Every time I play with one of these calculators I spend most of my time tweaking the radial and axial engagement values. What would be really nice is a plot of feed rate vs. axial engagement for several radial engagements (in percent).
Actually, that is already on my ToDo list - there will be a feature that let's you define a range of radial and axial engagements, and increments for each, it will generate a plot, or at least a data table that can be loaded into a spreadsheet and plotted. Those plots would be handy to have on the shop wall for quick manual and MDI work.Originally Posted by Flenser
Regards,
Ray L.
Here's a new version, with a few minor improvements:
Calculated values are now limited by user-defined Max RPM, Max HP, and Max Feedrate. If any of the values exceed the stated limits, appropriate adjustments are made to bring the final values within limits. And, it highlights the limit that was triggered, so you know what went wrong. If you define your machine correctly, it should rarely, if ever, generate values that don't work. I will likely add the ability to specify a torque-speed curve for the spindle, and thrust limiting with a thrust/speed curve to account for non-linearities.
I decided these changes were necessary today when I was trying to push my machine to the limit, and found it lacking in spindle power at high RPM, costing me two very nice 1/2" 3-flute carbide end mills when the spindle bogged down, due to not having enough torque at 2X base speed. Really makes a mess when the spindle bogs down when doing 1/2" slotting with a 1/4" DOC at 75 IPM....
I've also made the power calculation more conservative, to provide a bit of headroom, and to account for real-world motor efficiency.
BTW - The proper way to use this tool is to enter your values, see what it comes up with, then do some test cuts. I would suggest starting at about 1/2 the specified DOC, and see how it cuts. If all is well, go a bit deeper. Keep going until you start getting nasty noises, poor surface finish, a drop in spindle speed, or some other indication of impending disaster. Use your final values to go back and adjust the limits in the tool, and you should, in fairly short order, come up with limits that will generate good values for your machine almost every time. When I add all the configurability, you should be able to tailor it very closely to your machines capabilities.
Regards,
Ray L.
Ray,
As the saying "Houston, we have a problem"
The link to the file doesn't work!
Art
AKA Country Bubba (Older Than Dirt)
OK, got it now!
Art
AKA Country Bubba (Older Than Dirt)
Sounds really cool Ray! I always just use the "seat-of-the-pants" method. It will be fun to see what your program really does.
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." Antoine de Saint-Exupery (1900 - 1944)
Been working hard the last few days to make some really major improvements to this tool (see screenshot below). I now have the XML reading and writing working, so it completely saves and restores state between sessions. I've also implemented the concepts of "machines", "tools" and "cuts", so you can save and recall all your favorites, and not spend so much time entering numbers into the data entry boxes.
For example, I have a knee mill, and an X2. I can define them as two separate machines, and go back and forth between them with one click. Each machine definition contains all the machine parameters that affect feeds and speeds - max RPM, max power, max feedrate, and a motor torque/power responses curves for the most common spindle drives - DC motors, brushless DC motors, and 3-phase AC motors with VFDs. So the tool can correctly model the way torque and power vary with RPM, to keep you within acceptable limits for whichever machine is selected.
Tools also can be defined and saved. Each tool is defined by its type (endmill, twist drill, etc.), as well as diameter, tool material (HSS, carbide, etc.), and number of flutes.
With each tool, you can define any number of "cuts", defined by the width and depth, as well as the material being cut. I find I typically have 2-4 different types of cuts I will routinely use for each tool. This saves me from having to re-enter the numbers each time. So, for example, my standard roughing cut is a 1/2" wide, 1/2" deep cut in 6061. I can define that and save it as "6061 Roughing".
The tool will allow calculation and output of feeds and speeds for all defined cuts for a given tool, or all tools, with one click.
Now, let's say you have an X2, and you've defined a bunch of tools and cuts. Then you upgrade the spindle with a belt drive, and your top speed is now 4000 RPM, instead of the stock 2500 RPM. Change the max RPM parameter in the X2 machine definition, and in just a few seconds you can have ALL of your feeds and speeds updated with just a few clicks.
You'll also be able to easily generate feed/speed "maps" for each tool, with user-selected increments of depth and width of cut. These can be printed in table format, or plotted, to hang on your shop wall for quick reference when doing manual milling.
I'm also considering adding the ability to both read and write SheetCAM tools files, and creating a SheetCAM plug-in to do on-the-fly feeds/speeds calculation during the POST.
Regards,
Ray L.
Man, this thing is awesome. Already using it all the time now. Thanks again.
Looks nice Ray
Thanks
Seems like it is maturing quickly here. You software guys really know your stuff. I am really liking the sheetcam linking if you get that done. Is there a new download or is it not ready for prime time just yet? Keep up the good work it is much appreciated. Peace
Pete
Pete,
Not ready yet. It'll be a bit, these are major changes.
Regards,
Ray L.
For people new to terminology you might consider changing radial engagement to Width of Cut, and axial to Depth of Cut. Seems like those are the terms people use when talking about them - even you did in your post. And maybe a toggle giving the option to be entered as a percent as many of the CAM systems define them in this way.
This is starting look to great though! Creating tool performance maps will be killer.
PM-45 CNC conversion in-process. Silly engineer wants to be a machinist.
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