Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Chris the Carpenter on March 05, 2012, 07:50:25 PM
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Hello folks,
I am having an issue whilst adding tabs to a job. A "standard" scenario would be simply cutting out say, a 2" circle out of 3/4 MDF. I add the tabs via LazyCam, usually 4 of them at .4" wide and .125" high. With a 1/4" bit, the tabs are left just a bit wider than 1/8" (.15) which seems to be about right. In a "just chunk it out" cut, I would be doing the cut as (3) 1/4" deep passes.
The issue is that, during the first pass at cutting the hole out (first pass, at 1/4" deep) the machine "dives" down to cut the tab. After passing the tab, the bit is raised back to the 1/4" depth and the cut of the circle continues. As the next tab is reached, the cycle repeats. So far, in MDF and with a fairly slow feed rate, the bit and router have handled this sudden 5/8" deep cut. I would like to remedy the issue however.
My machine and build updates can be found here:
https://sites.google.com/a/rocketbrandstudios.com/rocket-brand-studios/cnc-project (https://sites.google.com/a/rocketbrandstudios.com/rocket-brand-studios/cnc-project)
I appreciate, in advance, your time.
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:)
Check the "Plunge Speed" for your selected tool.
Adjust if necessary.
Russ
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Alas, it is not the speed at which the "dive" happens that is the problem. It is the fact that the machine is not waiting until it gets down to the level of the tabs before milling them. The tabs should be milled during the last pass of the cut --During the pass that, when finished, will release the part from the stock.
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Oh, I see.
So, do you have the "Max Cut p/pass" set correctly ?
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The issue is that, during the first pass at cutting the hole out (first pass, at 1/4" deep) the machine "dives" down to cut the tab. After passing the tab, the bit is raised back to the 1/4" depth and the cut of the circle continues.
This is a bit confusing as the TAB process actually LEAVES the tab, doesn't CUT the tab.
You should get 3 passes similar to the attached pic.
Russ
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Yes, the tab is indeed being left, but the material above it must be removed. The issue is that this material (all of it, down to the top of the tab) is being removed during the first pass resulting in the "dive". Enclosed is the tool path that will explain a lot, I think.
--I am just getting used to the in's and out's of this forum. The photo is hopefully attached properly, if not a direct link appears below.
https://picasaweb.google.com/101426164395172997809/March52012#5716604927190850690
(https://picasaweb.google.com/101426164395172997809/March52012#5716604927190850690)
(https://picasaweb.google.com/101426164395172997809/March52012#5716604927190850690)
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Hmmm .. that is weird. LCam might not be to blame for that, never saw that before, could be something in the DXF ? ? Care to post it ? Is it ACad VersionR12 ?
Did you CLEAN and Optimize the dxf after loading it ?
To attach files, use the REPLY button, not Quick reply.
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Gotta be coming from LazyCam. The original DXF is via InkScape and is designed as if it were 2D --Like you were going to run it through a laser cutter. All depths, pockets (if there were any), passes and tabs are all done in Lazy. I can post the DXF if you like, but there is nothing special there at all. I can draw a square with a circle in the middle and replicate this issue each time. Oh, and yes, the bit information is spot-on --Depth per pass, feed rate etc. all are correct during the normal milling process. This "dive" is at a depth greater than the "max cut" I have set for the bit.
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Oh, and yes --I do a clean right after the DXF import.
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Lazy Cam can be a real pita at times. I'm getting mixed results with a few simple files here now too. I agree, probably not your drawing.
After multiple attempts at various functions LC has been known to continiously get more and more out of whack.
Many have given up on it. I still love the challenge but it often beats me. RICH is expert at it, I hope he can help you.
He should be along. There is a good manual but doesnt go too deep into tabbing (like your bit does lol).
You might just try shutting down and restarting...for the heck of it.
Other than that, I wish you the best of luck , and will watch this post for the solution.
Wish I could help,
Russ
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Sir,
You are a gentleman and a scholar, I thank you. I appreciate your help thus far and will wait patiently to see if your buddy can turn anything up. --And yes, I have found that LC DOES do some funky stuff from time to time. --I guess I am getting used to it. :)
Thanks again,
Chris
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ha ... you're too kind.
Here is a tab manual. I think our problem is beyond a manual though.
http://www.machsupport.com/forum/index.php/topic,12078.msg107109.html#msg107109
Good luck Chris,
Russ
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Chris,
Your pic was very small, so I enlarged it for better viewing.
Russ
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Haven't read all of this. I did a tutorial on tabing and thought it was posted in the Lazycam Thread.
I will say this about tabbing, whatever I was able to hack at and find out, is in the manual.
Some times LC for whatever reason just gets wierd and best thing to do is just save whatever as a Lcam and as Russ said shut it down and restart.
Maybe will have some time tomorrow and read what your up to.......
Right now fixing the wifes pc that got a virus and wipped it bad......only 55 more windows updates to be installed and then all the other stuff to fix ...PITA...
and fortunately had a 2 year old image made of it so i didn't loose the operating system.....
Two hours and on page 85 of the stupid manual found how to turn the bluetooth on,
hey :)hey :) manuals suck sometimes........ ;D ::)
RICH
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Thanks Rich,
I gotta tell ya, I am a bit of a "RTFM snob" myself and it drives me nuts when someone asks a question that is easily found or googleable. I think I did my homework in the google category and I studied all the manual had to tell me, but I gotta tell you, I had the darn'dest time trying to do any searching here. The search engine for this forum seems to be as tricky as LazyCam --depending on my search terms, I got either A)nothing or B) a fire hose of a stuff that didn't pertain to this issue. I suppose it does not help that the particular word I am working with is "tab" --I can tell you how to toggle the jog window on and off, though! :)
At any rate, I would love to take a look at your tutorial. --And I appreciate, in advance, any other thoughts you may have on the subject.
As for the strip/reload you got going on there... I wish you the best of luck, no, best of patience on that one. I personally strip my machines down to a bare drive with just the system about once a year. It is amazing how much there is to put back on. It is also amazing how many weeks go by of you noticing you still have something else to re-install. I don't envy you and I am thinking happy thoughts.
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Chris,
I posted the link to the manual a couple of posts back.
There's mor in the Members Docs near the bottom end of the forum home page.
I've gotten tabs to work here 10 times in a row. (afraid to try 11)
Here's a quick rundown:
Select the profile to offset
Select the tool from the offsets tab and create the offset
Remove the original vectors (Rem. Objects)
In the Project tree, click the Offset layer
The Layer tab will open. Tool info should be there complete. Set Rapid H, Cut start, Cut depth then click Set Layer
Click Chains tab, Set Length, thknss, # of tabs, OK
POST
Works here everytime now.
Cheers,
Russ
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Well, this is a little bitter-sweet. Your system worked... ...but I don't know why...
It is looking like this is an issue with "order of operations" when changing things in LazyCam. Alas, after doing it your way (step-by-step) I can't seem to remember how I had been doing it in the past. As a matter of fact, now I can't seem to replicate what I did in the first place nor can I seem to replicate the results (the incorrect results, the "dive"). I suppose that is a good thing and I should not look a gift horse in the mouth, but man --It is always nice when you have problems like this to be able to "toggle" between the wrong way and the right way to confirm and/or pinpoint the exact issue. I just can't seem to do this.
To cut to the chase, it does seem that something somewhere needs to be done in a specific order. Your system does this. I think I will go with it. :)
Once again, I appreciate the hell outta your help here. Thank you. I am going to spend the afternoon with some scrap MDF and see if I can isolate this guy a bit more. I will post anything I find here --I'm sure I am not the only one that has run into this.
-Chris
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Hi Chris,
Glad it's working better for ya.
Wish we could explain why.
There are bugs inside with minds of their own.
Be as kind as possible to them and they might cooperate.
It would take more internal work to kill them but being stuck in BETA, it's as good as it's going to get.
Luck be with you ... use the "Force".
"Endeavour to persevere".
Cheers,
Russ