Milling or etching PCB?

[Electronics4you]

What would be the positive and negative sides for both techniques?
What would you prefer?

 

[3v0]

Currently I am drilling holes via CNC using GCode generated with PCB-GCode The board is then etched using the PulsarProFx toner transfer system.The pcb-gcode software works with Eagle and runs under the board editor. I only use the software to drill holes but it was designed to mill the board, its main function. They have a yohoo group. Check with them to see what resolution they are obtaining.

Everything I say about milling a board is suspect till confirmed.

Etching
Pro: better detail/resolution.
Pro: faster.
Con: hand drilled holes.

Milling
Pro: execlent hole alignment.
Pro: no chemicals to work with.
Con: boards have to be dead flat if milled with a V bit.

 

[bloody-orc]

Milling:
Damn expensive, good resolution, high speed bits (danger), VERY noisy, very dusty + dust is not good for your lungs. BUT! you put the board in and press GO, and then you can do something else, not have to constantly look at it. Better to make 2 layer boards. But 2 layers is probably max (with household equipment)

Etching:
Faster, Depending on the quality of the tracks printed on the board VERY good resolution, a LOT cheaper. Takes more time to prepare + needs constant attention. (YOU have to do EVERYTHING). And as 3v0 said the drilling. Harder to make multilayer boards. But if you can get them done, then more than 2 layers is possible. (you have to know some special tricks you know )

 

[3v0]

Unless you have an expensive mill that can change bits by itself you have to be there to change tools, at least for the drilling.

I may get heck for asking this here but:
Have you ever made more then a 2 layer board at home. A while back someone was talking about laminating several boards using super glue. Thinking of tacking a single sided board to a 2 sided to make a 3 layer board. IF anyone wants to talk about this we can start another thread.

 

[Electronics4you]

I'm considering buying a CNC milling machine with the following data:

Positioning speed 60 mm/s
Mechanical resolution 0.0075 mm (0.295275591 mil)
Software resolution 0.025 mm (0.984251969 mil)

Does it sound resonable?

 

[3v0]

Depends on the cost and travel on each axis.

If you have the time spend it over at CNCZONE.COM. They have many forums on milling and milling machines. Also info on DIY. I would ask this question over there and include the name and model of the mill you are looking at. Read about what problems people have with various mills.

The mill I use is a MAXNC10 and costs about $2400 for a closed loop 3 axis system. It came with a program that understands GCode.

If you plan on using it for anything other then PCB you need to spend time looking into what software you will use for CAD/CAM. The cad/cam tools we use at school run about $16K per seat if you buy them. The EDU discount is about $400 per seat and $100 a year maintenance contract.

 

[Electronics4you]

The software included is of cource the interface software but also a Gerber and Excellon converter. I do Gerber files so that's fine, but can I convert CAD-files to Gerber files for cheap?

What software should I use to do e.g. front panel milling with text and shapes?

 

[picbits]

cnczone.com rules - I've lived over there for the past few weeks as I've got a load of linear rail and bearings on order for a CNC PCB drill I'm building on a budget.

 

[3v0]

Where did you find the best price on rail and bearings ?

 

[bloody-orc]

I may get heck for asking this here but:
Have you ever made more then a 2 layer board at home. A while back someone was talking about laminating several boards using super glue. Thinking of tacking a single sided board to a 2 sided to make a 3 layer board. IF anyone wants to talk about this we can start another thread.

Take one 2 sided board and etch it. then take one 1 sided board and cut off as much of this fiber (not the copper) off as possible (to make it thinner). and then glue the boards. glue drops must be as far away as possible from soldering points (unless using heat resistant glue).

 

[Nigel Goodwin]

Multilayer boards are simply very thin double sided and single sided boards stuck together, then through hole plating applied.

When the very first Pace Digital satellite receivers came out (for the South African market) they had sudden massive failures a few months into their use. The reason was a mistake by the PCB manufacturer, nor washing the boards properly before fastening them together. This left traces of etchant between the layers, which over time ate away the required tracks on that layer. Pace managed to find out which tracks were most commonly failing, and called in all their suitable empoyees to mod the boards, hardwiring the potentially faulty connections. If this didn't cure the board, they were disposed of - they didn't have the time to do any more fault finding on them, with literally thousands of receivers failing within a few weeks.

 

[Sceadwian]

What about the physical stress to the copper itself during milling? Especially on fine traces? One upside to milling is that it can of course be used to form a great variety of other materials, so it's a much more versatile tool. Once you have one you're probably going to find a lot of things you could do with one.

 

[picbits]

Where did you find the best price on rail and bearings ?

Over in the UK we get ripped off severely for bearings and rail (and just about everything else).

Best price I found was from a company called Marchant Dice.

I got 2x400mm rails, 2x800mm rails, 2x250mm rails, 12 linear bearings and housings and the shaft supports for around £185 delivered ($370 ish). All are 16mm.

I used to work at a bearings company and had a word with the MD but he couldn't get anywhere close to that price.

Bearings are not as smooth as the ones I used to use but they are a third of the price.

www.marchantdice.com and speak to Kevin

Now I've got to go and see the chap in B&Q and present him with the cuts I need for my 18mm MDF

 

[Pommie]

Take one 2 sided board and etch it. then take one 1 sided board and cut off as much of this fiber (not the copper) off as possible (to make it thinner). and then glue the boards. glue drops must be as far away as possible from soldering points (unless using heat resistant glue).

How do you solder to the sandwiched layer without through hole plating?

Mike.

 

[ericgibbs]

hi rain,
>> Take one 2 sided board and etch it. then take one 1 sided board and cut off as much of this fiber (not the copper) off as possible (to make it thinner). and then glue the boards. glue drops must be as far away as possible from soldering points (unless using heat resistant glue).

I used to buy 1mm thick single sided copper pcb for use a 'screening' it can be etched, but as Pommie points out............
>> How do you solder to the sandwiched layer without through hole plating?

 

[Nigel Goodwin]

How do you solder to the sandwiched layer without through hole plating?

I don't think you do! - through hole plating is essential for multi-layer boards.