Need Help: Lack of detail in V-Carve Desktop carving

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Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Fri Jul 12, 2019 5:37 pm

Hello all. I'm relatively new to CNC and to Vectric V-Carve Desktop. I created a line drawing from a photograph of a motorcycle and imported it into V-Carve. I attempted to v-carve that line drawing and the detail did not come out anywhere near what the v-carve preview looked like. It came out much darker than the preview. (See pics below) I used a 60 degree V-bit at a flat depth of .015 and carved it into hard maple. After the carving completed, I used black paint to fill in and highlight the carved out areas and sanded the over spray from the surface. As you can see the actual carving (Pic 4) has much less detail (more black area) than the V-Carve preview (Pic 3). I'm not understanding why the actual carving doesn't have as much detail as the preview. I'm assuming that I need to use a VBit or an engraving bit with a much smaller angle, say 30 degrees are maybe even smaller. You would think that the preview would reflects results based the size and shape of the bit, cut depth, material size, etc.

Bottom line is I want to be able to V-Carve or engrave detailed line drawings of motorcycles and other subjects and the lack of detail in Pic 4 doesn't get it. I'm not opposed to carving / engraving or using other materials like metal. I just want to achieve a more detailed result. Please advise how to get there.

I would greatly appreciate your critique and advice!

Thanks for your help
Doug
Attachments
VCarve Job Settings.jpg
Pic 1: Job Settings
Vcarve Toolpath Settings.jpg
Pic 2: Toolpath settings
VCarve Preview.jpg
Pic 3: V-Carve Preview
VCarve Actual Cut.jpg
Pic 4: The actual V-Carve Carving
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby Adrian » Fri Jul 12, 2019 5:46 pm

The preview does show what you will get but it assumes that the bit is exactly as described (60 degree bits are often 59 or 61 degrees or even more out than that) and it assumes that the z-zero has been set perfectly. With a design like that even having the z-zero a tiny fraction (the thickness of a piece of paper) too low will have an effect on how the piece carves. Finally wood moves and may not be totally flat to start with which can change the depth of cut etc.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Fri Jul 12, 2019 6:02 pm

Hey Adrian

Thanks for your reply. I use a CNC Router Parts Auto Z and corner finding touch plate to set Z-Zero and X / Y Zero. Also, I surfaced the wood prior to cutting. I get the bits possibly not being exactly as described and can see how that would make a difference.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby TReischl » Fri Jul 12, 2019 7:08 pm

firstshot425 wrote:Hey Adrian

Thanks for your reply. I use a CNC Router Parts Auto Z and corner finding touch plate to set Z-Zero and X / Y Zero. Also, I surfaced the wood prior to cutting. I get the bits possibly not being exactly as described and can see how that would make a difference.


Somewhere on the forum is a file for determining the angle of bits via a trial cut. The file is set up for a 90 degree cutter but the same can be done with any other angle.

You are correct in stating that maybe a 30 degree bit will give better results. It should but I would set the depth a bit deeper than .015.

The other thing you may be encountering but is difficult to see is paint bleed. Spray paint is very thing otherwise it could not be sprayed. That thin paint can be sucked up the wood fibers like a straw. What happens is that the edges become fuzzy looking from the paint bleed. A way to cure that is to do a "rough cut" first. In other words cut about .002 or .003 short of final depth. Give it a coat of really thin sanding sealer. The stuff in the hardware store is too thick, cut it by half again with alcohol. Put it on, let it dry, takes about 20 minutes and then do your finish cut. The same capillary action that sucks up the paint also will suck up the sanding sealer. Since the sealer is really thin and alcohol based it will penetrate deeper than the paint. In case you did not know, shellac is a good base for almost any finish including paint.

Edit: The sanding sealer technique is also a good way to help prevent tearout.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby martin54 » Fri Jul 12, 2019 8:47 pm

The toolpath preview is very accurate so if you are not getting the results shown in the preview then the problem lies with your machine, control software, set up or finishing proceedures :lol: :lol:

Adrian & Ted have mentioned checking the bit angle & that is one place to start but I would look at your finishing as well paint bleed as Ted has said is a common problem when the wood has not been sealed, from what I can see there are a lot of black areas where there hasn't been any carving done at all :lol: :lol:
Can't give much advice on finishing though as it's something I am not great at myself :oops: :oops:
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Sat Jul 13, 2019 12:13 am

Ted & martin54

I will definitely check out the process for verifying the bit angle.

I know you can't see it very well in the actual vcarve carving (Pic4), but I took a very close look at the actual carving and there doesn't appear to be any paint bleed. I put on 2 coats of shellac before doing the cut. Also, there are no areas are NO black areas where there hasn't been any carving done at all. Everything with black has been cut.

I may have found the problem though. I took a caliper and as best as I could measured the depth of a bunch of the cuts taking into consideration some areas may have been sanded more than others. I found cuts in the lower left that were right around .015 but also found areas in the middle and top right which measured up to .08. So, obviously, it was cutting deeper in some areas than in others. I did surface the wood prior to cutting but only surfaced one side. The bottom side was not surfaced at all and when I placed it on our granite counter top it did not sit flat at all. It rocked back and forth. So, once secured to the table, the top right side would have been higher than the left front corner where the Z measurement was taken. By cutting deeper, the VBit wouldhave cut the lines thicker than intended and the black lines would have overlapped making one solid black area.

I'm going to chaulk this one up to a rookie mistake and give it another go. (I am going to try a 30 degree engraving bit though :-)

Thanks to you all for your input!!!

Regards
Doug
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby TReischl » Sat Jul 13, 2019 12:33 am

firstshot425 wrote:Ted & martin54

I will definitely check out the process for verifying the bit angle.

I know you can't see it very well in the actual vcarve carving (Pic4), but I took a very close look at the actual carving and there doesn't appear to be any paint bleed. I put on 2 coats of shellac before doing the cut.

Putting on the shellac before cutting will not seal the cut areas. Think about it, the cut areas are exposing end grain which is notorious for slurping up finishes. You need to seal after you cut.


Also, there are no areas are NO black areas where there hasn't been any carving done at all. Everything with black has been cut.

I may have found the problem though. I took a caliper and as best as I could measured the depth of a bunch of the cuts taking into consideration some areas may have been sanded more than others. I found cuts in the lower left that were right around .015 but also found areas in the middle and top right which measured up to .08. So, obviously, it was cutting deeper in some areas than in others. I did surface the wood prior to cutting but only surfaced one side.

I do that quite often, it does not cause a problem. As long as the piece remained clamped where you surfaced it the top side will remain flat. Now, if you did not use clamps and instead used double sided tape, or clamps that apply force to the edge of the board all bets are off. Some guys seem to think that wedging a piece against a stop works. That is usually true for something like plywood unless they are using an upcut bit and discover that the bit is lifting the piece.

The bottom side was not surfaced at all and when I placed it on our granite counter top it did not sit flat at all. It rocked back and forth.

You said you flattened the top and then did the engraving? Did you do something in between? Like unclamp the piece? When you do work like this, you should surface on the machine and leave it in the clamps until you are finished.

So, once secured to the table, the top right side would have been higher than the left front corner where the Z measurement was taken. By cutting deeper, the VBit wouldhave cut the lines thicker than intended and the black lines would have overlapped making one solid black area.

I'm going to chaulk this one up to a rookie mistake and give it another go. (I am going to try a 30 degree engraving bit though :-)

Thanks to you all for your input!!!

Regards
Doug


Always, always, ALWAYS do the surfacing on the machine for this type of work. Sand the surface to remove machining marks, then set your tool height and do the cutting. You will get much better results, trust me!

I sometimes use a drum sander to surface stock, but I never do that when I am V carving or engraving. Both of those operations will show the least little difference in stock thickness.

One other thing while I am being blabbly: Have you surfaced the spoil board on your machine?
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Sat Jul 13, 2019 1:04 am

Ted
Putting on the shellac before cutting will not seal the cut areas. Think about it, the cut areas are exposing end grain which is notorious for slurping up finishes. You need to seal after you cut.
I gotcha on sealing after the cut and before the paint.

I do that quite often, it does not cause a problem. As long as the piece remained clamped where you surfaced it the top side will remain flat. Now, if you did not use clamps and instead used double sided tape, or clamps that apply force to the edge of the board all bets are off. Some guys seem to think that wedging a piece against a stop works. That is usually true for something like plywood unless they are using an upcut bit and discover that the bit is lifting the piece.
I had surfaced the piece after using hot glue to attach it to the spoil board and did not move it until after the VCarve. Based on what you said, I'm assuming that the hot glue must not have held it secure enough. Since I surfaced the piece prior to cutting, I don't know what else could account for the varying cut depths.

What's the issue with "clamps that apply force to the edge of the board"? How do you clamp it down if you do not clamp the edges?

You said you flattened the top and then did the engraving? Did you do something in between? Like unclamp the piece? When you do work like this, you should surface on the machine and leave it in the clamps until you are finished.
Once hot glued down, I flattened the top and then did the engraving.

One other thing while I am being blabbly: Have you surfaced the spoil board on your machine?
YES.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby TReischl » Sat Jul 13, 2019 1:30 pm

firstshot425 wrote:
What's the issue with "clamps that apply force to the edge of the board"? How do you clamp it down if you do not clamp the edges?

When I wrote about edges I was referring to the thickness of the board. Some folks use wedges on their sides to push the board against fixed stop rails. Those work to a degree if one is doing light cuts. Like anything, a person can do that all the time and then one day. . . .

Once hot glued down, I flattened the top and then did the engraving.

You are probably correct that some of the hot glue let go. It is handy stuff. My guess would be that after you hot glued it and then surfaced it a bit of stress was relieved in the board and there was enough force to pop a corner up on you.



Clamping work to the table is a subject all by itself. I try to avoid having any clamps on the top surface. There are two ways I do that. The first is that I use a pair of vises I made for smaller work, up to about 8 inches wide by 48 long. I do not put a lot of pressure on with them to avoid cupping the work. The second is that I cut a groove along two opposite edges with the table saw. Then I can put toe clamps in the groove. I use that a lot when I do thicker stuff. And then, when all of those will not work, yup, toe clamps on the top surface.

Here is an interesting factoid: Most of us are lazy as all get out. I see guys using two clamps to hold down a large piece. I used to be in the school that would put a clamp in each corner. Now I use six clamps if I am trying to do really fussy work like your engraving. I put the two extra ones in the middle where the board might want to bow after surfacing. Discovered that the hard way after chasing my tail around one day with a piece similar to yours. The darned thing would slooowwwwlllyyy cup as it was doing the engraving cuts.

Well, hope this helps you out, I am sure a lot of the other guys have methods that work for them too.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby martin54 » Sat Jul 13, 2019 1:37 pm

One other thing while I am being blabbly: Have you surfaced the spoil board on your machine?
YES.

Have you trammed your machine? One other possibility is that the machine Spindle is not sitting quite true to the spoilboard. :lol: :lol:
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Sat Jul 13, 2019 7:50 pm

martin54 wrote:One other thing while I am being blabbly: Have you surfaced the spoil board on your machine?
YES.

Have you trammed your machine? One other possibility is that the machine Spindle is not sitting quite true to the spoilboard. :lol: :lol:



Hey Martin

Yes, spoil board has been surfaced and the Spindel has been trammed.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Sat Jul 13, 2019 8:12 pm

[/quote]

Clamping work to the table is a subject all by itself. [/quote]



Ted or anyone else.

Have you tried the +painting tape + super glue" hold down method? Here is the link to YouTube link where Fast Cap 2P10 glue and activator is used.
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby TReischl » Sat Jul 13, 2019 10:00 pm

firstshot425 wrote:Ted or anyone else.

Have you tried the +painting tape + super glue" hold down method? Here is the link to YouTube link where Fast Cap 2P10 glue and activator is used.


Nope, and probably never will either. I get really aggressive with cutting and do not trust things like tape. When I say aggressive I am talking 350 IPM, 10mm depth of cut with a 10mm end mill. Even doing small stuff and surfacing I will push the machine up to 350 IPM with a large bit.

I like positive holding power, something mechanical, not a bond between two surfaces.

And yes, I have seen that technique. It is sometimes used by crazy turners.

A lot of the stuff I do takes a lot of carving time even at the feedrates I typically run so I am not keen about having a piece that has been running for a couple of hours suddenly decide it is time to move.

All that said, sure, I would use tape, etc if I were doing light work on a plywood piece and I was not concerned about having to do it over.

Edit: I just reread what I posted. Sound pretty negative. Sorry about that!
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby martin54 » Sun Jul 14, 2019 1:18 am

There are people on the forum who use that method & those that use a double sided tape, I have a range of different hold down methods & use what ever method I feel is most suitable for the job I am doing.
If you are not surfacing the underside of the board then this method may not be suitable, the tape/superglue combination is pretty thin so you could end up with a lot of ereas with absolutely no hold down.

Also, there are no areas are NO black areas where there hasn't been any carving done at all. Everything with black has been cut.


If you look at your final picture there is a very large part of it that looking at the Toolpath preview should not have been cut yet seems to be very black :lol: :lol:
The area above the bike according to the preview is not cut at all.

InkedVCarve Actual Cut_LI.jpg
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Re: Need Help: Lack of detail in V-Carve Desktop carving

Postby firstshot425 » Sun Jul 14, 2019 3:10 am

martin54 wrote:If you look at your final picture there is a very large part of it that looking at the Toolpath preview should not have been cut yet seems to be very black :lol: :lol:
The area above the bike according to the preview is not cut at all.
InkedVCarve Actual Cut_LI.jpg



Martin

The difference is due to some editing that I did after the VCarve completed. I deleted all of the area that you circled as well as a bunch of the "brick" area just to put more focus on the bike and eliminate a bunch of unneccessary cutting. My bad! I should have said something about that in my original post.
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