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View Full Version : NEWBIE: What do I need to cut 2mm anodised alu?



futuresoundsystems
20-09-2015, 06:37 PM
Hello!

I'm completely new to CNC Milling and Routing, but pretty desperate to find a way of working with alu. My profession is designing and building synthesizer modules, and for a good while I've had contractors making panels for me with hit-and-miss results in terms of quality, speed and expense.

What I'm after is a CNC milling machine which will CUT and engrave 2mm thick anodised aluminium.

The job needs to be clean, as these alu panels are the customer-facing control panels of my products, so I need to be able to manage swarf, etc. and any cuts need to be clean. I'm not necessarily too picky about precision, however.

I'm looking for something that will fit on a workbench in my studio. Note that it's improbable I'd ever be cutting a panel bigger than 300mm x 130mm.

It needs to interface easily with my existing computers, i.e. USB functionality is preferred.

So far I've been really eyeing this (http://www.amazon.co.uk/HPcutter-Machine-Engraving-Engraver-Cutting/dp/B013W64YSC/ref=pd_sim_sbs_60_1?ie=UTF8&refRID=190YSRP8ZAEY2MZXEEHQ&dpID=51wmq8PSVuL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_) up, but totally unsure if I'm getting a good deal or not. Any help would be hugely appreciated.

Cheers!
Fin

Christian Knuell
21-09-2015, 10:00 AM
Hi,

the big issue with anodised aluminum is that is very soft and tends to stick to the endmill which will break it within seconds.

So it is primarily a question of the right tool:


Single flute bit designed for aluminum. Preferably polished or with a suitable coating to prevent built up of aluminum on its surface. There are large differences between a high quality endmill designed specifically for aluminum from a quality supplier and just a random chinese end mill.
Suitable coolant. You don't need to flood the piece - but something like a spray mister will definitively help a lot.
But whatever you do - the tools will wear down relatively quick because Aluminum oxide (the anodised layer) is extremely abrasive.


Secondarily the machine:

Stiff with no backlash. Otherwise the quality of the cut will look bad and the tools will break prematurely due to vibrations.
Spindle with little runout and constant RPM. Again cutting edge quality and tool life.


The machine you've linked to will most likely be unsuitable for aluminum (I see unsupported rails, a strange spindle and do not expect much of the rest). You should expect to pay at least 2-3 times as much.

Christian

Boyan Silyavski
21-09-2015, 10:32 AM
The machine has to have supported square rails and ball screws to do precisely that job. While you are not aiming at precision the cut must be clear, so the engraving. Otherwise you will waste a lot of time cleaning, filing and polishing .

for xxx $ you can not do that. I would say for less than 3000euro spend, you can not do that, speaking of new machine. It must be small CNC mill or a very high quality small cnc router or you have to build one.

Your best bet will be to find small Chinese mill converted to cnc or another used smal CNC mill. Dont become victim to sellers hype.

Hope that helps.

komatias
21-09-2015, 10:51 AM
Fin,

This is probably going to start a flame war but have seen 3 startups recently spend too much time trying to learn CNC and failing due to lack of time.

Because you are aiming for perfection on your face plates, I would suggest you get them outsourced. That way you can claim warranty should the products not be to spec. You will just need to make drawings for your parts that are descriptive and precise.

Should you still want to go and buy a machine, then you will be better served if you look at the 6040 variety with a watercooled spindle. You will need to add a coolant delivery system and probably upgrade the cables and some of the electronics.

Based on the machine you linked to, am I right in assuming you are working on a small budget? Because realistically you will need to spend upwards of 1000 to get a good machine if buying brand new. Then you will need software etc so your budget will be increased. With 2000 you will probably be able to get plenty of perfect faceplates without ever coming close to a CNC machine yourself.

Best regards

George

Boyan Silyavski
21-09-2015, 11:32 AM
Fin,

This is probably going to start a flame war but have seen 3 startups recently spend too much time trying to learn CNC and failing due to lack of time.

Because you are aiming for perfection on your face plates, I would suggest you get them outsourced. That way you can claim warranty should the products not be to spec. You will just need to make drawings for your parts that are descriptive and precise.

George


You are absolutely right if he is planning to sell less than 50-60 pieces the following 365 days.

If he is planning to sell >100 per year its definitely worth the investment.

Its math, nothing more or less.

Fin,
Take a look at that story (http://blog.jdslabs.com/?cat=10) so you will know better what you are up to. As i said before, small mill, make money, better mill...

So at the end you could make more money making more product and offering it at more places and so on, or you could not. There is a risque and a lot of work behind any project...

Boyan Silyavski
21-09-2015, 12:20 PM
PS. this (http://blog.jdslabs.com/?m=201306) is the other interesting link that shows how things developed after one year with the small mill. these guys have awesome blog that all aspiring people should check

futuresoundsystems
21-09-2015, 04:32 PM
Thanks guys! Obviously not quite the route (no pun intended) that I should take right now then. I'll carry on my quest to find suppliers. Really good to know what I should be looking for when I hopefully make the step in a few years' time though.

DuffelBuffelWuffel
23-09-2015, 09:18 PM
I have done milling of alu frontpanels before and it is doable.
http://www.mycncuk.com/attachment.php?attachmentid=16158&stc=1
The scratches are from having the (secondary) front plate laying around on the workbench.
Also I try to make the "brushed" look by going over the frontpanel with some fine sandpaper.
It is much easier to buy the brushed aluminium in the first place.

This was done with a 2F endmill with the wrong coating that should not be used with alu... It was also the first thing I made with my cnc.
It is a Conrad alu frontplate 1.5? mm thick.
I also have a vacuum fixture now.

I usually have spare time in my weekend. If you want me to try something out than just PM me.

A good cnc machine for a small business is around 5-7K euro ex vat depending on the requirements.
Spending money on something cheaper is most likely a waste.

It also takes a bunch of time learning cnc'ing and setting stuff up. So If you look at the full picture you can "spend" 10k euro ex vat quite fast.
---
With the correct VHM blank alu 1-2 flute endmills , some compressed air and a little lubrication it is not hard.