Routing Aluminum Plate

[rmwarren]

So here is another classic example of making the thing I need to make the thing I want to make... :

I need to make some Bubinga cabinet pulls to finish our kitchen, about 40 of them, and decided to clamp the material and move the router rather that make a router table. I am space constrained so I don't want to have a router table in the way, and I also want the jigs to use for other stuff. This particular gadget needed two 8" by 2" by 1/4" plates with slots for screws, so I needed a way to fasten the AL plate and then run the router back-and-forth.

I used my first 40MM router guide with the 40MM guide ring. The problem with this guide is that it is rather bulky and fixed at 40MM, I wanted an adjustable version.

This video shows the setup in use (be kind, it is my first attempt at editing a video...).

Routing Aluminum Plate

The end result is this adjustable router jig that I can use for the next round of cutting stuff. I can set the width with calipers and use guide rings or piloted bits.

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Here it is in use, testing my setup to make a 40MM dado:

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Now to figger out how to hold the Bubinga at an angle...  ???

More to follow as this project develops.

RMW

 

[RONWEN]

Nice job! 
Did you try making heavier cuts than .2mm?  That is only .0078" per pass -- I'd be surprised if you couldn't take something more like 1mm per pass with your good setup.  You should get much longer end mill life too.
Nice job on the video.

 

[rmwarren]

Nice job! 
Did you try making heavier cuts than .2mm?  That is only .0078" per pass -- I'd be surprised if you couldn't take something more like 1mm per pass with your good setup.  You should get much longer end mill life too.
Nice job on the video.

Ron,

I was being cautious but I did take a couple cuts at 0.4MM and it seemed to put more strain on the router so I backed off. This was my first attempt at routing aluminum. There was a surprising amount of galling on the edges of the cut, would deeper passes tend to reduce this?

I will give it a try with deeper cuts and report back.

Thanks for the input.

RMW

 

[RONWEN]

Nice job! 
Did you try making heavier cuts than .2mm?  That is only .0078" per pass -- I'd be surprised if you couldn't take something more like 1mm per pass with your good setup.  You should get much longer end mill life too.
Nice job on the video.

Ron,

I was being cautious but I did take a couple cuts at 0.4MM and it seemed to put more strain on the router so I backed off. This was my first attempt at routing aluminum. There was a surprising amount of galling on the edges of the cut, would deeper passes tend to reduce this?

I will give it a try with deeper cuts and report back.

Thanks for the input.

RMW

Yes, there would also be less galling -- right now that .0078 of the tip is doing all of the work.  You don't mention a radius on the end mill but if .2mm is all that the router can handle (I doubt) a nice radius honed on the end mill will reduce the galling, give better cutter life and even a better finish on the aluminum.  If you were to brush on a little light oil or kerosene you would also see improvement.

 

[rmwarren]

Ron I had real issues today.  Tried a deeper cut, little oil and 2 different bits. Can't figure out what I am doing wrong.

Any advise?

Sent from my iPhone using Tapatalk

 

[Les]

Aluminium is inherently gummy. You should use a lube made for aluminium. What speed setting are u using?

 

[RONWEN]

Wow, that looks like it was fun. [eek]  You'll do better with a router to get rid of the end mills & go to carbide bits.

 

[rmwarren]

Aluminium is inherently gummy. You should use a lube made for aluminium. What speed setting are u using?

Les,

Speed may be the problem, I checked and the OF 1400's slowest speed is 10K RPM. My mini-mill cuts is nicely but tops out at about 1,200 RPM.

I am going to get a cheap router and try it with a speed control, see if I can get it down slow enough to work.

RMW

 

[John2532]

Richard,  My guess is that your router RPM's are just too high and instead of producing a proper chip, the bit ends up mainly rubbing the aluminum and creating excess heat.  For instance, if you are using a  .375" (2-flute) endmill running at 20k rpms you would need to move the router somewhere in the neighborhood of 100" per minute to create a 002" chip.  

John

Richard,  Just saw your new post.  Even at 10k rpms you would need 50 inches per minute, pretty fast.  I would use your mini-mill.

 

[rmwarren]

Richard,  My guess is that your router RPM's are just too high and instead of producing a proper chip, the bit ends up mainly rubbing the aluminum and creating excess heat.  For instance, if you are using a  .375" (2-flute) endmill running at 20k rpms you would need to move the router somewhere in the neighborhood of 100" per minute to create a 002" chip.  

John

Richard,  Just saw your new post.  Even at 10k rpms you would need 50 inches per minute, pretty fast.  I would use your mini-mill.

That confirms it.

Unfortunately the mini-mill has such limited travel it is hard, or at least really time consuming, to make long slots like these. The next gadget needs a couple 15" slots...  [blink]

Thanks John.

RMW

 

[RONWEN]

I would say more than speed the geometry of the end mill helix is wanting to grab on you.  Try a straight router bit with brazed carbide & it should cut like butter.  Obviously, pay attention to the feed direction (conventional vs. climb milling).

 

[rmwarren]

I would say more than speed the geometry of the end mill helix is wanting to grab on you.  Try a straight router bit with brazed carbide & it should cut like butter.  Obviously, pay attention to the feed direction (conventional vs. climb milling).

I will give that a try. Both end mills ended up loading with melted AL.

Thanks Ron.

RMW

 

[Les]

Melting aluminum = lack of lube, too high spindle speed, not enough feed rate or chip load. Try small diameter solid carbide bit this will help increase your chip load. You might try google for chip load formula and the cnc router forum.

 

[Tedric Pancoast]

Hey guys,

Another way to get a bigger chip is to switch to a single fluted bit.  Just by doing that you can double your chip size even without turning the spinde down more.  I would check on CR Onsrud's site for a more appropriate cutter.  They have all kinds of good advice there.

good luck

Ted

 

[rmwarren]

Well, I believe part of the problem on the last cut (in the 1/8" AL angle) is that the material was not 6061, it is the cheap HD material and probably a 50-series alloy.

Went back to the bar stock previously working with and made some progress. Took a number of the suggestions below and tried a old 1/4: single flute bit + moving the router faster, it worked great:

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This is .250" bar stock, 6061. I accidentally started the cut from the end with the bit fully lowered, it cut through an inch of the bar before I realized it, no real issue but it seemed prudent to take things a bit slower. I cut the rest in 0.5mm and 1.0mm chunks and both worked fine. The chips measured .006" +/-.

Then tried an old 1/2" straight 2-flute bit, taking 0.5mm cuts in a piece of 1/2" 6061, same results:

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In this case the chips came out about .005" thick.

In both tests there was no galling nor any build-up on the bits. Both bits are carbide but pretty old and not particularly sharp, the finish should improve a bit with a sharper bit. It is fine for my purposes, mostly making jigs and testing the brainstorm-of-the-day.  [embarassed]

No oil was used, I can't bring myself to use any with my OF 1400.

Thanks for all the input and suggestions.

RMW

 

[Alan m]

i dont know much about aluminium or mills but i guess the mill is like a morticer (motor and movable table)
maybe you could make a jig to allow you to acuratly move the piece a repeatable amount.
im thinking something like a table with rows of holes (like mft) and another piece on top that has pins to match the holes below. that way you can pop on on at one end and cut across then repaosition and start again . it should hold the acuracy as the top part it moved over.

could you mount another table (with a screw thread to move it) on top of the one that is on it anyway. that way the total travel might be enough

 

[Michael Kellough]

Visited Polich Tallix fine art foundry yesterday. An awesome place!!

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At one workstation a man was assembling and welding large boxes from 1/2"  thick aluminum plate. The parts were delivered to him square cut (90* edges) from the water-jet cutter and he had to miter the edges to assemble the parts.

He used a large router and an ordinary 45* WWing carbide chamfer bit with ball bearing pilot. He said he used high speed but lubed the bit with the sticky wax (something like this).

He clamped a length of angle flush with the water-jet cut edge to guide the pilot. The cuts looked pretty good. There was a little chatter which could have been reduced with a second pass but they were good enough for prep for welding.

An interesting thing about the welding. The parts of the boxes were aligned and tacked with the TIG welder. Since each part had a 45* beveled edge there was very little penetration of the weld. Grinding the surplus weld off the surfaces would leave almost no weld holding the parts together. So, after tacking, he opens the joints (on either side of the tack weld) with a a right angle dual counter rotating saw blade machine (DualSaw). The double wide kerf makes a joint wide enough to allow sufficient weld penetration and the counter rotating blades make the machine relatively easy to handle.

 

[Gary in Texas]

[member=297]Michael Kellough[/member]

You're responding to a thread that is over 3 years old since the last posting....

 

[Holmz]

Back when I did CNC machine programming and operating...
- we used to climb cut aluminum
- with water and soluble oil hosing onto the cutter.

We started out at a relatively low RPM, but ended up using a 3/4" end mill about 1/4" to 3/8" inch deep per pass and take off about 3/8" wide.
I think we were moving it at about 5"/second.

The chips would rooster-tail out the machine like a boat race and looked like a combination of a shiny Fritos chip and Haley's comet.

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A router runs at a much faster RPM.
Usually one does not climb cut.
There is no cooling water... but some oil or WD40 can be used.

I would think you either need a router that goes to very low RPM or you need to use a more correct tool.
(Like a milling machine.)

 

[Michael Kellough]

I would do what you said Holmz.

But, this guy went full speed to cut a full 1/2" chamfer with lube wax on the bit.

The results will be part of a sculpture that will sell for $$$$$$$.