PennsylvaniaQuote:
Originally Posted by CitizenOfDreams
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PennsylvaniaQuote:
Originally Posted by CitizenOfDreams
Hi all,
It has been a while ... hope you are well out there in the world :)
As it is I have now completed my CNC build - except for a few things like painting the supporting table and connecting wires to the emergency stop button - and it seems to be working very well for my purposes. I've done some cast iron, copper, and accidentally some 8.8. steel (I think it is?) milling and the results to my eyes and expectations are good.
AND ... in retrospect ... I hope I shall never be doing such work again - it's been no less than "enormous" drilling all those holes (>300), making all the threads (>150), sawing all the bars, milling the bars, and not least finding solutions for all the challenges involved in such a build. Also, had I had access to a CNC mill at a reasonable cost I would not have built it from cast iron bars but from solid blocks of cast iron. This probably would have saved me a couple of hundred hours of work time and likely made it more rigid. But it's fine as it is - good for my purposes.
One difference though relative to my original design is that I decided to replace the air cooled motor with a water cooled motor with - presumably - a higher torque and power rating (and according to what appears to be a qualified amazon review good tolerances). Learning that the air cooled motor was very noisy indeed and also would have heating issues working at low rpms I decided to buy a water cooled version instead. It works very well also at lower rpms without getting more than luke warm. It is, however, quite obvious that the torque is low at lower rpms, yet it is nevertheless capable of drilling smaller size holes (<= 6mm in cast iron) and use the end mills I want to use with good results - so I am satisfied. The ebay ad can be found here:
https://www.ebay.com/itm/FRA-2-2KW-2...72.m2749.l2649
And an amazon "preliminary" review here:
https://www.amazon.com/Waterproof-Sp...pe=all_reviews
Another I would say "add-on difference" I happened to think of late in the building process was a "dust remover" device so as to efficiently prevent cutter shavings from going most everywhere. This device - which I mainly 3D printed - has proved to be very efficient indeed so I have started a thread here offering to share the 3D model files - should anyone be interested:
https://www.cnczone.com/forums/gener...78846-cnc.html
There's also a couple of pictures of my CNC machine in this thread should you be interested in seeing what it has ended up looking like. The paper coverings in time will be replaced with something like the "backing" on sand paper, i.e. a quite strong, reasonably flexible and thick canvas - I just haven't yet found a vendor of such canvas :confused: ... As it is the canvas & dust remover combined essentially prevents all cutter shavings and dust from reaching any of the rails and ball-screws thus hopefully ensuring a long a prosperous life for the CNC mechanics :rolleyes:
And then - not least! : Thanks to people here making suggestions and helping out in making choices and guiding me in going in sensible directions. This thank you would go especially to Craig for his very good and extensive guidance - without which I would have made less optimum choices - and also to Roger for his helpful comments.
Cheers,
Jesper
Hi Jesper,
good work.
I seem to recall saying that at the time. I made my machine out of solid limps of cast iron on a manual mill, time consuming but each bed is very rigid.Quote:
Also, had I had access to a CNC mill at a reasonable cost I would not have built it from cast iron bars but from solid blocks of cast iron. This probably would have saved me a couple of hundred hours of work time and likely made it more rigid. But it's fine as it is - good for my purposes.
Craig
Hi Craig,
Thanks!
And, yes, you did mention this - but to my memory you pointed out that a solid bed would be "hugely superior" only after I had bought the cast iron bars (which I had then transported 300 kms in my car). So the timing was ever so slightly "offset" ;)Quote:
I seem to recall saying that at the time. I made my machine out of solid limps of cast iron on a manual mill, time consuming but each bed is very rigid.
In any case the manual mill I have had access to was not sufficiently precise. It is quite old - probably from the fifties - and the x-axis movement was only precise over a length of ~250 mms ... Outside of this the tolerance got quite high 0.2 & 0.3mms - so I couldn't see that there was a way to mill this in a sufficiently precise way.
And it is fine now.
Cheers & thanks again, Craig!
Jesper
Hi, I use a 10° x 0.1mm V-Bit. You have to make sure to get the right board for the tools you have or else it will dull out the bits. For example I was using FR-4 board which ended up dulling the bits. So I used FR-1 boards with these tools and I got very thin, clean circuits. I got the circuits to go as thin as 0.5-0.6mm width. This is the link to the bits I have: https://amzn.to/2McX8je
If you want to see the end result using these bits and a cheap CNC router, check out my YouTube video of the process of making a PCB from start to finish. I am almost done editing part 2 of the video where I apply UV solder mask to protect the board.
Here is the link to my video: https://bit.ly/2G9fo9l
Here is a useful PCB milling guide: https://www.inventables.com/projects...e-pcb#overview
Hi,
I have started a new mill project. I'm not unhappy with my original own-design mill but it has faults, some easily correctable and some not.
I have the funds (temporarily) to build a bigger, faster more rigid mill and that is what I've decided to do.
To date I have the 20mm THK rails and heavy duty cars in hand (three sets), they are new-old stock and in perfect condition.
I have just taken delivery of three sets of 32mm (5mm pitch) C5 THK ground ballscrews with double nuts and FK25's at each end. They are used but appear
to be in perfect condition.
Last night I ordered and paid for three Delta 750W B2 series servos and drives, one with a brake for the Z axis.
I have engaged the services of a local foundry to cast the beds. I was going to make my own pattern and have them make the molds and pour them.
As the beds are VERY simple for which only one pattern is required, I have elected to have them make the pattern also. They have their own pattern makers
whom are no doubt WAY more familiar than I about casting in general and the preferences of this particular foundry.
I am anticipating each of the beds will weigh 115kg as cast but after fettling. I was given guidance of $5 NZD per kg as cast which suggests the cost,
excluding the pattern, of $1725 NZD ($1085 USD).
The frame that mounts the beds at right angles is still under development......I'm thinking it may be a four piece mold, but hopefully without cores
but with an as cast (fettled) weight of 300kg. The pattern making and mold making could add substantially to the cost so I'm guessing around
$3000 NZD ($1900 USD). I'm thinking that the frame will be in SG iron, toughness and stability. The beds will be in plain grey iron.
Craig
Hi Craig,
Well, you have already told me about this but interesting to get some more details ... Good luck with the project ;)
Now I know that you are doing more things with your mill but considering the topic of this thread "bits for PCB milling" it nevertheless makes me smile considering that this several hundred kilos CNC mill will also be milling PCBs with just 0.5mm (I think it was, right?) end mills. I reckon it will be stable enough for this to work out fine :rolleyes:
Cheers,
Jesper
I have two commercially built PCB mills, based on substantial cast iron "torsion box" designs, they weigh 1000kg each and have beds of only 600mm x 470mm, which is effectively halved because each Y axis has two 60,000rpm spindles working in unison. Weight is clearly considered a good thing when dealing with such fragile tooling.Quote:
Originally Posted by evalon
If you are gong to use end mills of 0.5 mm diameter, you have better not have a TIR of 0.2 mm!
Good solid mills are to be praised.
Cheers
Roger
Hi,
when I first started becoming interested in CNC it was specifically to mill PCBs. I thought if I was going to buy/build a machine then I would
want it to be capable of more than just PCBs......I wanted to cut metals and steel/stainless included. Of course a machine that can cut ferrous metals
has to be ten to one hundredfold more rigid than a PCB milling machine.
What happened in fact is that the design and building of a CNC mill became the hobby project. As Roger points out accurate, high resolution,
rigid, very low TIR mills are just as useful for PCBs as they are for metal cutting work.
My first mill is still going strong but I want to use the knowledge/judgement that I have acquired as a result of my previous mistakes/misappreciations.
Craig
Hi RCaffin,
Indeed, but must say these end mills are expensive comparative to 30° 0.1mm V bits from Amazon these are very
affordable and disposable too.
You may want to see this,
https://www.cnczone.com/forums/pcb-m...44316-cnc.html
and scroll to post #15.
Cheers,
Hanspeter.