Lol that was all pulled completely from my something-something.
Measuring the RPMs is easy… even on the DeWalt 611 - just use a Digital Laser Photo Non Contact Tachometer. You can find them online for about $20.
And “chip load is a pretty inexact science” WTF?
Chip loads seem pretty exact to me… is it just that people can’t do math or measure the RPMs?
I think it has to do with poor RPM confidence with the Dewalt. It has no readout, varies slightly from router to router, and sags during cutting. Still, I agree that at least theoretical chip load should be included in a feeds and speeds spreadsheet.
It is not a problem of measurement. The problem is that even at the lowest setting the Dewalt RPM is too fast to have optimal chip loads at the feedrates the X-carve can achieve.
I’ve definitely experienced this. I looked up chip loads and played around with feedrates/DOC until I was milling HDPE at 0.024"DOC and 124ipm with a 2 flute upcut flat endmill, with the Dewalt set to one. I’m not getting fuzzy cuts any more, but there’s certainly chatter and reduced accuracy flying through that hard of a material at those speeds, even with a stiffened makeslide assembly.
That’s why I have a SuperPID in the mail right now. And some single flutes.
Hey I have a feed / speed spreadsheet too! : https://discuss-assets.s3.amazonaws.com/original/3X/9/8/988930d2ef4c574b732dd258e048fa8cbaac63f7.xls
you can read about it here. Repeatable process for setting Feed Rate and Depth of Cut in Easel and elsewhere
making one of these is starting to feel like a rite of passage,
like breaking in a new glove,
or calculating the trajectory book for your new howitzer…
am I naieve to think someday we may get to a single canonical version of one of these…?
Thanks for your work on this, I use a locally saved copy of this to get in the ballpark every time I get started with a new material
feel free to improve it based on your own experiences, and post it back…
we all learn from each other, and I based what i did on the work of others before me…
Very nice . Let’s try to cover all materials and make it a master sheet . For us beginners . For someone who’s thinking about an XCarve .
pretty sure DOC is meaningless without the end mill diameter specified. Did I miss that in the spreadsheet?
At the bottom it states that everything is based on the assumption of 1/8th inch bits.
So I decided to open the file up to editing. We’ll see how it does.
(Yes… I made a backup.)
That sounds great, NAM. Before everyone can start contributing, I propose that we first decide upon what variables should be included in the spreadsheet?
Here’s all I can think of:
- End Type (Ball / Flat / V)
- Nominal Bit Diameter
- Number of Flutes
- Depth of Cut
- Spindle Model
- Spindle Speed (Estimation for Dewalt based on 16,000 - 23,000. An in-sheet calculator would be nice, we can reference @MalcolmStanley’s calculator here)
- Toolpath Overlap (Optional; this is a variable in more advanced CAM processors. Units? % of tool diameter?)
Some variables that I think would be a good idea to include optionally would be:
- Machine upgrades, such as stiffening
- Machine size, 500 / 1000
- Dust Removal (Yes / No)
- Cooling (Yes / No)
All of those will have an effect on the quality of the other settings, which may cause those settings to be less effective for unupgraded/undustshoed/uncooled setups.
Honestly, I think that’s over complicating it a bit.
This (originally) was supposed to be more of a quick-reference baseline guide. Tweaks will have to get made in any environment, but this was to be a (better?) extrapolation of the default values supplied by Inventables in Easel. Adding to much granular detail is going to make it VERY hard to maintain. That’s why it’s based on 1/8" bits, 40% set over, and a fixed Dewalt setting.
(Obviously… that’s just my opinion.)
Good idea… maybe add a “log” in a separate tab and reserve the main tab for the distilled version.
Whether all of that information is excessive for what the spreadsheet is meant to accomplish, a person will have all of that information when the run a cutting program. So, it’s the difference between taking 15 seconds or 30 seconds to input all of the fields.
I like the idea of having a quick reference and a detail page, though. The sheet could be set up in a way that items entered on one would automatically populate on the other so that a person could look at either page (if they want the quick reference or details page) and see everyone’s input.
On another note, there’s something else I forgot to pitch:
Quality of cut
Settings that someone puts up on the sheet might be “ok,” which I then tweak with identical machine and bit set up until I find a better quality cut settings set. How would this scenario be taken care of? In the next week there’s going to be five different users that mill Acrylic with an 1/8" two flute flat end mill with Dewalt set to 1. Do we have multiple entries for the same setup but different feedrates and DOC, etc.? Or do we discuss the quality of cut for different settings and then decide which will be the current recommendation?
I think what we are doing here is sorely needed,
especially for new users who are just figuring things out.
I strongly suggest we standardize this information for a stock, unimproved, Out Of the Box X-carve,
That way there is guidance on what should work with what everyone starts with.
The idea that we log cuts and quality is good too.
It is a shame we cannot add that information as part of the Easel pre-flight/post-flight so it becomes something that everyone can contribute to as a matter of course, and access as part of the setup…
I wonder if we added that as a feature request if we could get it implemented?
Agreed. This should be a “lowest common denominator” file.
What characteristics, quantitative or qualitative, would you use to judge a cut finish?