[ScuD]

Hi guys,

This is my first post on this forum, so first of all I'd like to say hi :wave:

Well me and a friend have been talking about building a CNC router for about a year and a half now, and i've finally come round to actually drilling some holes

I'm going for a very basic, simple ULTRA low-budget machine, since i'm a student and have very low funds.. So scrounging for what i can find in the shed was my first step.

So, here's my actual question.
For my "thesis" (not sure what the english word is) i'm building a six-legged robot, which is mainly built out of 1mm aluminium sheeting.
I was wondering if the homemade routers i've seen here using the basic steel bar / skate bearings are capable of cutting this material?

[ScuD]

Slight *kick* and a little movie of what i've got so far..

Keep in mind it's ultra ultra low budget before laughing though pls

[MrBean]

I can't see any reason why you couldn't cut through Alu sheet with a machine like that. You'd probably need to do it in multiple passes and keep the feedrate slow. My machine is pretty bendy and it's cut through 10mm Alu. I have to make passes of 0.2mm depth. It takes a while but I'm in no hurry At least it's faster and more accurate than I could do by hand.

It looks like you could do with stiffening up the gantry sides. It may suffer from racking.

Regards Terry.

[ScuD]

It looks like you could do with stiffening up the gantry sides. It may suffer from racking.

Regards Terry.

MrBean, i'm not quite sure what you mean by racking? Sideways movement of the gantry due to pressure exerted by the router?
I'm sorry but my english isn't my native language :violin:

Anyway, any suggestions on how to reinforce it?

PS: at the moment i only have two decent steppers at disposal, a bipolar rated at 2,5A per phase and a unipolar with no further characteristics, but since it's about as big as the bipolar one i'm thinking it should have some power.
I do however have a servo motor which looks quite powerful, so i was wondering are there axis which need less torque then others, or is it best to look for 3 of the same kind of steppers /servo's?

Thx ,
ScuD

[CJL5585]

I'm sorry but my english isn't my native language :violin:

Your English is VERY GOOD. It is better than a lot of Americans on this site.
Welcome.

Jerry

[MrBean]

MrBean, i'm not quite sure what you mean by racking? Sideways movement of the gantry due to pressure exerted by the router?
I'm sorry but my english isn't my native language :violin:

Anyway, any suggestions on how to reinforce it?

Yes, I mean sideway pressure. Some simple supports at the side may help.

If there's room, maybe something along these lines.....

Regards Terry.

[zoltan]

Hi MrBean,

Could you, please, go in more details about cutting ALU? I mean pass, feedrate, RPM, type of cutter, if you use coolant, etc. I really appreciate your help in teaching me.

Thank you,

Zoltan

[kong]

Zoltan, assuming you are using a router, you need to keep the RPM's low. Feedrate should be as high as possible, around 600mm/min is a good starting point. Cutters should be either single or two-flute type spiral bits. Coolant if you have it, WD40 is good, a bit of wax can be used if you don't have coolant. Depth of cut is up to you, depnding on the rigidity of the machine and power of the spindle. Hope this helps!

[zoltan]

THANK YOU. And the plunge rate? I will use Kress router (900W) at 8000RPM, 3 mm endmill 2 flute. What do you advice me? My new machine is made from thick ALU. It is VERY rigid.

Thank you,

Zoltan

[kong]

Ideally you want to "ramp" into the material, so use a diagonal move from, say, (X0 Z5) to (X10 Z-1) if you see what I mean! It all depends on your CAM software. If you can't ramp, then a slow plunge is best, probably around 150mm/min for starters, then see how much vibration you get and go from there.
The Kress is a nice router, for a 3mm cutter, I used to run about 12-14000 RPM with WD40 as coolant.