At shallow depthps, my Shark Pro Plus cuts more than twice as deep as the specified cut depth. For example, when I have the cut depth set for .2", it will cut around .5" deep. I then set the depth to .11", ran it again, and it cut about .25" deep. I've been having this problem since I received my machine. I first noticed it cutting a channel specified at .575". It cuts over .6" deep. So, the percentage of the problem seems to get less as the cut depth increases. I cut 1.75" holes and pockets and those seem to be almost spot on. Does anyone have an idea of where I may look to try to solve this problem with the shallow depths?
Larry
Cutting depth problems
Moderators: al wolford, sbk, Bob, Kayvon
Re: Cutting depth problems
Hi Larry,
What type of toolpath are you using when you find a deeper than specified outcome? I assume for the holes and pockets you are using a Pocket Toolpath.
What type of toolpath are you using when you find a deeper than specified outcome? I assume for the holes and pockets you are using a Pocket Toolpath.
Re: Cutting depth problems
I found a few factors that will affect depth. Trick is knowing what you set in V-Carve in the tool path and in SHark Basic Control Panel.
For V-Carve, remember your safe Z zone (Rapid Gap Clearance) as well as do you have a Flat Depth box checked? If so this will allow the bit to plunge to that depth.
Another sneak is - is the wood set at nominal dimensions or true dimensions? It is easy to consider 3/4" thick material by common nominal but that is not the true thickness. Make certain each time you adjust or change you save the tool path. Each path must be saved seperatly.
Now, in the Shark Basic Control Panel, zero you axis on the material. I tend to leave my carve bit a little loose in the router collet this way if the Z axis plunges I don't take a chance on pushing the bit into the material (I have a habit of raising the Z axis to slide my material onto the work table but plum forgetting where my bit zeroed before I raised the router
). It also allows me to set the Z axis zero by moving the bit up or down to just above the material then tighten the collet.
Learned from the school of "hard knots".
Bobby
For V-Carve, remember your safe Z zone (Rapid Gap Clearance) as well as do you have a Flat Depth box checked? If so this will allow the bit to plunge to that depth.
Another sneak is - is the wood set at nominal dimensions or true dimensions? It is easy to consider 3/4" thick material by common nominal but that is not the true thickness. Make certain each time you adjust or change you save the tool path. Each path must be saved seperatly.
Now, in the Shark Basic Control Panel, zero you axis on the material. I tend to leave my carve bit a little loose in the router collet this way if the Z axis plunges I don't take a chance on pushing the bit into the material (I have a habit of raising the Z axis to slide my material onto the work table but plum forgetting where my bit zeroed before I raised the router
). It also allows me to set the Z axis zero by moving the bit up or down to just above the material then tighten the collet.Learned from the school of "hard knots".
Bobby
Re: Cutting depth problems
Joe, I am using pocketing toolpaths.
Bobby, I posted my question over in the VCarve forum before I posted here. I attached my .crv file and someone looked at the toolpaths and said there was nothing wrong there and the cut depth SHOULD be as specified in the toolpath. It was suggested that the problem was more likely with the Shark (controller, I suppose). How does the safe Z zone setting affect cut depth? I don't recall a "Flat Depth" box in the pocketing toolpath. Am I missing something? Also, when you mention settings in the Shark Basic Control Panel, the only thing I do there is set the XYZ zero. There I use the "one sheet of paper clearance" to set Z zero. Thanks for your tip about leaving the bit loose when setting.
Larry
Bobby, I posted my question over in the VCarve forum before I posted here. I attached my .crv file and someone looked at the toolpaths and said there was nothing wrong there and the cut depth SHOULD be as specified in the toolpath. It was suggested that the problem was more likely with the Shark (controller, I suppose). How does the safe Z zone setting affect cut depth? I don't recall a "Flat Depth" box in the pocketing toolpath. Am I missing something? Also, when you mention settings in the Shark Basic Control Panel, the only thing I do there is set the XYZ zero. There I use the "one sheet of paper clearance" to set Z zero. Thanks for your tip about leaving the bit loose when setting.
Larry
Re: Cutting depth problems
When you in your toolpath and you have the bit selected you should see the area for entering the top of the material and the flat depth area. I don't know for certain if this option is there for "pocketing" but I would think so.cvguitars wrote: How does the safe Z zone setting affect cut depth? I don't recall a "Flat Depth" box in the pocketing toolpath. Am I missing something?
Also, in the bit selection, you can edit the depth and passes of the bit you use.
Then you should be OK. As I stated I was pointing out some of my lessons; meaning that I set my axis' to zero but my bit clearance to the material might greater than that sheet of paper. When the program runs now it runs as though my material was within the safe zone. Sounds like you have that step covered, I was just mentioning in case you missed it - I know I have a time or two.cvguitars wrote: Also, when you mention settings in the Shark Basic Control Panel, the only thing I do there is set the XYZ zero. There I use the "one sheet of paper clearance" to set Z zero.
Since you mentioned you cut holes and pockets that were right on the mark, I don't think this problem is the Shark - well not in the control. It might be that you have clearance variance between the gantry (router mandral) and the table surface. I fought this issue for weeks where I would perform very shallow lettering carves but across my material the depth of the lettering would change. If the table is off a 1/32" it will show in the finished job. In places, my table was out by 1/16" even though the table was true and flat. I made some wood slats and secured to the table and machined flat with a 3/4" flat. No more depth problems since that modification.
Again, this is just suggestions from my experience. You may already have a machined spoiler and checked for "runout".
I hope this helps.
Bobby
Re: Cutting depth problems
Great discussion. I agree with Bobby (for what it's worth) - this almost certainly an issue of being square to the table. I've only been using the Pro Plus for a few weeks, and am still thinking about my first serious attempt at addressing this. However, in my case the table is not square across the worksurface and this does result in the kind of variance you are reporting. I've also read other posts where folks who have addressed this successfully have a very tight tolerance across the work surface.
Re: Cutting depth problems
Hello Gentlemen,
My name is Loren, I am new to this form, but not to CNC routing, been doing it for 30 ++ years. Are you using Mach3 software for your control? You may need to check your
lead screw settings for your Z axis. Here are my suggestions for an accurate "z".
1. Always face off the scarf table with the largest flat endmill that you can put in your collet. Raster the cut the longest way. Use a skin cut .010 to -030 in. if surface doesn't cleanup drop your z another .010 and run the program again until table is clean. I use 1/2 or 3/4 birch plywood for my scarf board because it is stable.
2. Always keep your bits as far into the collet as possible and keep them tight. A loose bit will usually pull out from the spiral forces if it is an upcut or may push further in
if you are doing a lot of plunge cuts. either way your z accuracy is gone and you may have a dangerous crash or broken bit flying in you face. (keep those safety glasses on!)
3. Watch that your feed rates are not too slow in z you may be loosing steps on the motors.
4. you can check the flatness of your table with an indicator attached to the spindle. Use an accurate standard to check your travel like a 1-2-3 block or a jo block.
5. Set your z on the top of your material. Use at least .100 for your "safe plane"
My name is Loren, I am new to this form, but not to CNC routing, been doing it for 30 ++ years. Are you using Mach3 software for your control? You may need to check your
lead screw settings for your Z axis. Here are my suggestions for an accurate "z".
1. Always face off the scarf table with the largest flat endmill that you can put in your collet. Raster the cut the longest way. Use a skin cut .010 to -030 in. if surface doesn't cleanup drop your z another .010 and run the program again until table is clean. I use 1/2 or 3/4 birch plywood for my scarf board because it is stable.
2. Always keep your bits as far into the collet as possible and keep them tight. A loose bit will usually pull out from the spiral forces if it is an upcut or may push further in
if you are doing a lot of plunge cuts. either way your z accuracy is gone and you may have a dangerous crash or broken bit flying in you face. (keep those safety glasses on!)
3. Watch that your feed rates are not too slow in z you may be loosing steps on the motors.
4. you can check the flatness of your table with an indicator attached to the spindle. Use an accurate standard to check your travel like a 1-2-3 block or a jo block.
5. Set your z on the top of your material. Use at least .100 for your "safe plane"
Re: Cutting depth problems
Guys, I can appreciate the importance of a totally flat work surface. However, this issue is clearly not caused by an out of square work surface. I am talking about cutting a circular pocketing toolpath that is 1.5" in diameter with a cut width of .3". I can start the cut 1 inch from where I set XYZ zero and the depth is off by more than .25". Consider how much of an angle the work surface/material would be on to get that kind of variance over less than 3". I repeat: I am specifying a cut depth of .2" and getting an actual cut depth of .5". Actually, that was yesterday. Today the .2" cut was ONLY cutting an actual depth of .273". Still, a huge and unacceptable difference when precision is needed. To get my cut of .2" today, I had to specify a cut depth of .122". And, tomorrow, using the same toolpath, maybe I will have to make another adjustment to get a cut of .2". Obviously something is wrong with either me, the software or the machine/controller. Someone with, I suppose, more experience than me ruled out the VCarve software and my settings as the problem.
I really do appreciate all the responses and welcome any other thoughts about what could be causing this problem.
Larry
I really do appreciate all the responses and welcome any other thoughts about what could be causing this problem.
Larry
Re: Cutting depth problems
Loren, you quickly made it to my "like" list!!beglylw wrote:I am new to this form, but not to CNC routing, been doing it for 30 ++ years. Are you using Mach3 software for your control? You may need to check your
lead screw settings for your Z axis.
Most of us are using the included Shark Basic Control Panel with Vectric software. I considered trying Mach3 but I am already brain fried with learning all that I have over the last few months. I may try it later when I graduate out of novice school.
For my slats (scarf board) I was going to use beech but I didn't get it in time. The humidity in my area is often all over the place so I will machining the slats frequently.
I appreciate the helpful pointers!
Bobby
Re: Cutting depth problems
Loren,
I am not using Mach3. I would like to, but I am still not certain what I would need to use it with the CNC Shark Pro Plus, using USB. I am investigating!
Thanks for the the other points and advice in your post.
Larry
I am not using Mach3. I would like to, but I am still not certain what I would need to use it with the CNC Shark Pro Plus, using USB. I am investigating!
Thanks for the the other points and advice in your post.
Larry