While using 1/4 (came with the shapeoko XL) mill to cut, its smoking and I see burn marks on the wood. Does this mean that the bit is dull and need a new one? Also the cut is not clean. When I first used it it would cut really nice and clean with maybe a little for me to clean up but now the cut is leaving so much that i have to use a razor to cut it off before sanding. Any Ideas what could be the issue? Thanks in advance
Yes, if a cut which worked once no longer works then the endmill is dulling.
It might be that you can relegate this to roughing only at a suitable feed and speed rate.
Thank you. Guess I need to order. Which brand would be the best quality in your personal experiences?
Looks like the endmill was overheated — check your feeds and speeds.
I use Carbide 3D tools since I work for the company, but have also had good experience w/ Garr Tools, and Harvey, and
My next order will probably be from the Precise Bits folks:
Carbide3d is competitive and is an exact match for Carbide Create. I also have several Whiteside up and down cut 2 flute spiral bits. I also have some Frued bits as well as some generic bits from Amazon. The Amana bits are supposed to be good but they are quite expensive. Most #201 replacement bits are around the $20.00 range, a little less a little more.
When buying tools always, always, buy the best your budget allows. When you buy cheap tools you are almost always sorry. You will never be sorry for buying quality tools.
@jmcreations05, while you do need a fresh endmill now, you also should try and understand why you burned this one, and it is likely incorrect feeds and speeds, as Will mentioned.
What RPM and feedrate were you using and for which material ? You were very likely using a too low feedrate for the RPM.
Thank you. Is there A chart to where I would be able to reference what speed or feed rate goes to what Endmill? I was trying to search online but unable to find a reference. Im using the router that came with my CNC and I don’t really mess around the numbers or adjust the speed rate or feed rate. Im glad this forum is here because I am still very much learning the ins and out.
That makes a lot of sense. Thank you for your advice and tips
Thank you. Im trying to find references in regards to feed rates with different end mills and different types of woods but im unable to find any online.
The router speed setting should match the feeds and speeds for your selection of endmill and material.
For #201 endmills in a Shapeoko and #102 endmills in a Nomad please see:
(there’s a row matching dial settings to RPMs at the bottom)
There’s an interactive version at: https://public.tableau.com/profile/willadams#!/vizhome/Carbide3DCNCFeedsandSpeeds/Sheet1?publish=yes
Note that the feeds and speeds calculations in Carbide Create were updated for trim routers in 433 and 440 and later use a curated set of feeds and speeds which are stored in CSV files.
See https://www.youtube.com/watch?v=S9bceJxpqG0 for concepts on this and see the series #MaterialMonday: #MaterialMonday on YouTube for specifics.
You should test feeds and speeds in a piece of scrap using the technique at: https://precisebits.com/tutorials/calibrating_feeds_n_speeds.htm
Another consideration is Climb vs. Conventional Milling and tooling engagement — where possible avoid slotting and add geometry and cut as a pocket (Adding geometry to cut as a pocket with a finishing pass ) and consider leaving a roughing clearance and taking a finishing pass.
Extensive discussion at: Origin/consistency of chipload recommendations and https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z/feeds-and-speeds-basics with a spreadsheet for this at: Speeds, Feeds, Power, and Force (SFPF) Calculator
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Feeds and speeds is a topic on its own, so at first the easiest would be to follow the recommendation found in e.g. Carbide Create tool library for similar endmill/material combinations.
Sooner or later you may need to figure out feeds and speeds for a combination that does not exist in CC tool library, and then it helps to know the basics (basically one formula) to compute them. My (long) take on this is here, but I’ll give you the TLDR version:
a) chipload equals Feedrate / (number of flutes x RPM)
b) chipload should be maintained above 0.001" or so for usual endmills
For a given RPM, if you feed to slow, chipload is too low, you will rub and burn
For a given feedrate, if you crank the RPM too high, same result
The combination of RPM and feedrate needs to be “in the sweet spot” (most of the time 0.001" to 0.002" for wood) to get a nice clean cut while not putting too much force on the machine.
Looking at the picture of your bit, looks like sap build up. Do you cut a lot of pine? Clean your bits every so often with bit and blade cleaner or some Simple Green diluted with water to get the tar and sap off.
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I do and regular wood from home depo or lowes
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