CNC router for pcbs and metal work

[snoopy]

Hello

I need to do some light metalwork fabrication with 3mm sheet aluminium. You know the typical front and back panels with lots of holes for connectors and screws etc.

I was wondering whether or not it would be better and cheaper in the long run just to buy a CNC machine outright as there are lots of cheap ones on ebay at the moment that can not only mill metal but also do pcb milling as well which is great for quick prototyping.

Has anyone had any experience with these types of machines as opposed to outsourcing ?

Alternatively does anyone know of any sheet metal fabricators in the Melbourne area that handle prototypes and small runs ?

regards
david

[robrenz]

Are these one of parts or multiples?

[snoopy]

Are these one of parts or multiples?

It could be for multiples but not very big runs. It depends on how fast it could do the job but I like the idea of prototyping it first before sending it off to get quantity made.

regards
david

[Kjelt]

CNC for pcb and CNC for aluminium are two complete different machines, like a F1 racecar and a Hummer.

The cnc for pcb needs to be incredibly accurate (<0,003mm repetitive), esp. if you want to do smd, ultra fast (otherwise you have to wait hours and hours for one pcb) and the mill needs to superfast (>30000rpm).

The cnc for alu has an accuracy <0,01mm, fast but not superfast, has to weigh a lot or be mounted to something that weighs a lot for stability because the powers on the machine are large, the mill needs to be adjustable from 1000rpm to 10000rpm, you might want watercooling facility (not always necessary).

Are there cnc machines that can do both, yes but they are not good at both.

[poorchava]

With pcb milling you need superb dust protection mechanisms both for yourself and the machine. Fiberglass dust is quite nasty for your lungs and it will make moving parts of the machine (linear guides, leadscrews etc) seize.

For milling aluminum your machine has to be very rigid (as in made of strong alloy of aluminum at least) and for PCB you need extreme flatness of the table and the X-Y plane has to be perfectly parallel to the table surface.

[snoopy]

All points duly noted. It seems that they would be OK for standard through hole pcb technology and not much else.

Here is a youtube video of a similar unit in action although it is only cutting acrylic.



and another milling a pcb

[robrenz]

Forget about that thing cutting 3mm aluminum, aint gonna happen

[Kjelt]

I agree, the way it is build is not the most robust, for more info and advice I would suggest joining a cnc forum, there are the real experts 

[snoopy]

Forget about that thing cutting 3mm aluminum, aint gonna happen

I don't know about that. It seems to do a good job on thick aluminium billet

[snoopy]

I agree, the way it is build is not the most robust, for more info and advice I would suggest joining a cnc forum, there are the real experts 

It is a standard model CNC milling machine made by many different manufacturers. On Youtube or ebay do a search for CNC 3040.

[robrenz]

The first video you showed is a flimsy flexible shaft drive spindle with a 1/8" drill chuck to hold the tool. My comment still stands for that configuration. The other videos are a much heavier spindle with a collet holding the cutter that could obviously mill a 3mm panel.

[snoopy]

The first video you showed is a flimsy flexible shaft drive spindle with a 1/8" drill chuck to hold the tool. My comment still stands for that configuration. The other videos are a much heavier spindle with a collet holding the cutter that could obviously mill a 3mm panel.

thanks for pointing that out. I was wondering why there were differences between different brands.

regards
david

[Kjelt]

It is a standard model CNC milling machine made by many different manufacturers. On Youtube or ebay do a search for CNC 3040.

Well I bought a complete 5k$ cnc machine (Heiz 740T) and for that money (in retrospect) I better could have modified an industry manual router of 2k$ with steppermotors, drivers and standard software. That is what they are doing on those cnc fora. Now since you are already a member here, playing with steppermotors and connecting wires and fuses probably won't be a big deal. The difference is the application area, most of the cnc routers are for large area's, but if you only want to do alu frontplates and pcb's you don't need those large area's and you are better of with a more heavy machine that can also do metalwork (see picture) and modify it with steppermotors and controls. The nice thing is you can pick the (industry standard) drivers and software yourself. Buying on the net has a big risk getting some clunky half buggy piece of chinese software and drivers that will quit after a year because they operate at 105% load (not saying this is the case, just read a lot of horrorstories).
On the other hand if you know which there are also very good chinese routers with hf spindles to be gotten for bargain prices, but they know all that on those fora.

So the tip I wanted to share is go visit a cnc forum and start reading and talking to the cnc specialist people there and explain exactly what you want to do.
Go visit some member with such a machine in the neighbourhood and see if this is what you want. Probably in two weeks you know much more and are getting different wishes or insights in the machine to buy. In retrospect i wish somebody had given me that advice before i purchased my machine 

[flolic]

I am building my CNC router right now, capable of PCB and aluminium work.
Working area 300x300x150mm.
These things cost money if you want to built them right...

[snoopy]

I am building my CNC router right now, capable of PCB and aluminium work.
Working area 300x300x150mm.
These things cost money if you want to built them right...

I saw this homemade one on youtube the other day. Looks impressive.

[snoopy]

It is a standard model CNC milling machine made by many different manufacturers. On Youtube or ebay do a search for CNC 3040.

Well I bought a complete 5k$ cnc machine (Heiz 740T) and for that money (in retrospect) I better could have modified an industry manual router of 2k$ with steppermotors, drivers and standard software. That is what they are doing on those cnc fora. Now since you are already a member here, playing with steppermotors and connecting wires and fuses probably won't be a big deal. The difference is the application area, most of the cnc routers are for large area's, but if you only want to do alu frontplates and pcb's you don't need those large area's and you are better of with a more heavy machine that can also do metalwork (see picture) and modify it with steppermotors and controls. The nice thing is you can pick the (industry standard) drivers and software yourself. Buying on the net has a big risk getting some clunky half buggy piece of chinese software and drivers that will quit after a year because they operate at 105% load (not saying this is the case, just read a lot of horrorstories).
On the other hand if you know which there are also very good chinese routers with hf spindles to be gotten for bargain prices, but they know all that on those fora.

So the tip I wanted to share is go visit a cnc forum and start reading and talking to the cnc specialist people there and explain exactly what you want to do.
Go visit some member with such a machine in the neighbourhood and see if this is what you want. Probably in two weeks you know much more and are getting different wishes or insights in the machine to buy. In retrospect i wish somebody had given me that advice before i purchased my machine 

One of my panels is 13x7 inches which just fits within what a 3040 can do. PCB's is a secondary requirement but a nice feature to have.

regards
david