# Inlay tearout



## lrgreen (Oct 17, 2021)

Help! I built a machine after watching YouTube videos and reading online. I got it to run a program, and tried to carve an inlay. I am using a brand new 30 degree 1/4 inch bit, on a spindle running at 12000RPM at 60IPM feed rate. I'm carving in half inch mahogany. I've tried several times to carve the wood, and it always rips the wood to bits. What am I doing wrong? 

I've posted the image from Aspire, and the actual carving.


----------



## difalkner (Jan 3, 2012)

Welcome to the forum! I usually run the program a second time and that cleans it up considerably. Sometimes I drop Z by 0.001" for the second pass.


----------



## lrgreen (Oct 17, 2021)

difalkner said:


> Welcome to the forum! I usually run the program a second time and that cleans it up considerably. Sometimes I drop Z by 0.001" for the second pass.


My problem is that it's taking too much material. Some of the fine lines are tearing out of the wood.


----------



## old55 (Aug 11, 2013)

Welcome to the forum.


----------



## jw2170 (Jan 24, 2008)

Welcome to the forum, @lrgreen


----------



## difalkner (Jan 3, 2012)

lrgreen said:


> My problem is that it's taking too much material. Some of the fine lines are tearing out of the wood.


If you aren't able to control that in your CAM software then just set the Z height 1/8" above the work piece for the first pass and then lower it on a subsequent pass (or 1/16", whatever works).


----------



## gwilki (Nov 12, 2012)

Are you using the vcarve toolpath in Aspire? I not referring to the bit you are using, but to the toolpath you are selecting. Mahogany can be a bear owing to its grain structure. I do inlaid coasters and use a 60° V bit with a pointed tip. Keep in mind that, if you are using the vcarve toolpath, Aspire will cut as deep as it needs to in order for the bit to touch both lines in the carved out portion. That means, if you do not set a clearing depth, with a 30° bit, things can get very deep. It also means that your depths will not be consistent.


----------



## lrgreen (Oct 17, 2021)

gwilki said:


> Are you using the vcarve toolpath in Aspire? I not referring to the bit you are using, but to the toolpath you are selecting. Mahogany can be a bear owing to its grain structure. I do inlaid coasters and use a 60° V bit with a pointed tip. Keep in mind that, if you are using the vcarve toolpath, Aspire will cut as deep as it needs to in order for the bit to touch both lines in the carved out portion. That means, if you do not set a clearing depth, with a 30° bit, things can get very deep. It also means that your depths will not be consistent.


Yes, I am using the Vcarve toolpath in Aspire. My first attempt was with a 90 degree bit, it also tore out terribly, and I didn't like the looks of the carving. I couldn't test fit it because my machine wasn't dialed in yet and I was having some drift in my Y axis, so the sizes did not line up. I switched to a 30 degree bit hoping the tearout would diminish, but it hasn't. I will acquire a 60 and try again, but if the 30 AND the 90 both had tear out, I am concerned for the 60 as well. Every failed attempt costs me another $7.80 in wasted mahogany, so I'm hoping for a sure fix. My gut is telling me it's a feeds and speeds issue, but I don't know which way to go on that. The spindle is maxed out at 12,000 rpm.

The bits I have been using are 2 fluted bits. Would a 4 flute make a difference? My bits are a solid single milled bit, would a composite bit make a difference?


----------



## MEBCWD (Jan 14, 2012)

You don't say what size the carving area is so it is hard to tell how much material should be left. Using the 30 degree v-bit will make it easier for the narrow parts to chip off because there is not much material left to backup the fragile portions. Will this be an epoxy inlay? If so trying using a 90 degree or 60 degree bit so there will be more material left under the narrow places and you will also save a little bit of epoxy.


----------



## lrgreen (Oct 17, 2021)

MEBCWD said:


> You don't say what size the carving area is so it is hard to tell how much material should be left. Using the 30 degree v-bit will make it easier for the narrow parts to chip off because there is not much material left to backup the fragile portions. Will this be an epoxy inlay? If so trying using a 90 degree or 60 degree bit so there will be more material left under the narrow places and you will also save a little bit of epoxy.


This is the male part of a 6" tall inlay. I tried carving the female piece out of Poplar, it didn't fare any better. I'm experimenting on the (more expensive) mahogany thinking it's hardness would hold the detail better, but it's apparently brittle when it comes to the fine details, But the soft poplar did the exact same thing.


----------



## lrgreen (Oct 17, 2021)

The entire carving has a clearance program using a 1/4 end mill, and a detail cut using the V-bit. My first attempts, I ran the clearing program first, on the attempt in the pic I only ran the V-bit portion.


----------



## MEBCWD (Jan 14, 2012)

You say the top speed of your spindle is 12000 rpm so what kind of CNC are you using. That might be the problem. Your CNC might have too much flex to do v-carve inlays or other precise work.

I would use a 60-degree v-bit and hardwoods or if using softwoods I would stabilize it before carving. You might also use the blanks that were messed up to do some test cuts to see if you can adjust your feed rate for a better cut since you can't use higher speeds with your spindle.


----------



## lrgreen (Oct 17, 2021)

MEBCWD said:


> You say the top speed of your spindle is 12000 rpm so what kind of CNC are you using. That might be the problem. Your CNC might have too much flex to do v-carve inlays or other precise work.
> 
> I would use a 60-degree v-bit and hardwoods or if using softwoods I would stabilize it before carving. You might also use the blanks that were messed up to do some test cuts to see if you can adjust your feed rate for a better cut since you can't use higher speeds with your spindle.


I built it myself. I've spent 3 years getting it to stabilize. I started with the cheapest parts I could find and learned as I replaced almost all of them with higher quality parts.


----------



## MEBCWD (Jan 14, 2012)

Can you post pictures of your CNC? 

One other thought I have is your depth of cut, are you trying to cut full depth in one pass or are you using more than a single pass for the full depth?


----------



## lrgreen (Oct 17, 2021)

MEBCWD said:


> Can you post pictures of your CNC?
> 
> One other thought I have is your depth of cut, are you trying to cut full depth in one pass or are you using more than a single pass for the full depth?
> 
> ...


----------



## lrgreen (Oct 17, 2021)

(BTW, don't notice the clutter in the background.)


----------



## MEBCWD (Jan 14, 2012)

What clutter in the background? That is clean compared to what mine looks like right now.

There may be some looseness in your machine that is giving you some of your problems but you can check that by doing some test cutting.

I would say do test cutting with your bits to determine what speeds and feeds to use with your system. Don't try to take off too much at a time(add enough passes so you get a good clean cut), use small stepovers. Make sure you are within the chip loads for the bits you are using(you want chips not dust). Then change the cut depths, feeds, and speeds in the database for the bits so when they are chosen again they will cut as you want them to.

If you find that your machine just won't do v-carve inlays then you could make sure the pocket cuts cleanly and do epoxy inlays. You might have to do a little vector editing to get what you want but they will look good when finished. You could also look at using the standard inlay pocket toolpath and a small endmill, then epoxy for the inlay.


----------



## lrgreen (Oct 17, 2021)

MEBCWD said:


> What clutter in the background? That is clean compared to what mine looks like right now.
> 
> There may be some looseness in your machine that is giving you some of your problems but you can check that by doing some test cutting.
> 
> ...


I didn't really start on inlay work till I was getting perfect pockets. This one is .45 inches deep, 5 passes with a 1/4" mill end. Nice chips coming off of it where I had sawdust before. (The dark spot is a knot)


----------



## lrgreen (Oct 17, 2021)

Thank you for the advise, it gives me some stuff to think about.


----------



## lrgreen (Oct 17, 2021)

I AM getting sawdust from the V-bit. Slow the spindle or increase the feed rate?


----------



## MEBCWD (Jan 14, 2012)

lrgreen said:


> I AM getting sawdust from the V-bit. Slow the spindle or increase the feed rate?


Yes, slow spindle speed or increase feedrate to get the correct size chips for the bit being used. That is where test cutting helps. Set up several vector lines and produce toolpaths for each line with different settings to find the best cut for each bit then revise the tool database.


----------



## PhilBa (Sep 25, 2014)

I know I'm late to this but it looks to me that you are taking way too deep a cut. In the tool page for your V Bits, what is the pass depth set to? Try something shallow like 0.05 inches or even less. It will do multiple passes and take a long time but it _should_ be a lot cleaner. As you go deeper with a V Bit, you are increasing the chip volume so it makes sense to go easy.

On the subject of your machine. I would expect it to chatter if you push it too hard. What does it sound like when you run the program and getting the splintering? A continuous cut sound or choppy?

A suggestion, play around with a cheap hardwood like alder until you get a sense for how aggressive you can be. Also, practice with the wood you ruined - I can see at least 4 areas you use to try different things on and I'd guess it has a back side you can use. Maybe make a test program that is smaller but has similar characteristics.


----------



## Old Ray (Feb 19, 2021)

Slow it down a bit, maybe even a lot,, to get the cut smoother, cleaner, etc. . I start slower and speed up as possible, a little more time getting the results you want, is better than destroying good wood. ease into it. speaking from the one that used to destroy wood, the end result came sooner starting slower then speeding it as possible.


----------



## ger21 (Feb 10, 2019)

The only way that you MIGHT get that to work is to make many shallow passes. And I still doubt you'll be able to cut it without chipping. Too many very small areas, that are incredibly brittle.


----------

