New user, first project, Seeking advice

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New user, first project, Seeking advice

Postby grifftek » Tue Sep 09, 2008 6:36 am

Hi

My Name is Bill Griffin, I have been machining mostly 2 1/2 axis parts with an occasional surface thrown in once or twice a year. I have a project which has some simple 2 1/2 axis work, but the whole outside is a 3d surface. I have been playing with MC for a short time (installed it last night) and have a basic understanding of how it works. The block I want to mache the part from is only about .050 bigger in x and y and slightly more in z with the part flat against the bottom of the stock. (stock 3 x 3.8 x 1.5) It appears that I have to lie to the program and tell it my stock is larger than it is to get the cutter to machine completely around the part. I will screw the part down to a fixture block for machining so I can cut around the oerimiter without clamps etc in the way. I have uploaded all the files to www.grifftek.com/meshcam/tip if anyone would like to take a look and give me some advise, It would be most appreciated. tip.stl is the best stl to look at. You can also check out the NC files I have created and see if im on the right track. I had manually edited the tip2.nc file to add a finer finishing pass but I seem to have overwritten it.

If I can help anyone with what I have experience with I am more than happy to try and help. I have experience with building machines, retrofitting machines, 2 1/2 axis macining, etc. If anyone is interested to see what I do you can check it out at www.grifftek.com/grifftek

Regards

Bill Griffin
grifftek @ grifftek . com
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Re: New user, first project, Seeking advice

Postby Randy » Tue Sep 09, 2008 5:25 pm

Bill, your files look fine. Are you sure you've only been using MC for one day? :D I'm jealous too-80ipm cutting speed. My machine will only rapid at 65... What material are you cutting for this part?

I see you are using Solidworks. You can save yourself some work when importing your STL's into MC by defining a coordinate system with the axes the right way around (Insert / Reference Geometry / Coordinate System) and then use that coordinate system when generating the STL. That will save you rotating and translating the STL in MC.

The other suggestion I'd have would be to increase the roughing toolpath quality. That will smooth out the "jaggies" in the roughing path and make for smoother cutting.

Are you planning to try both the parallel and mixed waterline machining on two workpieces? I have tried several different strategies, and on my work I tend to do X-Y finishing. Robert has been working on the waterline though, and I will need to try it out again.

Best regards,

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
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Re: New user, first project, Seeking advice

Postby jeffD » Tue Sep 09, 2008 5:56 pm

Bill,

I didn't delve into your nearly as deeply as Randy but if he says they are OK you should be fine.
Regarding the question of lies to MC... my standard operating procedure. MC will catch most impossible situations but not all, you just have to be aware of what you are doing and why. Computers are really dumb and will tend to do as instructed not as you intended :-)

Jeff
I have no financial interests in MeshCam. Nothing I say here has had any approval from MC. Any errors or omissions are mine alone. Use at your own risk.
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Re: New user, first project, Seeking advice

Postby grifftek » Wed Sep 10, 2008 1:53 am

Randy

>Bill, your files look fine. Are you sure you've only been using MC for one day?

Only a few hours really, but it was 3am when I finally called it a night!

>I'm jealous too-80ipm cutting speed. My machine will only rapid at 65...

I plan on running this part on my Atrump B5ACW. It seems to cut nicely at that feed rate with 1/2" Carbide 2fl at 1/4" depth of cut and 6K rpm. I’m jealous of those with 10 and 20K spindles and 30 hp!

>What material are you cutting for this part?
6061T6 Alum extruded bar stock

>I see you are using Solidworks. You can save yourself some work when importing your STL's snip

I agree! I didn’t design this file and it was done in a newer version of SW and I couldn’t open it on my home computer as it has not been updated yet. I tried to manipulate this file in surfcam and couldn’t even remember how to rotate it as it’s so user un-friendly!

>The other suggestion I'd have would be to increase the roughing tool path quality. That will smooth out >the "jaggies" in the roughing path and make for smoother cutting.

I was playing with the settings trying to see what effect they had on the tool path and just had not reset that one. It would be nice if there was some tool path filtering that would fit arcs to all the little line segments. I have not looked at the code all that well, but along the same lines if the cutter is moving in a straight line, don’t output it as a series of short moves, this would reduce file size and make it easier on some machines.

>Are you planning to try both the parallel and mixed waterline machining on two work pieces?

Again I was playing with the various settings to see what they did. The guy who wants this part would prefer that I don’t spend a lot of time trying to get the part really smooth. The sample part has a "texture" to it from the stepover, I will play with various settings to try and get a balance between machining time vs. smoothness.

I was thinking that I would use the xy finish with a very course stepover to quickly knock the roughing steps down and then do a finish pass along x to get the effect I want. I would just create 2 programs and edit them together.

Jeff

> Regarding the question of lies to MC... my standard operating procedure.

When trying to cut the part out of a block, you wand the block to be as small as possible. It would be nice if MC didn’t use the stock as a boundary to keep the tool within. I was hoping someone would say that I was supposed to check or un check some dialog box to get it to do this. If I don’t lie and make the stock bigger, it doesn’t machine all areas of the part. When Finishing, I should just be able to pick the surface to machine and it should cut it if there isn’t any check surface or other containment. Again I’m hoping there is a setting I don’t know about.

I don’t want anyone to think that I am being overly critical or anything. I think the software is truly amazing at this price point and it is very easy to use. The programmer must be very talented!

Thanks
Bill Griffin

www.grifftek.com/grifftek
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Re: New user, first project, Seeking advice

Postby jeffD » Wed Sep 10, 2008 2:34 am

Bill,

I tend to just use a larger hammer :-)
For 3 axis work bounding box of model + a little more than than any tool diameter in X and Y is good for stock size.

It is amazing software but you still have to think like it does and understand how it works. Robert is damned good but can't be expected to anticipate all of the twisted ways some users think. (and I'm one of the major twisted abusers :-) )
No magic check boxes I've found yet to solve all problems. Although it would be really nice as a cure for idiot operator errors.

Jeff
I have no financial interests in MeshCam. Nothing I say here has had any approval from MC. Any errors or omissions are mine alone. Use at your own risk.
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Re: New user, first project, Seeking advice

Postby grifftek » Wed Sep 10, 2008 4:54 am

>For 3 axis work bounding box of model + a little more than than any tool diameter in X and Y is good for >stock size.

That is what I did to make it work.

Where do you set the the part zero? I normally make xy zero in the upper left top corner of the stock. In this case, it may be easier to set the zero to the center of the part / stock. Any way, I guess you still have to do the math to make it work whatever way you do it.

If any one else has any sugestions on how you do it Id like to hear what others are doing.

Bill
www.grifftek.com/grifftek
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Re: New user, first project, Seeking advice

Postby Randy » Wed Sep 10, 2008 5:08 am

Bill, I neglected to say "Welcome"! I know your name from other forums and was negligent here since it was your first posting.

grifftek wrote:When Finishing, I should just be able to pick the surface to machine and it should cut it if there isn’t any check surface or other containment.


Bill, I've requested just that from Robert in the past. If it were technically possible given his algorithms, he would do it. I trust Robert to do all that is possible, and he doesn't disappoint. :D I am extremely thankful that Robert works his magic, and we are not at the mercy of $$$$ M*sterC*m and such software.

I usually set my part zero as necessary to coordinate with SheetCam, which I use for all orthogonal pocketing and outlining (since SC will use arcs!) but for my current job am using top/SW corner because that is convenient, my having meticuously squared and sized my stock...

This is my latest project. It is 3.50" across, and machined with MeshCAM, other than the cavities and perimeter which were done with SheetCam. [Photos moved to the Gallery.]
Not to brag, but to show the capabilities of MC! :D
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
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Re: New user, first project, Seeking advice

Postby grifftek » Wed Sep 10, 2008 5:44 am

That is an impressive looking project. Id love to see more of your work, do you have a web page with pictues?
I wish I got to work on fun projects like that!
I use a program called Geopath for most all of my work, but it is pretty weak for 3d
I also have surfcam at work, but its no very user friendly. I have been planning on taking a class on it but havent made the time.
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Re: New user, first project, Seeking advice

Postby grifftek » Wed Sep 10, 2008 5:59 am

Hi Randy

I found the link to your web site, Very impressive! Im still looking around there!

Thanks
grifftek
 
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Re: New user, first project, Seeking advice

Postby jeffD » Wed Sep 10, 2008 3:10 pm

grifftek wrote:Where do you set the the part zero?


When the actual stock size is larger than what MC needs I'll use top center for zero. No math and minimal thinking involved. For some jobs I'll use top E or SW. It doesn't really matter where you put it just make sure you remember when loading the mill :-)

I always put a comment line in the g-code re where zero is.

Jeff
I have no financial interests in MeshCam. Nothing I say here has had any approval from MC. Any errors or omissions are mine alone. Use at your own risk.
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