[QSPSB]

Guys as usual i have another question... The thing is I'm finally starting to learn a little more about SheetCAM... Thanks to you al,l and Bubba Has been a great help!! I need to know how you guys determine the proper tool size per application and the proper feed/plunge rate? The thing is when i seupt the program for a bracket, no holes.. The program filled in all them fields all by it's self... Is this correct.. Or did it just load the same setting that was loaded in the prior program.. It just don't sound right to me.. If the software can set all the tool setting by it's self then it could surely cut a part with various holes in it from a single layer as well...

Is there a link with all the tool diameters and rates by chance?

Thanks
Stoney

[Bubba]

Stoney,
That would be the Holy Grail for us nebies! As far as size of tools go, that is easy; look at your favorite supplier to see what is available.

Proper size. Well, generally speaking, the bigger the stiffer and less distortion. But remember, you have to anchor the stock and that means some sort of clamping. You have have a tool that has to be able to negotiate the space available. Also, for a given material the smaller the tool, the faster the rpm has to be. As for feeds, speeds, plunge rates, there are all kinds of tables, programs, theory etc that will give you "suggested" data for a given material. However this needs to be modified for YOUR particular machine. It has taken me about 8 years to come "close" to what I think My machine and setups can handle. Also, for Aluminum, I rarely use anything but 2 flute endmills so I can have chip clearance. (OK guys, flame on:}). Also it also depends on coolant (a must for machining aluminum to minimize chip welding onto the cutter etc.)

As for toolsize, over the years, I have built up a set of tools that I use generally. I maintain two different toolsets in SheetCam. One for Aluminum and one for Steel. Each has the parameters encoded that I use.

Again in Sheetcam, if you have various holes and are going to drill them, by default the drills in the toolset will work with holes of +/-10% diameter. So yes, lets say you have some 1/4" holes and some 1/2" holes on the same layer, then the 1/4 drill will drill only the 1/4" holes etc. Now lets say you want to centerdrill ALL the holes on that layer. Set the max hole size >1/2" and now it will do all of them!

Hope this helps!

[yantra3d]

I would highly recommend getting a copy of the Machinery's Handbook if you don't already have one. they print a new version every year and they are probably at the 29th version by now (haven't checked lately). It's an invaluable source of information (most of which is not available online) and it has all the charts and calculations you will ever need to do anything you will ever want to make!

Having said that, just get your hands on a good CAM program and let it tell you which tool to use and what speed/feed rate to use. For your X2 you will have to scale this back proportionaly based on the limitations of your spindle speed and the rigidity of your machine.

You should be able to set the CAM prgrm up (post processor) so that it knows what you rmax spindle speed is. You can also set the max feed rate you want to work with as well. Then let it do the math for you. For my X3 I now have a 5000RPM spindle so I set the max speed to that in the post processor and then I generally cut the recommended feedrate by 50% to begin with. If it's too much for my machine to handle then I back it down in my controller software (currently using KmotionCNC) using the feedrate override option by just pulling it back in real time. I also do the inverse where I can increase the feedrate by up to 200% if it seems to be handling the initial 50% feedrate.

Also, for tool sizing you can swap the tools out in the CAM prgrm and re-calculate the tool path based on the new tool - if you don't have or agree with the tool size it recommends to you by default. I do this constantly because I am always short on tools!

This is definitely the easiest way to get your feet wet and avoid any major crashes which can be very expensive lessons to learn. It gets you in the general ballpark by giving you a good reference or starting point to work from.

[QSPSB]

Thanks for the replies guys.. I'm starting to figure out this sheetcam software.. And the tool diameters.. Thanks again bubba.. And everyone else here that's helped me out... I finally got the dxf's down as well as the tool diameters.. I'm sure there will be many more steps to learning this sheetcam.. Not mention the mach3 program... Can't wait to get going on the mach3 program.. Yikes!!!

bubba has helped me a ton on learning this sheetcam program and i I'm finally starting to understand the fundamentals of it..

Here are a few shots of the tooling section i got done.. as well as the dxf i did.. It's nothing to complicated... just a simple box.. I'm going to attempt to design one the brackets with all the holes in it next... That should be fun!!

I forgot to save the tooling section the first time around and had to redo the list.. it's now in order 0 through 20... I'm going to get all the various drill bits and other cutters on the soon

Thanks
Stoney

[yantra3d]

Something that I failed to mention in my last post is that there should also be a "stepover" rate factor that you can adjust in your cam program that will allow you to set the depth of each cutting pass (D.O.C.). I typically set this to 50% or even 33.3% of the full depth for use on my X3. The full depth is just too much for this size mill to handle (depending on tool size, etc..).

As a frame of reference, I am generally able to run the toolpaths at about 50% of the recommended feed and d.o.c. rate based on the 5000RPM max limit speed setting with my X3. However, this is only after I swapped the stock spindle motor with a 1 3/4HP AC servo and more powerful industry-standard dc servos driving the axis'. The problem I am now facing is the rigidity of the machine itself. I think I am going to add a brace plate to the bottom third of the rear column like you were planning to do. I think that will help some.

[QSPSB]

Yeah Bubba mentioned this as well.. He has been helping me out via email and I'm finally starting to pick up on all the CNC stuff... I'm sure i have many more bridges to cross before i can actually have enough confidence in myself to actually put together a program on my own.. Well i kinda am now,, I'm doing all the work and i send bubba the pics and dxf files to look at... i think i have the bracket dxf fill correct, other than perhaps change the table/drawing dimensions a tad..Once i get this all up to par I'm going to attempt to set all the tools up for this program and load the G-code.. This sure has been a blast learning all this stuff.. I do believe this route will be much more easier in the long run as compared to a DRO system. Not to mention more precise!


Yeah when i get around to bracing my mill I'm going to have two 3/4'' aluminum plates nuder the mill. I'm going to drill four holes in the top plate to attach the column to. Then I'm going to attach a webbed angle plate to the upright column brace.. I may even go to the extreme and box the column brace.. It would kinda look like an X3 column then... But that all depends on if the head flexes to much... I don't know the proper word for this.. you get my drift..LOL


Anyhow.. Here are a few recent shots of the Rearend housing bracket.

Thank for the help guys
Stoney