Here is a useful PCB milling guide: https://www.inventables.com/projects...e-pcb#overview
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
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.
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.
Hi Hanspeter
Yes, some of these tiny end mills are expensive. I would reply that you get what you pay for.
Yes, you can use those inexpensive carbide V-bits too. I have found that some of them are not ground al that well though. The tip might be 0.1 m wide (which gives a 0.2 mm groove in theory, but the tip was more than that off-centre. The shank had very little TIR in my spindle, but the tip - cut a bit wide.
In addition, I found that the V-bits tended to leave a lot of burr at the sides of the cut, which made for a lot of finishing work. I had to polish off the burs while not pushing any copper back into the groove, to create short circuits.
After making a number of PCBs, I found that having a 0.5 mm wide groove was not all that bad. It significantly reduced any shorts from stray copper whiskers, and it made soldering much easier. There was so much less risk of bridging the groove with solder. To be sure, if the PCB used small surface mount chips with small gaps between the legs, I might have to reduce the width of the groove, but for a lot of my work I try to only use DIL chips, in sockets. That makes maintenance much easier.
So - I use both.
This is modified V-bit: I had made the tip a bit wider and honed the edge. The PCB is for optical isolation, and is in use.
Cheers
Hi RCaffin,
I totally agree with you.
I had times to return these cheap V bits as the tips range from 0.1mm - 0.3mm for a 0.1mm bit.
Perfectly understand the Chinese aren't meticulous, for every 20 bits you buy, you may return 6.
The thing is I find them disposable and at the same time they do quite give me some life.
My reason for opting 0.1mm V bits it compensates for spindle runouts. If you see my milled PCB elsewhere
the track spacing ~0.25mm.
I must add that feed rate also contributes to burr at the edges of the track, reducing the feed rate should resolve
the issue. I hardly end up with burrs.
My PCB's are all SMD since 2010.
Cheers,
Hanspeter.
Last edited by HPB; 05-13-2020 at 07:34 AM.
reason for opting 0.1mm V bits it compensates for spindle runouts
Chuckle! Yeah, that works.
I do use SMDs - but I need a head-mounted magnifier for them these days. That PCB I showed was SMD.
Cheers
Roger
Hi,
I mostly use 0.5mm two flute endmills. They have a superior cut quality by comparison to engraving bits. This means of course the smallest path between isolated
tracks/pins is 0.5mm, in fact I have standardised on 0.6mm which still allows for SOIC surface mount ICs.
Occassionally when I require finer pitch ICs I will use an engraving bit and I recently got some from the same supplier as my endmills and they have proven
to be very good indeed.
https://www.ebay.com/itm/60-DEGREE-M...72.m2749.l2649
They are not cheap, in fact double the price of the 0.5mm endmills!! They have however outlasted the cheap Chinese engraving bit I have used previously by a factor of five.
They are made by Kyocera Microtools, there are NO rejects!
Craig
A very good brand, Kyocera. I buy some cutters and single-point thread mills from them.
The particular bits you referenced look very solid.
Cheers
Hi,
I must say that I was concerned the the rather broad include angle of the tip (60 degrees) would cause an overly wide kerf that would interfere with the
fine (0.2mm) intertrack spacings. That has not proven to be the case. The broad included angle has meant that the tip of the tool is very much more robust
than the 30 degree tool I had used prior to getting the Kyocera tools.
The 30 degree Chinese tools supposedly had a 0.1mm tip width. What happens in practice is that the tip breaks very early in the piece so that that actual tip
width becomes a rather uncontrollable 0.2-0.3mm. The broken tip produces a poor cut.
The 60 degree tips have, or rather I allow, a 0.2mm width, and it is consistent. I have 8 hours cutting on the first of the several I bought and its still producing a good cut
and the same 0.2mm kerf.
For less demanding (0.6mm inter-track/inter-pin spacing) I still prefer the 0.5mm endmil beacuse of the cut quality and they are cheaper, about $4.60USD or $5.00USD
including shipping. If I don't break them, which is thankfully less common as my procedures improve, I swap them out after 10-12 hours cutting on the basis of cut quality.
Craig
Last edited by joeavaerage; 05-14-2020 at 06:14 PM.
The broad included angle has meant that the tip of the tool is very much more robust than the 30 degree tool I had used
Ditto. Although I am happy with the 45 or 30 degree ones.
What happens in practice is that the tip breaks very early in the piece so that that actual tip width becomes a rather uncontrollable 0.2-0.3mm. The broken tip produces a poor cut.
They do break easily, don't they!
I touch up the broken ends with a diamond T&CG or (more often) with a diamond lap.
the 0.5mm endmill because of the cut quality and they are cheaper, about $4.60USD or $5.00USD including shipping.
Really? Where?
Cheers
Roger
Hi,
https://www.ebay.com/itm/38247476389...72.m2749.l2649the 0.5mm endmill because of the cut quality and they are cheaper, about $4.60USD or $5.00USD including shipping.
Really? Where?
This guy has been my favorite supplier for small carbide tools. A year or two back he had these same 0,5mm two flute Kyocera endmills on special for $2.65USD each, I got 30....but wish I'd bought 100 at that price.
Having said that I see that they are listed at $38USD for 10 which is still pretty good value.
Check out the Raptor's from Destiny Tools, best endmills is stainless I've ever encountered.
Craig
Ah - CarbidePlus. Already on my preferred supplier list. But thank you.
Have you tried CarbideChiu on ebay? Very happy with his services as well. He has done custom endmills for me in the past.
Cheers
Roger
Hi Roger,
Yes I have and prices are good, service is good but I've had better tools. Its not so much that his tools are bad but the name brand toolsHave you tried CarbideChiu on ebay?
are better.
For example the 1/8 Raptor four flute tools that I referred to in my previous post. They use variable helix and the TiAlN coating is stuck like 's****t to a blanket'
and does a better job. Whether it could be considered better value is another question, but sometimes value for money is less important than performance, and any
tool that does well in stainless is in that class.
Another gem are the Di-Boride coated tools for aluminum by Harvey Tools. They are eye-wateringly expensive by comparison to other uncoated aluminum tools,
but if you have some real 'sticky' aluminium like 5000 series, or worse 1000 series, they are worth their weight in gold.
Craig
Di-Boride? I will research that one.
Thank you.
I have been milling 5082 sheet Al successfully, using a kero/olive oil mist. While watching closely.
Cheers
Roger
Hi,
di-boride is as slippery in aluminum as it gets.
You may have noticed that many specialist carbide tools for aluminum are uncoated.
The normal coatings on carbide tools are TiN or TiAlN, both are tri-valent in nature. Guess what....aluminum is a tri-valent metal and
so the aluminum has an 'affinity' with a tri-valent coating. Enter di-boride, a quad-valent (four-valent??.....one-more-than-three-valent??
...two-less-than-hex-valent??) and its 'as greasy as a butchers prick' as my grandmother used to say!
I tend to use flood-cooling. I'm not convinced that the oil is as significant as the flood washing the chips out of the cutzone. Having said that
I have still had Built-Up-Edge in 5083 aluminum with flood cooling. Thats why I tried di-boride...and was impressed.
Craig