MA Burly

Mostly Printed CNC - MPCNC Your Builds
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(Somewhat of a continuation of this post)

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Built this around a month ago, probably right before the primo came out, and I didn’t know about these forums. I’m using 23.5mm tubing and have an actual work area of about 23"x23". I’m currently using a DW660 but plan to upgrade. I worked my way up cutting mdf to wood to aluminium. I used the mill to make a cool cutting board for a family member.

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Last night I tried aluminium. I was using the settings in the description of this video, with the same 1/8" single flute endmill. It had horrible chatter and I was only able to get acceptable chatter with the speed at 25%, but still not very good. I was not using trochoidal milling though. I’m also using 6061-T6, a harder alloy, don’t know how much harder though.

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Chatter so bad it looks like someone took a bite out of it.
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These are opposite sides, the one with an obviously worse surface finish was conventional milling and the cleaner one was climb milling. If I change it so that it climb mills all the way it might work better but would have an interrupted cut and would have to enter the material again.
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For a first try, not horrible.
My dad (I’m 14) brought home a 1/8" 4 flute endmill today. He works in a machine and assembly shop, so it was just an old one. I understand how unadvised a 4 flute endmill in aluminium at 30,000 rpm is, but I wanted to just see what would happen. I was not putting myself in any danger, I have an enclosure around my mill and wear a face shield, kinda like the covid ones but thicker.
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No surprises here, the flutes are packed and the aluminium is probably welded to the endmill, I can try and get it out tomorrow or something but probably not likely. Plus, kinda cool.

As mentioned in the post linked above, I am converting my mpcnc to use leadscrews, spare from my dads work. I made these nuts on the mill, then tapped them with a leadscrew I ground a flute in with my dremel and a cut off wheel.

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Measuring plastic with plastic calipers means you can squeeze till you see what you want.
I made these also that will hold the nuts.
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I’m making the rest of the parts once I get new filament.

Future Upgrades:
Leadscrews
Primo core, all the leadscrew parts fit on the burly frame parts, but one on the core so why not
This spindle w/ speed control. I have more details in the thread linked above, if you would check that out it would be greatly appreciated, there are some question there unanswered, if you knew anything that would be great.
Maybe GRBL

Like I said, I’m 14 so I don’t have a ton of money, I started going to work with my dad and doing assembly work to earn more. The MPCNC is something I saved up for and built all on my own. It’s a great machine. I had a little previous experience in cnc machining as I was previously interested in it a few years ago and did some of the Titans of CNC stuff but never had the means to build or acquire my own. Both this forum and the instructions written by Ryan, which is also my name, have been extremely helpful. Thank you all.

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Nice work! Learning all of this now you serve you for a lifetime, and possibly a career in manufacturing…keep it up!

I tried a 4 flute as well, with similar results. To clean the tool go get some lye (sodium hydroxide) based drain cleaner, and soak the tool in it for an hour or so. Rinse it really well. It will eat all of the aluminum but leave the base metal alone. Do this outside, use only as much lye as you need in a small container (I found a baby food jar was perfect), and be wary of splashing. Gloves and goggles are a good idea.

Good luck!

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Seems like a good idea, but this four flute was just an old one, it cut aluminium really well, but without flood coolant it’s kind of useless to me. I’ll probably get some 2 flutes to try and maybe a 3 flute.

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Do yourself a favor and get single flutes for metal. I tried 2 flutes and I still got alot of reweld.

2 flutes are great for wood.

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I tried a single flute and had a lot of chatter. I think with two flute I would have more cutting capacity therefore less chatter. Though if you are getting friction welding I’ll take caution. Just want to do trial and error, see what happens.

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Chatter usually has to do with rigidity and forces. Try taking a lighter cut.

A two flute has more cutting capacity, but you would have to run the feed faster to take advantage of it and keep the heat down. Because rigidity is not the MPCNC’s strong suit (as say, compared to a big steel milling machine), you have to take lighter cuts at lower speeds, which lend better to fewer flutes.

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I might be wrong here but with the same chip load and a faster feed rate wouldn’t I have the same amount of chatter? Meaning I can run a two flute at a faster feed rate as long as the chip load remains the same?

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sort of. As I understand chip load only describes the thickness of the chip, but ignores the length. You can have the same chip load on a .25" depth of cut and a .025" depth of cut, but much more force would be required to take the deeper cut. The deeper cut may chatter where the shallow would not, all with the same feed, speed, tool, chip load, etc.

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I’ll try it. Like I said, I’m just interested in trial and error right now and seeing what works best.

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Slick looking build…and awesome name!

Well you clearly have a handle on your settings because you actually got some half decent aluminum cuts. I would suggest doing a few plastic cuts to get some more “experience”. Wood is easy, so you can learn a lot by pushing the limits of your build in wood. Then move on to some plastic. It is more about time at the machine and getting a sense of what is a good cut and what is a really good cut. Metal is tricky sometimes you need a bigger bite, sometimes you don’t. Then you have to decide do I do that by moving faster, or deeper? Metal is just so unforgiving to an endmill it is expensive to learn on.

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It is pretty expensive to learn on. I think I’m pretty lucky, for my birthday I was given a bunch of aluminium 1/8" sheet. Definitely will try more plastic, with a full 1/2 depth of cut in HDPE and a two flute 1/8" endmill I was easily cutting at 600mm/min. Thanks Ryan! I bought one of your hats to, the kinda khaki colored ones, it’s super nice.

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Nice, I just got a new batch of hats and I got the khaki one because I saw your order come through! My box got lost so I waited weeks and they finally resent it.

HDPE is the best stuff to machine, and pretty easy to clean up. Love working with it. I should get some thicker stock so I can do some carving or maybe a mold I have been wanting to make.

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I think on the Mpcnc hdpe is probably the way to go for any load bearing functional part not viable for cutting out of a sheet. With aluminium it would take forever to move enough material out of bar stock to have something functional, and wood can’t be held to the same constraints both dimensionally and load wise. Won’t stop me from trying aluminium though. Do you know of any other material that you would deem better?

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What were your speeds and feeds for aluminum? I used a 1/4 inch carbide 4 tooth with not 0 chatter or gumming up.

Also, aluminum has a relatively low melting point. When it gets hot, it gets “gummy”. Then as it cools it hardens. This is why it’s collecting and welding to your bits. As your milling aluminum, you want to keep it cool. Two ways of keeping it cool: creating chips and wd-40.

Chip creation is automatic, but you also don’t want them to collect. When they collect they can re weld themselves to your metal and make the tool jump around. Use a vacuum.

Wd-40 lubricates the part reducing the heat generation. When you spray it, it also can clear out chips.

I recommend the can with the flexible nozzle hose.

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Also, what is your depth of cut? You might be taking too much at once if you’re getting chattering.

For really thin parts of aluminum, you need lots of downward clamping pressure to prevent it from moving around, another reason for chattering. You don’t want sideways pressure.

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I was originally using a 3.5mm/s feedrate and a 1mm doc and I was getting a lot of chattering. I slowed it down to 1mm/s and got a little but of chatter. Where you running the 1/4in bit in the 660? What feed rate and DOC, I’ve wanted to try a 1/4in bit but I didn’t think you would be able to at 30000rpm.

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I bought a speed controller. 30000 is too fast for most of the stuff I make.
I got the MLCS 9400 from Amazon. It allows you to dial your speed down. You can then either get a cheap tachometer to measure your speeds or just practice.

Tone the speeds down with a 1/4 inch. You can take a 1mm with that, that’s a bit much for a 1/8

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Doesn’t look like it’s on Amazon anymore. https://www.mlcswoodworking.com/shopsite_sc/store/html/9400.html

Or any router speed control 15Amps

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4000W High Power SCR Electronic Volt Regulator Speed Controller Motor AC 220V 110V

On amzon couldn’t get the link but that is the description of what I use

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In the thread linked at the top I somewhat detailed how I will set up gcode speed control for a 600W chinese spindle.