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Guys,
Below is a feeds and speeds calculator I've developed over the last few evenings, aimed specifically at more "hobby" users who want good starting parameters, without a lot of work. Seems like hardly a day goes by that this topic comes doesn't come up in this forum, so it should be of value to many here.
This is the very first release, so it's a bit rough yet, but seems to work well, and I believe it is FAR better than the many other freeware calculators I've seen. AFAIK, it's the only "freeware" app that correctly scales calculations for both width and depth of cut, taking into account chip thinning. It's nowhere near as comprehensive as commercial calculators, most particularly G-Wizard, but I think it does what most of us really need for our day-to-day work, and it's very easy to use.
This is the next step in my roughly 5+ year journey to understand, and automate, optimized feed and speed calculations. I started with a crude spreadsheet, which grew into very complex spreadsheet, then a large command-line Perl program to generate SheetCAM .tools files for all my tools, and now this.
I think operation should be pretty straight-forward, but if you have any questions, just ask. The calculations are based on my years of studying the many factors involved, plus a huge amount of experimentation over the years. I believe it is all working well, and generating pretty reasonable numbers. The numbers for carbide tooling are, at present, a bit optimistic at times, so be more careful with those. The HSS numbers seem pretty much spot-on to me, and are very much in line with the parameters I've been operating with for several years.
Over the next few weeks, I plan to add:
* Many more tool and work materials
* Drilling feeds and speeds
* Possibly tool flex calculation, so you can know when you're pushing your luck
* User configuration and persistence - All internal correction tables, tool data, material data, and machine parameters will be saved to an XML file, so they can be easily modified, and saved. This will make it easy to optimize operation to suit your particular machine and tooling.
* Stand-alone operation, so the calculation can be included into a G-code Post, so tool parameters can be calculated when the G-code is generated, based on specified cut parameters, rather than having to be explicitly specified. At least one of the most popular low-cost CAM programs will support this capability in an upcoming release. This, in fact, is my whole motivation for creating this app.
I also plan to do an interactive G-code editor, that will allow you to click on a specific toolpath (or toolpaths) within a G-code program, and modify the feed/speed for those paths. This will allow, for example, setting a high feedrate for pocketing operations, but slowing down for the initial slotting cuts. This can significantly reduce machining time, since you are otherwise forced to run at the slower rates for the entire pocketing operation.
Give it a try if you're feeling lucky! :-) Installation is simple - just open the ZIP file and run Setup.exe. If you don't like it, you can easily un-install it with ControlPanel->Add/Remove Programs. It does not mess up your system configuration in any way, so it's a very small, simple and "clean" installation.
I suggest comparing the values the app generates with what you're currently running, then give the calculated values a try. Start out by de-rating the feedrates by perhaps 20%, then gradually work your way up, and see how it goes. I think in most cases, you'll find the calculated values are pretty close to optimal, assuming you don't run into machine limitations (particularly lack of rigidity). Remember that when things are "right", you should get smooth, quiet operation, and the chips should be coming off HOT, while the tool should remain cool. Shaking, squealing, poor surface finish, and hot tools are all sure signs you're operation outside the ideal parameters.
Regards,
Ray L.
Ah! I meant to explain, the "Nominal Chipload" parameter is the chipload corresponding to a 1" diameter endmill. For all other tool diameters, this value is scaled to calculate the appropriate chipload for each unique tool. In most cases, the default 0.010"/in value should be near ideal. If you find the calculated feedrates consistently too fast, or too slow, for your machine, then modify this value accordingly, and the feedrates will be scaled more-or-less proportionally.
Regards,
Ray L.
Cool. Downloaded to try a little later. Thanks Himy!
Awesome Ray! Thanks for putting this online, it looks really useful.
Cheers,
Ian
It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!
This is great. Thank you. Any chance for other materials in the future? I use a lot of titanium - CP all the way through Grade 5. I have always just winged it, but to know what the speeds and feeds should be to optimize tool wear would be something worth paying for, for sure. Maybe you could make a product out of that concept? The basic program is free, but enhanced features cost $$.
I'm not really interested in making this a commercial product - far too many other things on my plate. And, Bob Warfield has already covered that base pretty well with G-Wizard. I just thought G-Wizard was a bit pricey for hobby use (and I personally HATE the fact that it NEEDS a network connection, and seems to want to update something every time you run it), and I was doing this for my own needs anyway, so figured I'd toss it out there as a freebie.Originally Posted by Winnfield
Yes, you will be able to easily add other work materials, and tool materials, once I implement the XML configuration feature. I plan on adding quite a few additional ones - mostly just a matter of digging up sources for good numbers.
I have no idea how to optimize for tool wear.... Got any references?
Regards,
Ray L.
Yeah - those were my thoughts exactly on G-wizard. The network connection kills it for me since I have machines scattered over 3 places, some with no internet at all.
I have no references whatsoever, I have simply been replacing tools after a certain amount of time, and make adjustments on the fly, depending on what I see at specific intervals.
In any case, it's a great little tool, and it's much appreciated.
I should point out, that right now, the User Input Values are not completely editable. If you click, or double-click on one of them, you must type in a complete new value. You can't use backspace, or just edit one digit. That will be fixed in the next release.
Also, one user reported that the labels to the left of the data entry boxes were over-writing the data entry boxes. Is anyone else seeing that?
Regards,
Ray L.
Here's a new version that fixes editing of input values...
Regards,
Ray L.
Is the addition of metric a possibility Ray?
I haven't seen the overwriting issue, but the editing of fields took a moment to get used to.
But as others have said, fantastic utility mate! Finally a CNC app I can understand!
cheers,
Ian
It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!
Ian,Is the addition of metric a possibility Ray?
I haven't seen the overwriting issue, but the editing of fields took a moment to get used to.
But as others have said, fantastic utility mate! Finally a CNC app I can understand!
cheers,
Ian
Metric is pretty trivial. I'll add that when I get a chance.
Regards,
Ray L.
Ian,Is the addition of metric a possibility Ray?
I haven't seen the overwriting issue, but the editing of fields took a moment to get used to.
But as others have said, fantastic utility mate! Finally a CNC app I can understand!
cheers,
Ian
I'm curious what "conventional" metric units for some of these factors would be?
I imagine SFPM becomes SMPM (Surface Meters Per Minute).
Feedrate in millimeters/min? or meters/minute?
Chipload in millimeters?
MRR in cu. mm/min?
Regards,
Ray L.
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