the project comes out as a hollowed out depression and sometimes there are scribe lines but I can never see any semblance of the original picture.

I tried the cute puppies, the woman, and the little boy that were in the Denny videos using the same settings with no success.

Does anyone have any idea what I am missing?
Thanks, Dave C

KeystoneChuck
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Re: I must not understand the product!

Post by KeystoneChuck »

If you have Vectric which it seems you do, what you see is what you get in the toolpathpreview***If your bits are entered in the programs software properly, AND you have a properly touched off board that is milled properly.

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martin54
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Re: I must not understand the product!

Post by martin54 »

I could never get one to look quite the way I wanted it to either, put it aside as I had lots of other things to progress & still haven't got round to picking it up again yet. I do have a list of things to try when I eventually go back to it though :lol: :lol:

What do the previews look like? As with all vectric software the previews are very accurate so if the preview looks good then the problem lies else where. From what I have read on this forum they often don't look great straight off the machine, it is all down to the finishing techniques used from what I am led to believe. I think that is probably where most of my problems lie.
if you are trying engraving bits then how small is the flat on the bottom, I know from some of the v carving I have done that to wide a flat can cause problems where the bit does not fit between vectors, I know this is a different process but I would say use a bit with a very small flat.

If you have followed the tutorial using the settings within the tutorial then you should at least get something recognisable, fine tuning using some of the settings listed in forum posts should only really enhance it.

Have you checked your z axis for things like backlash & binding, does the machine return to your original zero after cutting, lots of rapid z movements cutting these which can show up machine problems that don't show during other operations.

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BrianM
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Re: I must not understand the product!

Post by BrianM »

hi,
A common error is that you MUST have a contrast between the grooves and the surface material for the PhotoVCarve process to work. This is usually done by staining the grooves afterwards or cutting material which has a different colored surface to the substrate.

Brian

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dhellew2
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Re: I must not understand the product!

Post by dhellew2 »

Another common problem is not having a flat surface to begin with. Unless the top surface of the material is planed by the cnc one cannot get a uniform cut unless the bit is referenced at the absolute lowest point or set to cut slightly below the lowest point.

One other method is to set the reference at the table instead of the top of the part. This way you can set the depth at the lowest point on the part then the cutter will make the surface flat as it cuts the design.

Finally, cutting with the grain will hide the shallow v-cuts. Changing the angle will improve the end result but will still vary with the type of wood, size of grain, color variation in the grain.

As Brian said, adding stain will help bring out the engraving. I prefer gel stains because you have control over how much color is added. Another trick I use is to spray on a mat or semi-gloss lacquer the apply the gel stain over the lacquer. Once the stain dries I spray on more lacquer.

Hope this helps a bit.
Dale
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Young = time, no money
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Dale

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sawmiller
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Re: I must not understand the product!

Post by sawmiller »

try a melamine covered shelf board, white works good, then paint with black and wipe clean... interesting when you get it right
woodmizer sawmill and joe's hybrid cnc, a good combination
In the heart of Tn

dbchamber
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Re: I must not understand the product!

Post by dbchamber »

I see two basically different end results. One, which I cannot reproduce, appears to carve discrete lines which are then filled with stain or pigment. The other produces a smooth 3-d image.

Some of the photos that are posted appear to be very realistic photo-images with incredible detail. Some seem to be 3-D carvings.

Are these two different processes or just two end results and how do you determine which effect to try to obtain?

Most of my attempts do not shown discrete grooves but a smooth surface. I know that some people recommend a 10% line spacing.

Thanks

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sawmiller
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Re: I must not understand the product!

Post by sawmiller »

you can carve a smooth surface by using a ball nose bit with a small stepover for smooth rounded wood images, or use a semitransparent medium for lithopanes, or you can vcarve,lightly scratching the surface with a vbit and fill the scratches. different techniques requiring different bits and preprocessing of the image
woodmizer sawmill and joe's hybrid cnc, a good combination
In the heart of Tn

jamesr
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Re: I must not understand the product!

Post by jamesr »

Finally, someone with the same or similar problem as I have. I can't get photovcarve to do anything other than cave angled lines in the wood! Please let me know if you get it figured out. Now before the 'you haven't done's' start chimimg in, I have consulted with everyone I can think of and still no positive results!

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Adrian
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Re: I must not understand the product!

Post by Adrian »

Carving angled lines in the wood is what it's supposed to do. Are you staining the wood afterwards or using a material with a contrasting top layer? There has to be a contrast between the surface of the material and the cuts for the picture to show.

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FixitMike
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Re: I must not understand the product!

Post by FixitMike »

A further explanation: The darker parts of a PhotoVCarve picture are made by cutting deeper lines with a V Bit. The deeper lines will be wider. When filled with stain (or paint) they will appear darker. You can also get the lines to show the picture if you have a thin contrasting material on the surface of your material.
Good judgement comes from experience.
Experience comes from bad judgement.

LittleGreyMan
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Re: I must not understand the product!

Post by LittleGreyMan »

Hi,

I'm not a PhotoVCarve user, but I gave it a try in the past.

All I can say is that it works fine.

4 potentials issues here:
-your picture
-your material
-PhotoVcarve learning curve
-CNC learning curve

That was the bad news. The good new is you can get rid of the 3 first ones.

The software comes with sample projects. So obviously, the pictures and the settings are OK.

Don't use wood, but a material with a smooth and flat (both are important) surface: PU or MDF board.

Run the demo path. If the result is not correct, you have a problem with your CNC.

If it is OK, try using your picture. You may have to change its settings (contrast, luminosity, curves, …) with an image editor (GIMP, PhotoShop, …).

Once it is OK, try changing material, then settings.

Wood is not the ideal material to begin with.

HTH
Best regards

Didier

W7 - Aspire 8.517

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